Hi, Needing to change head gasket on Rover 100. Looked at a few msgs on this and seems to be conflicting info on weather to use new head bolts and if you have to have certain cylinders TDC BEFORE removing head.
Can anyone give some clear help of this? Thanks in advance Bob
If any bolts differ in length or they are over the permitted length then renew the lot. Also check the threads carefully, renew if there is any damage.
When I swapped mine I made sure that there was no cylinder at TDC/BDC so I could be sure all the valves would miss the cylinders. It's best to set the engine to 90BTDC on cyl 1 and you are then ready to time the cam again as soon as the head has been refitted.
Check for warpage of the head carefully.
General rules for changing any head gasket ...
1) Do a compression test so you know roughly where the leak is & so you know roughly where to look to see whether its just the gasket that has failed or its been caused by something more serious. 2) Drain the coolant (make sure you get the right kind of antifreeze when you refill) 3) Expect to drain & renew the oil afterwards 4) Always set the engine to TDC (& make sure its no 1 that's at TDC compression & not no 4!). In truth this is only really mandatory for OHC engines its not always an issue for Cam in block/pushrods - but its good practice anyway. 5) Always change the head bolts 6) If any of the valve gear has to be dismantled (cam followers etc) make sure it goes back on the same valves it came off - don't mix 'em up if you can avoid it! 7) Spend and excessive amount of time checking the surfaces of the head and the block looking for cracks & warping. If you have either its likely to be a fairly short lived repair. Ideally take it to someone who can check the head properly & skim it if necessary. 8) Fill the bores with rags or kitchen towel where the pistons are at the bottom (2 & 3) before you then clean up the surfaces of the head and the block with a razor/stanley knife blade - be very careful if its Aluminium. 9) De-grease the surfaces of the head & the block before reassembly & don't use any gasket sealer 10, Use a vaccuum to clean out any crud that falls down the bores before reassembly 10) Fit a new exhast manifold gasket. 11) Its never a bad idea to plan on replacing the exhast manifold studs & nuts - they'll probably be quite corroded anyway. 12) Always use a torque wrench & follow the correct sequence/procedure for tightening down 13) If its one that requires an Angle guage, don't guess, go & buy one & buy a decent one.Since you've got the head off & depending on what your compression test told you you might have a look at the valves & guides as well. Depends on mileage/general condition. I don't know how hard the K series is on its valves but if its an issue you may as well tackle it while your in there.
If you have one a digital camera is your friend for taking lots of pics of where all the wiring & various hoses are routed before you start & as you disassemble.
HTH
I.
I'd add to this- DO NOT rotate the crank with the headbolts (i.e. top to tail bolts) slacked / removed else you'll disturb the liners. Not good.
Tim..
Yes. Set the engine so the valves are in a suitable position *before* removing the head, and don't touch it until after it is fully tightened.
This only applies if the cam/cams have to be fitted before replacing the heads. If so, make sure they are rotated to a suitable position before fitting the heads. If they can be fitted afterwards, then none of the above applies as the valves will all be closed - simply fit the heads and follow instructions for fitting the cams from scratch.
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