924Board.org

[turbonic]

Rite then turbo bods, I have been running a '79 turbo for about a month and have dicovered the following probs!!

- Speedo "wobble" at low speed - becomes steady at about 40MPH - ODO meter/trip meter does not work either.

- Boost Gauge registers 4Bar max on boost when warm - and about 6Bar when cold. - I'm thinking seals or manifold/head leak??? (can smell exhaust fumes with window open at speed????

- Occasional starting problem - from cold - fires up on two/three cylinders even after replacing dizzy cap and leads. Performance seems a little down as well.

Also I'm not sure about the tappet noise coming from the engine - I have checked the clearances but it seems a bit noisy.


Any help would be greatfully accepted - need opinions/advice before I take anything apart.

Cheers

[924RACR]

The speedo wobble is common; usually cured by replacing the speedo cable. Can be improved a bit by lubricating the cable; best to just ignore

That's not your boost gauge! That's your oil pressure gauge You're only running 10lbs boost stock (.8bar), as I recall; that oil pressure sounds fine.

The exhaust fumes are a common problem; replace the seal on the hatch to fix.

My '82 starts like you describe, but clears out shortly. Haven't diagnosed the problem yet.

Cheers,


_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

[turbonic]

Great reply time, Warp factor twelve Mr Scott!!

Any ideas about getting the trip/milometer to work?? / plus buying and installing a TURBO!?!?! boost gauge.

Also is there a fix for the tappets ie turning the radio up / reducing the clearances??

Ta very much for the help!!

[cs]

you have to admit though that 6 bar of boost would be fun for the 6 milliseconds it would last. 85 pounds of boost, 8500 ft.lb. of torque.

[Vince Ponz]

Hard starting? The cheapest thing to do is change the grounds and there are about 4 or 5 of them. Real cheap about 10 US for all of them.
Next check the fuel pump then the accummulator and the check valve.

Yes I changed all of the above and now the car starts easily and cleanly. Total cost about $250. Accummulator cost about $100+.

Clean filter both air and fuel, plugs, give the engine a good cleaning and make sure the plug wires are not frayed and touching each other. Check hoses for leaks.

Lastly have someone with experience check the plate on the fuel distributor. Very carefully clean it. Be careful because it needs to be right on to work.

I hope this works.

[Vince Ponz]

Forgot the speedo. The gear broke or is off at the rear of the speedo. You can remove and replace or try to glue it. Someone else asked the same question so look for the post and fix the problem. You may have to look for a used working speedo.

[kevrl]

Tappets - Well if you have adjusted the clearances and it still makes a noise, check the oil feed tube that lubricates the camshaft, at the end of it there is a plastic elbow and it cracks and leaks. It costs about £1 from porscheshop.co.uk. Also consider that the Camshaft itself may need replacing (about £99 from eurocarparts.co.uk)

Boost guage - Remove the clock and replace it with a VDO (or similar) guage. Get one with a range of about 1 - 1.5 bar so that you can actually see the needle move when on boost. These are easy to fit, but you'll need to run an air line in to the engine bay.

Happy boosting !

Kevin
(Euro 931 - Intercooling project underway)

[turbonic]

Dudes!!
Cheers for the info - shall get rite onit and start adjusting/tampering/fixing/breaking.
Another take on the old engine noise front - the under-bonnet sound-deadening is perished and is flaking away (the sponge stuff stuck to the underside) - is there a replacement material that may be used??

Cheers Again,




Ta v much for the help

[Rick MacLaren]

Read my description of the circumstances leading up to my 931 blowing up. They sound very similar to what's happening to yours.

[larso]

Make sure you are getting the right clearances for the tappets, a previous owner or mechanic could have been following the haynes.

[turbonic]

Hey - What - the clearances in haynes are wrong???????????? - I realsie that most of the rest of the manual bears only a passing resemblence to stuff on the car but surely not the clearances??

I've recently done the clearances using the haynes manual - Are you serious - what should they be??

Very worried now!!

[larso]

YES, also there are torque specs, wiring diagrams, and instructions that are wrong. SUCH as: Jack the car up to reset the OXS counter/light. You don't need to do that, you just stick your hand in and push the button.

The valve clearances should be listed under your hood on the driver side close to the headlight. In the haynes they are off by 1 decimal! for example: intake valves 0.04-0.06 inches, wrong. Should be 0.004-0.006 .

Lars

[Rick MacLaren]

Ok, supposing someone actually used Haynes' specs, is it possible they could damage their engine doing so?

_________________
1980 Porsche 931 Bitched.
1979 Porsche 924 Tweaked.

[ This Message was edited by: Rick MacLaren on 2001-11-27 01:34 ]

[larso]

Yeah, well your cams will get all smackered up like a hoe, and if you go by their torque specs you will crack some oil line bolts with your torque wrench...

[John Mueller]

About 10 years ago that happened to me... Also now I know why my valves are noisy. Can we do a class action lawsuit????