engine wear rates
Turbo Mini Forums

OK,

I've seen various posts on what the overall mileage expectancy for a turbo'd "A" series is... but, what is the deciding factor ???

Assuming there is no mechanical failure, which wears fastest once turbo'd, ie, bores or crank ??? Or is it something else ???

Because I'll be spending a lot on the electronic side, I've decided my first attempt will be "budget" on the mechanical side so I've been going through all my bits today measuring them up to see which I might be able to use without rebore / crank grind.

Obviously I will need some suitable low compression pistons anyway (so may have to do a rebore if I can't get a size that matches my least worn block), but, given the choice of block or crank, where would you spend the money first ??? Worn crank or rebore ???

In other words, are the "A" series less tolerant of bore wear or crank wear once turbo'd than they are in standard form ???

Hope that makes sense...

Rod.

PS question is engine only... I've already worked out how many bits I need to replace/upgrade in the gearbox/drive train !!!

Schrödinger's cat - so which one am I ???

Judging by the lack of response, i think the answer is that we do not really know which wears fastest.

I think that it is possibly because parts break rather than reach the "worn-out" stage.

However, I would not assume that you have to regrind the crank or bore the block, just because you are building a turbocharged engine.

I'm assuming that we are talking about a midly boosted application in this instance. Obviously, if you are looking to go high boost, say above 10 psi, then it is a different ball game. The same goes if you are planning high mileages.

If the block can be cleaned up with a hone and the skirt to bore clearance is still within tolerance, then do not bore it. However, if you are re-using pistons then make sure they are in good condition, particularly the ring grooves.

Also it may be more cost effective to open out the head than buy low compression pistons.

Likewise, if the crank is within tolerence, then use it as it is.

My EFI test engine was an 80,000 mile MG Metro unit. The crank and bores were within tolerance, so i just honed the bores, new rings and new shells and it runs just great. No rattles, no smoke and minimal oil consumption.

It has now done 6000 miles since and has been regularly run up to 6000rpm recently doing the datalogs.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Schrödinger's cat - so which one am I ???

paul has sumed it up for you

Regular oil & filter changes plays a big part in things

and nothing less than a 15/40 grade