Let's design a 3.2 short stroke!

[Wayne 962]

Originally posted by dtw
Wayne, what is the "Mod S" cam you refer to? Any reason you didn't go with something hotter for this larger displacement motor?

The Mod-S cams are an improvement on the 'S' cam profile - designed by Elgin. I was going to go with 'S' cams, but then I saw these on eBay, and I just had to have them.

A hotter cam would probably give more power, but I want to keep the engine's power band pretty uniform (less peaky). The 'S' cam on the 3.2 is a well-proven combination that gives plenty of low-end torque.

-Wayne

[Wayne 962]

Originally posted by Tinker
Wayne,

How much is the dual HPX ignition?

Is this the most cost effective way of obtaining dual plug ignition?

Tinker

List price is about $1500, I think we sell it for less than that.

Cost effective? Probably about the same as the other methods, but you can control timing, and you never have to buy distributor caps again. Plus, the system has a good resale value on the market. I have an extra one used, if anyone is interested. I think I want $850 for it (it's an earlier model HPV system).

-Wayne

[Wayne 962]

Originally posted by Elombard
I am curious why Steve says no JEs for the street? I have been thinking they were a great way to go, do I need to reevaluate?

I don't think that Steve says this specifically, I think he said he would prefer Mahles to the JEs with everything else equal for street engines.

The JEs are a fine alternative, and can be very reliable too. Also, they are significantly less expensive when doing a rebuild.

-Wayne

[concentric]

Originally posted by Wayne at Pelican Parts
What I meant to imply that building a motor like this - gas mileage should not be top on your list - if you want good mileage, stick with the stock 3.2 + Motronic...

-Wayne

Thanks for the advice... I've been hemming and hawing over which way to go, twin-plug short-stroke 3.2, or 3.2 with a SoK supercharger. I'm leaning towards the SoK 3.2, much better bang for the buck, and supposedly good milage too.

As an aside, I got both the 101 projects and the Engine Rebuild book in the mail yesterday, they're great. Nice job on the info, layout, and look.

JCM

[emcon5]

Originally posted by Elombard
Bore and replate my Alucils (~$1000)

Can't do this with 3.0L 95mm cylinders. The grove for the sealing ring makes it impossible. EBS can bore out 3.2L 95mm jugs, as they don't have the groove.

Tom

[Elombard]

Thanks Tom I forgot about that. Better refigure my Budget.

[724doorE]

Now when they bore out the 95's to 98 do the need to replate?

[ChrisBennet]

Originally posted by 724doorE
Now when they bore out the 95's to 98 do the need to replate?

Yes.

[jacko241]

I have a 3.0 SC twin plug engine with 10.2 comp., ported heads, RSR cams, 46mm Webers, and Electomotive XDI twin plug ignition, 1 5/8 headers with megaphones. Any idea of what kind of power increase I would see by just swapping to 10.5 comp. 98 mm pistons and cylinders to make it a 3.2 short stroke? Are the 98mm cylinders slip in or do the require the case spigots to be bored?

[camgrinder]

Jacko, how high do you rev this engine, and what kind of fuel are you running?

[jacko241]

John, it is in a dedicated race car, and I am shifting at 7400 rpm. I am running 112 Sunoco leaded racing fuel.

[camgrinder]

I would increase the compression ratio up to 12-1 at least. with the type of fuel you are using you will have no problems and you will get a nice increase in torque and HP. I would also run the car on a chassis dyno with the combination you have now with the 112 fuel. I would also try some 100 or 104 octane. You should see a small increase in power with the lower octane fuel. With 10.2-1 and twin plugs the engine will be fine on 100 octane.

[jacko241]

Yes, I want to run it on the dyno, but it hasn't been in the budget. I always worry about reliability when increasing compression ratio.