Building a 7 bolt... What clutch?

[Matt D.]

Mike sure as hell knows how to build a motor, but Careys walked last year?
And it was determined to be caused by a soft crankshaft. The new crank he has now has been re-nitrided.

[Pimpin Dsmstyle]

And it was determined to be caused by a soft crankshaft. The new crank he has now has been re-nitrided.I'll quote mike. " Un even wear on the bearings". He said nothing about a soft crank to me. I'm not saying that was the problem, but he didn't mention that to me.

Point is even if you only spend 400 dollars to build this, that is 400 dollars you could have put into a good engine.

[JET]

Mike didn't mention anything about a soft crank to me either. He showed me a 7 bolt block and told me to look at the webbing in it. It is much thinner than a 6 bolt. The thinks it is allowing the crank to move around some. It seemed pretty viable to me. It definately is thinner than a 6 bolt.

[cudvig]

I say go for it jake! its cheap to do it and you got the parts at a killer price. If it walks...oh well. If it doesnt you will have a faster car for cheap. Plus how many motors actually walk anyway? not more than 50% do, and I hear if its less than a 50% chance, go for it. DO IT JAKE, YOU KNOW YOU WANNA!

PS if you need any help in your decision, give me a call!


-Colin

[Matt D.]

*shrug*
I know when I saw the crank and the thrust bearing side by side Mike pointed out that the crank's thrust surface was severly worn, but aside from the metal deposits from the crank on the bearing, the bearing itself was fine.

[Alpine TSi]

I too specifically remember Mike talking about the softer crank issue on the 2G 7 bolt. He had said that he was going to get it nitrided in an effort to prevent that damage again.

[JET]

Yeah, but the crank isn't even supposed to touch the bearing! As far as the bearings are concerned, the crank could be aluminum and be fine.

So how is the crank touching the bearing? There could be a lack of oil (or too much pressure breaking through the oil layer) or either the crank or bearing are getting out of position.

[dumb_ricer]

Cudvig, since when does a built motor mean a faster car?

You still dont want to tune much different and the compression ratio is the same, so the only thing you are changing is the ring's, so a little bit better compression numbers, but not neccesarily any more power for the price.

[niterydr]

Yeah, but the crank isn't even supposed to touch the bearing! As far as the bearings are concerned, the crank could be aluminum and be fine.

So how is the crank touching the bearing? There could be a lack of oil (or too much pressure breaking through the oil layer) or either the crank or bearing are getting out of position.
I would bet the 2900lb pressure plate pressing against the crank doesn't help. The oil layer in there is very thin, and can be seperated very easily. The point of nitrating the crank was to help prevent further wear once contact is made, but then the bearings die...
I say nerts to 7 bolts entirely, its like trying to make a ford fiesta fast, sure it can be done, sure it can be done for cheap, but why bother when there are better options?

Chris C's motor had alot $$ into the machine work (I won't disclose the amount, thats his decision). Everything was done to the block except maybe machine the block to retrofit thrust washers like the 6g72 and most honda motors... There was nothing conceiveable left to try to make it 'crankwalk proof' except switch the clutch out and give the crank a fighting chance.
I am sure it will still walk, its a 7 bolt, just hopefully at a slower pace. But thats just my $.02.

[Shane@DBPerformance]

I say nerts to 7 bolts entirely, its like trying to make a ford fiesta fast, sure it can be done, sure it can be done for cheap, but why bother when there are better options?


$200 block, $150 in machine work including balancing, keep old front cover and oil pan, 700whp...