....and you still decided to run a underdrive pulley?

When I went turbo,the underdrive pulley was the first thing to come off my car.

 

I disagree that the clutch should be balanced with the engine, unless you expect your engine to outlast the clutch.

 

Sarcasm?

 

I think you might be able to weld that back together.

That's why I spent $400 on a billet EDM'd oil pump.

Mark

 

That's what I was planing on, I might as well do it since it is all gonna be out there anyway.
Here is the real question for us to scratch our heads over.
If you lighten your crank (ie. knifedge*spelling) is it more likely to increase crank flex ,decrease or stay relatively the same. Common sense tells me, less metal=less strength=more flex. But I could be wrong. It is something I've been wanting to do, but I'm starting to change my mind.

Stealth-As far as clutch goes, I'd rather have a balanced assemby to begin with and then go slightly out of balance then have an unbalanced assembly from the start.
High performance OEM cars get their rotating assemblies balanced with the clutch assembly attached, so why wouldn't I?

 

I would think that the metal your taking off is far enough from the centerline that its wieght is being used as leverage against the crank rather than supporting it. But I won't lie, I don't know what I'm talking about when it comes to that, so its just a theory.

 

Mark, where did yo get your EDM'd gears? Did you just get a one-off, or from Bill W.?

JT-no it makes sense what you are saying, neither of us here have a clue, it's good to hear other points of view.

 

Dan, when you lighten the crank you take material off in areas that won't (or shouldn't) reduce it's strength. And because the crank is now well balanced, you should suffer less harmonic/imbalance issues.

 

Ben, that's what I was hoping to hear.

 

Mine was a first gen set from Bill W.

 

soft rev limit is set to 7000 and hard is set to 7200. typically i never rev it out that far, I don't have to. but the car was breaking loose like a ************ in 2nd and raping the rev limiter when it happened.

 

I was new to the turbo scene and took the advice of 2 people i USED TO respect in that area (OlderGuy and RobR ) and totally ignored the advice of the man that made my car the highest HP 1.8 Miata running the underestimated GT2560R, my boost mentor who I will never doubt again, TurboTim.

evidence here http://www.miatamob.org/speakeasy/in...ic,1741.0.html

jk Bruce.

 

Paul, quick question...were you running without the a/c compressor and bracket bolted up to the block?

I am trying to tie OP failures to something else.

Tony

 

I run no AC compressor and no power steering. My car has 1 belt.

 

Did you replace the bolt that the arrow is pointing to after taking off the a/c?

The reason I ask is that I have seen many Miatas with this bolt missing after someone removed the a/c.

 

actually that bolt was not in place. When I originally removed my AC and that godforsaken iron bracket I replaced that bolt. But last summer we put a 99 motor in my car and I noticed when removing it that that bolt was not there.

Whats your theory?

 

Paul, that bolt is the primary support for the left side of the oil pump.

The alternator bolt supports one side and that one supports the other side.

I am thinking that some of these pump failures are caused by that missing bolt. Since the pump is not tightly secured, it starts moving around at high rpm causing the gears to shatter.

Look at the size of the boss on the pump that the bolt fits...that bolt was meant to support the pump!

Try something...when you start putting it back together, tighten all the other bolts up on the pump and leave that one out. Then install that one and notice the clamping force and the movement of the pump.

I have been racing/building Miata engines for a long time, and I have seen this issue many a times.

Tony

 

^^^Good observation and good info. I'll keep that in mind for sure.

 

Rev limiter rape-age probably did't help lol

 

the oil pump had no movement even after ALL the bolts were removed. I had to pry it loose. There was no play.