924Board.org

[chrisbwy]

Hi All,

Can anybody help with advice on how to unseize a 924S engine?

It's been stood idle for about 7 years.

I've poured penetrating oil down all 4 bores ( through the spark plug holes ) but number 3 cylinder is still full of oil!

Tried rocking the crankshaft with long bar and socket on the pully nut but to no avail.

Thought I'd ask the experts before taking the head off - which I'd like to avoid if at all possible.

Look forward to any sensible comments.

Chris

[Porver9two4]

If it is seized as bad as that, then likely you will end up having to take it apart.... before you do that, you could try towing it in gear (leave the plugs out) which might crack it off - bear in mind that this is the sort of tactic to use when the motor is gonna be a cheap useable thrash - dont expect it to be a 'factory' repair!! Before you do try, do you know why it has seized? Is it definately from sitting, or was there a mechanical failure that led to the seizing in the first place..... you definately wanna be sure you know the engine will turn before you start trying to break it free.
As far as what it does once cracked off, if it runs OK and holds decent compression it will probably be OK as long as it hasnt knackered the piston rings, as the rings will shine off the bore quite quickly, likely leaving a little pitting (may use a litttle extra oil).
As for towing it, a nice high gear to give plenty of torque and be prepared to watch for the clutch to slip - keep changing down until it either locks the rear wheels or cracks off the engine - if it locks the wheels you can't do much more than try to increase grip (more weight, lower pressure etc.) or bounce the back end while towing - if it still wont crack off, you will have to strip it. I will add that i have used this method a number of times to free or attempt to free seized motors etc. without damage to driveline (just tyres and clutch!!), but as always - do your own research first!! (also make sure you check that you dont have seized ancilliaries giving the symptoms of a seized engine first i.e. distributor, alternator, water pump etc.

[Paul]

It's doing you a favor, had it cranked over it may have very well snapped your timing belt and bent your valves.

Check the condition of the belts before going any further.

Spray some PB Blaster into the bores, let sit a few hours, repeat a couple of times.

Then I usually take one of the hoses that's in my compression tester kit (just happens to also snap right onto my air compressor hose) and try pumping 130 PSI of air into any cylinder that has it's valves closed.

That said, I've had blocks (in a stand with the head off) that the pistons were so firmly seized that a hammer and block of wood would not break them loose.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

[chrisbwy]

Thanks Guys for the suggestions.

The engine is definitely seized due to having been stood for 7 years or so.

Prior to that all the belts were replaced.

Domestic reasons mean't that access was denied to the car!!!!! Hence it standing untouched for such a long time.

Some attempt by towing has been made to free it ( to no avail ) but I was concerned over the possible damage to the cylinder bore liners which I understand to be "special" on this "S" variant of the engine.

Is there anything else better/stronger than penetraiting oil I can put down the bores that won't affect the liners?

Paul mentions "PB Blaster". I don't know what that is?

Any more comments?

Thanks

Chris

[gohim]

Towing could damage the ribber clutch disc center if the engine does not break free. If the belts are over seven years old, they are way past the replacement period, regardless of how few miles are on them.

Since you already tried the towing routine, and it failed, I suspect that what you need to do is pull the engine and break it down.

[Llamaguy]

PB Blaster is another rust remover, they sell it at walmart for a couple bucks.
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1987 924S Guards Red
1997 Suzuki Tl1000 Supersport