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Old 22-12-2006, 09:37 AM
  #241  
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Mmmm, the middle two always suffer.

What plenum are you using?
Old 22-12-2006, 09:38 AM
  #242  
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Did both failures occur at the same boost and for the same time it has held flat out?
Old 22-12-2006, 09:40 AM
  #243  
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The only way to measure backpressure in a manifold is to run it without turbo and measure pressure as close to the head as possible. All cylinders need to be measured and compared to eachother, the difference between lowest and highest pressure can be called Bp, I dont think you will see any...

One question.. What intake manifolds are you running?(those who melt engines) start there, a tip for you all.
Old 22-12-2006, 09:40 AM
  #244  
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just sorting the pic now
Old 22-12-2006, 09:49 AM
  #245  
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Pic of the "holed" piston



Rich
Old 22-12-2006, 09:50 AM
  #246  
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Originally Posted by CossieRich
Pic of the "holed" piston



Rich
what is the crown (bowl) thickness????
Old 22-12-2006, 10:04 AM
  #247  
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Originally Posted by martin-reyland
Did both failures occur at the same boost and for the same time it has held flat out?
First failure happened as we went into fifth at 165 mph so not long on the throttle, this time went at 174 mph, flat out in fifth for 13 seconds. Similar boost levels.
Old 22-12-2006, 10:06 AM
  #248  
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Originally Posted by Mike Rainbird
Mmmm, the middle two always suffer.

What plenum are you using?
Swedish with EEC IV throttle body.
Old 22-12-2006, 10:07 AM
  #249  
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...people just dont measure things in the right places Hmm middle 2 lets look at the 2wd manifold
Old 22-12-2006, 10:07 AM
  #250  
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Originally Posted by martin-reyland
Originally Posted by CossieRich
Pic of the "holed" piston



Rich
what is the crown (bowl) thickness????
Not sure.
Old 22-12-2006, 10:09 AM
  #251  
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Originally Posted by MAD Ade
Originally Posted by martin-reyland
Originally Posted by CossieRich
Pic of the "holed" piston



Rich
what is the crown (bowl) thickness????
Not sure.
Maybe it's the picture but it looks to be very thin. Is it a un-machined CP piston that's designed to gine 7.2:1 comp? I have a set of these on the shelf and could measure the thickness of mine to see.
Old 22-12-2006, 10:11 AM
  #252  
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Originally Posted by Bosch-Man
...people just dont measure things in the right places Hmm middle 2 lets look at the 2wd manifold
Phil, enough with your crap mate. This has the potential to be a brilliant thread now a pic has been introduced
Old 22-12-2006, 10:13 AM
  #253  
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Originally Posted by CossieRich
Originally Posted by Bosch-Man
...people just dont measure things in the right places Hmm middle 2 lets look at the 2wd manifold
Phil, enough with your crap mate. This has the potential to be a brilliant thread now a pic has been introduced
what he said!! Phil
Old 22-12-2006, 10:14 AM
  #254  
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martin-reyland

What should be the thickness in your opinion mate?
Old 22-12-2006, 10:14 AM
  #255  
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Originally Posted by martin-reyland
Originally Posted by CossieRich
Originally Posted by Bosch-Man
...people just dont measure things in the right places Hmm middle 2 lets look at the 2wd manifold
Phil, enough with your crap mate. This has the potential to be a brilliant thread now a pic has been introduced
what he said!! Phil
Sadly, i think its too late. Phil already has his claws into this thread
Old 22-12-2006, 10:19 AM
  #256  
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Originally Posted by martin-reyland
Originally Posted by MAD Ade
Originally Posted by martin-reyland
Originally Posted by CossieRich
Pic of the "holed" piston



Rich
what is the crown (bowl) thickness????
Not sure.
Maybe it's the picture but it looks to be very thin. Is it a un-machined CP piston that's designed to gine 7.2:1 comp? I have a set of these on the shelf and could measure the thickness of mine to see.
They are custom made CP jobbies, no machining done.
Old 22-12-2006, 10:22 AM
  #257  
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Just stating fact you village people ...just cause i aint got a good reputation dont mean i am wrong..

Its like walking on egg shells in here
Old 22-12-2006, 10:25 AM
  #258  
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Originally Posted by MAD Ade
Originally Posted by martin-reyland
Originally Posted by MAD Ade
Originally Posted by martin-reyland
Originally Posted by CossieRich
Pic of the "holed" piston



Rich
what is the crown (bowl) thickness????
Not sure.
Maybe it's the picture but it looks to be very thin. Is it a un-machined CP piston that's designed to gine 7.2:1 comp? I have a set of these on the shelf and could measure the thickness of mine to see.
They are custom made CP jobbies, no machining done.
They look identical to the one's I have, they probably came through a guy in Sweden who has loads of these made by CP, I will measure mine.
Old 22-12-2006, 10:28 AM
  #259  
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Originally Posted by martin-reyland
Originally Posted by MAD Ade
Originally Posted by martin-reyland
Originally Posted by MAD Ade
Originally Posted by martin-reyland
Originally Posted by CossieRich
Pic of the "holed" piston



Rich
what is the crown (bowl) thickness????
Not sure.
Maybe it's the picture but it looks to be very thin. Is it a un-machined CP piston that's designed to gine 7.2:1 comp? I have a set of these on the shelf and could measure the thickness of mine to see.
They are custom made CP jobbies, no machining done.
They look identical to the one's I have, they probably came through a guy in Sweden who has loads of these made by CP, I will measure mine.
Mark deals with CP direct in the USA.
Old 22-12-2006, 10:35 AM
  #260  
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Originally Posted by MAD Ade
Originally Posted by martin-reyland
Originally Posted by MAD Ade
Originally Posted by martin-reyland
Originally Posted by MAD Ade
Originally Posted by martin-reyland
Originally Posted by CossieRich
Pic of the "holed" piston



Rich
what is the crown (bowl) thickness????
Not sure.
Maybe it's the picture but it looks to be very thin. Is it a un-machined CP piston that's designed to gine 7.2:1 comp? I have a set of these on the shelf and could measure the thickness of mine to see.
They are custom made CP jobbies, no machining done.
They look identical to the one's I have, they probably came through a guy in Sweden who has loads of these made by CP, I will measure mine.
Mark deals with CP direct in the USA.
Can the thickness be found out? If Mark has had these done by CP he should have a spec drawing that they would manufacture to. Have to go to work now Will check in later... over to you Phil...
Old 22-12-2006, 10:56 AM
  #261  
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Ade,
The turbo you are using, could it be that the exhaust housing is creating too much back-pressure in internally gated format, and not actually the manifold?

I only ask, as you say that you were using the same turbo as Rod's, but internally gated, and Rod's was an externally gated GT35? I just can't see an internally gated GT35 being ANY good what-so-ever and MUST be causing back-pressure issues, due to the exhaust housing not being man enough? Obviously with this being a new design of turbo, the back-pressure was measured and recorded on the dyno? Is Mark prepared to divulge this, as it would be a good indication of it's efficiency .

Also, the piston's used are not suitable in my opinion. There is nothing wrong with CP pistons, just the spec Mark has chosen is completely wrong for this application and not suitable for 600bhp IMO.

The ones that we use are rated to 750bhp / 800Nm / 9500rpm and 2.8 bar and have a 4.8mm to 6.7mm thick crown (compression rato dependent). Your one looks like a standard piston thickness, which is not suitable IMO.

So to conclude, I believe that the engine failed because it built up too much back-pressure due to the TURBO having too small a turbine, this caused high cylinder pressures and punched a whole in the pistons, which are too thin for these kind of cylinder pressures.

Providing you change either the turbo back housing for a more efficient one, or go for the thick crown, I think you have found your cure . Obviously going for the bigger housing will require a change of exhaust manifold, so Phil can still attribute it all to this .
Old 22-12-2006, 11:13 AM
  #262  
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Mike,

intersting theory.

What thickness is the crown on standard CP piston?
Old 22-12-2006, 11:15 AM
  #263  
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There is no standard, you have them designed and built to your spec .
Old 22-12-2006, 11:17 AM
  #264  
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Mike,

You just said in your post above that it looks like Ade is using a standard piston thickness Which is what?
Old 22-12-2006, 11:19 AM
  #265  
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STANDARD COSSIE PISTON THICKNESS YOU NUMBNUTS .
Old 22-12-2006, 11:20 AM
  #266  
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Originally Posted by Mike Rainbird
STANDARD COSSIE PISTON THICKNESS YOU NUMBNUTS .
Mike,

I know that. Im asking you what that thickness is in mm, because i dont know
Old 22-12-2006, 11:31 AM
  #268  
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Originally Posted by Mike Rainbird
Ade,
The turbo you are using, could it be that the exhaust housing is creating too much back-pressure in internally gated format, and not actually the manifold?

I only ask, as you say that you were using the same turbo as Rod's, but internally gated, and Rod's was an externally gated GT35? I just can't see an internally gated GT35 being ANY good what-so-ever and MUST be causing back-pressure issues, due to the exhaust housing not being man enough? Obviously with this being a new design of turbo, the back-pressure was measured and recorded on the dyno? Is Mark prepared to divulge this, as it would be a good indication of it's efficiency .

Also, the piston's used are not suitable in my opinion. There is nothing wrong with CP pistons, just the spec Mark has chosen is completely wrong for this application and not suitable for 600bhp IMO.

The ones that we use are rated to 750bhp / 800Nm / 9500rpm and 2.8 bar and have a 4.8mm to 6.7mm thick crown (compression rato dependent). Your one looks like a standard piston thickness, which is not suitable IMO.

So to conclude, I believe that the engine failed because it built up too much back-pressure due to the TURBO having too small a turbine, this caused high cylinder pressures and punched a whole in the pistons, which are too thin for these kind of cylinder pressures.

Providing you change either the turbo back housing for a more efficient one, or go for the thick crown, I think you have found your cure . Obviously going for the bigger housing will require a change of exhaust manifold, so Phil can still attribute it all to this .
Mike,

we were using a custom high flow waste gate housing from the states which should reduce the back pressure plus control the boost more accurately, Mark would be able to explain this better. The pistons are exactly the same as Rods, he has done 200 mph (unoficially) without nos, so what else could it be?
Old 22-12-2006, 11:33 AM
  #269  
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..to add mine runs the same type of pistons as Ade i think...and i am sure it aint right that Harvey is telling Mark how to build an engine
Old 22-12-2006, 11:36 AM
  #270  
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Originally Posted by MAD YUM
Originally Posted by Mike Rainbird
Ade,
The turbo you are using, could it be that the exhaust housing is creating too much back-pressure in internally gated format, and not actually the manifold?

I only ask, as you say that you were using the same turbo as Rod's, but internally gated, and Rod's was an externally gated GT35? I just can't see an internally gated GT35 being ANY good what-so-ever and MUST be causing back-pressure issues, due to the exhaust housing not being man enough? Obviously with this being a new design of turbo, the back-pressure was measured and recorded on the dyno? Is Mark prepared to divulge this, as it would be a good indication of it's efficiency .

Also, the piston's used are not suitable in my opinion. There is nothing wrong with CP pistons, just the spec Mark has chosen is completely wrong for this application and not suitable for 600bhp IMO.

The ones that we use are rated to 750bhp / 800Nm / 9500rpm and 2.8 bar and have a 4.8mm to 6.7mm thick crown (compression rato dependent). Your one looks like a standard piston thickness, which is not suitable IMO.

So to conclude, I believe that the engine failed because it built up too much back-pressure due to the TURBO having too small a turbine, this caused high cylinder pressures and punched a whole in the pistons, which are too thin for these kind of cylinder pressures.

Providing you change either the turbo back housing for a more efficient one, or go for the thick crown, I think you have found your cure . Obviously going for the bigger housing will require a change of exhaust manifold, so Phil can still attribute it all to this .

Big Up Harvey
Actually the first Harvey knew of this thread was five minutes ago, when I directed him to it .

Rich,
Having just measured a standard piston and a Cosworth one, they are actually a LOT thicker than I thought. I believe you need to find out the thickenss of these pistons used, as they LOOK thin, but that just might be the camera angle / optical illusion.

Standard Mahles = 6mm
Cosworth (forged to 7.2 c/r) = 7.6mm

Once the crown thickness is confirmed, if it is as thin as it looks, it could be ENTIRELY attributed to this .

Ade,
I don't doubt you are running CP psitons, but perhaps you are running different spec ones? Have you the longer rods etc same as Rods? (no pun intended ).

Anyway, as long as any of this helps the engine being built and run so it is as reliable as the usual MAD lumps, then I'm glad to have been of assistance .
Old 22-12-2006, 11:40 AM
  #271  
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double post
Old 22-12-2006, 11:40 AM
  #272  
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double post
Old 22-12-2006, 11:41 AM
  #274  
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Originally Posted by Mike Rainbird
Originally Posted by MAD YUM
Originally Posted by Mike Rainbird
Ade,
The turbo you are using, could it be that the exhaust housing is creating too much back-pressure in internally gated format, and not actually the manifold?

I only ask, as you say that you were using the same turbo as Rod's, but internally gated, and Rod's was an externally gated GT35? I just can't see an internally gated GT35 being ANY good what-so-ever and MUST be causing back-pressure issues, due to the exhaust housing not being man enough? Obviously with this being a new design of turbo, the back-pressure was measured and recorded on the dyno? Is Mark prepared to divulge this, as it would be a good indication of it's efficiency .

Also, the piston's used are not suitable in my opinion. There is nothing wrong with CP pistons, just the spec Mark has chosen is completely wrong for this application and not suitable for 600bhp IMO.

The ones that we use are rated to 750bhp / 800Nm / 9500rpm and 2.8 bar and have a 4.8mm to 6.7mm thick crown (compression rato dependent). Your one looks like a standard piston thickness, which is not suitable IMO.

So to conclude, I believe that the engine failed because it built up too much back-pressure due to the TURBO having too small a turbine, this caused high cylinder pressures and punched a whole in the pistons, which are too thin for these kind of cylinder pressures.

Providing you change either the turbo back housing for a more efficient one, or go for the thick crown, I think you have found your cure . Obviously going for the bigger housing will require a change of exhaust manifold, so Phil can still attribute it all to this .

Big Up Harvey
Actually the first Harvey knew of this thread was five minutes ago, when I directed him to it .

Rich,
Having just measured a standard piston and a Cosworth one, they are actually a LOT thicker than I thought. I believe you need to find out the thickenss of these pistons used, as they LOOK thin, but that just might be the camera angle / optical illusion.

Standard Mahles = 6mm
Cosworth (machined to 7.2 c/r) = 7.6mm

Once the crown thickness is confirmed, if it is as thin as it looks, it could be ENTIRELY attributed to this .
Mike,

Many thanks for taking the time to answer my question.

As Ade has just said though, he runs the same pistons as Rod and he hasnt had any bother. I think maybe its not down to the piston thickness. Mark will be able to explain more about the internally gated GT35
Old 22-12-2006, 11:46 AM
  #275  
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The crown thickness on my pistons is 6mm, Rods are actually 5.5mm, and he's never had any issues with pistons melting.
Old 22-12-2006, 11:47 AM
  #276  
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YUM,
Fuck off, one thing I DON'T do is lie .

Also, Martin arrived at the same conclusion from seeing the pictures - did he phone Harvey as well?

Rich,
See my edited post .
Old 22-12-2006, 11:50 AM
  #277  
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Originally Posted by Mike Rainbird
Originally Posted by MAD YUM
Originally Posted by Mike Rainbird
Ade,
The turbo you are using, could it be that the exhaust housing is creating too much back-pressure in internally gated format, and not actually the manifold?

I only ask, as you say that you were using the same turbo as Rod's, but internally gated, and Rod's was an externally gated GT35? I just can't see an internally gated GT35 being ANY good what-so-ever and MUST be causing back-pressure issues, due to the exhaust housing not being man enough? Obviously with this being a new design of turbo, the back-pressure was measured and recorded on the dyno? Is Mark prepared to divulge this, as it would be a good indication of it's efficiency .

Also, the piston's used are not suitable in my opinion. There is nothing wrong with CP pistons, just the spec Mark has chosen is completely wrong for this application and not suitable for 600bhp IMO.

The ones that we use are rated to 750bhp / 800Nm / 9500rpm and 2.8 bar and have a 4.8mm to 6.7mm thick crown (compression rato dependent). Your one looks like a standard piston thickness, which is not suitable IMO.

So to conclude, I believe that the engine failed because it built up too much back-pressure due to the TURBO having too small a turbine, this caused high cylinder pressures and punched a whole in the pistons, which are too thin for these kind of cylinder pressures.

Providing you change either the turbo back housing for a more efficient one, or go for the thick crown, I think you have found your cure . Obviously going for the bigger housing will require a change of exhaust manifold, so Phil can still attribute it all to this .

Big Up Harvey
Actually the first Harvey knew of this thread was five minutes ago, when I directed him to it .

Rich,
Having just measured a standard piston and a Cosworth one, they are actually a LOT thicker than I thought. I believe you need to find out the thickenss of these pistons used, as they LOOK thin, but that just might be the camera angle / optical illusion.

Standard Mahles = 6mm
Cosworth (forged to 7.2 c/r) = 7.6mm

Once the crown thickness is confirmed, if it is as thin as it looks, it could be ENTIRELY attributed to this .

Ade,
I don't doubt you are running CP psitons, but perhaps you are running different spec ones? Have you the longer rods etc same as Rods? (no pun intended ).

Anyway, as long as any of this helps the engine being built and run so it is as reliable as the usual MAD lumps, then I'm glad to have been of assistance .

Mike,

yes I am running 8mm longer rods, I think Rods are 6mm longer, he has a stroker crank, mine is standard dimension crank.
Old 22-12-2006, 11:52 AM
  #279  
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have read your edited post Mike. Still looking unlikely to be pistons thickness though imo


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