Cutting Valve Seats

XxSlowpokexX

Registered User
Any reccomendation as to cutting the valve seats on the SC heads for larger valves.?

Any reccomendations appreciated

Thanks

Damon
 
haha I am not doing it! I just heard some have installed new seats and some hav ecut teh factory ones while some have just installed the valves.

Thats the input I want. My experience is every machine shop has a different idea of whats ideal. I'd rather get it from the horses mouth
 
I did mine at a 30 deg it gives more lift off seat old david Visard trick.

also cut em a little low the lifter will take up the slack in valve train and lifter will open valve a little more.

oh yeah seats mine are narrow and beveled after seataing area. for better flow i had my seats cut out and larger seats installed for bigger valves while they were in there i had em fly cut the pocket at 70 deg this removed alot of the junk id be removing when porting the heads. saved me work .




but yeah remove old seats install new ones why trust ten -13 yr old seats they do crack and wearout peice of mind that your new valves are on new seats .

just my oppinion but im no pro just a home shade tree mechanic ah err grease monkey
 
There's a couple of things you can do. The cheapest way is to open the ID of the seat up with the cutter as much as possible. This is just like going to a larger seat. That way you don't get charged for cutting a seat out, machining a new recess and press another one in. Then you can just run a 1.86I/1.60E valve with stock seats. These would work well.

The reason for not recommending a larger valve size is because the valve isn't the limiting factor, the ports are. The throat is about 75% the size of those valves. You need to be 90% of whatever valve size you run.
 
The heads I have hd been pretty nicely ported. If you think I should just go stock valve size I will. I'm only going with a 500 lift cam anyhow..Its just that I have these valves sitting on the shelf....
 
What size are the valves? All valve sizes, that fit, will work fine. I was just stating what's more feasible. You definitely want valves that are larger than stock.
 
just lap them big valves in on stock seats. The valve will fit after lapping for a couple weeks. Use a drill on end of valve. Turn high speed ,as fast as the drill will go.
Randy
 
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