Re-ring or new P&L's? '88 3.2
 

My Carrera is currently at my good guys shop for a new clutch.

120k, changing early? due to financial circumstances.

Had a small blue cloud when sitting for a week or so with overall consumption of about 1quart per 3k oil change (always dino) Owned about 15 months and driven regularly.

Suggested renewing all valve guide seals, uppers/lowers and he found heavy carbon on piston tops and combustion chamber when he removed the heads.

Cylinder walls look good, virtually no buidlup at top end but black ring is present.

My guy wants to do P/L's but I just dont have the bucks. Asked him to look into re-ringing due to my limited funds.

Suggestions or ideas would be appreciated.

Thanks, Val

From what you describe your engine should never have been taken apart. Now that it is apart you or your mechanic should measure the wear on the piston rings and piston ring grooves. If they are well within the wear limit then I'd re-use them with the old rings. If you use new rings you take a chance on them not seating. Many mechanics don't want to take that chance hence the recommendation for new pistons and cylinders.

Most likely all you need on a 120k engine is new valve guides although with your oil consumption you probably didn't need those either.

The specs for rings from my Haynes manual are:
compression ring end gap .1-.2mm wear limit .8mm
oil control ring end gap .15-.3mm wear limit 1.0mm
side clearance top compression ring .07mm to .102mm wear limit .2mm

If your side clearance is greater that .2mm (.004 inches) then new rings are not recommended as they will quickly wear the pistons and then break. The old rings will be fine however.

I bought new rings last year that had an end gap of .5mm. That was worse than the old rings so I sent them back and used my old rings.

You should also replace the lower head studs on your engine because the ones you have will break sooner or later. Any of the newer studs or stock steel early studs will be fine.

-Andy

Re: Re-ring or new P&L's? '88 3.2
 

You had your mechanic open up the engine because it blew a little blue smoke on startup after sitting a while? All this while the car is in for a clutch job?

Wow. Who is your "good guy"?

Hey Val,

Most likely you have Nikasil cylinders which can be honed and re-ringed. That's one heck of a clutch job and one heck of a bill to go with it.

:eek:

Drago.....as usual, you're running off at the mouth without knowing the details....which at this point are none of your business.....and will stay that way.....

Eagle Driver and Boxer 6....thanks for your inputs.

Update for Eagle Driver and Boxer 6....

I went by the shop Friday afternoon; the oil control rings were major clogged and gummed up with junk. My mech picked up a new ring set after checking all the piston ring lands and they were well within spec for re-ringing. Hoping to be back on the road by Thursday.

Thanks again for your inputs.

Yes, and you were so forthcoming with details in your initial post.

What limited details you did share in your first post would indicate a fairly normal condition if the car sits for a while.

I'm not trying to flame you Val but I am curious who your "good guy" is.

I was told many years ago, NEVER hone Nikasil cylinders.
This was told to me by the GURU's at Andial.

Re: Re-ring or new P&L's? '88 3.2
 

that oil cosumption sounds pretty good. i think the manual says something like 1qt/800mi.

wonder if that carbon build up and other gunk could have been have been cleared up by some oil or fuel additives that breat that stuff down.

good luck, that repair will make the clutch job sound cheap.

Hi Ted,

I think I have read somewhere that qt/800 is a worse case scenario by Porsche?

I ddint think the oil consumption was terribly bad either; however, since I was doing an early (IMO) clutch job along with upper/lower valve seals,
why not look at everything. You might be right about oil/fuel additives adding to the crud, I dont know? PO was a cheap skate so nothing surprised me though the car was in overall pretty good condition. Good comp 155 and leakdown 3-4%. I was totally surprised at the carbon buildup and the condition of the oil rings.

When I was told the price to do P/L's, I said to him that my total budget was $5k. If he could do the majority of stuff for that then go ahead; however, that was my MAX, period, otherwise just do what we originally talked about...

I was an FSR for Mercedes about 30 years ago with a 4 state (Rocky Monutain area). I told the dealers that I would not honor any new car warranty engine/fuel system claims where they were using the oil/fuel adds. I based my position on Kenz-Leslie Racing who were big deals in Denver/Rockies along with Frank Peterson (same area) who ran and won several Pikes Peak trials with Toronados, both of them had done extensive testing in the mid to late 70's and that was their opinion......plus it was a rip off against the customer IMO.

My mech isnt going to hone the cylinders; so hoping the break-in goes smoothly, so to speak. I stop in twice a day to check on what is happening.

Thanks again.....I'll do a repost when she gets back on the road this week.

I use the term "hone" here too loosely as well. I think the proper reference should be "deglaze".

I know both Pete and Dieter at Andial and they are both VERY knowledgeable so I don't want to discredit them at all, but Nikasil cylinders can be honed (deglazed) and re-ringed. It's the Alusil cylinders that should not be honed. Also, Andial is one of the largest distributors in the United States of Mahle P&C's so they would rather sell you a new set;)

when i got home i checked my owners manual
0.5-1.0 US qts per 600 miles
(0.4-0.8 imp qts per 600 miles)

not bad for a 34yr old car if you ask me.

Re: Re: Re-ring or new P&L's? '88 3.2
 

Conway Motors Inc. ? Val

ehm.
Being new to the 911 world, and not knowing that kind of compresion the 88's are supposed to run, I will tell you that my '85 3.2 is running 187 on one cylinder, and a perfect 190 across all other five, with leakdown 4% or less.

If 155 is considered good...what's considered "marginal' or bad?

Yo Wolfe.....the comp on my car was with 110k on the clock so that's three times your mileage...dont know what is 'normal' but I was very happy with my results.

I went trekking (100 mile run) with PNWPCA on Saturday the 21st and the car ran great. The new clutch is awesome, just like I've read..buttery smooth. Opted for a non rubber hub disc and it feels great; my old disc had about 25% left but showed some abuse by one of more PO's.

Yes Ross, 'Conaway' and Sig is excellent. You must have a lot of free time to do nothing but keep on like a 3 year old child...FOAD.

Boxer 6...my 'good guy' came in considerably under budget. The additional work I asked for was a new cv joint boot, re-weld the broken sway bar bracket, aim the headlights and install the new trunk carpet kit.

I'm very satisfied with the quality of work by him.

Gentlemen, let's try to keep the tone on this forum, and this thread in particular, polite and professional. Thank you.