Yeah, this bites. replaced the timing chain on the 2.8 (the old one was shot) and fire her up, and no more 'knocking' yay!

Well, I went about 1/4 of a mile, and the knock came back.

Weirdest damn thing. Start the car up, extremely light knock, and as it sits there and idles, it just gets louder.

I want your guy's (and gals!) opinions on what it might be.

History of the car -

Ran great, then developed a lifter tick.
Turbocharged it (6psi, spiked to 8 once) (popped a set of used 22lbs/hr injectors in it, with a new prom chip)
Lifter imploded.
Replaced lifter/pushrod (I know, I PREACH to never do that, but I was broke at the time)
Replaced the timing chain.

Car has 110k miles on it. This knock is EXTREMELY loud (I can hear it over open exhaust! ) , and I want to say it's a rod knock, but the engine runs smooth. Accelerates smoothly, as long as you don't floor it - then it stalls.

Opinions?

 

time for a 3.1l (lower compression then 3.4l )

Are you sure all valves on got tightened down properly?

Have you done a compression check?

 

i asked my dad about it and he said that it about has to be a rod. he said that wouldn't necessarily keep it from running smoothly. but we don't know why it'd stall when you floor it. you still running your chip for the turbo? if so, it may be way too rich.

 

I think when I floor it, and go into PE mode, it's flooding it out... so yeah, AM91, that's probably it.

I'm pretty convinced it's a rod bearing, too.

Strange thing is, it's cheaper for the 3.1 crank kit, than the 2.8!

AM91, you remember that 3.1 I got from you? It's going to be getting a cam kit, crank kit, timing kit, and fresh heads on it. Did you ever run a compression test on it? Before I do all that, I'd like to be sure the rings are ok.

As far as the 2.8, I ran a compression test on it a few months back (well, like last year) and everything was 155psi, +/- 5 psi (from 152 to like 158)

I'm going to check the ridge on the 3.1. If it still looks good, I'm thinking that's going to be the best route.

 

doward, i never did a compression test on that motor. it always seemed like it was fine though. you're going to P&P those heads before a valve job, right? what have you gotten done to it so far?

 

For the money Id pick up one of them $200 new crate 2.8s off ebay.

 

why spend $200 on a new 2.8 when his current 2.8 is only in there till the 3.1 is done?

 

I like the 2.8 better.

 

well doward when you get around to sending me some winaldl datalogs then well be able to fix that. id still like you to purchase or find a GN maf. its got more resolution and a higher flowing calibration. just have to make a small change to the maf tables. easy stuff really.

 

Did u ever check to see if the distributor gear is worn or missing teeth?