Bowtie70SS Posted September 13, 2006 Report Share Posted September 13, 2006 Which pistons? Mahle, JE, Diamond? Which ones? I was told that my engine has JE, but...The c*#ksucker who raped me on my engine build apparently used Mahle pistons PN LS1340000F04 . Not that there's anything wrong with the pistons, except that I imagine there's way too much skirt clearence because I have constant piston slap. Another bonus will be to find out if I actually have eagle rods, I was told they are ESP's but we'll see when I get the engine out later this week. I WILL NEVER LET ANYONE ELSE BUILD AN ENGINE FOR ME AS LONG AS I LIVE. I swear. I guess I'll buy some of the stuff from Thunder racing, the rest from Jeg's or Summit racing. Damn, I could have had a SLP 408 at this point. Now I have the pleasure of building an engine and trans at the same time. I do feel fortunate that I can do all of this myself, I just hate to have to do it. I imagine I'll be posting pics of the carnage once I get it apart. Dave Quote Link to comment Share on other sites More sharing options...
popeye55 Posted September 13, 2006 Report Share Posted September 13, 2006 hey man sorry to hear all the hell your having, did you get your exhaust situation figured out? well if i can be of any help let me know. Quote Link to comment Share on other sites More sharing options...
zippy Posted September 13, 2006 Report Share Posted September 13, 2006 All 3 of those are excellent brands. My preferrence would be the Mahle's. The most important part of making that work without alot of piston slap is to find someone that bores the block and matches the bore to the piston. Quote Link to comment Share on other sites More sharing options...
Jonmalibuss Posted September 13, 2006 Report Share Posted September 13, 2006 All 3 of those are excellent brands. My preferrence would be the Mahle's. The most important part of making that work without alot of piston slap is to find someone that bores the block and matches the bore to the piston. <{POST_SNAPBACK}> And that doesn't mean measure one piston and bore the block, that means number and measure each and every piston and bore each cylinder to match. A "set" of pistons doesn't mean they are all going to measure the same no matter whos pistons they are, and the measurement given on the box is generally BS! Quote Link to comment Share on other sites More sharing options...
SuperSport Posted September 13, 2006 Report Share Posted September 13, 2006 Sorry to hear about all the drama, hopefully you can get everything squared this time. Quote Link to comment Share on other sites More sharing options...
Bowtie70SS Posted September 13, 2006 Author Report Share Posted September 13, 2006 Yeah, I would have made sure the pistons were matched to the bores. I'm guessing this guy had the machine work done at K-mart or something. I know that piston slap is gonna happen with forged pistons, when it's cold. The only time mine stops is when you beat the snot out of it and then it's quiet. When the engine is cold it sounds like a diesel. Dave Quote Link to comment Share on other sites More sharing options...
04CHASE Posted September 13, 2006 Report Share Posted September 13, 2006 is piston slap really that common with forged pistons?? im going to build a new motor with forged internals ( mahle or eagle pistons) and i dont want it to make that kind of noise after i just spent a bunch of $$ on it. Quote Link to comment Share on other sites More sharing options...
zippy Posted September 13, 2006 Report Share Posted September 13, 2006 It's something that you can't really avoid completely with forged pistons, but they are much worse when they aren't set up properly. Quote Link to comment Share on other sites More sharing options...
TurbochargedBerserker Posted September 14, 2006 Report Share Posted September 14, 2006 Mine don't make a sound... But I paid for a high dollar rebalance and used a race engine shop for the machine work. During break in, I occassionally heard a soft thunking at cold idle, but thats all gone these days. Quote Link to comment Share on other sites More sharing options...
adams2003 Posted September 14, 2006 Report Share Posted September 14, 2006 Can piston slap cause any damage? Quote Link to comment Share on other sites More sharing options...
misterp Posted September 14, 2006 Report Share Posted September 14, 2006 Can piston slap cause any damage? Yeah, long term reliability problems but I've personally never had the issue; then again you've gotta be smart about it. Pistons made from low silicon alloys grow and shrink quite a bit, they do not reach their final size until they are at 450-500 degrees so you have to warm-up the engine for 30-60 seconds until they have reached their "running dimension", after that warm-up they will be at the same bore clearance as stock cast pistons (tight) and properly holding the rings in place. What this means is that you have to warm the engine before driving, and this is not a big deal in the morning but a lot of people forget after driving to a mid-day appointment they must re-warm the engine (pistons) again before driving off, or there will be increased bore, land, and ring wear. It doesn't seem like a big deal but for a performance engine you want to have less than 2% leakdown to even hope to be competitive so every little bit of adverse wear matters (most new/healthy engines operate with 2-4% leakdown)... So everywhere you drive make sure the engine is up to temp before putting the trans in gear; that's just good advice even for a stock engine. I have to back up Berserker on quality machine work, because of the dimensional instability concerns with forged pistons expert machine work is *everything* in your engine build. When you have true craftsmanship in your cylinder prep you don't get piston slap after the engine warms up. But don't let this disuade you at all from using forged slugs, and NEVER run a cast or hypereutectic piston in a forced induction engine, the first bit of detonation under boost will litterally shatter it like glass. One other thing here that is not talked about but very important factor is that you can get forged pistons with both much lighter weight and tighter/higher ring package than stock and these features (piston + pin weight especially) make a drastic difference in survivability of parts at high RPM; if the pistons are super light then you can add some silicon to the piston and run 2-3 thousandths clearance (cold) versus 4-6 thousandths. Mr. P. Quote Link to comment Share on other sites More sharing options...
zippy Posted September 14, 2006 Report Share Posted September 14, 2006 Mine don't make a sound... But I paid for a high dollar rebalance and used a race engine shop for the machine work. During break in, I occassionally heard a soft thunking at cold idle, but thats all gone these days. Matt's 408 was the same way. It only made noise when it was in the 50's out and only for about the first minute or so. Quote Link to comment Share on other sites More sharing options...
adams2003 Posted September 14, 2006 Report Share Posted September 14, 2006 Can piston slap cause any damage? Yeah, long term reliability problems but I've personally never had the issue; then again you've gotta be smart about it. Pistons made from low silicon alloys grow and shrink quite a bit, they do not reach their final size until they are at 450-500 degrees so you have to warm-up the engine for 30-60 seconds until they have reached their "running dimension", after that warm-up they will be at the same bore clearance as stock cast pistons (tight) and properly holding the rings in place. What this means is that you have to warm the engine before driving, and this is not a big deal in the morning but a lot of people forget after driving to a mid-day appointment they must re-warm the engine (pistons) again before driving off, or there will be increased bore, land, and ring wear. It doesn't seem like a big deal but for a performance engine you want to have less than 2% leakdown to even hope to be competitive so every little bit of adverse wear matters (most new/healthy engines operate with 2-4% leakdown)... So everywhere you drive make sure the engine is up to temp before putting the trans in gear; that's just good advice even for a stock engine. I have to back up Berserker on quality machine work, because of the dimensional instability concerns with forged pistons expert machine work is *everything* in your engine build. When you have true craftsmanship in your cylinder prep you don't get piston slap after the engine warms up. But don't let this disuade you at all from using forged slugs, and NEVER run a cast or hypereutectic piston in a forced induction engine, the first bit of detonation under boost will litterally shatter it like glass. One other thing here that is not talked about but very important factor is that you can get forged pistons with both much lighter weight and tighter/higher ring package than stock and these features (piston + pin weight especially) make a drastic difference in survivability of parts at high RPM; if the pistons are super light then you can add some silicon to the piston and run 2-3 thousandths clearance (cold) versus 4-6 thousandths. Mr. P. <{POST_SNAPBACK}> Great info, thanks. Quote Link to comment Share on other sites More sharing options...
mwalls54 Posted September 14, 2006 Report Share Posted September 14, 2006 Mine don't make a sound... But I paid for a high dollar rebalance and used a race engine shop for the machine work. During break in, I occassionally heard a soft thunking at cold idle, but thats all gone these days. <{POST_SNAPBACK}> Matt's 408 was the same way. It only made noise when it was in the 50's out and only for about the first minute or so. <{POST_SNAPBACK}> it dont even do that now. Quote Link to comment Share on other sites More sharing options...
zippy Posted September 14, 2006 Report Share Posted September 14, 2006 Mine don't make a sound... But I paid for a high dollar rebalance and used a race engine shop for the machine work. During break in, I occassionally heard a soft thunking at cold idle, but thats all gone these days. Matt's 408 was the same way. It only made noise when it was in the 50's out and only for about the first minute or so. it dont even do that now. It is an impressively quiet engine for being all forged. How's it running lately? Quote Link to comment Share on other sites More sharing options...
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