[torqhead]

Not trying to be a jerk or controversial, but I'm not sure pulling a motor is the best option to find a noise, that's time and money.

Another question that may have been answered, was the shim installed behind the flexplate before it was bolted to the crank?

[Va68goat]

MXTex,

Thanks for taking the time to read through this thread..I'm sure it took a while! I'm not too sure if I'm qualified to answer that since I'm pretty clueless about cars but it does appear to knock at the revolution of the crank.

torqhead,
We have over 40 hours of diagnosis, repair and replace time in this motor since the car was started. There were, what we thought were witness marks on the rockers. I replaced the rockers with 1.65 Crower rockers. When we switched the rockers, we looked at the pushrods and rolled them on a piece of glass. A few of the pushrods wobbled on the glass so we switched out the pushrods with a thicker wall pushrod. I was then told the lifters may not be pumping up. We replaced the lifters (Johnson Hylift) and the same knocking noise was present. When we disconnected the torque converter from the flexplate, that was BEFORE we pulled the motor and identified there was not enough spacing on the windage tray. There were witness marks on the windage tray. I haven't pulled the torque converter from the flex plate since we corrected the spacing. The knocking from the windage tray masked the knocking noise that we are trying to figure out. Here is something interesting though...When I pulled the heads and had them inspected and we got the car on the road again.when I drove it home and parked it in the garage, I turned the car off and right at shut down a noise was heard that I can only explain as if two pieces of metal scrapping and coming to rest.

AG,
If I have to pull this motor again, I think it will be on it's way to Arizona to Paul..hahaha. I do have to say that Paul and Jeff have been awesome and they both have been excellent to deal with. They stand by their product and I would not hesitate to go back and have them build me another motor. Not too many people around like those guys..

torqhead,
The question about the shim exceeds my mechanical abilities and knowledge..hahaha! I have good friends that have been working on Pontiacs for many, many years. I trust them to do the work correctly. I'm assuming it was done correctly but we will find out soon. I agree with what you said about throwing money at parts. I have over $1,000 in parts, fluids, gaskets and Tylenol and have only driven the car less than 200 miles. I think we're getting there though!

[AG]

I doubt the flexplate has anything to do with that noise. Does the sound increase with RPM?

[Va68goat]

AG,

It's just wishful thinking about the flexplate. I can't say with 100% certainty if the knocking increases with RPM but it doesnt appear that way. I think this is the last step before the motor goes back. I know the flexplate is the only part that hasn't been replaced. Paul is scratching his head on this one as well. He's been part of this since the start of the motor. I think we are both hoping this resolves the problem!

[shaker455]

I've been told by my machine shop & dyno guy that Hyd roller lifters are failing constantly and not to use at this time.
The shop said he is trying to use as many solid rollers as possible.
Apparently Morrel makes the majority of the hyd roller lifters and they try to use excessive clearance as the blame to not warrantee.
I listened to the vids and sounds like collapsed lifters...even the replacements.
see if you can use solid roller lifters on that cam..
I wish you the best

[gtofreek]

It's not the lifters that are failing. It's the fact that the oil band is in the wrong place. That prevents them from filling up when they are on the base circle. I modify the blocks so that is not a problem anymore. Your machine shop just hasn't figured out what the real problem is, they just blame the lifters, which do have the band in the wrong place, but the lifters work fine when block is modified. These are Hylift/Johnson slow bleed lifters so they do not have too much internal clearance.

[AG]

The new Comps have the adjusted oil band height that is similar to a stock Pontiac, just put a set in a motor I am building now.

[TedRamAirII]

Maybe pull the plugs and get a socket on the crank and slowly turn it, to feel hear a bad spot? You may put a timing light on it and make a mark on the balancer so you can duplicate where on the rotation it makes the noise and if its every revolution or every other. If you can, video it in slow motion, with the timing light, that would certainly help on "when" (in the rotation) you hear it.

[jonmachota78]

Did the oil filter ever get disected and inspected? I wish you the best in figuring out the issue

[shaker455]

Originally Posted by gtofreek

It's not the lifters that are failing. It's the fact that the oil band is in the wrong place. That prevents them from filling up when they are on the base circle. I modify the blocks so that is not a problem anymore. Your machine shop just hasn't figured out what the real problem is, they just blame the lifters, which do have the band in the wrong place, but the lifters work fine when block is modified. These are Hylift/Johnson slow bleed lifters so they do not have too much internal clearance.

Thanks Len Caverly and our shop address that issue years ago.
Best on your return

[grivera]

Originally Posted by torqhead

Not trying to be a jerk or controversial, but I'm not sure pulling a motor is the best option to find a noise, that's time and money.

Another question that may have been answered, was the shim installed behind the flexplate before it was bolted to the crank?

I installed the flexplate and do not recall a shim.

Originally Posted by AG

I doubt the flexplate has anything to do with that noise. Does the sound increase with RPM?

Based on a video clip I found on-line, a cracked flexplate can make a similar sound. https://m.youtube.com/watch?v=A3mUQG1oGfo

Why do you doubt that this maybe the issue?

[AG]

Originally Posted by grivera

I installed the flexplate and do not recall a shim.



Based on a video clip I found on-line, a cracked flexplate can make a similar sound. https://m.youtube.com/watch?v=A3mUQG1oGfo

Why do you doubt that this maybe the issue?

I don't think it is the flexplate because a crack would have been noticeable at the time of installation, it's unlikely a crack formed in the short time the motor has been running without hammering on the car, and the noise from a crack would most likely be random and not in synch with rotation. If the flexplate was used there is the possibility of it being cracked, but I have disassemble more than 30 stock motors and have never seen a cracked flexplate. I have seen broken teeth and egged converter bolt holes. Just my opinion. If it was my motor I would take it out and inspect everything, the OP already has over 40 hours into this issue without finding a root cause.

[Sirrotica]

Since I've seen at least a dozen cracked flexplates over the years, it does sound like a cracked flexplate on that video. Pontiacs are less prone than chevys are, but I have seen both along with a few olds and buicks over the years.

It may not be a cracked flexplate, but the noise is consistent with one, and yes they are constant every crankshaft rotation. I've seen chevy impalas with 2 speed powerglides driven by senior citizens crack flexplates, the car doesn't have to be abused for them to crack. There is no rhyme nor reason why/when they crack, they do just crack for no apparent reason. It's actually metal fatigue that eventually finally overcomes the initial strength of the stamping.

I've seen them with small cracks and I've seen them where the whole center around the crank flange bolts is completely broken in 2 separate pieces. All that is needed a crack where the edges bind, and click against each other, and you get the noise. To someone that has little experience with engines it may sound as a rod knock, but it doesn't normally change with engine load as a rod knock does. It also is not as heavy as a rod knock.

One thing that confuses the issue is they have already removed the convertor bolts and ran it with the engine with the convertor pushed away from the flexplate. Since the flexplate has no stress on it when disconnected from the convertor, it should have gone away. So even though it sounds like a cracked flexplate it may not be that, given the detective work already done.

From the video, it does seem to be in the flexplate area of the engine, however sounds travel in a reciprocating engine and are not always what/where they seem to be. If I had to bet on it, it's not a flexplate, but the noise seems to be concentrated in that area of the engine/transmission assembly.

Pontiac did use a very fine/thin shim between the crank flange and flexplate on some applications around .010-.015 thick. If I remember correctly, I have left that shim out without any negative consequences, probably in this circumstance it would not cause the noise in question.

The noise does sound like it's from the sheetmetal accessories on the bottom rear area...………

[JSPONT]

By now there has to be witness marks somewhere. Take a mirror and make sure the flex plate bolts are not sticking out the backside of the crank. Camera's that attach to phone are cheap on amazon to explore back there.
Cut the oil filter open, if there is no metal, it is likely the flexplate or convertor area.

[gtofreek]

Good post Brad. When the torque converter was pulled away and noise still present, the windage tray had a clearance issue at that time that had not been resolved yet, so that may have been the noise they heard when they pulled the TC away. Hard to say.

There has never been any metal in the oil or filter so I'm confident it's not a bearing. When I keep looking at the video's of it on the dyno, there is no evidence of a knocking noise, not even at an idle. As loud as the noise is, if it was there when dynoed, I'm confident I would have either heard it then, or in the video.

[ponchjoe]

Is there an illusion in the video? About 38 seconds in the camera comes over the pipe and shows the starter and it looks like it’s moving in time with the noise.

[Va68goat]

jonmachota78,
We did dissect the oil filter and checked all the pleats. There was nothing in there that would be a reason for concern. It was inspected by HWYSTR455 (Mike) and he said it was fine.

Sirrotica,
I think what may be a good idea is for us to pull the converter back again and listen to it. If the flexplate was making noise when we did this test, we may not have heard it because we did have the windage tray making noise. grivera installed the flexplate and he doesn't recall using a shim. When I get home, I will repost all the video's of the noise. It's really odd because you can hear it while you're sitting in the car and it almost sounds like its coming from under the dash. I guess that's the way the sound is traveling but it is very noticeable.

JSPONT,
During this process, I did buy a bore scope. I will give that a try. I have changed the oil in this car 3 times already and each was inspected. There was nothing of concern that was brought to my attention guys that actually know what they're doing

[dataway]

Originally Posted by ponchjoe

Is there an illusion in the video? About 38 seconds in the camera comes over the pipe and shows the starter and it looks like it’s moving in time with the noise.

Yeah, it does look like that doesn't it.

[Sirrotica]

Ring gear starter interference is entirely possible, or a weak return solenoid spring allowing the Bendix gear to interfere from not returning fully. One would think that if the Bendix was touching the ring gear it would be intermittent because the starter isn't going to stop at the precise point each time. I didn't pay close enough attention to the video to know if it's a GM direct drive starter, or a gear reduction mini starter.

I suppose that after the engine is running, loosening the starter to block bolts would gain enough clearance to eliminate the starter rubbing the ring gear. If I were looking for the noise I might just try that next, only take a minute or two to test that theory. I have seen starter shims end up touching the ring gear also when they are shoved into place, one shim will sometimes twist out of line from the others. Instead of straddling the innermost bolt it will twist towards the rear, contacting the flexplate inadvertently.

The only other area I would be concerned about is contact from the torque convertor inside the bellhousing area, but if you're going to repeat the disconnected torque convertor test, you'll cover that area.

From my previous experience I don't believe there is any problems in the lower end of the engine, and oil filter dissection has pretty much taken the bottom end out of the equation. Paul IMO, seems conscientious enough to make sure the engine was done correctly before he shipped it, plus he said no noise on the dyno so some other variable in the car that wasn't present on the dyno, stands likely to be the source of the noise.

[NeighborsComplaint]

Originally Posted by ponchjoe

Is there an illusion in the video? About 38 seconds in the camera comes over the pipe and shows the starter and it looks like it’s moving in time with the noise.

I saw that too but thought it was the camera searching for focus. Seems like a lot of runout in that flexplate too.