Has anyone here measured the header temperature near the ports on their headers? What reading did you get?
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When warmed up somewhere between 650 and 850 depending on how high the idle is. Stuff like how much advance, idle mixture pipe thickness etc. Will have an affect on temps you ultimately see. Biggest reason I temp is to make sure temperature is even. No cold or really hot pipe.
Keith.
Keith.
I'm getting 615. This is new to me and I am trying to understand what is going on.
My plugs are reading hot so a new project here has started.
I have one step colder coming but won't be here until Tuesday because of the holiday.
I think my temps are too high and want to see what the colder plug will do with that.
Thanks for posting. Appreciated.
I would like to hear from as many others on this as I can as well.
My plugs are reading hot so a new project here has started.
I have one step colder coming but won't be here until Tuesday because of the holiday.
I think my temps are too high and want to see what the colder plug will do with that.
Thanks for posting. Appreciated.
I would like to hear from as many others on this as I can as well.
Color and coating on the headers also makes a difference. Hard to read plugs on a gas engine. Egt probe best bet or add a wide band.
Doug,
Have you considered adjusting jetting? You can cool it down by adding fuel....
Have you considered adjusting jetting? You can cool it down by adding fuel....
Plugs are too hot.
This is a Champion F9y. Going down to a F7y to see what effect it has.
This was all brought on by going from a 1-1/2" primary tube header to a 1-3/4".
They leaned the exhaust out that much.
This is a Champion F9y. Going down to a F7y to see what effect it has.
This was all brought on by going from a 1-1/2" primary tube header to a 1-3/4".
They leaned the exhaust out that much.
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quote:Originally posted by Rob Borruso:
Doug,
Have you considered adjusting jetting? You can cool it down by adding fuel....
Not the Pantera. My Shelby GT350.
The headers are ceramic coated. Carbs were just fattened at idle. Still too lean. Temps too hot.
Just looking for numbers to compare.
Getting into racing plug temps though. New territory for me.
The idles may be at max now. This might need a primary jet enlargement before the ceramic coating is just toast?
Stay tuned...
ah.. OK...351W or 289.., (cool car BTW.. we have very similar tastes ;-).. assessment stays the same. That plug looks scary to me. I would look for a vacuum leak first, before you end up chasing a ghost. If none, then totally agree, primary jetting up a couple. What kind of induction/carb set up are you running?
68 GT350. 302 stroked to 347. 2x4 Holleys.
Runs very well except for this new high temp issue, if it even is an issue?
I think the culprit may be that the carbs are 4180's from an 84-85 Mustang GT and it is possible that I can't enrichen the idle enough for this system.
It was running on 54 mains out of the box with no issues.
Logic hit me, scared me and I upjetted to 63 primaries like the 427/428 2x4 set up uses.
I don't think there is a vacuum leak but with a monster like this it makes such a racket at idle it isn't noticeable.
It had a solid 17 inches at idle yesterday. Probability is low on that.
Obviously when you get to this point, the engine is like a race engine and what was ok 15 minutes ago isn't necessarily now.
This one has no oxygen sensor provision so I can't use that in diagnosis of the a/f ratio...but I'm thinkin'.
On the surface these things sound so simple. That is hardly the reality though. Remember, there is no such thing as a bolt on.
No life and death struggle on this. It will get right eventually.
On that plug, remember, that is the equivalent of a BF32. That isn't a hot plug at all.
I need more header temp info on this. 615 is actually on the high side of normal.
A colder plug should bring that down some?
I may have to dial out some initial advance too. Probably is set at about 16 right now. Advance affects the exhausts temps disproportionally too.
I am very sure the current crop of race cars have gone through this recently. I'm pretty isolated from them and some of them speak Martian like I do but not all?
Runs very well except for this new high temp issue, if it even is an issue?
I think the culprit may be that the carbs are 4180's from an 84-85 Mustang GT and it is possible that I can't enrichen the idle enough for this system.
It was running on 54 mains out of the box with no issues.
Logic hit me, scared me and I upjetted to 63 primaries like the 427/428 2x4 set up uses.
I don't think there is a vacuum leak but with a monster like this it makes such a racket at idle it isn't noticeable.
It had a solid 17 inches at idle yesterday. Probability is low on that.
Obviously when you get to this point, the engine is like a race engine and what was ok 15 minutes ago isn't necessarily now.
This one has no oxygen sensor provision so I can't use that in diagnosis of the a/f ratio...but I'm thinkin'.
On the surface these things sound so simple. That is hardly the reality though. Remember, there is no such thing as a bolt on.
No life and death struggle on this. It will get right eventually.
On that plug, remember, that is the equivalent of a BF32. That isn't a hot plug at all.
I need more header temp info on this. 615 is actually on the high side of normal.
A colder plug should bring that down some?
I may have to dial out some initial advance too. Probably is set at about 16 right now. Advance affects the exhausts temps disproportionally too.
I am very sure the current crop of race cars have gone through this recently. I'm pretty isolated from them and some of them speak Martian like I do but not all?
Actual header temps can be deceiving. Coatings can make a big difference but so can how the headers are paired with different cylinders, port size, etc.
Also, just because the header is hot does not mean it's lean. If you can lean out the cylinder and watch it change in a given situation with an EGT sensor it is more meaningful.
When I built my first headers a long time ago, I made some major screw ups like pairing the wrong cylinders. I built a program on the computer to look at EGT's and it was very confusing.
When I ran the engine on a test stand I got some headers running 2x the temps at others:
At first I thought the gauges were wrong. I swapped sensors and the sensors were accurate.
Then I thought the hot cylinders were the lean cylinders. They were not. After looking at the inside of the headers I discovered that the hot temperatures were way rich:
Conventional wisdom says richer - cooler but there was a fault to this belief here.
In THIS situation, I really screwed up the pairing of the headers. The lean cylinders had back pressure. The rich cylinders had no back pressure!
The rich cylinders had pulled the air out of the cylinders before the fuel was done burning so the fuel was still burning in the headers causing a much larger temperature in the header. This did not mean the cylinder was hotter!
I found this all interesting. It points to the fact that it is all not as simple as it seams. It also points to the fact that specific numbers for heat lean or rich are irrelevant unless you can only change mixture in an exact scenario without changing anything else.
Also, just because the header is hot does not mean it's lean. If you can lean out the cylinder and watch it change in a given situation with an EGT sensor it is more meaningful.
When I built my first headers a long time ago, I made some major screw ups like pairing the wrong cylinders. I built a program on the computer to look at EGT's and it was very confusing.
When I ran the engine on a test stand I got some headers running 2x the temps at others:
At first I thought the gauges were wrong. I swapped sensors and the sensors were accurate.
Then I thought the hot cylinders were the lean cylinders. They were not. After looking at the inside of the headers I discovered that the hot temperatures were way rich:
Conventional wisdom says richer - cooler but there was a fault to this belief here.
In THIS situation, I really screwed up the pairing of the headers. The lean cylinders had back pressure. The rich cylinders had no back pressure!
The rich cylinders had pulled the air out of the cylinders before the fuel was done burning so the fuel was still burning in the headers causing a much larger temperature in the header. This did not mean the cylinder was hotter!
I found this all interesting. It points to the fact that it is all not as simple as it seams. It also points to the fact that specific numbers for heat lean or rich are irrelevant unless you can only change mixture in an exact scenario without changing anything else.
Bada-boom!
Oh no! I was afraid of this! My head just exploded! LMAO!
First things first FOR ME. First colder plugs. Then back off the ignition.
If that doesn't work, anyone have an inside phone number for NASA? Comp2. How did you tap into NASA?
I don't know why that plug is too hot yet.
Two possibilities. Too lean a mixture. Too much initial advance?
Actually a third possibility...brain transplant for me?
Akoshic Memory...Microsoft Cloud...Universal basis of knowledge(the one the Aliens use)...I need to tap into it. My puny brain hurts already. I don't think I would survive tapping in?
Oh no! I was afraid of this! My head just exploded! LMAO!
First things first FOR ME. First colder plugs. Then back off the ignition.
If that doesn't work, anyone have an inside phone number for NASA? Comp2. How did you tap into NASA?
I don't know why that plug is too hot yet.
Two possibilities. Too lean a mixture. Too much initial advance?
Actually a third possibility...brain transplant for me?
Akoshic Memory...Microsoft Cloud...Universal basis of knowledge(the one the Aliens use)...I need to tap into it. My puny brain hurts already. I don't think I would survive tapping in?
Questions,
Aluminum heads? rpm at idle? cam?
have you done a Leak down and compression test, even a exhaust gasket undersized can effect exhaust temperatures.
Any pr-ignition knock?
By the way I had very strange and varying problems with Champion plugs,I now swear by Autolite. Dropping the plug temperature will in turn cause a richer burn. You can do the WD-40 test on that intake, that could enplane allot if you have any leaks
Last question, does the engine overheat? May not be a problem.
This may help these are EGT temps @ 3200 rpm average 1200 F
high # 1 @ 1274 low @ 1118 #3
6000rpm ave. 1348F high 1429 #1 low 1281 #3
light brown plugs.
this is my 395ci stroker. # 64 plug.
Aluminum heads? rpm at idle? cam?
have you done a Leak down and compression test, even a exhaust gasket undersized can effect exhaust temperatures.
Any pr-ignition knock?
By the way I had very strange and varying problems with Champion plugs,I now swear by Autolite. Dropping the plug temperature will in turn cause a richer burn. You can do the WD-40 test on that intake, that could enplane allot if you have any leaks
Last question, does the engine overheat? May not be a problem.
This may help these are EGT temps @ 3200 rpm average 1200 F
high # 1 @ 1274 low @ 1118 #3
6000rpm ave. 1348F high 1429 #1 low 1281 #3
light brown plugs.
this is my 395ci stroker. # 64 plug.
Doug, I've never been able to get the same reading +- 10% twice in a row on any header tube with an IR gun. I think its due to the rounded surface combined with the very rapid cooling (relatively cool!) along the length. And aircraft thermocouples have a time lag measured in minutes...
quote:Originally posted by pantera chris:
Questions,
Aluminum heads? rpm at idle? cam?
have you done a Leak down and compression test, even a exhaust gasket undersized can effect exhaust temperatures.
Any pr-ignition knock?
By the way I had very strange and varying problems with Champion plugs,I now swear by Autolite. Dropping the plug temperature will in turn cause a richer burn. You can do the WD-40 test on that intake, that could enplane allot if you have any leaks
Last question, does the engine overheat? May not be a problem.
This may help these are EGT temps @ 3200 rpm average 1200 F
high # 1 @ 1274 low @ 1118 #3
6000rpm ave. 1348F high 1429 #1 low 1281 #3
light brown plugs.
this is my 395ci stroker. # 64 plug.
No pinging. No indication of detonation. Iron heads. 10.2:1 cr. 750 rpm idle.
I use Champions to dial in the heat range. More variety.
I've found that the heat ranges are the same as in the 60's or at least seem to be more accurate for what they are supposed to do.
One contradictory comment on that-they burn hotter with unleaded pump gas.
Notice the threaded part of the plug in the picture. NO DEPOSITS on the edge at all. NONE. Zero.
Motorcraft would be my choice but the BF32 has been eliminated in favor of the BF42.
Going to try the F7Y. That should be a BF22 heat range?
As far as the heat gun consistency, high tube was 615, 645, 245 within seconds of each other. Depended on the angle. Cylinder #6
Entire right side, 1-4 was in the 200's. There was a 180 in there.
I need probably to read the a/f ratio. No oxygen sensor in this car.
Exhausts smell good. Water drips from tips. Nice idle.
I don't know ANYONE who has messed with these carbs in the same way.
I wanted to try this because the 1850s had a heavier idle. These are leaned for emissions.
If you hold up the "white t-shirt" fabric to the exhaust they come off with NO carbon on them.
Petronix converted distributor w/coil in a can.
Fires the car right up. Looks stock-ish.
You appear to be lean, but about the IR temp gun.
The closer the hotter, at a bend hotter, their are many variables, like a cross over section.
I can make the same cylinder hotter or colder just on the positioning of the gun, try moving down the pipe or at the collector, it could just be the gun.
The closer the hotter, at a bend hotter, their are many variables, like a cross over section.
I can make the same cylinder hotter or colder just on the positioning of the gun, try moving down the pipe or at the collector, it could just be the gun.
Taking my own advice on Holley carbs "you can not change the a/f ratio at idle on them. That is designed into the carb. You can only change the VOLUME of fuel with the idle screws. Not the a/f ratio".
I opened up the idle mixture screws, idle just went up.
I opened up the idle mixture screws, idle just went up.
On a Holley, you can change the A/F mixture at idle if the carb has been tapped for adjustable idle air mixture jets.
Comp2. Could you go into more detail on pairing of wrong cylinders.
quote:Originally posted by Rocky:
Here Doug -
In the spirit of Christmas....
Maybe this will help.
(Be Kind!)
Amazon - Tuning Made Easy...
Ah! The Phoenix rises from the ashes!
Actually my pin vise is sitting right here ready to go but it is probably going to be simpler to just switch the carbs out to 1850's?
This setup originally had its own unique carbs made for it by Holley. Both 465's and 600's!
The 465's are repopped but the 600's are not.
These 4180's have annular discharges in the primaries which is also a positive feature over the 1850's.
I need to determine if I can even do surgery on the idle fuel restriction first?
Probably one carb would only be necessary for idle though?
All premature. I need more header temp numbers to compare first.Then idle fuel restriction dimensions.
On standard Holleys they are much easy to enlarge since reducing the size of the air bleed was not intended to be changeable by Holley on them.
For those who are interested, here is the difference in the 4180 idle circuit vs the 4160 and what needs to be done, BUT this thread is about header temps.
It can not be better explained than this is.
This is the Professor preaching Gospel.
http://www.ifsja.org/forums/vb...wthread.php?t=165441
The main reason you go through this is because you want the accuracy of the annular discharge.
You won't believe the difference it makes until you try it, AND I am balancing two Holleys here, vacuum secondaries at that.
There IS a reason for the madness here. 2x4's get real heavy, really fast and I want to keep them clean.
The response the carb with annular discharge is approaching that of fuel injection.
But I digress. Working on header temps still.
Holleys are son of a guns to work on. Weber IDAs are MUCH easier for me.
Warning: go very gently with the taps. They are small and you can break them off in the carb body EASILY. If you do, you will never get the broken piece out. It will be garbage then.
The "truck" carb is more plentiful and much cheaper. Use those rather than the "GT" carb which is getting pricey now.
quote:Originally posted by brother-bee:
Comp2. Could you go into more detail on pairing of wrong cylinders.
Looking at the headers as constructed.
On the right set cylinder 1 is paired with 4 and 2 is paired with 3.
Firing order is 15426378
Look at the exhaust ports from these two:
notice cyl 1 and 2 is expelling burning fuel. 1 and 4 is paired.
4 fires then 2,6,3,7,7 fire then 1 fires the time it takes 5 other cylinders to fire all back pressure is gone in the primary
After 1 fires, 5 fires then 4 fires. Cylinder 4 competing with the same exit as 1 has 1/5 the time for evacuation keeping back pressure in the tube.
The ideal pair would be:
1-6
5-3
4-7
2-8
The only way to do that would be to create a cross over pipe from the left back to the right bank to pair appropriate cylinders; thus a huge advantage of 180's
Contrast that
Doug any tuning shop should have the tools to test the air / Fuel ratio. When I swapped my setup back to a carb setup, the shop had a pair of wands that were inserted into the tailpipes (sniffers) I think they were called. Sounds like a technical term to me. But it quickly showed the ratio.
In order to get the ratio correct in my car we swapped out the jets. My guess and it's just a guess is that the primary jets need to be larger????
I can recommend a shop but it's up here in nh. If you're interested I'll pass along the info
In order to get the ratio correct in my car we swapped out the jets. My guess and it's just a guess is that the primary jets need to be larger????
I can recommend a shop but it's up here in nh. If you're interested I'll pass along the info
Hi Doug,
I follow the never to old to learn philosophy.
That said, I learned so much from the D.V.D.s
offered from this company www.AutoShopVideos.com
The explanations are easy to understand ( even for me ) and it turned my Holly nightmare into, I can fix any Holly!
Anyone who wants to come out of the ditch on corroborators can do so with these D.V.D.s
The D.V.D. I ordered was "Performance Corroborators " it cured my ignorance,
I highly recommend them. I have now fixed and now they run perfectly four carbs!!! the old saying that you can't teach an old dog new tricks is B.S.
I follow the never to old to learn philosophy.
That said, I learned so much from the D.V.D.s
offered from this company www.AutoShopVideos.com
The explanations are easy to understand ( even for me ) and it turned my Holly nightmare into, I can fix any Holly!
Anyone who wants to come out of the ditch on corroborators can do so with these D.V.D.s
The D.V.D. I ordered was "Performance Corroborators " it cured my ignorance,
I highly recommend them. I have now fixed and now they run perfectly four carbs!!! the old saying that you can't teach an old dog new tricks is B.S.
quote:Originally posted by pantera chris:
Hi Doug,
I follow the never to old to learn philosophy.
That said, I learned so much from the D.V.D.s
offered from this company www.AutoShopVideos.com
The explanations are easy to understand ( even for me ) and it turned my Holly nightmare into, I can fix any Holly!
Anyone who wants to come out of the ditch on corroborators can do so with these D.V.D.s
The D.V.D. I ordered was "Performance Corroborators " it cured my ignorance,
I highly recommend them. I have now fixed and now they run perfectly four carbs!!! the old saying that you can't teach an old dog new tricks is B.S.
One of the issues I am having is with the data on the equivelent spark plugs.
Some one needs to explain to me how one "equivent" in another brand can be the replacement for a BF-22, BF-32, BF-42 all at the same time?
This is why I try to standardize the comparison using Champions as the standard.
If you tell me that it is because the "equivalent" plug has a greater heat range than the Champion does, my next comment would be that we are trying to limit the high temp of the plug to eliminate detonation by going to a colder plug.
How does a greater heat range limit the upper temperature range of the plug?
Help me here?
The plug I am using in the Pantera, an NGK BP6ES is one such creature.
It replaced the Champion N-8's which would foul up at idle.
I attributed this to the aluminum head running cooler and requiring a hotter plug.
If you look at the NGK chart, it is an equivalent to an N-8, N-9, N-10.
This is all too much for my puny brain to handle. Maas servesa por favor Senior. That's the only thing that will help I think?
One of the things I am suspecting, trying to research but can not confirm at the moment, is that the change in the "equivelent" listings is because there is a change in the nature of the fuels?
In the 60's we used lead fuel which had different burn characteristics then the current un'leaded/plus ethanol does?
Are the heat ranges specific to one fuel or the other?
Current pump unleaded burns hotter and cleaner. I suspect for that reason alone the fuel change COULD make dropping down to a colder plug necessary?
It just doesn't pay to think. It does little but create these massive migranes? I don't think, thinking is healthy for longevity.
What did Jackson Brown say? "I'm going to be a happy idiot and struggle for the legal tender?" Gee-se?
I will also bet you, "donuts to Navy credits", that these carbs are tuned for "stoio chemic" a/f at idle (14.6 and VERY HOT)? That would explain a lot.
are your 4180 carbs the kind that the idle mix screws control air rather than fuel, opening the mix screw adds more air (lean) opposite of the standard commercial Holleys that the idle mix screw controls fuel?
either way all bets are off getting into carb signal, your cam & doubling up the carb count. one would think that the dual carbs have the capacity to supply sufficient idle fuel but they need the signal to do so, 1/2'ing the signal is a big ? as to what the engine is really getting, & same through the mid & full power ranges too
keep it simple, single cylinder 2 stroke bikes if you change the pipe then the jet needs to be tuned while watching the plug
limited equivalent listings, sounds like a small player trying to hang with the real plug mfgrs that actually produce a plug for each established heat range, a Jedi mind trick
either way all bets are off getting into carb signal, your cam & doubling up the carb count. one would think that the dual carbs have the capacity to supply sufficient idle fuel but they need the signal to do so, 1/2'ing the signal is a big ? as to what the engine is really getting, & same through the mid & full power ranges too
keep it simple, single cylinder 2 stroke bikes if you change the pipe then the jet needs to be tuned while watching the plug
limited equivalent listings, sounds like a small player trying to hang with the real plug mfgrs that actually produce a plug for each established heat range, a Jedi mind trick
quote:Originally posted by 4V & Proud:
a Jedi mind trick
Well the force ain't with me.
Carb is set at stoichimometirc (14.6:1) at idle, which is actually ok if I don't mind melting the headers into ash?
probably not the air metering carbs I was thinking of but you have 2-stage PV's?
excellent tuning tool but they're discontinued so get what you need ASAP
http://www.mustangsandmore.com...m12/HTML/012338.html
" If I recall correctly, the 4180 used on 1983 to 1985 Mustang 5.0L HO's
were similar to 4160 series Holley but was specially developed by Ford
to meet emissions without any electronic aids. It was rated at 595 CFM
and used annular boosters on all four corners, a dashpot for throttle
control during deceleration, vapor vent equipped fuel bowls, side hung
floats, a specific fuel inlet, two stage power valve, "close limit" main
jets (with tighter tolerances). I believe the metering block is different
as are the emulsion tubes and air bleeds. Also there were no idle mixture
screws in the primary metering block, unlike 4150/4160 the Holley. Instead,
there is an idle mixture screw for each barrel, however they are in the base
plate and are sealed to prevent tampering. You can drill a small hole in
the bottom of the base plate for each mixture screw and pick out the plug to
provides access to the mixture screws with a small Allen key. There is also
no idle speed screw in the base plate. Instead idle speed is set with the
dashpot. I'm told the secondary metering plate is different than a 4160
in shape, so they don`t interchange." ~ Dan Jones
excellent tuning tool but they're discontinued so get what you need ASAP
http://www.mustangsandmore.com...m12/HTML/012338.html
" If I recall correctly, the 4180 used on 1983 to 1985 Mustang 5.0L HO's
were similar to 4160 series Holley but was specially developed by Ford
to meet emissions without any electronic aids. It was rated at 595 CFM
and used annular boosters on all four corners, a dashpot for throttle
control during deceleration, vapor vent equipped fuel bowls, side hung
floats, a specific fuel inlet, two stage power valve, "close limit" main
jets (with tighter tolerances). I believe the metering block is different
as are the emulsion tubes and air bleeds. Also there were no idle mixture
screws in the primary metering block, unlike 4150/4160 the Holley. Instead,
there is an idle mixture screw for each barrel, however they are in the base
plate and are sealed to prevent tampering. You can drill a small hole in
the bottom of the base plate for each mixture screw and pick out the plug to
provides access to the mixture screws with a small Allen key. There is also
no idle speed screw in the base plate. Instead idle speed is set with the
dashpot. I'm told the secondary metering plate is different than a 4160
in shape, so they don`t interchange." ~ Dan Jones
The Innovative motorsports LM-2:
http://www.innovatemotorsports.com/products/lm2.php
I have an earlier version, the LM-1 I have used on many vehicles including my tractor. A few cars I actually added a O2 gauge and a vacuum gauge.
http://www.innovatemotorsports.com/products/lm2.php
I have an earlier version, the LM-1 I have used on many vehicles including my tractor. A few cars I actually added a O2 gauge and a vacuum gauge.
quote:Originally posted by comp2:
The Innovative motorsports LM-2:
http://www.innovatemotorsports.com/products/lm2.php
I have an earlier version, the LM-1 I have used on many vehicles including my tractor. A few cars I actually added a O2 gauge and a vacuum gauge.
@ Comp2. Thanks for the info.
@4v & Proud.
There are several inaccuracies in Dan's statement in that post.
The secondary meter plate is interchangeable but that really doesn't matter.
What you do is you remove the pressed in brass bushings/jets then thread them for allen set screws which in turn are drilled in a jet size. It's quite easy.
There is a curb idle screw to set rpm with.
The annular discharge venturis are only on the primaries. Secondaries are standard venturis.
The primary metering body has an "idle fuel jet" pressed into it and is located under the main fuel jet.
The idle set screws ARE hidden under hardened brass caps that need to be removed and ARE allen sockets adjusted with an allen key wrench.
They are set at 3/4 turns BUT only control the volume of atomized fuel. So that does not richen the idle mixture, it only will give more atomized fuel (mixed with a pre-set a/f ratio) and thus only raises or lowers the idle rpm.
To richen the mixture at idle, you need to "change the jets" which is EXACTLY the concept done in Weber IDA's but there is no provision for them to be changed here in these carbs because they were locked for emissions reasons on the original application, YOU have to modify the carb to make them changeable.
It is originally supplied with two stage power valves yes, but you change them just like in any other Holley carb.
Close tolerance jets? Yes but they change out to any Holley jet you want.
2x4 Holley idle. Here it doesn't matter. There is a primary carb and a secondary carb. Not two primary carbs.
The engine idles on the primaries in the primary carb. It idles clean. Too clean and that's the problem.
The typical Holley provision of a minimal idle circuit to circulate fuel through the bowls is there. Yes. That's all they do.
The value of a 2x4 Holley set up is that it is completely progressive unlike a 2x4 Carter, AFB or Edelbrock system since that set up has mechanical secondaries.
The car runs on only two barrels of the Primary carb up to about 3200rpm when the secondaries primaries begin to open.
Those are all in by about 6,000 rpm.
The secondaries are vacuum operated and open on engine demand.
The intake manifold is designed to be a 180 intake and has characteristics of both a 180 manifold AND a tunnel ram at WOT.
Because the engine is running most of the time on the primaries of a single 600 cfm vacuum secondary carb, you are getting about 20 mpg out of this setup as opposed to using a single 780cfm Holley which would give you about 12mpg.
These set ups will dyno at a solid 25 to 30 hp over the single holley as well.
You can run it with two 465cfm carbs but I find that the 600's are smoother all along and make more power on top.
Call these 595's if you want to but that is just because Ford always rated the carbs at a different vacuum drop than Holley.
I suppose "you" could re-phrase what I am trying to do here as arrive at a good idle mixture by reading the exhaust temp of the headers rather than measure a/f ratio through the exhaust with an exhaust analyser, which I do not have.
In a way it isn't that difficult to do. Just keep making the idle richer until the headers stop glowing?
Pictures are in the link I posted in a previous post.
Here is the link again.
http://www.ifsja.org/forums/vb...wthread.php?t=165441
Nothing like short answers, huh?
I thought you might like this. The O2 gauges are getting quite abundant. I did not want it on the dash in the MGB (Chevy V6) so I installed it behind the radio delete plate which is held on with magnets:
quote:Originally posted by comp2:
I thought you might like this. The O2 gauges are getting quite abundant. I did not want it on the dash in the MGB (Chevy V6) so I installed it behind the radio delete plate which is held on with magnets:
I like it but what do you do for entertainment? Sing?
quote:Originally posted by PanteraDoug:
I like it but what do you do for entertainment? Sing?
Drive in the pouring rain with the top down!
I am just following and trying to learn...
your original concern is that the header tubes are "too hot" and asking what others are seeing.
Is the hot tube concern at idle or while running?
Just my thinking, could your hot exhaust tubes be related to the cam you are using?
Now, is the spark plug heat range discussion just a divergent or is there a thought the plug heat range has an effect on exhaust temperature?
your original concern is that the header tubes are "too hot" and asking what others are seeing.
Is the hot tube concern at idle or while running?
Just my thinking, could your hot exhaust tubes be related to the cam you are using?
Now, is the spark plug heat range discussion just a divergent or is there a thought the plug heat range has an effect on exhaust temperature?
Idle.
A hotter plug is one that permits a higher combustion temperature. A colder plug colder combustion temps.
Adding more fuel to the idle mixture would have a similar effect of cooling the exhaust.
Looks like it will be a combination of both in this case.
It could also be that I have some sort of an anomaly here. I'm using data (plug heat ranges) that was for leaded fuel and unleaded with ethanol has this "slightly" different result with higher exhaust temps. What's the difference in temperatures? 200 F degrees?
Makes sense in a way. Obviously the main reason for unleaded fuel was to remove the lead but raising the exhaust temps also reduces certain emissions so that's two fold effect.
Shelby stopped putting headers on the cars after 66 because Ford had added air injection to the exhaust to comply with California clean air numbers and they thought steel tube headers were "incompatible" with that.
"Incompatible" might just have meant the "steel tube headers will melt" from the heat? Cast iron would last longer. That was still leaded gas and they hadn't yet seen the effect I've got here now.
When I was racing it was still with leaded fuel. The AF22's were fine on the track but would foul at idle on the street. Come to think of it, the plug was never tried with unleaded to my memory?
A hotter plug is one that permits a higher combustion temperature. A colder plug colder combustion temps.
Adding more fuel to the idle mixture would have a similar effect of cooling the exhaust.
Looks like it will be a combination of both in this case.
It could also be that I have some sort of an anomaly here. I'm using data (plug heat ranges) that was for leaded fuel and unleaded with ethanol has this "slightly" different result with higher exhaust temps. What's the difference in temperatures? 200 F degrees?
Makes sense in a way. Obviously the main reason for unleaded fuel was to remove the lead but raising the exhaust temps also reduces certain emissions so that's two fold effect.
Shelby stopped putting headers on the cars after 66 because Ford had added air injection to the exhaust to comply with California clean air numbers and they thought steel tube headers were "incompatible" with that.
"Incompatible" might just have meant the "steel tube headers will melt" from the heat? Cast iron would last longer. That was still leaded gas and they hadn't yet seen the effect I've got here now.
When I was racing it was still with leaded fuel. The AF22's were fine on the track but would foul at idle on the street. Come to think of it, the plug was never tried with unleaded to my memory?
quote:Originally posted by PanteraDoug:
....
A hotter plug is one that permits a higher combustion temperature. A colder plug colder combustion temps.
...
?
Never knew that.
I thought "heat range" was the plugs ability to transfer heat away from the tip. the plug tip needing to be at an optimum temperature to prevent fouling or pre-ignition.
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Which is the controlling factor?
I thought ethanol in the fuel mix would reduce exhaust temps?
less potential BTU's so less BTU's produced
less potential BTU's so less BTU's produced
quote:A hotter plug is one that permits a higher combustion temperature. A colder plug colder combustion temps.
Regarding Plugs:
I think there is a general misunderstanding here, I have always learned that a HOT plug means that its CORE is running hotter than a COLD Plug. It is only a matter of the Plugs ability to disperse of heat and therefore its ability to stay clean. A Plugs Temperature rating has NO control over the Combustion Temperature. Some Engines needs a colder and some a hotter, only the Lord knows which. The rest of us has to test them individually to find the correct one for a particular setup. The trouble is if you choose a Plug that is too hot it will build up heat on its Core under high load and eventually glow permanently and therefore induce uncontrolled ignition (detonation) It will blow up your Engine and ruin your Day! Therefore always start your experimenting with a colder and work your way to a hotter until it remains clean without any or only little deposit! You have to drive several hundreds of miles to get a deposit if you are close to the correct temperature Plug and normally deposit can form at prolonged idle but should easily be burned off at 3000 rpm for a short while.
Be aware some Plug manufacturers uses reversed numbers for Heat Range!
Regarding Holley 4150:
Idle Screws controls Fuel! Here the trouble is that with a performance Cam the Carb does not deliver enough Air UNLESS you turn up the Curb Idle Screw and THAT induces a problem. By turning up the Curb Idle Screw you disables the Idle Circuitry because the Throttle Blades are past the Slots from the Idle Circuitry and then turning the Idle Screws has now no or little effect on the mixture. Some Carbs has an independent adjustable idle AIR supply, the 4150´s that I have seen has NOT. There are several possible ways to cure it. One is (initially) to turn up the Curb Idle on the SECONDARY Throttle Blades. It is a bit difficult to get to but it can be done with a Slot Bits and a 1/4" Wrench. Then counter turn the Curb Idle Screw on the PRIMARY ensuring that Primary and secondary Throttle Blades are EQUALLY opened. This might be "just" enough Air and hopefully both Sets are clearing the Idle Circuitry Slots in the Bores. IF NOT (and its easily checked by turning the Idle Screws to see if they have an effect now) you will have to Drill Air bypass Holes in your Throttle Blades (Primary and Secondary also if you have the 4 Idle Screw version) to allow Air into your Idle Mixture. I think I Started with 2mm Holes and it worked on first attempt. You might have to experiment or even go higher.
The importance is that both Sets of Throttle Blades are only just opening enough to secure they are not binding when they are in "closed" position. The only Air supplied for Idle is the amount of Air that can enter true that little Gap. It is normally not enough if you are using a 4150/4160 an a Performance Cam. (I only know about Holleys)
Adjusting your Idle Mixture by the Main Jets is not a great idea as it affects the whole RPM range which is not what you wanted. The above mentioned is the cure to have a controllable Idle Mixture. I don't know if you have access to a CO Gauge or an A/F Ratio Gauge but either is a valuable tool to find the correct Main Jets and to check your Power Valve(s) under load/acceleration.
Btw Doug your Spark Plug looks just fine to me, is it a fairly new Plug or has it run for a while?
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These are 4180 Holleys. They have a separate fuel jet in the metering block behind the fuel jet unlike other series Holleys.
Fuel is premixed (atomized) and the adjustment screws just effect the idle rpm. They don't change the a/f ratio.
This is done to lock out the possibility of changing the a/f ratio at idle.
I have already pointed out that this is how the Weber IDA idle system works as well. The idle a/f ratio is set with a fuel jet and and air jet. The idle screws there are also just for volume and is how you set the idle rpm.
That does not affect the air fuel ratio at idle either.
It has a four corner idle adjustment.
All other systems in the carb are tuneable just like any other Holley is.
Just the idle circuit needs to be modified because it is so lean. The idle air bleeds need to be closed down which means removing them and using Allen set screws as jets.
Plug has about 500 miles on it.
The headers are too hot. I'm going to play with plug heat range, fuel a/f for a while and see what happens.
I have a nice set of 1850's waiting if these don't work out.
Fuel is premixed (atomized) and the adjustment screws just effect the idle rpm. They don't change the a/f ratio.
This is done to lock out the possibility of changing the a/f ratio at idle.
I have already pointed out that this is how the Weber IDA idle system works as well. The idle a/f ratio is set with a fuel jet and and air jet. The idle screws there are also just for volume and is how you set the idle rpm.
That does not affect the air fuel ratio at idle either.
It has a four corner idle adjustment.
All other systems in the carb are tuneable just like any other Holley is.
Just the idle circuit needs to be modified because it is so lean. The idle air bleeds need to be closed down which means removing them and using Allen set screws as jets.
Plug has about 500 miles on it.
The headers are too hot. I'm going to play with plug heat range, fuel a/f for a while and see what happens.
I have a nice set of 1850's waiting if these don't work out.