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scotchw · Joined: 14 Aug 2005 Posts: 30 Location: Basingstoke, UK

Thanks for the feedback guys.

Good to know that the breather mayo is "normal" (the climate is always a bit damp over here in Blighty) - it does seem to be the turbo breather pipe that collects condensation (I see in other threads that a mod to take this into the head rather than the oil separator was available...)

I've only seen the steamy exhaust a couple of times in months of daily driving... so I could be waiting a while to pull a plug.

I'm driving with the exp tank cap released by half a turn (to avoid 'bloat'), & I can see bubbles coming into tank from rad breather pipe when I start up (& I can bleed air out of tstat bleed valve after every 30 mile highway journey...).

I will sort out a leak-down test (friend has a compressor, I have a compression test gauge/connector & hose) - car is running well so I think you're right: doubt that compression can be far out on any cylinder.

Lastly, reading the thread again I see that re-torquing head bolts is worth a try. I'll give this a go after I've found the suspect cylinder from a leak-down test. Car did have a professional head rebuild with previous owner (but he did very few miles in the car after that). Here's hoping it could be that simple...
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'82MY 924 Turbo Euro RHD

Khal · Posted: Thu Oct 05, 2006 10:07 am Post subject:

Gregarious · Joined: 13 Sep 2003 Posts: 86 Location: Los Angeles

The latest on this car is that the number one cylinder had the rings go. I was staying at my brothers, and he refused to let me keep it there, or fix ut there, and I didn't have the cash. I had to junk it. And my mechanic, before the rings went, told me he thought it would bring 8k. Arrggh!

scotchw · Joined: 14 Aug 2005 Posts: 30 Location: Basingstoke, UK

Ouch - I hope my car isn't going that way

I'm hoping to do a leak down test & (assuming the worst) pop the head this weekend to examine my head gasket.

I've never had the head off, so given that I primarily want to change the head gasket (not rebuild the whole head), what do I need to strip off?

I'm assuming:

disconnect exhaust manifold from J-tube & turbo joints
remove pressure pipe/air box/fuel dizzy (disconnect injector lines @ dizzy or injectors?)
remove alternator & mount (for improved access)
disconnect inlet manifold (can you get to all the necessary nuts/bolts?)
remove cam cover & cambelt
slacken & remove head bolts
pull the head off

- then renew head gasket & rebuild (assuming head has no cracks or warping evident!)

Any tips appreciated...
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'82MY 924 Turbo Euro RHD

Khal · Posted: Sat Oct 07, 2006 3:19 am Post subject:

Well, yours is going to be the same as mine, so I''ll see how good my memory is;

scotchw · Joined: 14 Aug 2005 Posts: 30 Location: Basingstoke, UK

Thanks Khal - good memory!

You're right about poppin' the dizzy: there's the 2 coolant hoses off the temp sender housing @ back of head that need to come off, & I found it easiest to pop the dizzy to get in there (I replaced the heater feed hose).

If it weren't for the hoses I think you could leave the dizzy in place (as it's driven from within the head).

And I'll be catching my coolant (it's new from last weekend when I replaced the other hose that'll have to come off: w/pump->tstat housing hose).

Interesting that you popped the head with both exhaust AND inlet manifolds still attached. I thought it would be easier to leave the inlet manifold behind in engine bay (so not having to disconnect all those hoses & wires around the inlet manifold, WUR, AAV etc.) I'll see how it goes...

I'm hoping I can get all the head bolts out without popping the cam - but maybe that's why you ended up taking your cam out: maybe some of 'em bind on the cam on removal?

Here's the motor before I attack it!

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'82MY 924 Turbo Euro RHD

Khal · Posted: Sat Oct 07, 2006 11:15 am Post subject:

Paul · Posted: Sat Oct 07, 2006 1:24 pm Post subject:

Stock head bolt removal can be done without removing the cam.
_________________
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.

scotchw · Joined: 14 Aug 2005 Posts: 30 Location: Basingstoke, UK

Compression test gave: 175, 120, 135, 145 on cyls 1-4. Not too good... and old head bolts were torqued up correctly.

So I've pulled my head. It was hard work!

I had to cut my J-pipe 'cos the nuts were so corroded onto the wastegate that they rounded off in an instant (even with a good tight socket). The head wouldn't release until I'd removed the (now half-sized!) J-pipe.

I decided to remove the inlet manifold to save disconnecting so much wiring & hosing. I still had a lot to release before the inlet would slide off the head though, so it probably didn't save much time. But I would have struggled to lift the head with both manifolds on! It was heavy enough with just exhaust one!

Okay - I'm looking for some hints on what I should be checking before reassembly. Some pics below. Thread tip on no.2 spark plug showing some corrosion. Old head bolts (Allen key type, not splined - not what I thought would be there) had corrosion on a couple of them, so coolant was leaking around somehow. But head gasket hasn't blown out anywhere - does look pretty rough though (rust from coolant channels & 'bulging' gasket in these areas). I guess I won't see anything on the head until I clean it up? No obvious cracks visible at the moment.

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'82MY 924 Turbo Euro RHD

Paul · Posted: Mon Oct 09, 2006 9:52 am Post subject:

Please email me some higher resolution pictures....

While cleaning the head, make sure all the coolant passages in the head are not clogged.
_________________
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.

scotchw · Joined: 14 Aug 2005 Posts: 30 Location: Basingstoke, UK

Sure Paul - thanks for taking the time...

Which pics are you after? I'm only on dial-up at home

so it'll take ages to send you all of 'em.

Head coolant passages look pretty nasty considering I ran a chemical flush through the cooling system last weekend... so will need some clean-up.
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'82MY 924 Turbo Euro RHD

Paul · Posted: Mon Oct 09, 2006 10:10 am Post subject:

I've seen some really nasty crap flush out of 924 heads over the years...

I just wanted a closer look at both sides of the head gasket, the head and block, but as you've noted it's hard to see issues with the block and head until they are cleaned up.

So if you want to take the time, please email pictures of both sides of the head gasket.

So far I don't see any issues with the head gasket.
_________________
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.

scotchw · Joined: 14 Aug 2005 Posts: 30 Location: Basingstoke, UK

Okay - I think I've discovered the source of my problems.

While cleaning up the head it became apparent that it was heavily corroded around all the waterways. This had pushed the head gasket away & allowed 'seepage' of coolant through to cylinders (& probably to oil ways too).

Here's the head before, during & after clean-up:

Here's the top-side of the head gasket (still on block) - hi-res link:

The block (being cast iron) was pretty good - hence underside of head gasket wasn't too bad. But I think the trouble was occurring between the corroded head & the topside of the head gasket.

Do you think the cleaned up head will seal down okay onto new head gasket (with a bit of semi-setting (red) gasket sealant)? Or does it need to be machined?
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'82MY 924 Turbo Euro RHD

Paul · Posted: Wed Oct 11, 2006 9:36 am Post subject:

It needs to be machined.

I'm sure you will use the correct coolant once it's back together....
_________________
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.

Paul · Posted: Wed Oct 11, 2006 9:39 am Post subject:

Is that a crack between the head bolt hole and the coolant passage near 6 o'clock?

_________________
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.