Does the 4.5 use a billet crank ?
Discussion
This whole misconception that "billet" is the thing to go for kind of worries me. Surely what you want is a forged steel crank, rather than one which is cut from a billet?
Or does the reference to "billet" refer to there being a crank forged from a steel billet? Either way I'd still say "forged steel" was the type of crank required, just in case there is any confusion.
Anyway, I have read a lot of reports claiming the 4.5 always had a forged steel crank installed but nothing as concrete as a factory claim.
Or does the reference to "billet" refer to there being a crank forged from a steel billet? Either way I'd still say "forged steel" was the type of crank required, just in case there is any confusion.
Anyway, I have read a lot of reports claiming the 4.5 always had a forged steel crank installed but nothing as concrete as a factory claim.
Edited for spelling - remember "there, their and they're"
Edited by Mars on Sunday 11th May 19:38
Power. Interesting concept to quantify in terms of component breakages. What is it about the power delivery that breaks engines?
I'd say that the issue is rarely about the power figure that the engine makes (that printout you get from the RR). Pistons can be broken by too high a BMEP figure... cylinder pressure essentially, which I believe peaks at low revs, or they can break if the engine is revved too hard. A high BMEP will put a hole in the piston or break off a ring land, maybe disintegrate a piston entirely. Revs will break the piston at the skirt/pin area (a ridiculous number of tonnes are exerted on a pin at 8000rpm through the accelerative forces).
A piston is more likely to break through excessive BMEP than a rod, so a rod is usually only likely to break because of excessive revs.
Cranks are limited by revs too but even that figure can be massaged by proper balancing.
I used to run a Caterham and had a few rebuilds over the years. I learned a lot from the people who did the work and the forums they contributed to. One guy, who worked at Rover, had tested the cast cranks and rods against the forged steel ones and found that if you could keep the harmonic vibrations down, they deformed less than the steel ones, up until they failed. So if you balance those rotating parts properly, you can achieve quite remarkably powerful and robust engines.
The 4.5 may or may not be on a forged crank but don't be put off by it potentially having a cast crank. I'm not aware of any failures of the 4.5 cranks, rods or pistons and I'm fairly sure the rods and pistons are "nothing special" even if the crank is.
I'd say that the issue is rarely about the power figure that the engine makes (that printout you get from the RR). Pistons can be broken by too high a BMEP figure... cylinder pressure essentially, which I believe peaks at low revs, or they can break if the engine is revved too hard. A high BMEP will put a hole in the piston or break off a ring land, maybe disintegrate a piston entirely. Revs will break the piston at the skirt/pin area (a ridiculous number of tonnes are exerted on a pin at 8000rpm through the accelerative forces).
A piston is more likely to break through excessive BMEP than a rod, so a rod is usually only likely to break because of excessive revs.
Cranks are limited by revs too but even that figure can be massaged by proper balancing.
I used to run a Caterham and had a few rebuilds over the years. I learned a lot from the people who did the work and the forums they contributed to. One guy, who worked at Rover, had tested the cast cranks and rods against the forged steel ones and found that if you could keep the harmonic vibrations down, they deformed less than the steel ones, up until they failed. So if you balance those rotating parts properly, you can achieve quite remarkably powerful and robust engines.
The 4.5 may or may not be on a forged crank but don't be put off by it potentially having a cast crank. I'm not aware of any failures of the 4.5 cranks, rods or pistons and I'm fairly sure the rods and pistons are "nothing special" even if the crank is.
Suspension points are different, I think the GT was the sort of prototype for the 4.5.
There is a thread with pictures in here somewhere, it was a Jules's workshop for a while.
Oh on crank front, had mine open, 4.5 rr 2001 steel crank yes, forged not billet , was noted that the crank, rods pistons very well ballanced. In fact the guys said it was "one of the best put together engines they had seen"
There is a thread with pictures in here somewhere, it was a Jules's workshop for a while.
Oh on crank front, had mine open, 4.5 rr 2001 steel crank yes, forged not billet , was noted that the crank, rods pistons very well ballanced. In fact the guys said it was "one of the best put together engines they had seen"
Edited by Nickccc on Monday 12th May 17:26
Edited by Nickccc on Monday 12th May 17:33
Nickccc said:
Suspension points are different, I think the GT was the sort of prototype for the 4.5.
There is a thread with pictures in here somewhere, it was a Jules's workshop for a while.
Oh on crank front, had mine open, 4.5 rr 2001 steel crank yes, forged not billet , was noted that the crank, rods pistons very well ballanced. In fact the guys said it was "one of the best put together engines they had seen"
No surprises there then Nick, I don't think many 'standard' 4.5's or 4.5RR would make 440hp even with fettling, nice to know its a good'un internally though There is a thread with pictures in here somewhere, it was a Jules's workshop for a while.
Oh on crank front, had mine open, 4.5 rr 2001 steel crank yes, forged not billet , was noted that the crank, rods pistons very well ballanced. In fact the guys said it was "one of the best put together engines they had seen"
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