Rich mixture - how long before ring damage?

Rick Lee · Rick Lee's Garage

Turns out my newly rebuilt engine had a bad air flow meter, which is what caused it to run so rich. I noticed this pretty quickly, though I waited about 400 miles until I took it to the shop. Oil temps were fine, exhaust didn't smell as rich as my old 3.2, but gas mileage was sucking! Wrench said it was running 4.5% at ilde, when 0.8% is normal. Engine's PO had done some tweaking in the AFM to cure rich running, but I think it may have gotten jostled pretty good when he rolled and totalled his car. So assuming it was set right before the accident, I have been running rich only since I installed the engine about 400 miles ago. What are the chances I've diluted the oil real bad and done ring damage? AFM install and mixture setting will be all done tomorrow. I'll probably do an oil change Fri. night just to be safe. I'm nervous about ring damage though. Please reassure me.

cstreit · cstreit's Garage

Ring damage for this probably wouldn't happen that quickly. I had it happen in my turbo, but it was running VERY VERY rich for 5k miles. It would take a good amount of fuel wash down the cylinders walls.

4.5% isn't THAT bad...

APKhaos · 03-12-2003, 07:44 AM

Likely no damage at all, Richard. 400 miles of slightly diluted oil running fresh valve stem oil seals is nothing in the grand scheme of things.
Stan should confirm this - stop worrying.

No, wait.....there is a risk, and we don't want you to be worried. So, I'll trade your suspect 3.2 for my recently rebuilt 3.2, if you do the engine swap. Name the day. No more nagging worries about possible damage. And you get a freshly rebuilt engine with no history. What a deal!

Rick Lee · Rick Lee's Garage

If you want my new 3.2, then I know it must be too good to get rid of. I know I can always count on the local Pelicanheads to look out for me. But I really am dying to do another engine swap. I've only done 4 or 5 engine drops in the last 6 mos. and don't want to get rusty.

APKhaos · 03-12-2003, 08:02 AM

I'm serious - think of the peace of mind you will have.
AND you get all the theraputic benefits of the engine swap.

Jim Richards · 03-12-2003, 08:23 AM

Yes Richard, your new 3.2 is ruined. You must do another engine swap. I think a 2.4L E engine will work. What'dya think?

Rick Lee · Rick Lee's Garage

Actually Jim, I was leaning toward a 3.6.

kstylianos · 03-12-2003, 08:50 AM

Richard,

How about a bulletproof 3.0? The top end will be brand spanking new coming back from Competition Engineering in a few weeks. Heads, rings, full port job and the 20/21 cams you like. I'd sacrifice my rebuild for your piece of mind

BTW: The engine will be going back in fairly soon, so your engine drop/instal fix is coming up.