Head Service + Valve Seats Cut = 6 Out of Spec Spacers

[jay1622]

If someone doesn't mind taking a few minutes to go over my math?  Every example I have come across involved subtracting, not adding for the difference (I know, it's a contradiction in math terms). I tried getting the wife involved, hence the artwork. Thoughts? I really appreciate any input.

[Laitch]

Your thread title is cryptic and that's ok. You've made the simple complicated, but only by thinking about it. I only looked at the figures in the lower left section; the rest was too spooky to contemplate. You seem ok at arithmetic. You're not being a bad daddy. Having six valve clearances out of spec in the same direction is probably not as unusual as having six toes. It's time for some confidence. Approval is for puppies.

The tedious part is cleaning the gasket mating surfaces, applying the sealant and getting the cover bolted up without gaskets shifting and oil leaking. You won't be the first if you need to do that part of the procedure again. Be sure the spring is installed. Leaving it out can be shocking, I hear.

So much for my thoughts.

[TimTyler]

I think it's ideal to aim for 0.15mm on the intake valves so you may want to use 2.55mm shims instead of 2.50's.

You can use the shim from the #2 exhaust :)

Somebody correct me if I'm wrong.

[Laitch]

Somebody correct me if I'm wrong.

I don't think you're mistaken, Tim. I think that an engine that has shown a tendency toward tightening valve clearances—if they were set within the range in the first place—won't be bothered by clearances set at the loose end of the range. It's not like the system allows for fine tuning anyway.

It's a simple procedure to recheck at will regardless, especially if you enjoy torquing bolts and enjoy working with two gaskets simultaneously.

[The Mighty Gryphon]

I think it's ideal to aim for 0.15mm on the intake valves so you may want to use 2.55mm shims instead of 2.50's.

You can use the shim from the #2 exhaust :)

Somebody correct me if I'm wrong.

I would lean toward having the exhaust valve clearance at the wide end of the spec.  To achieve that you need to use a THINNER shim, not a thicker shim.  2.55mm is going in the wrong direction. 

[jay1622]

I think he's saying to use that left-over 2.55 shim from the exhaust in place for one of the intake ones.

Yes?

[TimTyler]

Yes.

It's best to have the intake valve spec on the tight side, and the exhaust valve spec on the loose side, as I recall.

[The Mighty Gryphon]

Oops!  Didn't see the word "intake" in the post I was quoting.  Yes, tight intake valves breathe better, and the fuel/air mix cools them where the exhaust aren't cooled except by contact with the seat.

[jay1622]

Mama once told me experience will always trump education. I went ahead and made the changes so the intakes will be at .15 and the exhaust will be at .30. Thank you guys, the spacers are ordered.

Oh, it's never been about approval or lack of confidence; rather, having the balls to know when to ask a question and listen, but I can appreciate the dig regardless.

It's down to fixing the tank (two pin holes) and paint! Looking to have her on the road in the next two months.