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View Full Version : needing some valve seat guidance here



twigworker
12-05-2012, 02:54 PM
Late, fourth generation, TR3/TR4 head.

It needs all of the valve seats replaced.

Machine shop has no access through their catalogs.

Victoria British shows #1-9011 as the intake seat up through 1963, but no exhaust.

From 63 to 67 they show #1-9011 for the intake AND #1-5636 for the exhaust. The intake cost is $12.95 and the exhaust cost is $10.95

The Roadster Factory wants $19.95 and $15.95.

My question is, has anyone had experience, good or bad, with seats from either of these vendors? And, does anyone have a recommendations for an alternative?

Thanks in advance, Jack

waltesefalcon
12-05-2012, 03:00 PM
I used VBs seats in my old 1500 Spit when I did a valve job on it about 9 years ago. I have no complaints about them.

TR3driver
12-05-2012, 03:57 PM
Replacing intake seats on the TR3/4 head is generally regarded as a bad idea, as they wind up having to be 'siamesed' with the exhaust seats, increasing the chances that a seat will come loose. If the intake seats can't be saved with oversize valves, you're probably better off looking for a different head, IMO.

I got both hardened exhaust seats and oversize intakes from BFE https://www.britishframeandengine.com/parts1.html but that was quite a few years ago.

Don Elliott
12-07-2012, 01:55 PM
On the engine in my 1958 TR3A, I had new seats installed for the 4 exhaust valves only. The displacement is 1991 cc so the piston diameters and chambers in the head are still like the originals. The engine rebuild shop (who I trust 100%) told me he would supply the ring inserts as his equipment is set up to bore the diameters to the correct interference fit for his inserts. I supplied 4 new intake valves, 4 new exhaust valves and 8 new valve guides I bought from one of the two largest US parts suppiers of TR parts. He bored the head and pressed his 4 seat inserts into the head. He can measure the force needed to insert these rings so he knows they will never fall out.
After inserting the new seats, he ground them plus gave a valve seat re-grind for the 4 inlet valves.

I put it all back together with 123,000 miles on the engine as it was done. I have driven a further 67,000 miles with no issues.

My engine re-build shop presses the exhaust seat inserts into the head because he knows they won't fall out. A friend had his TR3A dome and the shop chilled the ring inserts so they would fit into the head more easily. But one fell down like a full collar around the bottom of the exhaust valve - clanging away on every stroke -because that insert didn't have enough interference in the fit. This happened one morning as he was starting up his TR3A. Luckily he wasn't on a quiet road in the country hundreds of miles from home.

Hap Waldrop
12-10-2012, 09:45 AM
Jack, valve seats are not sold per say for a certain car, but rather based on their size, based on valve size, if your machine shop guy doesn't already know this, it might be time for you to come down the mountain, and let me introduce you to my friend, Chris Dover that does this for me. Most machinist that actually do this sort of work often, do not like you walking into their shop with valve seat inserts you got elsewhere, they get used to using a certain supplier, and like to know what they are working with, so they prefer to aquire thier own seat inserts. As a technical advisor for Moss Motors, I'm often ask what parts do we have, we shouldn't sell, and what parts do we not have, we should aquire and sell, recently I was asked, should we (Moss) sell valve seat inserts, and my answer to them was a resounding, NO.

twigworker
12-10-2012, 11:09 AM
As always, I thank everyone for their input.

My question had to do with the quality of the inserts noted and if there was any correlation with the price differences. And, I further asked for first hand experience feedback. I included the intake seats just for reference, as we will not be changing them. Although I said that ALL of the seats need replacing, and the intakes really should be for perfection, we will not be doing them. Instead a very careful cutting of the material will be done followed by the appropriate shimming of the rocker pedestals.

The machinist and I, are both aware of the wisdom of pressing the seats at room temperature so that isn't an issue. We are also aware of the folly of getting involved with installing intake seats.

The reason for looking to VB or TRF is that the shop cannot find a reference to the TR applications among their standard catalog listings. If anyone has a part number for them, published by any of the standard machine shop supply houses, I would obviously like to hear from you.

Jack

Hap Waldrop
12-11-2012, 09:00 AM
Jack, as I said before, seats are order to size, not always car, and sometimes the ID, or OD has to altered on a lathe for given application, much like cylinder sleeve. most seats are made from stellite, but there are other materials, everything sold these days are suited for unleaded fuels. Of course the only reason to replace a intake seat, would be from too many valve jobs in the head's life, or damage to the seat area. I often use the too many valve job deal on the intake seat to justify a larger intake valve if offered, because this will put the seat in different area, and save the customer money and offer a performance gain.