In-Car Re-Ring?

[Jake Latham]

Quoth a fellow with a car to sell:

I did a compression test and it is 130 130 125 100 [Should be 150+ -J ]

The leakdown test for #4 shows a 50percent leakdown tho.

I used a borescope and the piston and cylinder wall is not damaged in any visible way.

It idles fine..just has a lot of blowby. It's not like I am saying the motor is perfect...but the *blown piston* comment was overrated and it obviously has enough compression to run on all 4. I still believe He did have it rebuilt like he said....BUT I think he or someone went balls to the walls with boost right away and the rings got messed up.
....
It does run and drive now, all it needs is rings. I was going to do an in car re-ring. It actually runs pretty good, just has a lot of blowby. I am gonna post this up soon but wanted to offer it to whomever was interested before. You can even drive it home!



Anybody out there have any experience with something like re-ringing a recently built engine in-car? Cost ballparks? Bugaboos? Worthwhile fix, or recipe for disaster? This'd be for a daily driver that had a backup - something a bit more fun than the Civic day-to-day.

Cheers!

-Jake

[EGbeater]

Quoth a fellow with a car to sell:

"I did a compression test and it is 130 130 125 100" [Should be 150+ -J ]

Anybody out there have any experience with something like re-ringing a recently built engine in-car?

-Jake

Do you know if that Jspec 3S-GTE was built up with OEM spec pistons or not? My MR2 engine is built with 8.5:1 C/R forged pistons, and at this altitude, by compression figures are right around 125-130 psi across the board - and my leakdown results are less than 5%.

Obviously, it's not good that you have a 23% variance from lowest to highest readings, but why not test drive the car, and if it runs well enough, and you can buy it cheap enough, just drive it and see what comes about?

[Jake Latham]

Do you know if that Jspec 3S-GTE was built up with OEM spec pistons or not? My MR2 engine is built with 8.5:1 C/R forged pistons, and at this altitude, by compression figures are right around 125-130 psi across the board - and my leakdown results are less than 5%.


Haven't been able to determine for sure yet. Lot of conflicting info on the mr2oc. DSM specs are the same way, you'd expect lower. a 2g with 150+ is in good shape, and a 1g with 140+ is usually pretty happy. Like I said, my 1g was 120 and lower, and it still did 12's without much issue. the 50% leakdown on #4 is a question though.


Obviously, it's not good that you have a 23% variance from lowest to highest readings, but why not test drive the car, and if it runs well enough, and you can buy it cheap enough, just drive it and see what comes about?

That's the idea. Just want to know what my options are first, and what they cost. Better to know than to assume, right? (read your thread on the "oil leak" - that was hilarious)

-Jake

[EGbeater]

Anybody out there have any experience with something like re-ringing a recently built engine in-car? Worthwhile fix, or recipe for disaster?

I think that if you don't even blink at the work involved with pulling the oil pan, removing the bearing caps, and pulling the pistons, rods, etc out from the bottom, it's worth a shot.

New rings and handhoning the cylinder walls won't cost much - a lot less than a full rebuild obviously. So all you're possibly wasting is your time and labor, if it doesn't work out long term.

This is all just speculation though, I haven't done it myself, or heard any stories first hand about whether a re-ring job worked out or not.

[Jarod]

Just for reference, I compression tested my car not too long ago and got 130 130 130 125 on what I think is a healthy USDM 3SGTE.

[Jake Latham]

Just for reference, I compression tested my car not too long ago and got 130 130 130 125 on what I think is a healthy USDM 3SGTE.

Looks like that's what Hsun's numbers are as well, so it seems that it's just #4 that is hurt, especially with that poor leakdown. I'll see if Joel has the leakdown numbers on the other three cylinders.

-Jake

[00 SS]

Jake,

When you did the leak down, were you able to determine that it was absolutley the rings doing the leaking? A slighly bent valve, a cracked head or block or a gasket issue could also be the culprit of the pressure loss.

[Jake Latham]

Jake,

When you did the leak down, were you able to determine that it was absolutley the rings doing the leaking? A slighly bent valve, a cracked head or block or a gasket issue could also be the culprit of the pressure loss.

Hi Mike -

I didn't do the leakdown, I'm just parroting numbers from the fellow that did. He did mention using a boroscope to check out the cylinder walls, and reports that those look fine. Are there ways to determine a bent valve, cracked head/block or gasket issue with the head on the car, or would you have to yank it and have a look-see?

-Jake

[EGbeater]

Looks like that's what Hsun's numbers are as well, so it seems that it's just #4 that is hurt, especially with that poor leakdown. I'll see if Joel has the leakdown numbers on the other three cylinders.

-Jake

Well, recall that my figures are a touch lower than a normal 3S-GTE should be, because I'm at 8.5 C/R instead of 8.8, and I have aftermarket cams too.

But - my engine has less than 10K miles on it, and Jarod's is assumedly closing on 100K or possibly more. And, with the newness of my engine and regular use of water injection, my carbon deposits are probably close to non-existent.

All pointing to the fact that compression figures are mainly good for checking for consistency across all cylinders - not for comparison from car to car.

[00 SS]

You can check all the possibilities with the leak down test itself. With the cylinder being tested at TDC compression, apply compressed air to the cylinder. Then listen at the tail pipe, throttle body and oil fill cap for air sounds and check the radiator for bubbles.

Radiator bubbles = gasket, block or head problems
tail pipe = exhaust valve
throttle body = intake valve
oil fill cap = rings