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Old 10-30-2009, 09:23 AM   #5 (permalink)
MaineLotus
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Join Date: Feb 2005
Location: Maine
Posts: 1,436
Quote:
Originally Posted by good2go View Post
My 05 Elise N/A engine (53K mi) was knocking recently. I took it to my regular mechanic shop in San Diego and was told that piston #1 was slapping - checked everything else still look good: the valves, connecting rods, cams, rockers...etc.

First heard of Piston Slap as I'm not mechanical savvy - researched online and learned a lot. Anyway, I got some new Mahle Pistons, stiffer MWR valve springs and titanium retainers from Monkey Wrench Racing. It is normal for have piston slap on engine at only 53K miles. I maybe redlined it only once or twice for a second or so! Only a few track days and regularly maintained the engine by a qualified shop/mechanic.

The engine is getting a valve job, cleaned and bored and the above new parts will be installed - new again, yeah!

Question: the Mahle pistons is 12.3:1, not same as the stock 11.5:1 - will there be any issue?
Mahle Piston Set - Toyota 2zz - 12.3:1 compression 82mm - MAH-21123820 van Mahle - Monkeywrench

The website advised that the pistons are a direct drop-in to an unmodified 2zz engine. Is it safe and should be ok?

Also as in term of break-in, my mechanic advised that he will put in non-synthetic oil (less slippery) for break-in period of about 1000 miles, and take it easy - basically same as new engine.

Anything else (different) I should or should not do during the break-in period for our high compression N/A 2zz engine? I've researched online about breaking it new pistons and engine. Thank you very much in advance for any advice/suggestions, folks.

I'm actually excited bout getting the "re-new" engine!
53k miles sounds too soon to develop piston slap. If it truely has piston slap, that is usually developed when the bore is worn. If it is, then the block is ruined and you'd need to sleeve the block. You mentioned boring - that can't be done on the 2zz block - it has a special coating. You'd need to have the block machined to accept iron sleeves.

If you currently have Mahle pistons, you can have some slap before the engine is warmed up because the pistons are forged instead of cast (OEM).
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Last edited by MaineLotus : 10-31-2009 at 12:33 PM.
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