View Full Version : Valve recession issues?

12-05-2008, 04:14 PM
Just wondering.
Was looking at a reconditioned head on ebay (TR3) and emailed the builder as there were no hardened seats applied (oversized valves left no room to safely do so).
In his opinion valve recession on Tr's is more a myth than reality.
I've a TRF rebuilt head (PO receipt) and am not sure if hardened seats were put in or not (rebuilt around '98).

Has anyone here had any issues with valve recession in a 50's early 60's Tr?
How have the seats looked during your rebuild(s)?

12-05-2008, 04:39 PM
I have a TR3A head that has suffered severe valve seat recession. Oddly enough, it happened only AFTER installing supposedly hardened seats !

Sorry I don't have photos handy to share, but #4 exhaust is so deep into the cylinder head that full valve lift only brings the valve head about flush to the combustion chamber surface; and the rocker hits the valve spring retainer with the valve closed. I also had to shim up the rocker pedestals (not long before I took the head off), because the adjusters had run out of travel.

But, that is the only TR head I've ever had trouble with; several others have shown no signs of recession at all after many tens of thousands of miles on unleaded fuel (and original valve seats).

So, my advice remains to save your money until you actually have a problem. 99% of the time there won't be a problem; and if there is, it only ruins the part that will be replaced anyway.

12-05-2008, 04:47 PM
I am worried about the economic recession and now I have to worry about valve recession??!! ACK!! :laugh: :laugh:

12-05-2008, 06:12 PM
Not overly worried as I've had no issues but always concerned about the no lead.
Just wondering about the experiences of those that have had their 3's a long time.

12-05-2008, 07:30 PM
It's a long, tangled story, but the head that was on TS39781LO when I got it must've had well over 150,000 miles on it when I sold that engine (in another car) and no evidence of recession. And the head I put on after the one with the recession also didn't seem to have any problems with the original seats. That was 2001 and it got wrecked in 2005 I think, so probably 40,000 miles on it with no problems.

Geo Hahn
12-05-2008, 08:30 PM
I didn't seem to have an issue with recession until a 80+ (mostly plus) mph trip home from Triumphest -- lost compression on #3. Upon examination the exhaust valve had receded to a point where it would not adjust to spec. Didn't really analyse the situation, just pulled the head and got the hardened seats.

12-05-2008, 09:33 PM
Hi Pat, Back 15 years ago when the quality of gasoline was very much in question, I was running a fleet of 350 trucks every day and we would have problems of what we referred to as "our motor sucked a valve". Meaning that the valve was harder than the cylinder head and would wipe out a valve seat by wearing away the head (valve seat). We found a way to solve the problem with a local machine shop. He was an old guy and very knowledgeable, his solution was he would "flame harden the seats". It worked for us and saved us a ton of money. I have a TR-3 with new valves and I think that I am having problems now and I suspect that I may be wearing out my valve seat. Time will tell. Good Luck. Bill C. Mesa, Az.

Don Elliott
12-05-2008, 11:40 PM
In 1990 as I was just finishing the restoration of my 1958 TR3A, Canada passed a law that leaded gas would no longer be available starting in 1990. I had just completed a rebuild of the engine, including grinding the valves and seats. The engine was like new with zero miles on it.

I decided to see how long I could drive before I got into a critical situation with the "dreaded valve seat recession". I used no lead sustitute additive. I drove 35,000 miles, checking the valve clearances every 3,000 miles or so. Then I had to re-gap the exhaust valves sooner and sooner till between 40,000 miles to 43,000 miles, I was re-gapping the valves every 1,000 miles. The clearance for the exhaust valves was closing fron 0.012" to 0.002" every 1000 miles.

I considered that this was telling me that it was time to pull the head and have 4 inserts installed for the exhaust valves. I gave the engine shop my head, plus 8 new valves and guides "for unleaded" gas. He supplied the four inserts because his equipment was set up for the insert diameters he had. He milled the cast iron head and pressed in the 4 inserts. He can measure the force during pressing these into the head so he knows that his interference fit will keep them secure - so they don't drop out.

See what happened to the head of a friend's TR3A. Some shops will chill the insert and heat up the head to put in the inserts, but then you never know if they will come loose because you don't feel the force to put them in.

Since, I had my head done, I have driven my TR3A another 57,000 miles and I have never had to re-gap the valves more than a thou or two on some valves once in a while every 5,000 miles. I had the head off again 7,000 miles ago and one valve seat needed to be ground again to "touch it up" said the owner of the engine shop.

12-06-2008, 12:10 AM
Very good information (and pics) and it sounds to me like it's pretty much a crap shoot. Sometime's it happes sometime's not.
I have valve clatter but have never had trouble setting the proper clearance so suspect worn/grooved rockers (hard to set properly) more than anything.
TRF can't remember if they used hardened seats when they rebuilt my head ('97) for the PO.
I do run the little four pretty hard (100 mph plus on occasion) so
time will tell. They were made to run hard so what the heck (see Basil no cussing).
Thanks for the info guys, as always, great feedback.

12-06-2008, 12:30 AM
Is that the black hardtop TR3 you're talking about...the recent rebuild?

12-06-2008, 01:02 AM
Here's a photo of #1 on the 'recessed' head. Not so bad, but you can see the valve head is lower than it should be.

12-06-2008, 01:03 AM
But here's the show stopper; #4.

12-06-2008, 01:14 AM
Whoa, that is a show stopper and that would be the supposedly 'hardened' seats that receded like that?
I guess that means there are hardened seats and then there are hardened seats.
But you've had stock (unhardened) motors that have done fine on unleaded.
Did you ever figure out why these hardened seats reacted like they did?

12-08-2008, 01:11 PM
Did you ever figure out why these hardened seats reacted like they did?
Not really. It may be because I also used "racing" valve springs with them; or it might be because I had the head milled too much (though I don't see how that would affect the valve seats). Or it may be that the shop I paid to install them ruined the hardening somehow. Might even be that the seats themselves were defective.

12-08-2008, 01:43 PM
Hard to figure what happened unless you have some kind of controlled experiment.
I've decided to try the red line lead additive just to be on the safe side. I do tend to run her hard.