Hey guys,

I just rebuilt this D16Y7. New gaskets, new OEM oil pump, water pump timing belt, plastigauged the bearings, did everything correctly...unless I missed something. The knock only occurs when accelerating. Sounds perfect at idle. It's timed correctly, and I did the ignition timing with my timing light. All of that looks good. Good oil pressure. Changed the oil at 50 miles. No signs of debris. Anyone have any other ideas? Can't seem to figure this one out...

 

Compression test numbers? Valves adjusted? Clear video for us to see?

 

Valves were adjusted. I was thinking about doing them again. I'll try to get a clear video of it and get compression numbers.

 

You didn't specify your cylinder measurements.

If your taper and/or out of round is beyond spec you will get piston slap issues.

There is more to rebuilding an engine than just plastigaging bearings.

Even there, plastigauge is to verify your measurements as a double check, not to be your sole measuring device.

I suspect you honed your cylinders to be beyond spec and now your piston to wall clearance is beyond spec causing piston slap.

 

I had a machine shop do all the machining and honing. Told them they were stock pistons. I don't usually double check machine shop work, but it sounds like I might start to.

I know plastigauge isn't measuring the exact clearances. As you stated, it's a verification.

I may just have to tear it down again if there's nothing else that comes to anyone's mind.

Thanks for your help.

 

Your machine shop didn't ask for the pistons when they bored and honed your engine? Hmmmm.... I've come across this issue before. One shop asked for my pistons along with the block and it came out perfect. Another shop took the block only, even though I suggested they take my pistons also. Guess what? This motor wasn't machined correctly and PTW clearance is too tight.

 

A good shop bores and hones to the pistons. So telling them they are standard pistons still isn't enough information for high quality work, there are variances. If the shop doesn't want the pistons to measure off of and then provide you with which one is #1 and #2 etc... Then you should go to a different shop.