I'm buying a 93 Prelude tomorrow that has some engine troubles. The H23 in it was rebuilt 30,000 miles ago. I think that consisted of new rings/pistons, and maybe something else.

The problem: After the car warms up, and the idle drops, or after driving and returning to idle (like at a stop sign, or completely stopping), the low oil pressure light comes on and it starts knocking, sputtering, and making strange noises. I havent heard it first-hand, but someone that has owned several Honda's, and built several motors for them has heard it. I'm thinking it has something to do with the oil pump, but I've never heard of a Honda oil pump going bad.

Any thoughts? I'll know a little more tomorrow after I look at myself.

 

The oil heats up and gets thin enough to lose oil pressure, could be the pump. It wouldn't surprise me if they dumped some heavy oil in it to get that far. Main thing is, if the oil light comes on your at the point it has already done damage to the motor. I'd steer clear of that one!

 

I'm gettin it cheap enough to afford some repairs, and maybe a shortblock. When this started happening, they parked it and it hasn't been driven very much.

 

I got to listen to the car today. It had been sitting for about 5 days, and cranked right up. It was knocking real bad at first. Almost like a piston slap, but then got quieter after a few minutes. I let it run for about 5 minutes before shutting it off. Never saw the low oil pressure light.

The motor was rebuilt 30K miles ago with the following from what I could understand of it: some new bearings (not all), new rings, some new parts in the valvetrain, and some headwork. I don't know to what extent all of the work was done, and when I say some, I mean not all. They put the stock pistons and rods back in with the new rings. There may have been a few other parts, but the owner wasn't sure. He didn't drive it very much at all after it started knocking, which I believe because he's pretty picky, and owns two other cars.

Any suggestions or thoughts? I'm getting it cheap enough to afford parts to fix it. The body is damn near perfect, and comes with a lot of extra stuff, so it's worth fixing.

 

Dropped the oil pan today and found some shavings in it. Looks like I'll need a shortblock...