RB30 engine conversion (lots of pics)

[Asim R32GTR]

Originally Posted by Hugh Keir

sleepyfox,

As far as I understand it, the cam belt flex is induced by the resistance of rotating the cams + crankshaft flex.

As the engine becomes more loaded under high boost at high RPM the crank will flex more with each combustion which causes more inaccuracies in cam and ignition timing.

Removing the ignition timing aspect of the above by triggering the ECU from a non cam belt driven source is a large part of the solution.

How big of a problem is the fluctuating ignition timing??
To be hones, i knew about the drawbacks of using a cam driven sensor for crank position. But i never knew it was a problem until now.

Did i do the right thing in selling my pfc, and going for the autronic?

Asim,....

[R32 Combat]

I've turned the trigger disk now, modded the crank pulley and sorted out the 'fixing onto the bottom pulley' problem.

Next is milling the teeth...

[Asim R32GTR]

Originally Posted by R32 Combat

I've turned the trigger disk now, modded the crank pulley and sorted out the 'fixing onto the bottom pulley' problem.

Next is milling the teeth...

Any pic of your work so far Mr Combat

Asim...

[R32 Combat]

1st turn the pulley like this..





Then make this..



And it should look like this..




Obviously that are not bolted together yet and there are no teeth(30).

It's important that the outer part of the pulley has a little room to move without touching the trigger disk..

[ahapartridge]

Will you be getting the assembled unit balanced Andy?

[R32 Combat]

Good point, I hadn't thought of that. Then yes, I guess I will. Thanks

[Scooby]

Guys;

Not doubting that belt flex contributes to the scatter issue, but might it be exacerbated by wear in the CAS spline? There are cases where scatter has been alleviated significantly by addressing this.

Cheers

[AndrewD]

How is the milling process controlled? ie is it manual or are you cnc'ing it?

Would it not be easier to get the outer tooth profile wire cut and then perform the lathe operations?

You could use the key that is already used for mounting the shaft for the trigger wheel also. No need to bolt anything in. Also you then have the same reference and only that reference if you need to reassebmle the unit.

[R32 Combat]

I'll CNC mill the teeth. I don't have access to a 4 axis EDM machine, which I would need to cut the teeth accurately. If I cut the teeth first, it would ring like hell turing the OD and I'l have a fair amount of chatter. I thought about mounting it straight onto the crank, but I don't think lining it up will be hard, I'd have to do that whatever I did.

Certainly I think the CAS mount on the camshaft IS an area where movement can occure, but thats not an issue doing it this way.

[R32 Combat]

I've finished the disk at last, its being plated tonight, I'll post up some pics tomorrow..

[R32 Combat]

The finished article.

[sleepyfox]

Nice work. Looks like someone had a similar idea to you with their RB26 powered 240z

[NISFAN]

Good stuff Andy much neater than my bought laser cut job.
Do you not need a missing tooth for clocking engine position with the AEM? Or is it cam signal that positions cycle?

Sleepyfox,
Looks just like my setup for my DTA Fast, also on ATI damper.

[R32 Combat]

I don't need a missing tooth, I'll use the CAS #1 for sync.

I think missing tooth is pointless on a 4 stroke, what does it tell you? Where #1 TDC is, but which stroke? Hence using the CAS.

[NISFAN]

Originally Posted by R32 Combat

I don't need a missing tooth, I'll use the CAS #1 for sync.

I think missing tooth is pointless on a 4 stroke, what does it tell you? Where #1 TDC is, but which stroke? Hence using the CAS.

Yes true, but many aftermarket ECU's are designed to run without a Cam sensor, so as a basic requirement need a missing tooth.

This helps on ECU's like mine, because if the cam sensor fails whilst driving, it will go into wasted spark, and non sequential injection. Still allows me to drive home.

You'd be surprised at the number of people using non seq. on race type ECU's, even though they have the capability. Makes no difference to power apparently, so they go for simplest option.