Mahle Stroker Piston Quietness
03-30-2006, 11:41 AM
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Mahle Stroker Piston Quietness I am planning to build a 408 iron block stroker and I am planning to use Mahle pistons (4.030" with -12 cc dish). These look to be good pistons for my daily driver, NA engine. However, they do not have offset piston pins so they will be subject to more rocking and possible piston slap during warm-up.
Does anyone have any experience with the Mahle pistons in a stroker. Are they quiet or do they have a noticeable slap during warm-up?
Thanks,
Steve
Does anyone have any experience with the Mahle pistons in a stroker. Are they quiet or do they have a noticeable slap during warm-up?
Thanks,
Steve
03-30-2006, 06:32 PM
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TTT
There have been a fair number of lookers thus far. I could ask this same question of anyone with stroker and 4032 alloy pistons without offset pins. Another alternative that I'm seriously considering is a set of custom Wiseco 4032 pistons with offset pins. Please share your experiences if you have a stroker.
Thanks,
Steve
There have been a fair number of lookers thus far. I could ask this same question of anyone with stroker and 4032 alloy pistons without offset pins. Another alternative that I'm seriously considering is a set of custom Wiseco 4032 pistons with offset pins. Please share your experiences if you have a stroker.
Thanks,
Steve
04-01-2006, 06:16 PM
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They may be designed to fit tight enough in the bores so they won't rock when cold, yet not expand too much as to score the cylinder walls under high temps from boost or prolonged high rpm usage. just a guess though
Jason
Jason
04-02-2006, 04:33 PM
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Steve, I"m running these in the 382ci motor that is my daily driver. Mahle calls for .0025-.003" clearance on their pistons for street application. The tighter clearance does help with piston slap on cold starts. I'm running mine a hair looser than that (.0040") since I have plans to spray this motor and the are still very quiet on cold starts, even with the pins not off-set.
These are awesome pistons for the price. I would highly recommend them.
Jason
These are awesome pistons for the price. I would highly recommend them.
Jason
04-02-2006, 07:15 PM
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Jason,
Thanks very much. This is exactly the kind of information that I'm looking for! I have some piston slap currently with the stock pistons when cold for maybe 30 seconds, so I can live with some mild piston slap. I plan to run NA with piston to cylinder clearance of .003". I'll only be running 87 or 89 Octane.
Now, I have a related question. Ideally, I need an 18 cc dish volume with 72 cc combustion chambers with a .040 quench to get my target 9.6:1 CR. If I use the shelf -12 cc pistons, I could simply use a .060 gasket for the compression or I could have the pistons milled for 6 cc's more dish and run a more optimal gasket in the .040" range. I'm going to align hone the main bearing journals, set the deck heights at zero for the stroke/rod/piston length and then overbore/hone .030".
My gut tendency is to use the thicker gasket and forget the optimal quench due to cost and probably little gain for what I'm doing (daily driver/tow vehicle). I could also stay with the .040 gasket yielding 10:1 CR and retard the time a bit via EFILive. I could also set up dual switchable spark tables. I'm running a custom OS on my PCM now. I could add a switch and have a premium and a regular switch position. What is your opinion?
Thanks again,
Steve
Thanks very much. This is exactly the kind of information that I'm looking for! I have some piston slap currently with the stock pistons when cold for maybe 30 seconds, so I can live with some mild piston slap. I plan to run NA with piston to cylinder clearance of .003". I'll only be running 87 or 89 Octane.
Now, I have a related question. Ideally, I need an 18 cc dish volume with 72 cc combustion chambers with a .040 quench to get my target 9.6:1 CR. If I use the shelf -12 cc pistons, I could simply use a .060 gasket for the compression or I could have the pistons milled for 6 cc's more dish and run a more optimal gasket in the .040" range. I'm going to align hone the main bearing journals, set the deck heights at zero for the stroke/rod/piston length and then overbore/hone .030".
My gut tendency is to use the thicker gasket and forget the optimal quench due to cost and probably little gain for what I'm doing (daily driver/tow vehicle). I could also stay with the .040 gasket yielding 10:1 CR and retard the time a bit via EFILive. I could also set up dual switchable spark tables. I'm running a custom OS on my PCM now. I could add a switch and have a premium and a regular switch position. What is your opinion?
Thanks again,
Steve
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04-02-2006, 07:20 PM
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Originally Posted by Jason99T/A
Steve, I"m running these in the 382ci motor that is my daily driver. Mahle calls for .0025-.003" clearance on their pistons for street application. The tighter clearance does help with piston slap on cold starts. I'm running mine a hair looser than that (.0040") since I have plans to spray this motor and the are still very quiet on cold starts, even with the pins not off-set.
These are awesome pistons for the price. I would highly recommend them.
Jason
These are awesome pistons for the price. I would highly recommend them.
Jason
Jason
04-03-2006, 10:26 AM
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Steve,
I would just use the shelf pistons with the .060" gasket and not worry about the minimal gains you could get if from flycutting the pistons exactly where you want them to get that quench. Since you're wanting to use 87 or maybe 89, it sounds to me like you're on a budget and aren't looking for exact, optimal performance for a given combo.
However, what I would do whichever route you take is run colder plugs to help with detonation and knock retard, especially since you plan on towing. You may have to change them a little more often, but your truck will be alot easier on the knuckles then an f-body. Obviously a 160 thermostat and conservative spark advance will be a must here as well. Essentially I would do what I could to stay out of detonation before having to richen up the air/fuel below the 12.9/1 range so gas mileage won't go totally down the drain.
I can't speak from experience here, so you may want to consult a notable engine builder or someone who's gone this route before, but I would think they'd recommend something similar.
Jason
I would just use the shelf pistons with the .060" gasket and not worry about the minimal gains you could get if from flycutting the pistons exactly where you want them to get that quench. Since you're wanting to use 87 or maybe 89, it sounds to me like you're on a budget and aren't looking for exact, optimal performance for a given combo.
However, what I would do whichever route you take is run colder plugs to help with detonation and knock retard, especially since you plan on towing. You may have to change them a little more often, but your truck will be alot easier on the knuckles then an f-body. Obviously a 160 thermostat and conservative spark advance will be a must here as well. Essentially I would do what I could to stay out of detonation before having to richen up the air/fuel below the 12.9/1 range so gas mileage won't go totally down the drain.
I can't speak from experience here, so you may want to consult a notable engine builder or someone who's gone this route before, but I would think they'd recommend something similar.
Jason
04-03-2006, 04:33 PM
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Originally Posted by Camaro99SS
I just watched your 1/4 mile run. Awesome run! Were those times with your 382 stroker or 347? Also, what were your shiftpoints? Also, how have the stock lifters and rockers held up to that wicked cam? I'm considering a setup just like this but maybe with a T-Rex cam.
Jason
Jason
Originally Posted by Steve Bryant
Thanks Jason!
Jason99T/A - What are your thoughts on this subject?
Thanks,
Steve
Jason99T/A - What are your thoughts on this subject?
Thanks,
Steve
Jason
04-04-2006, 10:34 PM
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I understand the warning on align honing of the mains. I have top notch shop that's going to do the machine work. Properly done, align honing is the basis of the other machining. The recent thread )https://ls1tech.com/forums/generation-iii-internal-engine/464633-there-any-0010-short-timing-chains-tensioners-available.html) on the block with the spun bearing is a warning to all.
Thanks,
Steve
Thanks,
Steve
