I have a kindof strange situation, and am looking for some help. I have a 1990 miata with a 1991 Escort GT swap in it. I have been running a Jackson racing M45 kit on it for about 2 years, and it has been working great.
I am now in the process of putting together a homebrew GM 3800 M62 kit to replace the Jackson racing kit.
Step one is to upgrade to a 6 rib belt. It appeared that the easiest way to do this was to buy an overlay crank pulley from: fastforwardsuperchargers
So, I bought the one listed for 92-05:
Well - it doesn't fit. Why not, you say? Well, it appears that my Escort GT has the long nose crank (or small nose, whatever you want to call it), and appears to have a unique (not found on any Miata) balancer pulley. So, the 4 bolt pattern is much smaller than the overlay pulley, and the overlay pulley is not deep enough to fit inside the balancer.
So, I bought the other crank pulley that Fastforward has for sale - listed as fitting 90-92:
At first glance, this looks like it will work just fine. But it doesn't.
Why not, you say? Well, it looks like the unique Escort balancer pulley may have the step in a different location than the miata pulley? The OD of the crank overlay interferes with the step on the balancer, so it doesn't sit flush.
See the gap here:
I'm thinking this may be fixable by using a 1.6L short nose balancer pulley???? - the kind from early 1990-1991 Miatas.
Specifically, this one here, most easily identified by the 4 oval slots and the keyway in the middle:
Here is a comparison of the late "Long nose" 1.6 crank pulley on the left which I don't need, and the "Short nose" one on the right which I think might work.
Any thoughts on this???
I can buy a brand new short nose balancer pulley and associated parts from Mazdaspeed for ~$150. But, I could also buy an entire Escort GT engine with the big nose crank for $200.
But, I'm not sure that the big nose crank works with the Fastforward pulley anyways.
Here is a comparison of Big nose vs Small Nose Escort GT balancer pulleys:
And, here is a photo of the big nose escort balancer pulley with the "correct" fastforward 6 rib pulley:
And, here is the giant gap between the pulleys - meaning the late fastforward pulley doesn't work with this either: