Head gasket replacement

[Novamonte]

Hi,
I had my car to the shop some time agp to fix a damaged spark plug thread. All that went well as such, but apparently they drained some coolant and took the WRD away to get access, which resulted in an air lock and an overheated engine. I have refilled the system and gotten rid of the air, but unfortunately the head gasket now leaks a bit and needs replacement (white smoke and coolant slowly disappears). I consider doing that myself over tthe winter, but have never done that on this engine before (only on cars with the camshaft in the block), so I am seeking as much information as I can get before starting the job (and can only hope that the head isn't warped).

The Haynes manual describes a procedure where the head is removed with the camshaft in place and the intake and exhaust manifold still attached. From various posts on this forum I however understand that the procedure used by most people includes removal of camshaft, rockers and manifolds. As this would make the work more complex it is of course tempting to follow the Haynes procedure, but I would really appreciate comments from more experienced members on the forum.

Best regards,
Clas

[garymand]

The cam stays on.  The rockers stay on.  keep the engine on TDC  0 .  You need to keep the timing chain retained.  The manifolds will have to come off.  For me, the timing chain is the tricky part.  you should bring the motor up to TDC and see how far behind the cam is.  At 100K miles, I would change out the chain and cam gear.  Which motor, miles?  Valve guides and seals?

[ctaylor738]

I recommend that you get a hook-type valve spring compressor.  Remove the rocker arms and bring the engine up to TDC.  Then proceed to remove the cam gear. 

I suggest removing the intake and exhaust manifolds unless you have a hoist because the assembly is very heavy and awkward.  The bolts and nuts that attach the exhaust manifolds to the downpipes are much easier to access with the intake removed.

Hint.  Have three 12mm box end wrenches available.  Place them on the three nuts on the top ends of the manifold-downpipe bolts.  Then you can go under the car with a 13 mm socket and a long extension and take off all the bolts on one of the manifolds at one time.

[ja17]

I like to leave the exhaust manifolds and the down pipes alone. Simply jack up the exhaust a bit from below, and slide the cylinder head off the manifold. Yes, always remove the intake manifold as one of the first procedures.

Same procedure in reverse for the installation with only the camshaft on the head. After the head is torqued down and the cam is checked for ease of rotation, I attach the timing chain in sync and the install the rocker arms one at a time while I adjust the valves.

The cylinder head should be re-torqued after first warm up and again at around 500 miles. Re-adjust the valves at 500 miles also.

[220sebCoupe]

Just going through some old posts to get some further technical tip-bits

This an old post, so apologies for not starting a new one.

JA17 can you answer a query on your comment about re-torque after first warm up - after the initial tighten down of the head, do you adjust valves while still cold (or would there not be a need if the valve clearances were ok before removal) and then warm up the car at idle without the radiator cap on so there is no pressure in the cylinder head, and no doubt air pockets escaping all over the place. Then, as soon as the head is at operating temperature, shut it down and re-torque the head while its still hot. then next day when cold again, adjust the valve clearances, and drive away for 500 miles before re-torquing again?? The re-torque at 500 miles being when the engine is hot again?? that is

1. 3 stage tighten when cold (40, 60 and 80 nm)
2. warm up at idle to operating temp with no radiator cap, loosen off the head bolts, one at a time, and retighten to maximum (90nm in my case)
3. adjust valve clearances and drive for 500 trouble-free (ha ha!!) miles
4. warm up at idle to operating temp with no radiator cap again, loosen off the head bolts, one at a time, and retighten to maximum (90nm in my case)

I'm certain I did something wrong last time I did this procedure and want to be absolutely sure this time around - assuming I haven't managed to break something else along the way.

Also, to copper spray or not to copper spray, I had advice previously that new gasket, this is an Elring brand, have an inbuilt sealer that performs something similar to the permatex spray, is this true?? would you do the permatex anyway and can it simply go over the whole gasket or are there areas on the gasket that shouldn't be sprayed?

Thanks in advance

Justin