I just finished my engine build on my D16 and started her up and it sounds like an old mercedes diesel turbo.

I have a D16 bored 30 over and sleeved by Earl/Benson
SRP 9.0:1 forged pistons
Eagle H-Beam rods

Ferra valves
Crower springs/retainers
Crower stage II turbo cam.
AEM CAm gear
3-angle valve job and a P&P...

I asked a few people and they seem to be saying that its just piston slap or some ***** like that. I dunno, opinions?

 

It defenetely sounds like piston slap.
does it do it after the car has been fully warmed up?
whats the PTWC?

 

yea it still sounds diesel but not as bad. I dont even konw what PTWC stands for.

 

what kind of headcasket you using?

 

PTWC = Piston to wall clearance

Hondas are actually a little notorious for this happening until it reaches operating temp. Since you're running forged pistons I'm taking a wild guess that you have a little more PTWC than stock. (0.003" - 0.0035") You can bet that's your main reason right there.

 

yea probably, i dont really care about the noise, i just want to make sure it wont hurt my car in the long run...or even the short run for that matter.

 

I put SRP pistons in mine with about a .0035-.0038 clearance. They slap like hell until it's warmed up. (but I expected that)

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mmuller &raquo;</TD></TR><TR><TD CLASS="quote">It defenetely sounds like piston slap.
does it do it after the car has been fully warmed up?
whats the PTWC?</TD></TR></TABLE>

Agreed, get used to it.

 

but is it harmful?

 

Nope, very typical. Forged pistons expand once heated and the "slap" is just the time before its expanded and it rattles around in your cylinder. Once it heats up the rattling subsides since the piston has expanded to fill the cyl. Your ok.

 

I've heard quite a lot of piston slap in my day and have yet to here a honda that sounds like a diesel mercedes due to piston slap. Those things aren't quiet. But maybe.

 

honda calls for .0004-.0016 for stock piston to wall. Most aftermarket forget pistons call for .0030 or more, depending on how much you want to boost.
On your case you say that when its fully warmed up it still does it?
how loud is it?
I mean because as everybody is saying the tapping should mostly stop when warm, unless you are running a pretty big clearance.
And obviously more of a clearance and slap, the cylinder walls wont last as long.

 

it quiets down after its warmed up but i cant really tell by how much because my two heat shields on my exhauast rattle...my block's sleeved by benson so the walls should hold for a while i guess...i dont konw

THanks for all the info people.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by franken-B &raquo;</TD></TR><TR><TD CLASS="quote">

Hondas are actually a little notorious for this happening until it reaches operating temp. </TD></TR></TABLE>

No they are not. Hondas are known for TIGHT clearances.

Then again, almost all built motors using forged pistons have some piston slap until warmed up. If it doesn't go away once warm, I'd be concerned.

 

It is really "normal" for forged pistons to have that piston slap or is it just common? Forged pistons dont expand as much as stock pistons do so shouldnt the piston to wall clearance be tighter, preventing piston slap?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Muckman &raquo;</TD></TR><TR><TD CLASS="quote">It is really "normal" for forged pistons to have that piston slap or is it just common? Forged pistons dont expand as much as stock pistons do so shouldnt the piston to wall clearance be tighter, preventing piston slap?</TD></TR></TABLE>

It's all in how the motor's bulit. On a motor built for boost, you run the PTCW clearance bigger to compensate for the piston's expansion. Since the boost will cause the combustion chamber to be a lot hotter than normal (*basically*) the pistons will expand more from the added heat, and hence you will need more of a gap to prevent the pistons from expanding too much and siezing.

If you run the clearances looser, then you will have to put up with the slap until the motor gets hot.