RWyatt's "It's takin forever" Build Thread
#641
I may regret this, but...I've ordered and received those "lash caps" (I couldn't help myself
Anyway, these puppies will fit between the valve stem and the post of the SOB and will take up the gap (measured at 0.071 in) between the shim and the base circle of the cams. Of course, at .085 in, that makes these caps too thick, so I'm going to VERY SLOWLY and carefully "face the caps bit by bit until I get the valve lash that I want. Is that going to be tedious? Absolutely! Will I regret that decision halfway through? Probably. Will I fly against all wisdom and common sense just to fell smug about having SS valves and solving a stupid problem (hopefully without trashing my top-end)? You betcha!
It wont be the first time, and it probably won't be the last time.
Here's some "Valve Cap" pics showing my first test fit.
Here's a cap, pre-installation
Seating on the valve step. It's a slight interference fit so it seats with a satisfying "snap"
Left side is w/ the cap, right side is w/o
Anyway, these puppies will fit between the valve stem and the post of the SOB and will take up the gap (measured at 0.071 in) between the shim and the base circle of the cams. Of course, at .085 in, that makes these caps too thick, so I'm going to VERY SLOWLY and carefully "face the caps bit by bit until I get the valve lash that I want. Is that going to be tedious? Absolutely! Will I regret that decision halfway through? Probably. Will I fly against all wisdom and common sense just to fell smug about having SS valves and solving a stupid problem (hopefully without trashing my top-end)? You betcha!
It wont be the first time, and it probably won't be the last time.
Here's some "Valve Cap" pics showing my first test fit.
Here's a cap, pre-installation
Seating on the valve step. It's a slight interference fit so it seats with a satisfying "snap"
Left side is w/ the cap, right side is w/o
#642
Cpt. Slow
iTrader: (25)
Join Date: Oct 2005
Location: Oregon City, OR
Posts: 14,360
Total Cats: 1,184
Do not try to hand lap the shims, it won't go well. You need a precision grinding table to do it. Take the head off, bring it to a machine shop, and have them properly grind the tips of the valves to fit your shims.
#651
I was also worried about this.
My machine shop’s comment was that there are a lot of factors that can contribute to accelerated wear on the valves. How was the valve seat cut? I.e. How much contact area the valve has to transfer heat. Did the valve faces get ground or lapped, removing the harder treated layer? What was the engines tune like, EGT, usage, etc. is the rest of the valve train setup correctly for the use case? Then, of course, there could’ve been bad production runs of the valves themselves.
I ended up doing stainless intake, and inconel exhaust. I asked for a conservative wide valve seat profile, which may hurt flow a little bit, but who cares. No lapping or grinding of the valve faces. I will swap to Inconel intake valves if it becomes an issue.
If the normal retailers do not have stock of the valves you need, reach out to Supertech. They will sell direct if you’re in a jam.
My machine shop’s comment was that there are a lot of factors that can contribute to accelerated wear on the valves. How was the valve seat cut? I.e. How much contact area the valve has to transfer heat. Did the valve faces get ground or lapped, removing the harder treated layer? What was the engines tune like, EGT, usage, etc. is the rest of the valve train setup correctly for the use case? Then, of course, there could’ve been bad production runs of the valves themselves.
I ended up doing stainless intake, and inconel exhaust. I asked for a conservative wide valve seat profile, which may hurt flow a little bit, but who cares. No lapping or grinding of the valve faces. I will swap to Inconel intake valves if it becomes an issue.
If the normal retailers do not have stock of the valves you need, reach out to Supertech. They will sell direct if you’re in a jam.
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