And my last thought for today....

The suggestion that skimming heads raises compression ratio and causes premature reoccurrence of the previously fixed problem.... would hold more weight if the carbon deposits on top of the piston and in the combustion area didn't already raise the ratio and possibly a thicker layer than the skim a workshop would take off.

The engine certainly runs better with that carbon gone and the ports cleaned out. A slight increase in compression ratio (and thousands of an inch won't raise it much) is a small bonus in my opinion.

 

From memory the top rear bolts hold brackets for loom and plug wires, and hooks for lifting the engine out. My current engine lacked the hooks and brackets but had bolts.

I can't really tell where that is.

 

Hi

The reply from Rimmer Brothers came today... a bit of a disappointment as it only shows how to increase the valve clearance rather than decrease it because of wear on both faces of the rockers and within the hydraulic tappets.

I wish I had checked the clearance before I stripped the engine down to get an idea of the float and am loathe to stump up almost $200 on adjustable push rods if I didn't need to.

A right enigma...

 

how much were the head decked? gives you the measurements in the rave

 

Hi

I may not get the heads machined as, after cleaning them up, I don't see any damage to the faces from the blown gasket.

I have the downloaded pdf Discovery manual and it just gives the torque value for fitting the rocker shafts... I could not find mention of valve clearance or float and the Rimmer suggestion presumably only applies if you have a substantial amount machined off the face of the head that lowers it and causes the float/clearance to diminish by a similar amount.

If you can find the page I would appreciate a look at it....

I think that when I reassemble it, which won't be for a while now, I will fit the pushrods and rocker shafts and check the clearance at the front and rear valve positions. If it's outside the limit I will have to pull the rocker shafts off and buy the adjustable push rods though my gut feel is I won't need to.

 

You can get a black impact socket made in China.
5/8" 6 point for the head gaskets.
That is all you need.
Any autoparts store will have it.

Exhaust bolts are pretty common 12 point size.
Never take those out fast. They will snap for sure.
Work them back and forth.

 

Wow! You can't buy fine and coarse valve grinding paste in the USA, just a generic tube of unknown coarseness you can buy from Autozone and O'Reilly. So I ordered some from the UK that will arrive later on the week.

So valve grinding has to wait this weekend so I will work on the Piston tops and cleaning up the cylinder block faces.

I bought a wet/dry vacuum cleaner with fine tip nozzles that I will use to clear bolt holes and debris from the decarb.

 

I think the tube you find in the US these days is "fine". I don't think I've ever needed the coarse stuff, though I do have some, just incase.

 

Hi

Thanks for confirming that... it might be all that I need but I like to have both options available, much as you do, in case any are problematic.

It'a about 100 degrees here outside while I clean up the piston tops and block... not fun