Heater works when it wants. Doesnt have a pattern, its just random. No coolant leaks.…
The timing slipped and am putting in new valves and guides. I don’t know how deep to drive the valve guides
How deep to drive the valve guides
Insert the valve guides in the cylinder head in their original positions. Drive the guide in until it stops against the bore.
Valve Guide repair options
Whether you repair guides on an “as needed” basis or automatically redo all the guides anytime a head is rebuilt, you have a variety of guide repair options from which to choose. Most re-builders either go with thin wall bronze liners and reclaimed valves, or install new or re-chromed valves with oversized stems. Replacing guides is another option with aluminum heads as well as some cast iron heads, as is knurling. Most re-builders have tried all of these techniques at one time or another, but usually stick with a single technique that fits their operation best, or gives them the least amount of problems.
One recommendation here is to preheat the heads in an oven prior to guide removal and to lubricate dry liners before driving them out. The head should
also be preheated before the new guides are installed. Chilling the replacement guides can reduce the amount of interference during installation. Lubricant also helps prevent galling. With tapered guides, care must be taken to install them from the right side. Most wet guides are tapered, and also require sealer to prevent leaks.