Possible spun rod

[Desperado]

I won't know for sure until I get the oil pan off if I have spun a rod bearing yet. I've got 130 cold compression across all six Pistons and my oil pressure is good, but it sure makes a bad sounding knock like notice when I increase the throttle. But nothing showing up on my logger. My question is if it is a spun rod what are some good rods and Pistons to buy. I doubt I'll ever be over 500 hp, and just running stock now. I would like going aftermarket without killing the bank, but willing to spend for what I get. I'm not expecting 1200 rods for 300 bucks kinda thing

[sergechronos]

I won't know for sure until I get the oil pan off if I have spun a rod bearing yet. I've got 130 cold compression across all six Pistons and my oil pressure is good, but it sure makes a bad sounding knock like notice when I increase the throttle. But nothing showing up on my logger. My question is if it is a spun rod what are some good rods and Pistons to buy. I doubt I'll ever be over 500 hp, and just running stock now. I would like going aftermarket without killing the bank, but willing to spend for what I get. I'm not expecting 1200 rods for 300 bucks kinda thing

Not sure I'd go aftermarket, especially given your modest power goals. Forged rods and pistons require machining, to both the block and the crank. The bores need to be done to accomodate the way the forged pistons increase in size as they warm, a new hone, the rotating assembly needs balanced and weight matched, the big ends on the rods should be resized to achieve proper clearances (most come kinda loose.) You're normally talking about 1200 for the parts, and likely another 400 or more at the machine shop. I'd likely just try to source either another complete short block and sell what you've got (someone may want a spare block to build) or a used set of stock internals if you're not looking to go big with your turbo set up. If you want to go aftermarket, I run Ninja rods and Wiseco pistons, but Pampena pistons are pretty sweet as well (just a bit more than I could afford.) You also may want to look into a new set of wrist pins, in several cases people have found the ones that come with the aftermarket pistons are not up to snuff.

That having all been said, compression should be checked warm after running generally, but your numbers are fairly close. I'd pull the valve cover and check for signs of a rocker arm popped off or similar. The lifters/lash adjusters can also be a source of a loud noise that sounds like knock. Pulling the oil pan and checking your bearings is really the only sure way to tell whether or not you've got actual rod knock.

[Chris@Rvengeperformance]

cut open the oil filter, you'll know then.

[Desperado]

I ran the car for a bit pulling each spark plug off so see if I could determine one cylinder was making more noise than another. On that I couldnt tell a difference. After that I ran compression again with a charged battery and a warm engine and this time I was getting 40's and a couple 45s. Then I pulled the valve covers just to make sure I didn't lose a rocker. I've got the car where it idles good now, but you give it any gas and it stats to get rougher sounding and backfires. I've checked twice now, but tomorrow I'll redo my timing belt and this weekend I'll cut open my filter like you suggest. I'll then drop the oil pan if I still can't tell

[sergechronos]

I ran the car for a bit pulling each spark plug off so see if I could determine one cylinder was making more noise than another. On that I couldnt tell a difference. After that I ran compression again with a charged battery and a warm engine and this time I was getting 40's and a couple 45s. Then I pulled the valve covers just to make sure I didn't lose a rocker. I've got the car where it idles good now, but you give it any gas and it stats to get rougher sounding and backfires. I've checked twice now, but tomorrow I'll redo my timing belt and this weekend I'll cut open my filter like you suggest. I'll then drop the oil pan if I still can't tell

Getting rougher and backfiring wouldn't sound like an engine knock. Does it move at all or does it try to shut off when you give it any gas? I had an issue where my CAS failed and while it would start and idle fine, even rev okay in neutral, but any throttle and attempt to drive it would have it lurching and it would backfire and try to die. FSM says to check it via oscillioscope, but you can check resistance pretty easy to determine if that's your problem.

Before pulling the timing belt, just double check that your timing marks line up, if so, no reason to pull the belt. Cutting the oil filter open is an easier way to see if you might have an issue there, the timing belt being off wouldn't cause knock. Worst case it would've bent valves, but generally you see rocker arms popped off if that's the case.

[Desperado]

Well originaly my CAS was the issue. In the beginning my car would run great, I turn it off it would run terrible. Wait about 15 minuets or longer it would run great again. And this would happen for about 2 weeks until it just wouldn't run at all. Unfortunately this was in the dead of winter so I was too happy when it worked and was too cold to investigate. I put a data logger on my car and it said it was the CAS so I bought one off a forum user and the car would run again but as is now rough. I'm not getting fault codes but should I bite the bullet and buy a new one? I have a 94+ jap engine so I did a quick disconnect with the crank & cam sensors so I could try a 93tt ecu I had plus the jap ecu that came with the engine but didn't seem to help. At this point I hate to assume anything but my thought is if I had a bent valve I wouldn't get the compression that I'm getting.

[Chris@Rvengeperformance]

I ran the car for a bit pulling each spark plug off so see if I could determine one cylinder was making more noise than another. On that I couldnt tell a difference. After that I ran compression again with a charged battery and a warm engine and this time I was getting 40's and a couple 45s. Then I pulled the valve covers just to make sure I didn't lose a rocker. I've got the car where it idles good now, but you give it any gas and it stats to get rougher sounding and backfires. I've checked twice now, but tomorrow I'll redo my timing belt and this weekend I'll cut open my filter like you suggest. I'll then drop the oil pan if I still can't tell

A spun bearing has pretty much nothing to do wit how the car runs. When mine developed rod knock it ran literally perfect. Just had 10 PSI or less at idle and knocked so hard you could feel it in the clutch, lol.

Get one of these and use it everytime you change oil:

JEGS Performance Products 80532, JEGS Oil Filter Cutting Tool | JEGS Performance Products (http://www.jegs.com/i/JEGS+Performance+Products/555/80532/10002/-1)

[futurevr4man]

Take 5 minutes out of your life and pull the oil filter off. Cut it open. Look at it. It's really quite simple.

[Desperado]

Thanks Forest, got it ordered today. As for vr4man I appreciate your inspiring advice and as soon as my cutter comes in I'll do just that.

[Desperado]

Ok havn't got to the oil yet but I rehooked up my wideband, and not very long after I start the car it goes from 14.4 to 19.9 in less than a minute. Same situation with 2 different ecu's. My fuel presure is around 42 not hot wired and 50 hot wired with a supra pump. Oh and I just had my injectors rebuilt and cleaned. Going to disable one injector at a time to check the difference and one plug at a time. But all 6 are firing from the coil

[sergechronos]

Probably a stupid question at this point, but have you checked for boost leaks? Or tried unplugging your MAF and running it?

[Desperado]

It's not a stupid question, because as soon as you assume something that's what it will be. But after changing the CAS and ptu I checked the maf and did a vac check, after that I rechecked my timing just to make sure I didnt jump a tooth. But I think I have figured it out, just don't know how to fix it. When I hooked up the data logger I disabled the first injector and it almost stalled. When I did the 2nd thru the 5th no change. I do the 6th and same as 1 it almost stalled out. Just to confirm it wasn't just the sofware I pulled the connectors off of 1 thru 3 with the same results. Then I pulled those three plug wires and they are definitely getting spark. So any ideas

[sergechronos]

Did this start happening after the injectors were rebuilt and cleaned? How did you check the MAF, by unplugging it and trying to drive or with an multimeter? Do any of your plugs smell like fuel, or are they wet?

If you have no boost leaks and your wideband is showing that you're fully lean at idle seems like you have a fuel delivery issue or an ignition issue. If all of your plugs show that they're getting spark (pull the plug from the cylinder, reconnect the plug wire and then lay it on the intake or valve cover and see if you can see sparking when you try to start it) then either you aren't getting enough spark, your timing is way off (either mechanical or the CAS sensor) or it's not the problem.

You could pull the injectors and fuel rail, set the injectors inside of some mason jars or baby food jars or similar and try to run the car. Make sure all of them are delivering fuel and that they're all delivering roughly the same amount of fuel. If you have any injectors clogging up then it you would get different amounts of fuel out in each container.

Honestly just not sure off hand. I'll drink some coffee and think on it, see what I can come up with. Given that cylinders 1 &6 cause an observable reaction, I find that a bit odd. The fueling for those cylinders isn't shared, but the ignition is and the timing is of course. A noid light on the fuel injectors would tell you if it's getting the pulse signal correctly.

[Desperado]

No this was happening before I had the rebuilt injectors. Before I sent them off I'd done like you where suggesting and I had them out, but unlike your good idea I had just put shop towels under the injectors. I saw 6 wet spots for each, but I figured it really couldn't hurt to have them cleaned and I had an extra set to play with. But yeah I'm going to use a jar this time and make sure they are working and I can always put in the other injector if they aren't working and see if there is a difference. If I have time today which noid light do I want to get? When I looked them up I see a lot for Gm cars. Btw thanks again for the advise and help