Is valve recession a myth?

[thescrapman]

I had it on my Mk1 2 litre Vitesse engine, eventually resulted in a cracked valve. Had seats fitted at that time, it had done 20k odd since having poor seats heavily ground in to get a good seal in the early 90's.

ISTR a couple of Mk1 2000 saloon with very bad VSR, they'd were driven hard.

I had seats fitted to 2 other engines whils,t they were under going major rebuilds, the seats were going to have to be cut back to clean them up, so I reckoned worth the extra cost at the time.

It is very rare on Triumph engines I think is the conclusion.

[johny]

yes although mine runs pretty cool now (Honda Civic rad) after my traumatic trip Im still nervous and wonder if I can squeeze a TR6 rad in there. I think the width is right but the valance might need modifying to drop it low enough...

[Nigel Clark]

To add to the experience of VSR, I ran my GT6 for about 30k miles on premium unleaded without additives before stripping the engine. There was very little sign of recession. Driving was a mixture of local A and B roads with some motorway miles too, so the engine worked fairly hard but didn't spend much time above 4,000rpm. The Ford Essex V6 in my Scimitar has been similar, with no VSR problem after 20k miles on unleaded, and that has done a lot of motorway miles.

I suspect VSR is really only likely to be a problem at sustained high rpm in competition.

Nigel

[johny]

Which model of GT6 was it Nigel? The Mk1 engine seems to have a worse reputation and my car has no OD so revs are obviously higher at motorway speeds....

[Peaks]

Interesting thread!

It's not a myth, I too have experienced valve seat recession, but on a Ford Essex engine, not a Triumph. 

I agree with John; it has a lot to do with how the car is used. 

Also, very possibly the quality of valve/head materials originally used has a significant effect on the liklihood of recession occurring.

As an aside, I am a marine engineer with particular experience in marine diesel engines. On some engines we have experienced valve seat recession on inlet valves. This has only happened on engines used in high load applications. To remedy this an inlet manifold oiler was designed,  tested and fitted, and as the name suggests,  this device injected very small amounts of lubricating oil into the inlet. The amount of oil injected depended on the engine.load, but it was in the region of one tea spoonful every hour on a 1.3 MW engine which would be in the region of 60 litres in size. 

Injecting oil, even at these small amounts, completely cured the valve ressesion problem. 

[Nigel Clark]

On 28/06/2021 at 09:56, johny said:

Which model of GT6 was it Nigel? The Mk1 engine seems to have a worse reputation and my car has no OD so revs are obviously higher at motorway speeds....

It's a Mk3, with overdrive. 70mph equates to about 3500rpm

Nigel

[PeteH]

1 hour ago, Peaks said:

Interesting thread!

It's not a myth, I too have experienced valve seat recession, but on a Ford Essex engine, not a Triumph. 

I agree with John; it has a lot to do with how the car is used. 

Also, very possibly the quality of valve/head materials originally used has a significant effect on the liklihood of recession occurring.

As an aside, I am a marine engineer with particular experience in marine diesel engines. On some engines we have experienced valve seat recession on inlet valves. This has only happened on engines used in high load applications. To remedy this an inlet manifold oiler was designed,  tested and fitted, and as the name suggests,  this device injected very small amounts of lubricating oil into the inlet. The amount of oil injected depended on the engine.load, but it was in the region of one tea spoonful every hour on a 1.3 MW engine which would be in the region of 60 litres in size. 

Injecting oil, even at these small amounts, completely cured the valve ressesion problem. 

Interesting that. One of my experinces On Medium Speed Engines, (Pielstick) was a sudden increase in Exhaust Valve burn out, we seemed to be changing one every few day`s. we could keep it under control IF we reduced the exhaust temp; (speed) Which affected schedules! and was not popular!.. What we dicovered was that High Vanadium content in the MFO was the culprit. We stopped Bunkering in Venezuala (Cheaper) and Took Fuel in Miami instead. That solved the issue.

Pete

Pete

[JohnD]

Johnny,

Moving aside for a moment, I have a Honda Civic rad in SofS, with no overheating on or off the track.  (Was it Johnny mentioned overheating?) But I also have Craig-Davis electric water pump.

Have you ever looked at the Triumph pump rotor?  It's weeny, filling less than half of the pump space!     I've ground the vanes off mine, and rely just on the C-D pump.   The water 'pump is now just an idler.

John

[johny]

no, overheating isnt a particular problem now but Im always open to improvements as you cant have too much cooling capacity can you (assuming the thermostat works as it should of course).

Ive thought about the water pump and have even filled the back of its casing with metal epoxy to close the the gap between it and the vanes as much as possible. However as the TR6 and 2.5PI use the same unit I assume its not a limiting factor.... 

[JohnD]

Depends on the stress.  I used to get overheating on track.  No more.

[Pete Lewis]

20 hours ago, PeteH said:

Fuel in Miami instead.

thats a bit far  i have to use sainsbugs 

Pete

[PeteH]

3 hours ago, Pete Lewis said:

thats a bit far  i have to use sainsbugs 

Pete

Does your Sainsbury, do Marine HFO?. Would need a Iong Bunker Pipe though?. I`ve Filled with "regular gas" at Walmart near Kissimee. Only 60 US Gallons though. Not 2000 "long" tons.🤣.

Pete

[Dick Twitchen]

Come on Pete, you know this is the slick way to take fuel, but no run ashore! (Sorry about the size of the picture)

[Pete Lewis]

is the net to catch excess  rum antics??

Pete

 

[PeteH]

Dick,

Got to give them credit, those Merchant Navy RFA boys know how to do a service call.👍

Did they wipe the bridge windows and check the oil as well?.😀

Pete

[Andy Moss]

Seem to be getting a bit off topic.  So VSR can occur, but typically needs a bit more stress than routine driving. This may be due to the quality of the parts used by triumph. Later cars may have higher likelihood of VSR due to degraded parts quality during the 70s. Fuel quality may also have some effect, but difficult to quantify. Is that a reasonable summary?

[Peaks]

16 hours ago, PeteH said:

 those Merchant Navy RFA boys know how to do a service call.👍

Did they wipe the bridge windows and check the oil as well?.😀

Pete

That was me! Could never reach the bridge windows during a RAS though, we didn't have a squeegee mop with a long enough handle. 

[Peaks]

14 hours ago, Andy Moss said:

Seem to be getting a bit off topic.  So VSR can occur, but typically needs a bit more stress than routine driving. This may be due to the quality of the parts used by triumph. Later cars may have higher likelihood of VSR due to degraded parts quality during the 70s. Fuel quality may also have some effect, but difficult to quantify. Is that a reasonable summary?

That pretty much sums it up Andy. Valves and their seats will.all wear out eventually,  but the speed at which they do is dependent on parts quality and style of driving.

The best advice I heard regarding this is to use your car as you always have, and id/when the valve seats require work convert to hardened seats then. 

I certainly wouldn't bother with that lead replacement stuff you are supposed to pour into your tank every time.you top up with fuel. 

[PeteH]

I did Try an alleged "octane booster" in the BMW (bike) for a while to see if it would improve anything. To be fair, despite the claim by BMW that the bike needed 90Ron or above. I could not detect any noticable change. Mostly just ran it on stock unleaded.

Pete

[Badwolf]

When I put the Spitfire back on the road I got a bottle of Castrol Valvemaster. Still using it 4 years later. Keep forgetting to put it in. When it's gone I have no plans to replace it. I will see how she runs. Engine was fettled and new valves ground in about 1988ish, before unleaded went. There may just be enough lead still there, who knows.