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Mad
ist crazy , I bought a set Speed pro pistons and Hasting Piston rings, but it did not work.
After 10 hours running on idle , 3 zylinders from the right bank only have 5 bar compression.
My engine builder say that the piston rings /Hasting cast rings / are shit. So I dissambled the engine after 10 hours running and maybe 50 miles, to check everything.
Piston to wall clerance is about .004, zylinders look nice, valves are ok and gasoline stands on them the hole night.
The piston ring gap is 0,5mm , the top ring stands about 120 degree to the 2nd ring.
Cylinder 1,2, 4 have this low compression , cylinder 3, 5,6 ,7 , 8 are between 12 and 14 bar.
My engine builder say that the rings are "galzed" and I should install new rings with better quality.
So my question : Wich rings should I buy ?
I like Mahle very much. Never had a problem with mahle rings. But I do not know exactly how to find the right rings :-/
What do you suggest ?
Thanks
Peter
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...Piston Rings are Lubricated by 'Splash' from the Crankshaft.
10 Hours at Idle!?

That is Not the Way to 'Seat' New Rings. In My Opinion. I was Always advised, when First Firing a Newly Built Engine, DO NOT Let it IDLE!! Run it in, with Differing RPM for 30 Minutes, and then take it out on the Highway and do the same for 100 Miles. DO NOT 'Lug' the Engine! Then come back and change the Oil.

I use TRW Forged and Coated Pistons with SpeedPro Chrome-Moly Rings. The TRW Installation Instructions state the Clearance at a Max. of .002"
Last edited by marlinjack
Yes thats right George! In fact , we did a lot of engines in the past and always use mahle rings. When the oil preassure is ok, it was always ok , when audi or bmw or toyota engines were running longer times on idle. Sometimes , I let them run a few secounds at high rpm , but most of the time they run idle . Thats what I did in the past and I had never a problem like this.
Normaly, when I repair a engine, I buy the parts from Rothmund and the sales agend give me the "good stuff". Never had piston rings, wich do no compression , when they are new , or running for a few hours!? For only 20 bucks more they sell moly rings, so why they sell "cast" -rings ?

All the work 4 nothing - ok this time I use moly rings , and will drive with the car for brakein. Maybe a carburated engine is diffrent to modern engine.
What rings would you suggest ? Does somebody drive cast rings ? Thanks
Marlin Hi
agree on the model reving the engine up and down ..not to high but NOT to low ..low is more danger as to my knowledge on rebuilding old Porsche engines resulted in "an oval" on the mains. Hence no good.
I used to rev the engine up WHILE DRIVING and down all the time. Which is what Chuck is saying as well Smiler
GUESS THAT IS WHAT YOU MEAN BY "LUG = constand rpm" the engine?
TX
Matthias
quote:
Originally posted by GT4Peter:
Yes thats right George! In fact , we did a lot of engines in the past and always use mahle rings. When the oil preassure is ok, it was always ok , when audi or bmw or toyota engines were running longer times on idle. Sometimes , I let them run a few secounds at high rpm , but most of the time they run idle . Thats what I did in the past and I had never a problem like this.
Normaly, when I repair a engine, I buy the parts from Rothmund and the sales agend give me the "good stuff". Never had piston rings, wich do no compression , when they are new , or running for a few hours!? For only 20 bucks more they sell moly rings, so why they sell "cast" -rings ?

All the work 4 nothing - ok this time I use moly rings , and will drive with the car for brakein. Maybe a carburated engine is diffrent to modern engine.
What rings would you suggest ? Does somebody drive cast rings ? Thanks


Some recommend a combination. Molly on top, cast iron on #2.

I generally use molly on both. I'm not seeing where there should be any kind of issue unless the cross hatch on the honing is wrong?

I don't disagree with the break in recommendations but the reality is that they are seated within 5 minutes of start up and to do that you need to keep the engine running which means probably something around 1800 to 2000 rpm.

It's like something you would see with a cold start and fast idle until warmed up. That's enough right there and once you can get it to idle down without stalling the rings are done seating themselves.
I agree with Doug. Coincidently, there's an extensive thread on engine break-in on my Engine Builders Forum right now (www.speedtalk.com). A half-dozen pro builders disagree on details but nearly ALL agree that the best way to break in a new engine is on a dyno; after warm-up, by the third pull under load to maybe 5000 rpm the power stabilizes and rings & valves are seated as well as they will ever be. Good quality moly-faced rings break in almost immediately per the above. Old-school cast iron rings are cheap, for easily satisfied poor boys with time but no money and need to be prepped as we did 50+ years ago.

Others say to break in a street engine by immediately driving it as you expect to use it in the future. All agree- do NOT let it idle AT ALL and do not use synthetic oil during break-in. Change oil & filter after 50 or so miles & inspect for debris. Engine break-in is essentially rapid, controlled wear of the new parts, and modern synthetics & additives are especially designed to prevent this!
quote:
Originally posted by Mat_G:
Tx Chuck!
well the language of the experts is not necessarily clear to non natives, and I guess even for normal US folks.. Smiler

Your definition provided fits my pattern!
..break-in will happen within next 2 month..as car is nearly restored...but we still have Winter..

Matthias


Normal? I don't know if I like that term? Do you honestly think that anyone in the US (or anywhere else) that can put up with a Pantera is NORMAL? You are kidding, right?

I think I might be insulted? Big Grin
What can I say..as a Pantera new comer?!! There is so much expertise and experience within the nice US team that what ever ME at least can say you folks are Experienced with the facts and goodies of our NICE Monsters (due to Term Panter vs cat - I do not want to go into direction of questioning beeing NORMAL to deal with it Smiler). It might sound ironic to call long gained experience on the Monster by the team as EXPERTS, no non of that .. is just a term I used to appreciate your inside and willing to expose it!

Well yes sometimes "so called" Experts go far out on an explanation which appears a bit too scientific (if I leave it on that level for now), well I take it with a positive smile..got a very long carrier in high end technology.. well sometimes I did feel like an Expert and might even been called an Expert but next day no more.
To me it is only the honesty to deal with the topic and offer "EXPERTISE"..so for me at least an "EXPERT" for the day..

Tx anyways..will continune to poke you on YOUR "Expertise!!!"

Matthias
quote:
Originally posted by George P:
It occurred to me as I was reading the forums today that rings that won’t seal properly are possibly as sign of a crankshaft that is unbalanced or incorrectly balanced.

I thought I'd throw that into the mix.


It is also crankcase vacuum/pressure related. The rings will seal much faster with a negative crankcase pressure of about 10 inches.

It's easier to measure that with a vacuum gauge so simpler to state that in inches but 1 inch of vacuum is approximately 1 psi of negative pressure.

If for some reason the engine has a positive pressure like could happen with a supercharger then the tension that the rings naturally provide will be counteracted by that pressure.

A blow through supercharger system will pressurize the crankcase also.

So make sure that you have a functioning pcv system at least until the engine is determined to be "seated".
quote:
Originally posted by George P:
quote:
Originally posted by PanteraDoug:

... 1 inch of vacuum is approximately 1 psi of negative pressure ...



Not even close. 1"Hg = 0.49 psig


What's a psig?

If you say so. I know that with the supercharger 1 atmosphere is the weight of the atmosphere at sea level. That's taken as a standard 14psi.

Ooo, now you made me forget how many inches of vacuum that is?

If you look at the supercharger gauges, some are marked in atmospheres and psi.

3 atmospheres is around 35-37 psi in reality. That I saw running in a SB Chebbie and I couldn't get the conversion numbers right? We couldn't figure out what it would take to blow out the head gaskets...but I digress.

As I said, I look at it in inches of vacuum since that's how my gauges are marked on the vacuum side but once they go to boost they are marked in psi.

I'll get out a caliper and measure the increments of both and make a conversion factor and tatoo it on my far head...wait, I won't be able to see that? Scratch that idea.

12 inches is about all the seals like the crankshaft can take without getting sucked in so the thought is for a safety factor 10 inches is a good number to aim for?

Venting the crankcase through the headers only yields around 4 inches of vacuum and that is at high rpm basically.

Every engine needs crankcase vacuum to seal the rings or maybe more correctly make them work right.

So I'm off "just a little" on my conversions? So shoot me? Just don't tell Marlin. He'll be sending me dirty emails. Big Grin
...YOU were 'WRONG'??? PSIG = Pounds Per Square Inch (reading taken at the ) Gauge.

Atmospheric Pressure at Sea Level is 14.7 PSIG, how many of You have realized, That number also represents the Perfectly Tuned Stoichiometric RATIO of Air to Fuel 14.7:1.

I do concur with Doug about the PVC Valve.
I put My PVC system back on permanently. I did not like seeing the 'Blow-By' Spuing Out of the Breathers, in the rearview mirror. But, I designed and use 'Vapor Separators', at both valve covers to prevent the 'Intake' of Oil. So The Oil Level does Not Recede Down the Dipstick. Vacuum in the Crankcase, as Doug reminded Us, Helps to Seal the Rings and Restricts Excess Oil from Burning.

...And NO, I do Not send dirty emails! I just send the Boys out to Do You Body Damage!!
Last edited by marlinjack
In the old days of multi-carbed flat heads, the magic fix for glazed rings usually from over carburetion could be corrected by removing the air cleaner turn your idle up to 2500 then with a couple of teaspoons of "Bartenders Friend" (a very mild abrasive powder used to clean pans sinks etc.) blow it into your carb. I was told this but never did it. I did find that the reason was a blown power valve, that was washing down the cylinders. I installed a new power valve ( about $6.00 )and the rings sealed. Their are no magic fixes.
Last edited by panterachris
quote:
Originally posted by George P:
quote:

Originally posted by PanteraDoug:

... Every engine needs crankcase vacuum to seal the rings or maybe more correctly make them work right ...



too much vacuum applied to a crankcase will prevent the oil pump from pumping oil.

quote:

Originally posted by PanteraDoug:

... So shoot me ...



Don't tempt me


Yes, but the number is thought to be less than 12 inches. 8-10 is what to aim at.

That is what a functioning pcv system should provide.

Should I duck? Eeker
quote:
Originally posted by George P:..
too much vacuum applied to a crankcase will prevent the oil pump from pumping oil....


I KNOW I should stay out, BUT I can't help myself.

would the reason for that be the vacuum begins to pull the entrained air out of the oil causing it to foam up.

I was wondering about the use of an abrasize in the combustion mix to seat rings. How about a solvent to wash off the wall glaze
getting back to the question, you broke the engine in the wrong way, this maybe why your rings did not seal, but, since you are doing all this for the first time follow the instructions referenced by Jack ( boss wrench ). Your rings will seal in time providing your air fuel ratio is correct. Running to rich ( to much fuel ) washes down the cylinders eliminating the oil that seals the rings to the cylinder wall, this is called glazing and is normally again caused by a blown power valve, incorrect over jetting or in a word your carburetor.
the rails of the 3 piece oil control ring act as springs, if you hold the circular rail at your finger tips and squeeze inward the ends at the gap will always spring the same way ....

which way do you orient the deflection?

all the same pointing upward

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all the same pointing downward

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opposed pointing toward each other

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opposed pointing away from each other

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