changing cylinder head gasket...
- Thread starter madonmac
- Start date
Join the relevant club and get the factory workshop manual. Like most pushrod engines it's pretty simple, all you need do is follow the set procedures to torque the head and return everything you remove to the right place. In fact engines don't get any simpler except for the complications due to steel bolts into aluminium. The skill comes in inspection and determining why the head gasket has failed. Tin gaskets are really robust and don't often simply just give up. You'll likely want to get the heads tested for cracks and for warping as well as a thorough visual inspection. Do your best also to check the linearity of the block too as well as cracks around waterways and pistons. Cleanliness and flatness is super essential with aluminium and the faxt tin gaskets have less "give" than other materials. If you are running 10.5:1, you could use a composite gasket which'll drop the CR to 9.9 or so - might help you if you want to run 95 unleaded. Best to sort the root problem though as tin should be fine.
One thing you might want to do if any work has been done before is check the lifter preload has been done correctly on reassembly. That procedure has been covered on this forum before. Depending on the mileage since last overhaul, while you have it apart you might want to replace the timing gear and even the cam, these are super, super cheap but removing the timing case can be a PITA (while this is off swap the rope seal for the modern, nitrile type!). It's a false economy not to do this unless you are 100% sure it was done very recently. Standard Rover timing gear starts to wear very quickly. Certainly it's best performance is finished within 50k. I didn't trust refitting the head bolts either and fitted new, not sure what others feel about this. I'm not that experienced, I erred on super cautious. I also had a friend who knows US engines very well. A case of beer might be a good investment...
One thing you might want to do if any work has been done before is check the lifter preload has been done correctly on reassembly. That procedure has been covered on this forum before. Depending on the mileage since last overhaul, while you have it apart you might want to replace the timing gear and even the cam, these are super, super cheap but removing the timing case can be a PITA (while this is off swap the rope seal for the modern, nitrile type!). It's a false economy not to do this unless you are 100% sure it was done very recently. Standard Rover timing gear starts to wear very quickly. Certainly it's best performance is finished within 50k. I didn't trust refitting the head bolts either and fitted new, not sure what others feel about this. I'm not that experienced, I erred on super cautious. I also had a friend who knows US engines very well. A case of beer might be a good investment...
mrtask
Well-Known Member
I'll just second what PeterZRH said. I did the job once with tin gaskets and re-using the cylinder head bolts. I soon had to do it all again! Second time around I bought a new set of cylinder head bolts, opted for composite gaskets, and perhaps most importantly used a new and trusted torque wrench! Wish I hadn't skimped the first time round. Good luck.
Oh yeah, also be careful with the threads in the alloy heads for the intake manifold bolts. Ended up having to fit a Helicoil after I knackered the last one of them tightening the intake back in place. All good fun if it works in the end.
Oh yeah, also be careful with the threads in the alloy heads for the intake manifold bolts. Ended up having to fit a Helicoil after I knackered the last one of them tightening the intake back in place. All good fun if it works in the end.
arthuy
Well-Known Member
When removing the head bolts follow the sequence in the workshop manual.
Also you may shear a bolt. There is always a temptation to use more force to remove the bolt it happened to me and it is not a good thing. I now slacken and tighten until it is fully out, it does take a bit longer but havent had a breakage since.
Watch out for poor quality gaskets, I have seen the coating on the inside of the valley gasket flaking off which you dont want.
Also you may shear a bolt. There is always a temptation to use more force to remove the bolt it happened to me and it is not a good thing. I now slacken and tighten until it is fully out, it does take a bit longer but havent had a breakage since.
Watch out for poor quality gaskets, I have seen the coating on the inside of the valley gasket flaking off which you dont want.
jp928
Well-Known Member
I once pulled a head (RR, ate a stromberg needle retaining screw) and broke a bolt flush with the block. Asked a mate for advice and was advised that without tension on it the stub may just come out easily - applied small taps via a jewellers screwdriver, and it came out readily. Another time I pulled heads on a S1 p6b due to a misfire. Found a piston holed, replaced it and its shells, went to reassemble - previously somebody had fitted a short bolt into an intermediate hole and stripped part of the block threads. Found a longer bolt that would almost bottom and very gingerly tightened it , worked fine. After it was all together, still had a misfire - tracking inside the dizzy cap was the fundamental cause!