For my E type restoration, I took off the 4.2 L engine head and had it professionally rebuilt. I also replaced piston rings and when all back together, it had great compression
But later an accident (described in another post) caused some valves to be bent. I have the head off again with original intention to back to the engine shop.
On second thought, I wonder if I can’t replace the valves with new ones myself, having watched videos of valve removal and replacement. My questions:
-can a semi competent old guy do this?
-does a new valve need to be lapped?
-is getting valve clearance/shim size a fairly easy task?
Bent valves are a SERIOUS problem, often involving collateral damage (pistons?). I didn’t read your previous post, but be sure you understand the cause. Yes, new valves need to be lapped. Setting clearances is NOT trivial.
If you don’t do this right, your troubles won’t be over.
Bob Frisby
S2 FHC
Boise, Idaho
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With all due respect, the question itself indicates that you may want to at least have an experienced Jaguar owner oversee your work.
Lapping valves isn’t difficult, but one needs to be able to “read” the lapped surfaces correctly.
Ok, you two have persuaded me to take back to the machine shop.
I haven’t known any machine shop that laps valves. They grind them and hand them back. They aren’t paid enough for that kind of work. You have to specify what you want done to your head and have enough faith in the shop that they know what they are doing.
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Apparently well cut seats and matching valves fit well enough that lapping is not necessary. But I‘d definitely lap in a new valve to replace a bent one. It’s easy, cheap and shows results.
The shop should know what’s best.
You are correct: well-machined valves and seats do not require hand-lapping.