JamesBryan
ClioSport Club Member
The first time it went he was on the way to get the belts done along with 197 cams fitted.
Both times have been bad luck, nothing more.
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Buying track car and engine life
- Thread starter Bowser
- Start date
The first time it went he was on the way to get the belts done along with 197 cams fitted.
Both times have been bad luck, nothing more.
i never saw the point of supertech valves, the oem ones have been proven good enough across a multitude of builds, that and the fact they are ridiculously expensive
JamesBryan
ClioSport Club Member
Standard valves are shite and probably the number one killer after aux belt taking out the cambelt.
Plus with cams, 99% of the time you will be raising the rev limit to get the most out of them. In the danger zone for standard valves then.
The standard valves die when they get clouted by the piston because the valves been open at the incorrect time, im pretty sure a supertech valve wouldnt like getting smashed by the piston either and probably bend or worse. I definately wouldnt be getting Supertech valves for a lightly modified cammed engine, or even itbs, only on a very high powered FI build
JamesBryan
ClioSport Club Member
It's actually the valve head they drop most of the time because they are 2 piece.
£400 is a good insurance for valves IMO.
PH2 172
As someone that IS prepared to learn, and does not have ALL the answers, please expand on 2 piece valves.
I have not encountered these before, possibly as my background is in bike engines, but from what little internet information I can find, they definitely exist.
Fire away please James.
PH2 172
If a pair of valves go together, then it is 99.9% certain that it is due to piston/valve contact, but a single valve of a pair will be a failure for another reason.
I look forward to James reply concerning 2 piece valves.
JamesBryan
ClioSport Club Member
As far as I know it's so that the head of the valve can be made from a more resistant material and is then welded to the stem. High revs cause vibrations and strain due to the speed they are moving, so they separate at this weld.
Supertech valves are high grade stainless steel for the intake and inconel for exhaust.
MK7 Golf R, Clio 182
Clio engines aren't expensive. Rev for Harambe, blow up, replace, repeat
PH2 172
Thanks for that.
I have never considered that valves were ever machined from anything other than a single billet.
But before becoming involved with F4R`s, I had not encountered pressed lobe cams either.
Is the reason for constructing a welded valve purely cost?
If you have a 22mm valve with an 8mm stem, you will need to start with a 23mm piece of billet the total length of the valve, but if welded, two pieces of billet of vastly different O/D dimensions?
Looking at JB21`s singe valve failure, the stem is clearly visable in the valve guide.
Have you any feedback on Sinus valves v Supertech?
I keep reading that engines are cheap - but whenever i look, the only cheap ones are the ones with cambelts snapped and therefore probably just as knackered as the one you're replacing.
The running engine seems to be £500 odd, then add on the price of belts, its not exactly cheap.
Not to mention the ball ache of shipping, and fitment.
The running engine seems to be £500 odd, then add on the price of belts, its not exactly cheap.
Not to mention the ball ache of shipping, and fitment.
PH2 172
Left standard, but well maintained, they go on forever, fingers crossed.
PH2 172
Left standard, but well maintained, they go on forever, fingers crossed
MK7 Golf R, Clio 182
500 for a performance model engine is dirt cheap.
Add the price of belts and the other bits you'd probably replace whilst the engine is out and its will soon add up.
Better just to stay on top of belt changes.
JamesBryan
ClioSport Club Member
Yeah just a cost thing really.
Not heard of Sinus valves, but the supertech are rated by most of the top engine builders for these engines.
JamesBryan
ClioSport Club Member
Interesting, look to be a catcam product so should be decent.
standard valves are two piece friction welded afik very close to the head supertec are done higher up away from the head of the valve.
re phil's i'm 99% certain it dropped a valve seat not the head of the valve but the seat killed the valve. i've opened three f4r engines that have dropped a valve head, all have been pretty much 7,000rpm or higher at the time of failure and have just about destroyed the crown of the piston. all had the seat intact and the pictures of a few others i've seen had seats intact.
it did actually throw me at first when i lifted the upper inlet and there was a piece of the seat that had dropped out of the breather hole and was sitting on the plate. took me a few minutes to work out it was a piece of the seat.
re phil's i'm 99% certain it dropped a valve seat not the head of the valve but the seat killed the valve. i've opened three f4r engines that have dropped a valve head, all have been pretty much 7,000rpm or higher at the time of failure and have just about destroyed the crown of the piston. all had the seat intact and the pictures of a few others i've seen had seats intact.
it did actually throw me at first when i lifted the upper inlet and there was a piece of the seat that had dropped out of the breather hole and was sitting on the plate. took me a few minutes to work out it was a piece of the seat.
Thanks, i was aware of that.
I've changed gearboxs, but only because I bought one with a Gripper in ;-)
Still have the original box which came with the car, fully working.
SWL16
ClioSport Club Member
Clio 182
Mine was £240 delivered lol. If that's not cheap I dunno what is
