Porsche Enthusiasts Club Forum

Hi, been a while, been a bit busy rebuilding a mx5,a freebie. . .well it started out that way. . .I,ll stick a few pics on if anyone would like to see them, very clean. . BUT
Jumped in my 86.5 lux yesterday, started her up and the oil pressure took a few seconds to register, hmmm, checked the oil, fine, and everything was good to go. Jumped in today, and the oil pressure didn't want to register, and the engine sounded very tappet, so I switched it off, checked the oil again, all ok. So restarted it, and very gingerly tickled the revs a couple of times, and the gauge went up. So I took a slow drive, oil pressure is 5 bar at 2500, about 3 on tickover, but there is a strange noise when I rev the engine now. It might have been there before, but now there is a problem I,m paranoid and listening for every noise. It doesn't sound like tappets, its only there when I rev it, but it sounds top endy. The oil was changed about 4 1/2 thousand miles ago, 10/40 semi synthetic, with a new bosch oil filter. Is there any obvious causes, any known problems, or am I taking the lump out for a re-build. . . . .. The car has done 147 k, had the belts and waterpump done early last year and up till now I havnt had any engine trouble. . . help !.
cheers
Dave

Possibilities not necessarily in order of likelihood:-
1. Hydraulic tappet, even though it doesn't sound like top end, would be most noticeable on start up but is related to oil pressure.
2. Broken spring, accompanied by misfire at highish revs.
3. Piston related, scored bore, broken ring, not related to oil pressure, smokey exhaust. Easily examined by borescope. (had that one)
4. Big end, oil pressure and load related. You pray it's not that and (3)
5. Loose crank sprocket again not pressure related, easily discounted.

I've had various knocks over the years including a broken crank, diagnosed as a noisy tappet by a "mechanic".

Use a long screwdriver carefully to try to locate it or stethoscope.

Take it to a well knowledgeable mechanic or several, they will have heard the same noise over the years.
There will be other possibilities but best not to drive it too much until you have it diagnosed.

Cheers Endoman,
I work in a garage, so I,m kind off used to engine noises, its the oil pressure thing that has me concerned most, driving at 2,5k, the o/p is splendid, on tickover its about 2.5/3, so I don't think big ends, there isn't any miss-fire, it drives fine, just twice now the start up issue. . . . . . .bugger !

Dave, have a look at your oil pressure relief valve if it's the old type it might need replacing, also double check your crank pulley bolt as it's just the surface to surface grip that drives the oil pump.

Just out of interest what 10/40 did you use, my car went very tappetey with shell helix in after a about 2k miles, changed it to comma XT2000 now all noise gone.

Cracked oil pick up bringing air in? Sticky OPRV? Dodgy gauge although the noises seem to indicate that isn't the case.

Well, started the car this morning, and oil pressure was there straight away, still a strange noise tho, so that's what I,m gonna have to investigate, The oil pick up, I would have thought it would be doing it all the time if it was cracked, but that's just me, I,m sure there is someone out there who no's better than me !.
OPR,V, is that a common problem ? and are they a bugger to change. . . . .,
thanx for the reply's
Dave

P.S. As for the oil, I use CarLube R, 10/40 semi synthetic, used it for years on other stuff and never had any bother. . . but again, I could be wrong !

OPRV is easy to get at, OS front wheel arch look past the ARB mount and you should see a big flange with a small head, I have read that the old type (two Part) can make a tapping noise or sometimes a squeal when they need a refurb/replace, but they are not cheap.

£282.00 last time I looked

this might help

http://members.rennlist.com/tom86951/oi ... l_repl.htm

Thanx Waylander, so if I remove it, how will I no if its at fault, ? is the rebuild kit available from Porsche only, is there an up-rated version. . . ?. Got to check all avenues before I go stripping the thing . .!,
thanx again,
Dave

Don't think they are practical to rebuild, I just fitted new O rings to mine and cleaned it out, seems to be fine so far

There is no kit as far as I know, the only one available it the one piece variety from opc

I had the same noise on mine after it was laid up for a bit, these cars hate being laid up, I think I also have a top end hydraulic tappet noise, as I rev it, but it goes away when warm, I keep meaning to get someone to have a look at it for me as its beyond my level of mechanical skills. hope you find a cause soon though & please share what you find it to be, it will help me & others, cheers, Tony

Only the up-rated version is available.

If the pickup is cracked it can be diagnosed by over-filling with oil. Get enough it an oil pressure will be restored.

Hi
Can someone advise me where to buy the original and oil seal for my oil pressure relief valve in the UK. It's the latest version valve in my 944 S2.

Your local Porsche centre, not far short of £300 for a new pressure relief valve

Sorry my post never typed right....it's the 2 O rings I'm after

same for the O rings few pence each