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.