The set up is all stock USDM ITR engine with crower rods and wiesco pistons. The pistons are 11.5:1 and everything else in the engine is stock. The ECU is a stock GSR. The cam timing is set to TDC and the ignition timing "fully" retarded on the dizzy.

It sounds as if there is some "pinging" or more a valve slap sound when the engine is at idle.... any suggestions on how to clear up the slap? The cam gears are adjustable, but there is no other tuning device on the car as of yet. Will this car run without engine management or at least without upgraded injectors?

Or is there anyone with a cam timing that works with this set up?

thanks for any help.

 

Set distributor timing at 15deg.

Make sure valve lash is correct.

You shouldn't get much piston slap with Weisco's, did the block get machined at all? Were any of the piston-wall clearances measured?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 92TypeR &raquo;</TD></TR><TR><TD CLASS="quote">You shouldn't get much piston slap with Weisco's, did the block get machined at all? Were any of the piston-wall clearances measured?</TD></TR></TABLE>

what do you mean by piston slap?

 

Upon cold startup, forged pistons tend to be loose. Piston slap refferrs to the sound they make until they tighten up. Certain pistons are known for this, JE's specifically.

Manufacturers use different concentrations of silicon, copper, nickel and manganese in their forgings of aluminum, and some have better heating properties than others.

I like a tighter piston, like CP, where there is little heat expansion and little to no slap at colder temps.

 

thanks for the info, I will be sure of the timing and well hope for the best cause its all together now...

 

up for more info

 

are Probe Pistons prone to slapping? and does that mean not drive until motor is at running temp?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by allnaturalb16 &raquo;</TD></TR><TR><TD CLASS="quote">are Probe Pistons prone to slapping? and does that mean not drive until motor is at running temp?</TD></TR></TABLE>

Call Probe and ask what stock aluminum forgings they use. Or ask someone who runs Probe. Never delt with, nor do I know anyone who uses Probe.

Piston slap, to my knowledge, does not harm the cylinders or ring seating.

 

the engine sounds great today...I let it warm up and about 90 percent of the sound went away....now it just sounds "built"

thanks for the help