Porsche 924 white

[mat_the_cat]

Although the thought of tackling the head gasket frightens the life out of me (I'd honestly only ever changed a wheel on a car before I joined here 18 months ago)

 

And I've learned loads already about what all this engine stuff is and what it does. And that's what I really get out of doing it, more than saving money. I read loads on here about what you chaps and lady chap do, and I have no idea how to do most of it, but I suppose you all started by giving a go at some point.

 

 

Nobody's born with the knowledge, we all started somewhere. But fair play to you, usually the leaning curve isn't quite as steep!

 

With the sheered bolts, it may help to give the head a sharp tap with a hammer before/during loosening, and/or working it backwards and forwards rather than simply pulling on it to loosen. But sometimes it's just unavoidable

[Parky]

Stick with it, there is so much advice and support on here, WCPGW?

[billyboy406v6]

All credit to you for tackling this job, when she is purring along you will have the satisfaction knowing you did this ! Another tip is to take loads of photographs as you go to remind you what goes where. Good luck, Bill.

[Jim Bell]

Kick its ass Seabass!

[Rusty_Rocket]

Here is one top tip .

 

Make sure the holes where the headbolts are blown out with an airline before you put the head on .

 

Excellent advise.  I would also recommend turning the engine over by hand after fitting and tensioning the timing belt 'just in case'.  As long as you take your time, ensure both the head and block faces are spotlessly clean and make sure the head is torqued correctly, you'll be fine!

[dome]

It's not an easy job but it will be satisfying. Take photos before you start and as you go along. And be prepared for snapped bolts. Oh and drink plenty of tea and eat biscuits-I'm bad for pushing on when I'm getting tired and that's when the silly mistakes happen.

[Dave_Q]

Best of luck with it, although I think you'll be fine.

 

Yes it looks complicated but it's just nuts and bolts, albeit quite a lot of them.

 

My top tip is to get an assistant to help you lift the head on and off, they're b'starding heavy and I bent some valves on a BMW one once putting it back on single handed.

[Danblez]

Fantastic! Great to see you getting stuck in. Keep the faith it WILL all go back together eventually! It's surprising what kind of fits back together naturally when you start reassembling.

[twosmoke300]

Dome has the right idea for a DIY like this . Accept it's gonna take a while . If you come across snags , walk away and have a cuppa. Many problems you have will just disappear when you come back refreshed . Also accept that you will make a few mistakes and don't get too down about it . Don't be afraid to ask on here either .

[beko1987]

When I do hoovers I put each screw through some card a d label it. Could help you here!

 

Then, when reassembling it, all I have to do is work from the bottom of the screw card up. You may need more than the side of a cornflake packet though for a whole porche head!

 

You'll be fine

[ERBS]

at least when you replace the headgasket, you will know that won't fail for a long time. worth keeping the car once this done

[inconsistant]

I spent another 2 hours on this on Saturday morning...

 

A bit of bother getting the inlet manifold off due to a cheeky hidden bolt, but got there in the end:

 

 

Then stuffed orifices with clean rags:

 

 

Supported the exhaust with a perfectly sized ammo box while I slipped under the car and undid the exhaust downpipe/manifold joint, having doused with lots of plusgas an hour or so beforehand.

 

 

General opinion is that you don't undo these, you sheer them off and then deal with it off the car.

 

 

 

I managed to undo all four without any sheering, so I briefly felt like god of spanners. Then the rocker cover came off:

 

 

And I tried to get the cam caps off but couldn't work out how to get them off. I gave up at this point, did a bit of reading up and found out that I didn't need to take them off, so went back out and tightened them back up (to be re torqued later):

 

 

and put a clean sheet over the oily bits to keep it clean:

 

 

Then went out and played with 1:32 scale scalextric cars, which was much more fun:

 

[stripped fred]

Good work there. Breaking it up into manageable bits is the way to go.

[inconsistant]

Thanks Fred, you're right... we laid the straights first, then the bends, and then put the borders on and connected up the mains power. Had it running in no time. lolz

[The Reverend Bluejeans]

Sods the toys, the head's nearly off! Start with the outer head bolts and work your way inwards in a diagonal pattern. It's 2.20 now - the head could be at the machine shop in a couple of hours. You will have to remove the cam btw - with it fitted there will be valves open, making it impossible to skim the head. Mark the caps for correct positioning and location, slacken them a few turns at a time in a diagonal fashion so the cam is released evenly and refit the caps exactly as they came off. The machine shop should also chemically clean the head as well. Also, remove the valve buckets (tappets), making very sure you mark them so that they go back in the same location - not sure if these are hydraulic (probably not) and if not, they will be shimmed.

[stripped fred]

Thanks Fred, you're right... we laid the straights first, then the bends, and then put the borders on and collected up the mains power. Had it running in no time. lolz

Had to read that a few times to work it out! Yes, those scalextric tracks can be tricky...

[garethj]

Chuffin' hell, that Scalextric track is massive!  Perhaps you need to borrow a few of my cars?

 

Good work on the Porsche, stick at it!

[inconsistant]

Chuffin' hell, that Scalextric track is massive!  Perhaps you need to borrow a few of my cars?

 

Come along to the next one and bring a few of them!

[inconsistant]

Back to work, the final push to get this head off.

 

I got the lower wire off the oil pressure sender. It's nestling tightly between the back of the head and the firewall. I gave up a couple of times thinking it was impossible before realising that I could get just my left hand around and under the block to reach it from underneath and catch the nut as I undid it with my right hand.

 

 

Then onto head bolts. I had a handy undoing pattern from Haynes book

 

 

Bloody Hell! These are properly tight. I couldn't get myself into a position/angle to apply appropriate purchase, and after climbing onto the car and kneeling on the inner wing and pulling as hard as I dared I almost gave up, afraid that I'd either sheer them, break the tool or the tool would come off the bolt and end up through the windscreen or similar. I had a rummage around the shed and found a bit of scaffold bar to make a longer handle and that finally loosened them. Mega purchase required.

 

 

Then came the really frustrating bit, that took me at least an hour. With the head bolts out the head moved freely across the block, so I knew it was lose, but I couldn't lift it off as it was stuck onto the exhaust manifold. I gave it a wiggle, tried moving it in all directions and angles to try to free it, which is difficult when the block wants to slide towards you all the time. I wedged a block of timber between the head and the inner arch and got another bit of scaffold bar which I rested on the top lip of the downpipe and got a bfo hammer and gave it many whacks to try to free it from the manifold.

 

 

No joy, stuck fast. I got under the car and moved the ammo box to allow the exhaust to fall away a bit, thinking that it was wedged into position too well. Still no joy. I checked the 3 nuts and 1 bolt I'd removed just in case I had actually sheered the end off the bolt, which I thought might have still been holding the pipe and manifold together, but the bolt was complete.

I tried all sorts, plusgas, wedging a flat screwdriver into the gap via the wheelarch, and all failed. Then, for some reason I was feeling the joint from the top and felt a nut on the underside, and it dawned on me. There was a 5th fixing that I'd missed.
From underneath I could only see 4 fixings, as photographed previously... 2 on the block side and 2 on the wheelarch side. The 2 on the wheelarch side that I could see from the top I thought were the same 2 but from underneath I was seeing the bottom 2 of 3, and from the top I was seeing the top 2 of 3. (hope that makes sense?).

So... the lesson I learned today is that there are 5 fixings. 4 nuts and 1 bolt holding the downpipe to the exhaust manifold.

 

 

With that nut removed (came out easily in seconds!) the head came free and lifted out with relative ease.

 

 

...and I got my first look at my arch nemesis, the head gasket. I was probably more excited than I should have been, but it was brilliant having got to the bottom of something. A bit like solving a mystery:

 

 

 

And the underside of the head:

 

 

 

I'm no expert, but I'd say it's fairly obvious which of the cylinders is causing the problem!

 

 

 

 

 

 

The head gasket:

 

 

 

 

 

Close up of that end (some of the damage possibly caused when trying to move head from block?):

 

 

 

Pistons/block:

 

 

 

Hurrah I did it! About 8 hours so far I reckon. 2 sheered bolts, only light scratches to myself. 

 

 

[Pillock]

Well done, I award you with an Autoshite Star rating of 3 spanners (one of which is an imperial that's close enough to metric to be ok, and another that has got a bend in it to do a fiddly job ages ago)

[inconsistant]

I award you with an Autoshite Star rating of 3 spanners

 

 

Can it be these three?

[twosmoke300]

Ex bt?

[xtriple]

Bloody good job you are doing there. It's always easier putting it back together so the hard part is done.

[billyboy406v6]

Great progress, respect for problem solving. Congratulations on the 3 spanners award !!

[Jim Bell]

You are a man. Three Crudely Drawn Cock award.

[Danblez]

Superb well done. Go and treat yourself to a breaker bar before your break that ratchet!

[Parky]

Get that baby skimmed and decoked, lovely new belts and water pump and sit back and enjoy years of fun!

 

Not to mention boasting rights at the water cooler "yeah, head gasket went but I fixed it myself, etc"

 

Head rebuilds are cool, my favourite thing

[dome]

Well done. Now get that cam off and get the head tested and maybe skimmed-it'll cost about £50-£100 tops and you'll know it's good to go back on. You don't want to do this again...

 

Worth also seeing what else you can do when it's this far stripped down-access to a lot of parts will be a lot easier with no head in the way. Vacuum pipes and the like are worth checking and replacing.

[inconsistant]

"Blimey, a month without an update, what's bin happening then?" ...I imagine you all asking excitedly. Well, I'm glad you asked because I'm going to update this thread with exactly that info.

 

Recap: got head off, and got my Autoshite Bronze badge for spannering.

 

With the head in the shed I took the last few bits and bobs off, coolant temp sender housing:

 

 

 

and distributor housing thingy.

 

 

Exhaust manifold next, lots of plusgas yesterday and more this evening meant all 8 bolts/nuts came off fairly easily.

 

 

 

Then I had a go at cleaning up the surface of the head:

 

 

HERON HEAD FTW!!!

 

After cleaning the head up a bit I took the head to the engineering place yesterday so he could take a look at it. There’s some pitting where the gasket failed, so he’s going to skim 10 thou, and if that doesn’t get rid of it he’ll build it up with weld then give it another 10thou skim.

 

 

He’s going to sort the two sheered bolts for me, and give the head/valves a clean up and decoke. I’m trying to remember what he said, so I might have got this wrong. We discussed replacing the (inlet?) valves, but he’s going to get it all apart and see what they looked like first. He took the rocker cover off and had a look in there. We noticed there was some wear marks on the pointy edge of a couple of the cams, especially no3 cylinder, which also had a slight flat spot too.

 

 

With a torch we could see that the same cylinder also had wear on the top surface of the ‘bucket’(?) which had gone through the case hardening. Couldn't get a photo of that unfortunately, it was too dark/close up.

 

So it’s looking like:
Skim
Decoke
2x sheered bolts sorted
New camshaft
New bucket

 

On further inspection I was told I'll need 6 or 7 followers as they're showing signs of wear, a replacement cam and all 4 exhaust valves and an exhaust valve guide. With all that and labour it's looking a bit pricey, and I'm not talking about Katie.
The head bloke is also struggling to locate these parts. It's getting more, not less tricky. I though taking it off would be the difficult part. Cams are NLA, so will need a good 2nd hand one. Followers also NLA. 

 

-----

After posting this info on the 924OC someone came to my rescue, he's stripping a low miles (70,000m) 924 and said that if I took the head off I could have it for super cheap.  So I will have another head with a good cam and followers, and the head man is going to check for flatness and give it a skim because I don't want to just assume the best and bung it on, especially if I'm being cautious. Which I am.

 

-----

 

Last weekend I spotted a pair of ramps on ebay at £10 that had just finished with no bids. I contacted the seller who lived a couple of miles away, and arranged to pop over to collect them. You know that feeling when you can't remember the house number, but you're on the right road, and you see this:
 

 

...and you think 'that must be the house'. And then on the drive you see this:

 

 

...and you know it's the place. Anyway, really nice bloke, owned and restored several interesting cars over the years. He was interested in the 924, wanted me to pop over with it when I'd got it running again so he could have a look. We chatted for ages about cars and mechanical stuff. It was great seeing the chassis on the drive, we had a good look over it and I could begin to understand what all the various bits were on it, based on what I'd found out by taking the head off mine. Anyone want to guess what this is? (Slightly misleading clue: 2 litres and 7 gears.)

 

----------

 

I went to get the head that I'd been offered. Here it is in it's natural environment:

 

 

A good dose of 924 knowledge and experience, a few short cuts and a couple of 'alternative methods' and I was shown how to get a head off in an hour and a half tops, including a cuppa and (lots of) time spent hunting for tools.

 

 

 

 

Check the lobes on that baby:

 

 

 

And it's off:

 

 

I couldn't get the exhaust manifold off so took it over the the head bloke as is... hopefully a check, skim etc and then pop this one on mine. Otherwise he will make up a good head from the best of the two. Either way at least a step in the right direction.

 

--------

 

While I was waiting to get the head back I took the exhaust manifold and heat shield into work to sandblast. 

 

 

 

 

 

 

 

I've got some Frost paint on the way so hoping to get them painted in the next couple of days ready for reassembly.

 

http://www.frost.co.uk/vht-very-high-temperature-flame-proof-paints-11oz-312g.html

 

----------

 

Head collected on Friday, and it all looks good. It's the head off of the other car, with only a couple of valves swapped over from mine which were better. It came to £200, which included sorting the sheered bolts and some other work he's done to mine before I got the other head. Seemed reasonable to me.

 

 

 

 

 

And I got a container of bits back too:

 

 

http://en.wikipedia.org/wiki/Heron_cylinder_head

 

 

Pix of the pitted followers from my head:

 

 

 

 

And the pitted cam lobes:

 

 

 

 

I'm spending the evenings this week cleaning everything up, and hopefully the weather will be sympathetic this weekend as I'll start putting everything back on the car then. Wish me luck!

[alf892]

Looking forward to seeing that up and running!

 

Good to see you found a decent engineering shop too.........good advice is not always easy to come by.