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tomshobby

tomshobby

Yoda
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I have been gathering information and advice for a year and a half and yesterday started ordering parts to build my engine and sent my distributor to Jeff at Advanced.

From Goodparts, GP2 chilled iron camshaft, valve tappet set, valve spring set, valve guides, valve seals, main bolt kit, rod bolt kit, aluminum shroud, black w/oil cooler cutout, and cam bearings.

I had an interesting conversation with Richard Good this morning. The topic was valves and seats. Richard recommended staying with the standard intake valves and original cast-in-head seats if the seats are in good condition. His reasoning was that the intake valves run cooler and will stand up just fine. For the exhaust valves he recommended stellite valves and replacing the seats. He suggested that I use valves and seats for the older TR6 heads because they are bigger while using the original size for the intake. He felt this would get better flow and use of the cam. A reason for the stellite exhaust valves was that he feels that the valve stem ends stand up better, both with standard rockers and with roller rockers. He said the original intake valves seem to do fine but the original exhaust valves seem to tend to break down on the stem end over time.

So it begins!
 
I certainly can't fault his thoughts about the valves. I wen't with the Stellite exhausts on the GT6 for the same reason.
Jeff
 
That's exactly the advice I got from a great old machine shop in my hometown, except I think they even wanted to keep the same seats on the Stellite exhaust valves.

In fact, it's been over a year, but I recall trying to argue the point, and they said that unless the seats were worn beyond a certain spec, their experience was not to mess with them. The main mechanic said the seats looked good, even though it had been 10 years since the last rebuild of the engine. '66 TR4A

Whatever the case, my car ran great from the moment I put the rebuilt head on the car.

Question: From looking at the underside of the cylinder head, I couldn't even see anything that looked "removable." What does a valve seat look like when secured in the head? thx
 
The original seats are an integral part of the casting. To replace them, a pocket is machined in the head, and a suitable sized seat is pressed, or shrunk, into place. Then they are cut and ground to the proper shape.
Jeff
 
Yup, In this picture you can see where the valve seats meet the port walls.. Obviously they've been blended

ProPocket3.gif
 
Richard Good gave me two reasons for installing new exhaust seats. The first is that he recommended larger exhaust valves (valves for older TR6 head installed in my 1976 head). The other was that he felt that small particles of metal can weld themselves to the cast seats and he did not think that happens with the harder replacement seats. I do not remember his explanation for the source of the particles.

With a stock engine it probably is not an issue. I think it has at least some to do with the higher cam lift, uprated valve springs, and roller rockers.
 
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