Cylinder head

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Cylinder head

Post by adika » Tue Dec 03, 2019 7:57 pm

Hello everyone, I was changing my spark plugs and 2 snapped right in the engine. I tried using an extractor but it seems they are badly rusted in there. I believe my only other option is to remove the head and have the taken out somewhere, not really sure tho. Has someone removed the cylinder head and has posted clear instructions on how to do it? I will be changing gaskets and stuff while I'm there too. Any help would be appreciated.

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Re: Cylinder head

Post by PatinaBeforePolish » Thu Dec 05, 2019 4:48 pm

Always surprises on these somewhere around 40 year old cars. You can get carried away with the "while I'm in there" approach and may find a few more surprises. Hopefully it's not your only car...

Removing the cylinder head is pretty easy, just a matter of removing intake and exhaust components and keeping track of wiring connections and bolts and washers. I've read some accounts of leaving the manifolds on but for me, the head's heavy enough by itself. I suggest taking pictures and drawing diagrams. First step is to drain the coolant from the block. The 19mm (I think) plug is at the rear of the engine underneath the exhaust manifold. I'd drain the engine oil as well. It's tempting to remove the hood for easier access, but they're a real PITA to reinstall.

The upper timing chain cover needs to come off, removing the distributor first. The upper timing cover is secured in both a horizontal and vertical plane. The 2 vertical 10 mm bolts sit between web castings in the cover. That area needs to be free of gunk and dirt in order to fit a wrench or socket. The one on the passenger side can be tough, I recommend a thin wall socket and a shorty ratchet or a short 10 mm wrench as longer wrenches will hit the radiator. The bottom of the upper timing cover gasket is part of the head gasket and replace the gaskets on each side of the cover. There's a correct tightening sequence for the cover reinstallation but I'll need to reference the manual. Someone else know?

The timing chain tensioner at the top passenger side of the lower timing case needs to be removed. It's spring loaded and will pop out in an oily mess. Once the upper timing case is off, you can remove the cam sprocket by removing the 4 bolts. There are 2 securing plates, 1 for 2 bolts, that likely have tabs bent around the bolts as a safety fastener. The plates are NLA and I'd love to know if anyone has found a substitute. Otherwise be careful as you'll need to reuse them, just make sure to bend the other side.

In addition to fixing the head, while you're in there you could: Send the injectors out for a cleaning, new injector hoses and gaskets, new gaskets for intake and exhaust, new water pump, thermostat, motor mounts, water hoses and clamps and I'm sure I missed a few things. All this because the damned sparks plugs corroded in the head! I'm not sure if the head bolts are stretch bolts and cannot be reused but I'd order new ones with washers anyway. With the head off, position cylinder 1 at top dead center and make sure cylinder 1 on the head is set to compression (both valves closed) before you reinstall. I'm interested to hear other opinions about replacing the timing chain while you're in there. That involves removing the crank pulley to remove the lower timing case.

An experienced tech could do this job in a few hours if they were using a new head - it would probably take me a month of Sundays. I'm sure others here have more tips, tricks and corrections to this post to make the job as painless as possible. Search engines and youtube are your friends.
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Re: Cylinder head

Post by maybeillbuyit » Fri Dec 06, 2019 4:20 pm

Excellent write up there Jon. I would add that as far as I know the headbolts are not stretch bolts or "torque to yield" and can be used again. I used mine again without any problems but if your fussy you can buy new ones. From what I've read most guys do the timing chain while in there . I didn't on my beat old e24 as I didn't really know what kind of shape the engine was in. I would on a nicer car though. Its easy to keep adding stuff. You could raise the engine and remove the oil pan and rebuild the oil pump while in there as well. Especially if the pan is leaking like most.
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Re: Cylinder head

Post by adika » Wed Dec 11, 2019 7:51 pm

Thanks for the info. Yeah I will be replacing a lot of that stuff while everything is disassembled. Do you guys know in what order I need to remove the head bolts? I want to avoid warping the head. Thanks again.

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