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

[jodadejss06gt]

Yea it appears that if he left it at 3.5 and those guys are saying 4 to 4.5 atleast. The guys at diamond said maybe open a little more than that if it were a strip car blasting down the 1320 on a cold engine.

 

[crownaviation]

My pistons and rings set me back almost $1,600 alone. I checked my cylinders after getting the block back from the machine shop and Friday I am taking it to another shop to verify just because humans make mistakes. I have seen since if the best shops make mistakes but with the massive money in this setup I just don't want any problems that can be avoided

Are the pistons trashed also?

My custom diamonds call for .0050 ptw then subtract .002 for the coating then add back .001-.002 for drag race power adder. Off the top of my head that came to .005 if I remember the numbers right (offset wrist pin 2618)

 

[niner555]

Were the rings confirmed as installed with the right side up? I have always been told if the second compression ring is installed upside down, the engine will smoke constantly.

 

[crownaviation]

You have offset wrist pins? I see the relief cut and also the "f" stamp. I thought they only marked the "f" on offset wrist pin pistons but don't know that for sure. If offset they only go one way and will be a left or right bank piston

 

[jodadejss06gt]

These are the pistons I got except 30034 instead of the 30064. Diamonds catalog shows them as offset wrist pins. I upgraded to the H-13 Tool Steel wrist pins.

http://www.excessiveracing.com/DRP-30064.aspx

 

[BruceH]

Not an engine builder but I've put a few together successfully. First off I'd disregard the vertical marks for now. I really don't think they are part of the oil problem.

Are the rings stainless steel? Is there a chance that the #7 piston is somehow not up to spec somewhere? My internet guess is that there is a bad valve guide.

When you called Diamond did they know what piston size you had? My uncoated Diamond pistons for a 3.701" bore call for a .0035" ptb and that's what will happen when the bore is 3.701". Do you have the ability to measure the bore and piston just to look for obvious differences?

I don't know enough to know what the hone should be for specific rings. I always leave that to the machine shop. I'm pretty sure that Todd tmolger does his own machine work and would know if the wrong hone was used. You might want to send him a pm to get his thoughts.

Good luck, I hope you get it sorted out.

 

[thump_rrr]

Not an engine builder but I've put a few together successfully. First off I'd disregard the vertical marks for now. I really don't think they are part of the oil problem.

Are the rings stainless steel? Is there a chance that the #7 piston is somehow not up to spec somewhere? My internet guess is that there is a bad valve guide.

When you called Diamond did they know what piston size you had? My uncoated Diamond pistons for a 3.701" bore call for a .0035" ptb and that's what will happen when the bore is 3.701". Do you have the ability to measure the bore and piston just to look for obvious differences?

I don't know enough to know what the hone should be for specific rings. I always leave that to the machine shop. I'm pretty sure that Todd tmolger does his own machine work and would know if the wrong hone was used. You might want to send him a pm to get his thoughts.

Good luck, I hope you get it sorted out.

Todd is tmcolegr and I'm sure he can give you the right answers on all things pertaining to our mod motors.

 

[jodadejss06gt]

I agree that something was wrong with the rings. The hone had more circular layers to it, and I've been told that occasionally certain ring combos like a steeper angle closer to 45* rather than the 30*or so that it was set at. Don't know if there is any truth to that.

 

[BeachMonkey100]

coming from building race motors a moly ring will be okay with a 30-45* angle and anywhere from a 400-600 grit honing finish, a stainless ring package from what I have used works best with strictly a 45* angle and anywhere from a 240-400 grit finish. It only takes a few swipes to get the desired finished. After honing is complete, a few swipes with the brush and good to go.

 

[jodadejss06gt]

yea I just got off the phone with the builder and he said that he never goes that steep generally 22-26* off horizontal and that he's never had any issues before with mod motors running that with this type ring set. 280 stone

 

[BeachMonkey100]

yea I just got off the phone with the builder and he said that he never goes that steep generally 22-26* off horizontal and that he's never had any issues before with mod motors running that with this type ring set. 280 stone

all depends on the set up and what it will be used for generally. But what he says does work for a street car motor. If the builder is confident in what he says and says it works, don't doubt him!

 

[jodadejss06gt]

Its just really hard for me not knowing what happened/what went wrong the first go around to be able to say yea sure go ahead and do your thing and let me throw this motor back in. Nobody wants to go through a build and have a failure with nothing to point your finger at and say "that is my problem". I'm just hoping the block is still salvageable.

 

[crownaviation]

Its just really hard for me not knowing what happened/what went wrong the first go around to be able to say yea sure go ahead and do your thing and let me throw this motor back in. Nobody wants to go through a build and have a failure with nothing to point your finger at and say "that is my problem". I'm just hoping the block is still salvageable.

They can likey clean up the block. You need more clearance anyway lol. Maybe this time they will not charge you for the bore/hone.

 

[jodadejss06gt]

Well I mean without having to get another set of pistons and rebalance the RA.

 

[BeachMonkey100]

Your pistons are fine, clean the bottom of the skirts up with a ceramic stone and scotch brite the tops of the pistons and you should be fine, let them hone it out to the recommended ptw clearance and put it back together. I don't see a horrible need for new pistons or having to re balance the assembly.

 

[blownGTvert]

It does sound like your engine builder is knowledgeable. Have him do whatever is necessary and move on. Sucks but what else can you do? Good luck and hope your back on the road soon.

 

[crownaviation]

It does sound like your engine builder is knowledgeable. Have him do whatever is necessary and move on. Sucks but what else can you do? Good luck and hope your back on the road soon.

Don't know any of those guys but sounds like they are honest too.. And I agree with aboce.. pistons are likely salvagable. Your shop will give you their opinion. They certainly don't want any more problems either

 

[jodadejss06gt]

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.

 

[Fullboogie]

Fourth picture from the top - what is that pitting at the bottom of the bore?

 

[thump_rrr]

Fourth picture from the top - what is that pitting at the bottom of the bore?

Exactly what I asked in post #2.