There you go again, 8/9 microns is less than half a thou. Have a care with your postings… disinformation like that just confuses and makes you look careless.
Measuring a block after it has been in service is not the same as measuring it before. I had a long and detailed conversation with a man from Perfect bore on this very subject. His experiences showed that every time a K engine was assembled and dis-assembled,even with no usage, liner out of round and general alignment would vary - significantly. Following use they would vary some more. That is with stock liners and PB liners.
I always test the blocks I put together with a torque plate and gasket attached and have never observed anything to worry about, This is mostly done in front of the engine’s owner. Some have been measured with a head on and tightened.
I still do not understand how you can fit a piston to a bore that is 7 thou out of round when the pistons clearance is only 2.5 thou.
You should your experiences up with Scholar and see what they have to say, us two contradicting ourselves with our own differing experiences just clouds the whole issue.
For the record I have never built, nor helped to build any engine with an EVO4 block.
Because they are heavy, second rate, backward engines, that cost a fortune for 200/220bhp at best.
And if you try puhing them above 8500rpm, this happens :-
220bhp out the box for an actual short engine thats going to cost you �1500.
You speak of stock engines then an imagine of a broken engine rev’d beyond 8500 when stock engines aren’t rev’d that high as peak power is lower anyway. Your usual lies and distraction.
As DVA pointed out in that thread, which for some reason you chose not to quote:
"I have just undertaken a hardness test on an EVO4 block which came into my workshop for a short period. I tested the added material at the top of the block, the parent material around the bolt holes and at the ends of the block where the original parent material supports the gasket restricting bars, the head as a whole is supported on the liners which in turn are supported at their bases.
The original parent material at either end was an average of 115 Brinell, the parent material near the bolt holes was on average 95 Brinell and the added material an average of 80 Brinell. A test on the base of the block showed an average hardness of 112 Brinell, a test on the underside of the bores at the very base of the liners showed around 110 Brinell."
Thanks Johnboy for reposting and clearing that up. The test was done with freshly calibrated tester in full view of the owner who had heard stories about softening, TBH only the ends of the block where the compression bars sit need to be hard, the rest of the compressive forces are taken on the liners and liner lands.
[quoteThe VHPDisaster of course has a higher limit - 7800 rpm which is why the damper is totally useless, unless of course, it is used as a shopping trolly engine - ie those responsible for the engine - PTP - did not do the work.
[/quote]
I thought it was Janspeed there were responsible for producing the VHPDs for Lotus - they claim the following on their website:
OE suppliers for the Lotus 340R power-train, (348 engines built)
Built the Lotus Exige power-train, (600 engines built) 177bhp motor
Vibration may reasonably be expected to cause broken brackets (fatigue) and lose/missing bolts etc, This could be engine vibration, out of balance alternator/poor quality or some odd belt resonance.
Vibration could damage the electronics. But failure of the electronics maybe due to low spec electronics or over heating.
How often is it that the electronics fail?
I would expect the cooling air for the alternator electronics to be fed in the rear and expelled at the front. Is this the case?
The heat shield would only reduce the radiated heat. How easy is it to feed cool air to the rear electronics?
Are higher spec more heat tolerant electronics available?
In practice there is little airflow over the alternator in its installed position. The heat shield twixt exhaust and alternator exacerbates this problem.
All but one of the alternator failures I have seen have suffered with heat damage rather than damage sustained as a result of vibration/over spinning. It is possible to duct air from the side vent to the alternator and this will tend to reduce the possible effects.