ramaircjm

iTrader: (4)

I did a leak down test on my engine (LS7 with close to 500 passes on it) tonight after losing 3MPH suddenly over the weekend between my 3rd and 4th pass at the track and the numbers are pretty bad.

Here's what the results were:

1 - 30%
3 - 20%
5 - 44%
7 - 12%

2 - 17%
4 - 10%
6 - 40%
8 - 28%

I'll preface this by saying that while I know the best thing to do would be to simply have the engine completely rebuilt, with it being the middle of the race season I would like to avoid it if possible and was curious if anybody had ever replaced just the rings (and without honing the cylinders) and had any success with it.

What makes me think it might actually work (or at least get me thru to the end of the season) is that when I recently replaced the #7 piston and rings I didn't touch the cylinder wall and that one had the second best leak down numbers.

I've already got the rings as Diamond accidentally sent me a complete set when I ordered the new piston so I figure at worst I'd be out about 20 hours of labor if it didn't work.

Anybody have any direct or indirect experience with this?

Thanks in advance,
Christopher

DAVESS02

iTrader: (30)

Never tried it but I dont see how you'll ever get decent seal on the cylinders. I bet it uses oil like a **** to boot! I wouldnt waste a good set of rings. If they were a real soft ring set instead of some premium ones, you might have a better result.

Whistler

iTrader: (46)

At the absolute minumum run a hone on a drill through it with some oil.

formula17

iTrader: (4)

My opinion, Take it for what it's worth. IF you have the sense to take apart an engine and put it back together correctly, Then you should have the sense to know why it would be imperative to hone the cylinders before putting it back together.

crainholio

iTrader: (2)

The earlier LS1s had oil consumption problems, and GM's corrective bulletin required replacement of the #2 compression ring and oil control rings **without** honing the cylinders. GM was very specific on this, as #1 compression ring was not being replaced.

I've seen two Vettes that had this done, and oil consumption was near zero after the repair.

For a mid-season refresh I'd be OK with a basic ring job, just clean the cylinder walls extremely well w/ ATF and paper towels and then lube w/ 30wt oil. You won't expect as good a ring seal as with a freshly honed surface, but if properly done it will keep you in action.

ramaircjm

iTrader: (4)

I ended up talking to somebody from Total Seal (I believe they supply Diamond with their rings) and he said a 240 grit brush type honing tool from Brush Research would do the trick so I went ahead and ordered one from Summit Racing earlier today.

Even though it's likely to be messy trying to do it with the engine still in the car I think it's preferable to having to pull it.

crainholio

iTrader: (2)

Going to pull the crank before slinging abrasives around?

If not, just go ahead and junk the engine now so you'll save time.

TurbopigB4C

iTrader: (5)

Shortcuts work sometimes but be prepared to do it again just in case. I have heard lots of stories of what people used to do back in the 60's, 70's, and 80's to sell cars with bad engines to save a buck and they usually revolve around less than what you plan to do so it can't hurt to try.

kevin kuether

iTrader: (1)

Engines need to be thoroughly cleaned after honing. I would suggest pulling the engine and doing it right.

VandykeT/A

I rebuilt a 305 not long ago and didn't hone it. I just threw new rings and bearings in it and put it together. It runs good but I probably didn't have 500 bucks in it and if it blew its not like I really lost anything. In your case tho I would do it the right way. I love my little 305 by the way. If only my T5 hadn't **** the bed.

Whistler

iTrader: (46)

I was unaware you were planning on leaving the block in the car. I strongly suggest removing it and honing the cylinders. Some debris will surely find it's way to the bearigs otherwise, how much will depend how good a job you do in containing the mess and cleaning it afterwards.
Good luck with whatever you do and let us know how it goes either way!

TurbopigB4C

iTrader: (5)

If you can shortcut it for less than $500 and your doing it yourself it is worth the risk compared to doing it right at over $2000. If the cost is close though and just labor is involved I would go the better more conservative route.

litle88

iTrader: (20)

Let me get this right, you want to "hone" your cylinder walls while the motor is still on the car.

So you can replace the piston rings only?
While the motor is still in the car?

Am I missing something?
How are you going to pull the piston out to replace the rings?

slt200mph

iTrader: (42)

This should be fun to watch ... please post up a video ...

Marc 85Z28

iTrader: (8)

There are hundreds, maybe even thousands of older LS1 Corvettes running around that have the rings replaced under warranty without a hone and have no issues. My father owns one. 30K miles later it still runs strong with no oil consumption.

litle88

iTrader: (20)

I believe that, but did the tech leave the motor in the car too?

sssuch

Chris go ahead and hone it in the car with the dingleberry hone it won't hurt anything. Just be sure to clean up thoroughly with HOT soapy water and a scrub brush , blow it out real good , and flush again with kerosene. I actually did this same thing back in the 70's to a customers Dodge truck that was using oil and after fighting the dealer with excessive oil consumption (no problem found) He brought it to me. I found the oil control ring absent in one cylinder , I put in new rings and rod bearings and he was happy as a clam. He also had NO bottom end troubles for the next 100K miles. Stan

crainholio

iTrader: (2)

Did you have the crank still in the engine, or removed?

10camaross

Yeah i would atleast run a drill hone threw it to take off the glaze so the new rings can have something to seal to

sssuch

The crank was still in it . At that time I wasn't equipped to pull the motor or remove a trans and transfer case , so I had to make do with what I had. Stan.