forged engine noise
02-28-2009, 05:49 PM
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forged engine noise my forged engine has 3000 miles on it and it has a lower end knocking when started and knocks until fully warm.then it stops. is this normal?
02-28-2009, 11:09 PM
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i have original builder is telling me it is normal and williams performance telling me something is wrong. it is at williams now.
Last edited by jmdgto; 03-21-2009 at 07:28 AM.
02-28-2009, 11:31 PM
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You're going to be spending a lot of money chasing a non-existant problem. The clearances on forged pistons are different than with normal pistons. They are built with looser tolerances due to expanding. So... the reason is sounds like a diesel on a cold start is due to the pistons being cold-The reason the sound goes away when it's warmed up is due to expansion from the heat. Thermal dynamic is neat. Williams saw a sucker, and they're going to get plenty of labor tearing your engine apart. Good luck.
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03-01-2009, 09:21 AM
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You're going to be spending a lot of money chasing a non-existant problem. The clearances on forged pistons are different than with normal pistons. They are built with looser tolerances due to expanding. So... the reason is sounds like a diesel on a cold start is due to the pistons being cold-The reason the sound goes away when it's warmed up is due to expansion from the heat. Thermal dynamic is neat. Williams saw a sucker, and they're going to get plenty of labor tearing your engine apart. Good luck.
03-02-2009, 07:30 AM
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williams has a stellar reputation. they have some of the fastest cars in the country. some of my friends have had work done by them and it was a great experience for them. they will be looking at the car for me.
03-02-2009, 09:24 AM
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Just to clear some some of the controversy of whether piston noise is normal or not in a forged bottom-yes and no.Depending on the piston manf-some pistons have offset pins to quite the pistons while others do not-diamond and wiseco have offset pins and mahle and je do not.The other issue is clearance-engines set up for n2o or f/i have alot more piston clearance and will have more piston noise on cold startup than a n/a motor with the same kind of pistons.So basically some forged engines will make more noise than others.and having something checked out you unsure of is always a great idea.
03-02-2009, 11:17 AM
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There you go, its most likely piston slap, but see what they have to say. Running FI, you will definitely have some sort of noise. Has this done it since it was first run? Any other reasons to believe it isn't piston slap such as poor oil pressure or inconsistant oil pressure?
03-02-2009, 11:30 AM
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Sounds pretty normal to me being how you said it goes away when it is warmed up. Look its up to you to get it checked out if you think it is a problem but if you look at the reply's on here the consensus show that it is normal at start up and especially on cold mornings reason being is a forged piston needs more clearance when its cold y. The piston is a very dense piece of aluminum unlike a hyperutetic which is not cast under pressure the denser the material the more it will expand as it warms up the engine as you stated stops making the noise at operating temperature. It's a common know fact in racing a forged engine needs to be warmed before it is ready to be ran hard same on cars as with motocross racing those little engines rev to the moon but you cant do it with forged internals unless it is given enough time to warm up.
03-02-2009, 02:39 PM
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There you go, its most likely piston slap, but see what they have to say. Running FI, you will definitely have some sort of noise. Has this done it since it was first run? Any other reasons to believe it isn't piston slap such as poor oil pressure or inconsistant oil pressure?
03-02-2009, 04:20 PM
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I had one guy come in with a piston noise,turns out whoever built the engine only used a single spirolock when 2 was needed,anyway the piston pin came out and dug a nice groove in the cylinder wall-that's why it's always best to have a pro look at it.