924Board.org

paulh · Joined: 14 Sep 2006 Posts: 38

Hi My 924 NA 1981 refuses to start, it was overheating when I last ran her, and I'm not sure what to expect. There was also a kind of "ticking" noise under hard acceleration.

heads?
valves?

any ideas ?

Paul

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Mont Macedon Victoria Australia
1981 942 NA was brown now red- soon to be an Electric Porsche

Scorpio · Posted: Fri Oct 10, 2008 5:09 pm Post subject:

Paul..throw your question over to general discussions

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1979 NA
MS1..EFI..
GARRETT T25 TURBO
BILSTEIN SHOCKS
GT BASED CUSTOM BODYKIT

Brisbane , Australia
Think mean think fast
all youll see is
my Porsches Arse!!!

paulh · Joined: 14 Sep 2006 Posts: 38

I thought I had,

thanks though

Paul
_________________
Mont Macedon Victoria Australia
1981 942 NA was brown now red- soon to be an Electric Porsche

Ozzie · Posted: Fri Oct 10, 2008 11:38 pm Post subject:

Is the fuel pump running and are you getting fuel at the injectors?

Are you getting spark?

If yes to both then it could be timing belt has slipped and ign and valve timing is up the creek.

A compression test will tell if the head, rings or valves are shot
_________________
Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance

paulh · Joined: 14 Sep 2006 Posts: 38

yep, got fuel got spark.

Timing belt slipping sounds good, that should also produce a lack of compressions to won't it/
_________________
Mont Macedon Victoria Australia
1981 942 NA was brown now red- soon to be an Electric Porsche

Ozzie · Posted: Sat Oct 11, 2008 7:27 am Post subject:

If the belt has slipped then the valves can be open when they are meant to be closed and cause lack of compression, backfiring and no start.
_________________
Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance

paulh · Joined: 14 Sep 2006 Posts: 38

Ok, I've done a real work over and go it started, checked the belt timing Ok.

Only front 2 cylinders running, as in the car will start with plug leads to back 2 cylinders un-plugged and not make a real difference when plugged in.

Runs rough and has a lot a "clatter" in the sound

injectors Ok.. tested by un plugging and spraying into a jar, swapping them doesn't really change things.

So why running on 2 cylinders?

burnt valves?
tappet adjustment right out?

Another strange thing is a "grinding" sound that seems to come from the "fuel distributor" don't really know what it is....

Thanks for help so far .

Paul
_________________
Mont Macedon Victoria Australia
1981 942 NA was brown now red- soon to be an Electric Porsche

Ozzie · Posted: Sat Oct 11, 2008 8:17 pm Post subject:

leads are stuffed?
_________________
Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance

Martijnus · Joined: 29 Dec 2006 Posts: 2019 Location: Netherlands

I'd go for a compression test.

Overheating can be killer

_________________
"Rule: Turbo's make torque, and torque makes fun." (C. Bell)

924 "50-jahre", 1981.
MSII/extra, LPG, ITB's, 5lug.
To be turbo'ed in a while.
Killed her at the Nurburgring, Porscheless at the moment

Ozzie · Posted: Sun Oct 12, 2008 7:39 am Post subject:

I think I mentioned compression check.
Tool is cheap and determines real quick if the motor is fubar.
_________________
Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance

968rz · Joined: 21 Aug 2006 Posts: 537 Location: S. E. Wisconsin

+1 on the comp test, also verify that the HG didn't bolw. Look for milk shake in the oil, if you can get a cooling system pressure tester; pump it up to about 12lbs and leave it sit till morning then check for coolant in the cylinders.
_________________
Rick
79 924 coupe Petrol Blue 3spd auto (wife's DD)
93 968 coupe Amazon Green 4spd Tip (my DD)

paulh · Joined: 14 Sep 2006 Posts: 38

Thanks Guys... am picking up compression tester tomorrow.

will let you know.

Paul
_________________
Mont Macedon Victoria Australia
1981 942 NA was brown now red- soon to be an Electric Porsche

paulh · Joined: 14 Sep 2006 Posts: 38

yes, I can confirm that I have lost the fight and the headgasket is gone, starting it pushed the water into the oil eeeeeeek

any handy hints to replacement?

thanks for you help thus far.

Paul
_________________
Mont Macedon Victoria Australia
1981 942 NA was brown now red- soon to be an Electric Porsche

924RACR · Posted: Fri Oct 17, 2008 10:11 pm Post subject:

Well, good news is it's a relatively simple job.

Consider having the valves done while you have it off; plan to clean everything thoroughly.
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Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

paulh · Joined: 14 Sep 2006 Posts: 38

Convert the Porsche to run on batteries....

I guess it's now a bit more work than the just the head, and a gasket....I'm getting help.

My drive train engineer brother in law has said it's do-able. We are currently preparing to do the job then we will release the detailed plans. Circuit diagrams and any software developed.

I am setting up a website to blog about progress here it is Electric Porsche

At the moment we are wanting to make it really perform as opposed to being a practical daily car.

If any one has any advice for us please let me know. I'm guessing that I'II be in regular contact with lot's of questions. So I'd like to thank in advance anyone who does helps.
electricsports.org Electric Porsche plans
_________________
Mont Macedon Victoria Australia
1981 942 NA was brown now red- soon to be an Electric Porsche