z24i engine noise

[Milliterate]

I have an 89 d21 that I just purchased, It has a z24i crate engine from Jasper engines. I was told there are only around 5k miles on it. I haven't hardly had a chance to drive it much, but I had driven it enough to gather that the engine seemed pretty solid.
It has been sitting for over a week and I haven't done a thing to it, but when I started it up to go get it registered, I noticed a loud rattling noise coming from what sounds like the middle to lower part of the engine. Its an unsteady mechanical rumbling/rattling. It is clearly audible at idle, and it gets more aggressive with throttle, so it must be associated with some rotating mass. Is something loose in my crankcase? I've thought maybe the starter solenoid isn't disengaging the teeth from the flywheel, as it does have trouble starting sometimes. What would cause this? And how could it have happened when I wasn't even driving the truck? It's just disappointing as I thought this crate engine was pretty mechanically sound...Anyone have any experience with Jasper engines?

[Rev_D21]

I dealt with Jasper back in my medium duty truck repair days. I can't say anything bad about them. They are supposed to have one of the best tech help depts out there. It could be a chain noise you are hearing. Have you tried contacting Jasper yet?

[Milliterate]

I haven't tried contacting Jasper yet. I could try that tomorrow. Is there any sort of timing chain guide in the z24 thats prone to wear? I had to pull one out of my ka24 that had snapped off and was just hanging out under the valvecover. But this really sounds like a loose object in the crankcase. Hard to pinpoint the source, but somewhere deeper in the engine.

[Rev_D21]

Z24 engines don't have the same chain issues the KA did, you are lucky that way. Could be loose rod caps if it's coming from the bowels of the block.

[Milliterate]

Should I yank out the oil pan and check it out in and around there? It looks like it would come out pretty easy, wish I had an FSM, I understand they're hard to get ahold of for the older D21's.

[Rev_D21]

Shouldn't be too hard. I think the only thing in your way is the crossmember under the oil pan. We have a huge FSM collection at www.nicoclub.com/FSM if that helps. I have an 85 FSM I reference for some of the 720 guys from time to time that covers the Z24.

[Milliterate]

Do you have any scans of the Engine Mechanical section? Or torque specs perhaps?

[Rev_D21]

Here you go. Click the link for a full size version of this scan.

http://img811.imageshack.us/img811/135/z24breakdown.jpg

[Milliterate]

Thanks so much! I'll at least try to inspect this before I take it in anywhere.

[Milliterate]

Turned out to be the flywheel, the bolts were coming loose from the crankshaft. I took it to a transmission shop and got it taken care of. That's practically the only mechanical part on the truck that hasn't been replaced, figures it was about to crap out..

Mostly I was concerned with the crate engine, but it appears to be unaffected.

[jdansmith]

Thanks for updating, I didn't think about that. Glad you got to the bottom of the noise.

[Milliterate]

The previous owner said the transmission was rebuilt about 40,000 miles ago...apparently they did a pretty shoddy job, it was missing the pilot bushing, which explains why the flywheel was working its way off the crank...and it was missing a bushing for the shifter too, that thing was so loose before I couldn't hardly tell if it was in neutral or not. Drives MUCH better now, good thing I got all that out of the way early on.