Thorwon

I'm going to build it back to a 4.0, all I need are pistons. I have the rest of the parts.

What I didn't do was check the original 258 rod/piston assembly weight compared to the new rod/piston assembly weight. What I have found so far. The rod/piston assemblies are 124gr different from the original 258 rod/piston assemblies. The new rod/piston assemblies are lighter by 124gr. All new rod/piston assemblies are less than 1gr different in weight. This weight is including rod, piston, rings and bearings. The local speed/machine shop wants $375 + any heavy metal needed to check/balance the crankshaft.

The power steering pump and harmonic balancer are only things that were new when I put the engine in the truck. Everything else is from the engine I took out of the truck that I built the stroker from. No fan clutch or fan. I'm running three electric fans. The flex plate is from the truck. It's original as far as I know. I have two more in the shop I'm going to compare all of them today.

Well the balancer didn't help it. I guess I'll be pulling the engine, so I can remove the crankshaft. I've got to see if there's a shop local that can balance it.

Good article. I made a spacer for the extra length. My 6 x 18 Craftsman lathe comes in handy for things like this. My concern is the new balancer may be made wrong/unbalanced. I'm going to change it with a used one off a known good running engine.

I understand they are internally balanced. But if the new balancer is not right changing it should tell me. The torque converter bolted up with no issues. I was just wondering if the crank pilot bore may need a bushing for the AW4 torque converter. I don't think the AW4 was ever put behind the 4.2L.

It's the 4 weight crank. I have no pics of it. I'm going to change the balancer, if I can find the old one, to be able to rule that out. Can anyone answer this? Question for ya'll. I'm running a AW4 behind the 4.6, can anyone tell me what the pilot hole in the rear of the crankshaft is? I never checked to make sure the torque converter fit the crank.

Yes it makes it when parked and revving the engine. It's the non weighted crank. I've always just called it the light weight crank. I am positive the vibration get bad as the RPM goes up. Question for ya'll. I'm running a AW4 behind the 4.6, can anyone tell me what the pilot hole in the rear of the crankshaft is? I never checked to make sure the torque converter fit the crank.

The crankshaft was not spin balanced but all the other components were balanced. I checked every thing.

I've built a 4.6L short rod stroker. I used a 1988 Comanche block, the light crankshaft and rods from a 4.2L. SPEED PRO Hyper H802CP40 pistons. The camshaft is a Crane Cam H-260-2, .456 intake .484 exhaust. And a 7120 head. I put a new Dorman 594-018 Harmonic Balancer on it. It starts and runs great, but at about 2500 RPM there's a vibration and the higher the RPM the worse it gets. Idling it's as smooth as it should be. Everything I can think of is right. Anyone have any ideas what it could be?

My 1988 MJ has a new pair of wires coming through the firewall just below the MAP sensor that my CPS plugs into. I guess someone has done something similar to my Comanche. It also has the old CPS wire still in the main harness.

Thanks for the offer. I have a friend that's bringing 2 over so we can see if that's the issue.

So nobody can tell me if this will work?

You can buy the correct fittings to connect to the fuel rail. Just purchase fuel line rated for fuel injection and clamps for fuel injection, then build them. This is how I replaced the lines on my MJ.

I have a 1988 4.0 that I just realized has a HO distributor in it. I don't have a Renix distributor at all. I've taken 3 Renix systems from 3 different vehicles apart and they were all the late model distributor. Is this common or did someone not know what they were doing and install the wrong distributor. What mods are needed to run a HO distributor in a Renix? Or are they interchangeable? This is the distributor I have.