Hi Guys,
My friend has a JDM B16A engine with Spoon 81.25 ITR Pistons, ITR Retainers and Valve springs, B16A Valves, Stock head gasket, milled (50 thou) head, ITR Cams and a Chipped P28.

It is an incredible engine its very powerful......................

We did a compression test and it resulted as follows cylinder 1,2 and 4 265 and no 3 150

We pulled the head and found something strange,

Two cracked retainers and bent valves on that no 3.

My friend is telling me that he didn't over rev it or something.

It is running on RON 95 fuel.

Can anybody help us please?

Should we install ITR Valve now instead of B16 ones?

Is there too much compression?

Regards,

 

I wish I could help you out, but bump for a very well put together post with some actual tech value.

 

was the motor clayed first? I can't really imagine there being any clearance issues since ITR pistons are being used. Are there any knicks in the pistons?
.05 is quite a bit to take off the head, but I've heard of many others taking that much off before.

How does the head look now?

 

[QUOTE=WAFFLES]was the motor clayed first? I can't really imagine there being any clearance issues since ITR pistons are being used. Are there any knicks in the pistons?
.05 is quite a bit to take off the head, but I've heard of many others taking that much off before.

How does the head look now?
Hi,the head is still good,and there are no knicks on the piston.Everything looks fine,and for the fuel ron ,i think that here in malta is much lower ,it is about 90 ron or under.

 

what was the motor being rev'd to?

 

It is being revved to 8800 on the tacho.

 

That could be the problem(although stock tachs are normally off a bit). I bet anything you over revved. Besides, there really wouldnt be a reason to rev that setup past 8500 because it wouldnt be making power past that if it does in the first place.

 

Do you think we should put itr valves and a thicker head gasket?

 

did you guys put clay on the pistons to see if there would be any clearance issues? I would have the head completely inspected to make sure the valve guides are still good. Stock valves would be okay, ITR might be a little better, but nothing extreme. But first off, I would install stiffer valve springs and possibly Ti retainers.

After the engine gets reassembled, I would immediately take the car to a dyno. See where it stops making power. Look at the tach while you are making your runs, and note any difference between what the tach says and how high you are really spinning the motor. Theres no need to spin a motor to 9000rpm if it doesnt make power past 8000, unless your gearing is totally worthless.

 

We clay the motor first with the stock gasket and after we'll see what we do.Thanks alot for your info

 

Thanks a lot for your input guys.

As usual we really appreciate all your help.


Its up to JDM97R then ....he's our tuner......he's


Rgds,

 

clay the motor, if clearances are good, re-install the head. make sure you install new valve springs that are stiffer, or dont rev past 8500. good luck guys