Oil on top of pistons..NEED HELP...

[okm12346]

I popped the spark plugs out and there's alot of oil on top of all 4 pistons and spark plug threads are wet (its not coming from the Valve Cover seals). These are stock pistons with 97k miles , just honed the block. Didnt do that before. I had them out, inspected them, cleaned them and put them back in. The bottom end received new bearings and BS delete.
The head I installed came from a 6 bolt N/A j/y car (unknown). It got cleaned, new BC springs, Viton seals, brand new valves. It has an OEM HG. Turbo is brand new.

The only thing that wasnt replaced was the valve guides.

The engine has 750 miles after the semi rebuild. It almost overheated once because I was experimenting with the fan shroud. Car smokes on cold startup after that it seems to stop, but I cant really tell since I was driving it.

Im open to suggestions

 

[donniekak]

What kind of hone? Did you replace the rings?

 

[Bo0sTdTsI]

Check your spark plug oring gasket on the valv cover that what my issue was made the car misfire so I just changed spark oring gaskets and spark plugs and my issue was fixed, just an idea. If not could also be your turbo seals.

 

[kchaazz]

There are several things that could be attributing to the issue. Poor oil control because the rings aren't seated well, valve guides, maybe the headgasket is leaking a bit. First though, since all the above things have been freshened up recently,Id check the state of the PCV system since its the easiest thing to check, and its often the most overlooked.

http://www.dsmtuners.com/forums/articles-engine-fuel/366890-4g63t-pcv-system.html

 

[okm12346]

There are several things that could be attributing to the issue. Poor oil control because the rings aren't seated well, valve guides, maybe the headgasket is leaking a bit. First though, since all the above things have been freshened up recently,Id check the state of the PCV system since its the easiest thing to check, and its often the most overlooked.

http://www.dsmtuners.com/forums/articles-engine-fuel/366890-4g63t-pcv-system.html

PCV and all related ports were blocked off as I was trying to narrow things down.



No the rings were not replaced. The hone tool is one of tripod looking ones.


As I mentioned above, oil is not leaking from the spark plug tubes. Spark plugs are dry on top, only threads and piston dishes are wet.

 

[donniekak]

Putting a rough hone on the cylinder walls, and using old rings is asking for a sealing issue.

 

[jrs187]

Id recommend a ball hone and new rings. Do a leak down test and compression test. That wil help decide if it is actually your rings or if something else is wrong. Good luck

 

[okm12346]

I dont know man. Im pulling 22-24inHg of vacuum. I'll do compression test tomorrow to see what exactly the numbers are. Besides that I can drop both manifolds and see if the runners are wet around the guides. I'll take some photos too

 

[donniekak]

I had an engine once with perfect compression that burned a quart of oil every few hundred miles past the rings. I would rule everything else out first, but don't let a good compression test rule out the rings.

 

[kchaazz]

You put a fresh hone in the cylinders and didnt replace the rings? No offense, but thats just asking for trouble. Id just bite the bullet, tear it down, rehone and then mic the cylinders then gap new rings and reassemble and start all over at this point...

 

[BogusSVO]

What grit stone was on the hone?

The oil return ports behind the oil scraper rings could be clogged. Now when this happens, oil builds up in the ring land and too much oil is on the cylinder walls.

Also oil scraper rings are more delicate than the compression rings

 

[Dsmkauai]

Get the proper flex hone for your block and new a rings and do it right! Of course if the cylinders are within specs and not out of round!

 

[JacksonAuto]

"flex hone" and "do it right" don't belong in the same sentence.

 

[crimsondragon]

"flex hone" and "do it right" don't belong in the same sentence.

They actually taught us in aircraft maintenance school how to use a flex hone. I never understood why since any reputable manufacturer such as Continental or Lycoming would never allow such a thing in their factory.

 

[Dsmkauai]

What's wrong with a flex hone to deglaze for some new rings? Not everyone has there own machine shop available to them! And hmm lots of top Nhra guys run a flex hone down the cylinders right before they drop there new pistons in. And then go on to make a 300mph pass on a 8000hp motor! If you know what your doing there's nothing wrong with deglazing the cylinder with a flex hone to help new rings seat properly. They are way better and much more accurate than those old 3 bar stone type! And I meant do it right by deglaze the cylinder walls and use new rings. Unlike the o.p. who used the old piston rings! What is it with you people and not reading sentences correctly! And again this is assuming you've mic'd the cylinders and are not out-of-round!

 

[Archer Fabrications]

What's wrong with a flex hone to deglaze for some new rings? Not everyone has there own machine shop available to them! And hmm lots of top Nhra guys run a flex hone down the cylinders right before they drop there new pistons in. And then go on to make a 300mph pass on a 8000hp motor! If you know what your doing there's nothing wrong with deglazing the cylinder with a flex hone to help new rings seat properly. They are way better and much more accurate than those old 3 bar stone type! And I meant do it right by deglaze the cylinder walls and use new rings. Unlike the o.p. who used the old piston rings! What is it with you people and not reading sentences correctly!

You wont get the same cross hatching that a mill would. And it wont be nearly as accurate. Like you said.

 

[Dsmkauai]

I don't have any problem getting the proper cross hatching when using the correct flex hone for the rings I'm using! It's not rocket science! For a quick deglaze and re-ring job the flex hone works amazing for me and I havnt had one single issue yet! And that's actually the whole point of the flex hone to get proper cross hatch so the rings will seat easier and faster! This of course is to assume you have mic'd the cylinders and they are not out of round

 

[JacksonAuto]

The OP stated "semi rebuild" in the first post. Are we to assume that the cylinders were properly bored and honed then? If not, then it's a safe bet that the cylinders are std bore and I will guarantee that they're not round anymore. A flex hone will not correct this problem. It will only follow what's there, round or not. It will deglaze the walls just fine if that's what you're trying to accomplish. Simply offering up the advice to use a flex hone and install new rings is not the most sound advice.

My suggestion would be to first mic they cylinders and see what kind of condition they're in. If they're out-of-round, then you'll need to bore them and use oversized pistons. If they're okay, then you could use a flex hone or something similar to deglaze the cylinder walls, install some new rings and give it a go.

 

[Dsmkauai]

There I fixed my posts so they sound more proper for you! Sorry I figured if the o.p. had the car taken apart that much he knew to mic things first and check for out of round. Especially since he said he honed the block. I don't know maybe he doesn't know !

 

[TaLN91tsI]

Don't forget valveguides and proper valve guide seals. Ensure using proper seal for application. Worn valve guides allow oil to leak down onto the top of the pistons after non-use. This appears to be the first order complaint. Several engines including my M3 had a bad valve guide and misinstalled valveguide seal at the factory! Just check the guides or have a machine shop do it if you don't have the right micrometers for the job to rule this often overlooked problem out.

 

[okm12346]

So finally took the engine apart and nothing seemed to be wrong until i removed the rings well the oil rings to be exact. The holes on the piston behind the rings were completely clogged. I reused the pistons when i did the semi rebuild, I gave them a good cleaning, but i guess the chemical caked up the grime and filled the holes shut. Either way cleaned the holes, put new rings and bearings and it runs again.

Thanks for the help.