New Engine....scored cylinder walls, need diagnosis help

[BruceH]

Thanks, should know more about the hone tomorrow. Hopefully it cleans up without having to take the block .030. If that is the case I'll pick up another seasoned alum block.

Why? Just so you can use the same pistons? There are several of us who have run .030 over with higher boost numbers and never had an issue.

 

[thump_rrr]

Why? Just so you can use the same pistons? There are several of us who have run .030 over with higher boost numbers and never had an issue.

Did you see this pic?
Look near the bottom of the cylinder.
I don't think that another 0.010" will clean that up.

 

[jodadejss06gt]

The fourth pic is just oil at the bottom of the cylinder...

Bruce, just didn't want to spend another grand for new pistons. Block bored and honed would be cheaper and I could sell mine for someone wanting 030

Edit: I think

 

[BruceH]

Did you see this pic?
Look near the bottom of the cylinder.
I don't think that another 0.010" will clean that up.

No I didn't. If it's not just the picture playing tricks with the surface it should of never been assembled.

 

[jodadejss06gt]

I don't think that my stock block with no issues ever would have looked like that. The builder said when he disassembled the stock block it looked great. I'm hoping that it is just an optical illusion or oil on the surface.

 

[one eyed willy]

might as well add my opinion...lol

Looking at the very top of the bore and bottom where the rings never touch, you can clearly see good crosshatching.

Looking at section where the rings do touch, the cross hatching is almost gone and the vertical marks are a lot more than I've ever seen in motors with thousands of miles on them.

What do the other cylinder walls look like? is number 7 the only one looking like this? did all the pistons just slide out?

looks like a clearance issue on #7 or a bad ring/ gap. If the ring gap is wrong and binds, it will not compress, will get very hot and will lose the tension, a lot like he describes when he removed the pistons? If #7 is the only one, maybe he just missed gaping that ring?

 

[jodadejss06gt]

Thanks for the thoughts ^!

All of the cylinders looked this way and I really am starting to think it was a ring gaping issue or the hone wasn't good enough. He said that they all slide out when he tapped them.

Edit: and congrats on COTM. That car is so beautiful!

 

[jodadejss06gt]

Update 8-26:

Engine builder was able to get a clean hone on the block. He said its at about 3.5725 now and will leave about 4.5 P2B. He got rings today and will be putting it back together this week. He is also going to put new stem seals on for piece of mind on the oil in the 1 particular cylinder.

Anyone have any thoughts on the oil in just the one cylinder(#7). With having the messed up bores all the way around could have been the luck of the draw with piston position for that oil to have only been on one plug or does it make more sense that its coming from the head in that cylinder #7?

 

[eighty6gt]

I wouldn't suspect the head. Why not look at the valve stems/faces to see if they had oil/deposits on them?

4.5 piston to bore is big, I assume those are 2618 pistons, let us know how it sounds.

 

[jodadejss06gt]

I looked at the bottom of the valves(cylinder side) and a few different cylinders showed obvious signs of oil, but #7 was't any worse than 2 or 3 others.

 

[eighty6gt]

Keeping my fingers crossed this thing rips on round two. Based on other's experiences I am figuring on a 30% chance my forged build screws the pooch on my first attempt.

 

[crownaviation]

Keeping my fingers crossed this thing rips on round two. Based on other's experiences I am figuring on a 30% chance my forged build screws the pooch on my first attempt.

Naw, you just hear about the ones that have problems

 

[jodadejss06gt]

Keeping my fingers crossed this thing rips on round two.

Thanks man! Me too, if not get the parts while they are cold, cuz i'll be running it into a fiery grave.

 

[BeachMonkey100]

New seals are a plus, I would look at the guides as well. Their pretty stout, but anything can happen. Since there were signs of oil I would check it all to be on the safe side.

 

[thump_rrr]

Update 8-26:

Engine builder was able to get a clean hone on the block. He said its at about 3.5725 now and will leave about 4.5 P2B. He got rings today and will be putting it back together this week. He is also going to put new stem seals on for piece of mind on the oil in the 1 particular cylinder.

Anyone have any thoughts on the oil in just the one cylinder(#7). With having the messed up bores all the way around could have been the luck of the draw with piston position for that oil to have only been on one plug or does it make more sense that its coming from the head in that cylinder #7?

Speak to other builders to confirm your P2B tolerances.
On my JDM Stroker the P2B clearances are 0.0027" according to my build sheet.
Could this be the cause of the loose pistons and oil consumption.

I also have an old mod motor here which I could try to check for P2B

 

[jodadejss06gt]

I had spoke with diamond and Jordan at Mod Head Shop and both say that 3.5 is for a NA car, while 4.5 and up is good for a car running boost!

 

[tmcolegr]

Speak to other builders to confirm your P2B tolerances.
On my JDM Stroker the P2B clearances are 0.0027" according to my build sheet.
Could this be the cause of the loose pistons and oil consumption.

I also have an old mod motor here which I could try to check for P2B

same here

 

[05stroker]

I run 2.5 to 3.0 on my motors as well. I would think 4.5 would have some noise on cold start up.

 

[crownaviation]

I had spoke with diamond and Jordan at Mod Head Shop and both say that 3.5 is for a NA car, while 4.5 and up is good for a car running boost!

Yup. That is confirmed by l&m also. Mine is recommended at .0050 which is why they also push the offset wrist pins. The corrections for the coating offset the corrections for drag race and power adder cancel each other out

 

[jodadejss06gt]

Yea i mean some piston manufactures seem to call for tight P2B while others call for a little looser. It may have been 2 tight to start with, but I don't think that is what caused my issues unless the rings were just gapped incorrectly.

I talked with another local engine builder yesterday for 40 minutes and he said it sounded a little like fuel wash to him. He mentioned that if it were fuel wash though, he'd expect to see wear on the bearings with the added fuel in the oil. I guess anything could happen, but if it were fuel wash any way the bearings could still be fine with the rings and cylinder walls jacked up??? I guess it could have been an initial issue that was corrected but damage already done before too much fuel got into the oil???