Not trying to start the Speed six debate
Discussion
But was down at a dealers yesterday, and they had a recent tuscan with typical cam follower damage.
Now, according to them the speed 6 engine hasn't been sorted and is still giving reliability problems.
According to them the problem is the radical cam setup, which can only be cured by calming down the cam profile, and therefore losing power, which TVR are obviously not prepared to do.
If they are still getting the same problems with recent 6 engines, why is the feeling that things have been sorted with the speed six engine?
Now, according to them the speed 6 engine hasn't been sorted and is still giving reliability problems.
According to them the problem is the radical cam setup, which can only be cured by calming down the cam profile, and therefore losing power, which TVR are obviously not prepared to do.
If they are still getting the same problems with recent 6 engines, why is the feeling that things have been sorted with the speed six engine?
Having just done a full tappet adjustment on a Speed Six engine, I would say that they have definitely NOT sorted the problems, and here are my reasons:
The engine had a full rebuild 4.5k ago last year, and has only done 3.5k since it's 1k post rebuild tappet service. As it is due for a service, but not tappets, I recommended we have a quick check of the clearances before it went to the dealers.
Guess what? The tappet clearances were all over the place and worst of all one of the exhaust valves had no clearance at all! This has resulted in cam and follower damage which means back to square one, again!
There is either valve stretch, or a valve seat regression problem. Either way, the engine is goosed in less than 4500 miles. The owner is an engineer, undestands mechanical sympathy, and yet it has still happened to him!
All this is compounded by the fact that to do any work on the engine, it has to come out of the car, adding large amounts of time and money to an already expensive folly.
P.S. how is the BMW 3 series steering rack going Julian?
The engine had a full rebuild 4.5k ago last year, and has only done 3.5k since it's 1k post rebuild tappet service. As it is due for a service, but not tappets, I recommended we have a quick check of the clearances before it went to the dealers.
Guess what? The tappet clearances were all over the place and worst of all one of the exhaust valves had no clearance at all! This has resulted in cam and follower damage which means back to square one, again!
There is either valve stretch, or a valve seat regression problem. Either way, the engine is goosed in less than 4500 miles. The owner is an engineer, undestands mechanical sympathy, and yet it has still happened to him!
All this is compounded by the fact that to do any work on the engine, it has to come out of the car, adding large amounts of time and money to an already expensive folly.
P.S. how is the BMW 3 series steering rack going Julian?
Shall we put a padlock on now before Mungo gets here? 
Well without naming names, I am told the engine HAS been sorted and this
is not from a TVR employee but from someone who is really in the know
but on the 'outside'.
I think that truth is, it is not bullet proof and a percentage will still
let go, but then neither is the AJP perfect.
Naturally, if one Speed Six goes bang, there will be 10 people to tell you
it is proof that it is not sorted, never mind the other 499 that are fine.
Just my opinion based on what I hear.
Well without naming names, I am told the engine HAS been sorted and this
is not from a TVR employee but from someone who is really in the know
but on the 'outside'.
I think that truth is, it is not bullet proof and a percentage will still
let go, but then neither is the AJP perfect.
Naturally, if one Speed Six goes bang, there will be 10 people to tell you
it is proof that it is not sorted, never mind the other 499 that are fine.
Just my opinion based on what I hear.
Is it really a surprise that the Speed 6 is still a mess? (I am just waiting for mine to blow). TVR aren't selling enough cars to keep themselves afloat and not a single Sagaris race car has been ordered. No wonder 'goodwill' rebuilds have been stopped, though I doubt the Courts will take such a relaxed view of selling road engines that don't last 5k miles. 
PW saw Moleskins coming a mile off and fleeced him good!
With only Speed 6 cars being produced TVR's future doesn't look too bright if the initiator of this thread is correct.
PW saw Moleskins coming a mile off and fleeced him good!
With only Speed 6 cars being produced TVR's future doesn't look too bright if the initiator of this thread is correct.
Well, the argument is that the cam is far too radical and looks like a sheer face to the tappet. The cam then slowly gets a groove in its face, always in the same place until it has penetrated the case hardening, at which point the follower obviously lets go.
The problem for TVR if I understand correctly is that the fix is easy, don't make the cam so steep. But the knockon effect is that the engine breathing is restricted and the car has less poke.
If its truly as cut and dried as that then whats the answer? Twin cam redesign is likely out of the question, but it does beg the question of would you want this engine with a supercharger on?
P.S. Rumour has it that there is going to be a new player in the TVR cam market soon.
The problem for TVR if I understand correctly is that the fix is easy, don't make the cam so steep. But the knockon effect is that the engine breathing is restricted and the car has less poke.
If its truly as cut and dried as that then whats the answer? Twin cam redesign is likely out of the question, but it does beg the question of would you want this engine with a supercharger on?
P.S. Rumour has it that there is going to be a new player in the TVR cam market soon.
I can't believe it's a profile issue, what I can believe though is that there's an ongoing clearnace-closure issue that prevents adequate lubrication of the wiping surfaces (there's oil spray and mist lubrication).
It's the closing clearance issue that needs addressing first, then see if there's any lubrication effects that need addressing afterwards. could be that if you create consistent working clearance there'd be no cam / follower wear?
It's the closing clearance issue that needs addressing first, then see if there's any lubrication effects that need addressing afterwards. could be that if you create consistent working clearance there'd be no cam / follower wear?
_DeeJay_ said:
Nope, 'fraid not. I'll take your word for it. As long as it results in a speed-6 that I can confidently do 20k miles a year in then I'll be extremely pleased!
For other reasons I have had to delete my posts so far, which has been a little childish on my part. Please edit your posts accordingly too. Thanks.
Bud, keep an eye on the Tuscan forum, I will post there in due course with info on the job and its cost.
>> Edited by SXS on Friday 28th January 20:04
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