Is this rod knock? (2 Viewers)

[CruiserTrash]

If sound is increasing when you're on the Bellhousing, it seems like sound is traveling through the block. BGarcia beat me to it, but I too would check the valve train, particularly the lifter/pushrods before tearing anything apart.

FWIW, if/when you get to that point of replacing the Pilot bearing, JimC sells a super-duper one I've been itching to try:

Pilot bearing, 1F/2F/3F series engines

There's nothing worse than having to drop the transmission & transfer case and pull off the clutch to change a dried out pilot bearing. That's a lot of backbreaking labor that could have been saved by installing this top quality made in EU by SKF aerospace bearing filled with synthetic grease...

tlcperformance.com

Interesting. So the sound would be emanating from the lifters down below, or the valves up top? Devil's advocate question: why wouldn't I hear that more loudly directly at the source? Why is it loudest at the bellhousing?

 

[Spike Strip]

The Physics of sound...

Things like this can be very tricky because vibrations (like electrons) will travel through the path of least resistance and the bellhousing may be acting like a diaphragm in a speaker, or like two tin cans with taunt string between them like a childhood walkie-talkie. You 'hear' the vibrations where they can move air, like the speaker.

The Cam shaft end is right up against the Bellhousing.

It may very well be that there is a bearing or other issue right at that point in the Bellhousing / Crank juxtaposition that doesn't involve the valve train, nobody is gonna know but you - but I'd sure want to be 100% sure before tearing stuff apart.

I hate to harp on this, but this is where a proper Stethoscope with a long rod will help you isolate where the sound is originating.

 

[Zjohnsonua]

We've had a few engines come through the shop with slipping cam gears that kind of sound like this. Cam gear starts walking off the cam and every time the cam loads up it bounces off the rear cup plug. Had a few new builds from other shops come in for the same noise caused by aftermarket cup plugs that got squeezed in further by the bell housing during reassembly.

One of these such noises was so severe that the fellow pulled the pan and found shavings...he assumed it was rod knock and did the swap he'd been planning...we got the engine, tore it down, and found a pristine lower end...the rear cup plug was nearly ground through. If it had run much longer he'd have ground through it and emptied the oil pan into the bell housing.

 

[CruiserTrash]

We've had a few engines come through the shop with slipping cam gears that kind of sound like this. Cam gear starts walking off the cam and every time the cam loads up it bounces off the rear cup plug. Had a few new builds from other shops come in for the same noise caused by aftermarket cup plugs that got squeezed in further by the bell housing during reassembly.

One of these such noises was so severe that the fellow pulled the pan and found shavings...he assumed it was rod knock and did the swap he'd been planning...we got the engine, tore it down, and found a pristine lower end...the rear cup plug was nearly ground through. If it had run much longer he'd have ground through it and emptied the oil pan into the bell housing.

this went way over my head because I’ve never torn an engine apart. You’re saying because the cam gear is loose on the shaft, the entire camshaft is bouncing fore and aft, repeatedly slamming into something behind it?

When you say the gear is walking off the shaft when it loads up, you mean when the engine’s under load?

 

[CruiserTrash]

@Zjohnsonua Also curious what would cause that scenario in an original motor. Just trying to wrap my head around it so I can be looking in the right places when I do some more diagnosis.

 

[Spike Strip]

There's a locking clip on the front of the Cam that holds the gear in place. If it breaks or wears away, the Camshaft tens to push on the Welsh plug at the rear of the block that is an oil seal. That plug is up against the Bell housing

Post in thread 'How not to build the 2F' How not to build the 2F - https://forum.ih8mud.com/threads/how-not-to-build-the-2f.563170/post-7377892

 

[CruiserTrash]

There's a locking clip on the front of the Cam that holds the gear in place. If it breaks or wears away, the Camshaft tens to push on the Welsh plug at the rear of the block that is an oil seal. That plug is up against the Bell housing

The C-clip makes sense. I assumed that’s under the cover plate on the front?

My front main does leak … might be an w cause to go in there. But everything’s an excuse. Go in to replace a vacuum line and end up rebuilding the motor haha.

 

[klinetime574]

This is an interesting noise. The videos with and without the inspection cover sound completely different. I’m thinking flywheel or pressure plate issue. Loose bolts, worn dowels, oblong holes, random failure, etc. Definitely will be watching to see your findings @CruiserTrash

 

[CruiserTrash]

This is an interesting noise. The videos with and without the inspection cover sound completely different. I’m thinking flywheel or pressure plate issue. Loose bolts, worn dowels, oblong holes, random failure, etc. Definitely will be watching to see your findings @CruiserTrash

I’m going to dig in more tonight. Worst case scenario I order some parts and use the rebuilt H42 sitting on my shop floor to swap new stuff in.

@RodrigzCrzr suggested that if I do that, to run the motor with the transmission out to potentially isolate the camshaft issue - or other engine issues versus transmission problems.

 

[LandoNick]

I’m going to dig in more tonight. Worst case scenario I order some parts and use the rebuilt H42 sitting on my shop floor to swap new stuff in.

@RodrigzCrzr suggested that if I do that, to run the motor with the transmission out to potentially isolate the camshaft issue - or other engine issues versus transmission problems.

So pull the Trans to see if anything looks funky? Then run motor to see if the noise still is there? have you pulled belts off one my one to see if the noise stops? and I think you did the pull each plug wire method, and no change?

 

[CruiserTrash]

So pull the Trans to see if anything looks funky? Then run motor to see if the noise still is there? have you pulled belts off one my one to see if the noise stops? and I think you did the pull each plug wire method, and no change?

Correct on plug wires one by one and belts. No change for those tests. Really don't want to be dropping a transmission, but maybe that's my weekend.

 

[CruiserTrash]

Finally absconded with some time to dig in more. This is kind of crazy but the noise is loudest at the power steering pump. Granted, it’s kind of all over: right side of oil pan, block on the left side by cylinder 3, bellhousing, quite a bit in the clutch fork. I am not getting it in the valve cover, head, anything pulley driven - except the PS pump - front cover, etc.

Took the fuel pump off. It’s a year old and looks good. Taking belts off now.

 

[The Analyst]

Spoke with some of you today via text and on IG, but thought I’d throw it out to a wider audience. This noise is pretty concerning. It does vary with rpm, but engine temp, clutch, and steering have no effect. This original engine has 137k miles and compression was around 150 across the board when I checked it in November.

The engine feels and sounds smooth under acceleration. All gauges are as normal as they’ve always been, and there aren’t any new leaks or significant increases to old leaks.

This started very intermittently about 6 weeks ago after some “spirited driving” in the city - maybe 40mph and acceleration pulls to 3300rpm or so. It stayed intermittent until two days ago, when it became pretty consistent at idle.

I have not done any thorough checking but will be doing so tonight. Thanks for any help!

Do you own a micrometer? Calibrated 3/8 torque wrench? Plastique Guage? then take one connecting rod cap off and install the plastic Guage and retorque the end caps and remove and measure the thickness.

 

[The Analyst]

the sound is definitely originating from the clutch/flywheel/pressure plate area, or possibly the rear crankshaft bearing. The flywheel spins true and nothing in the vicinity is rattling. Checked the bell housing bolts I could reach and they’re good, the hard to reach ones pass visual inspection with the motor running. Rear main cap bolts I gently tested - so not to change the torque - and they’re not loose.

I’m thinking rear main bearing at this point.

One way to know which cylinder is is to remove spark plug wire and if it does not quite down enough on any one cylinder, open up a exhaust valve to drop the pressure on the cylinder and the knocking will come to almost a stop. Just pray and hope the crankshaft con journal is not damaged. replace the barring shells and use plastic gauge to verify. Verify before and after oil pressure.

 

[The Analyst]

Stethoscope is saying flying wheel inspection cover. Diving in to that now.

The thin sheet metal could amplify the sound like a drum cover and that is why it may sound loud. Do this, take one spark plug out at a time and ground it first "don't want to short out the secondary coil winding. Does the sound drop when running the engine? if you have a oil pressure gauge installed, does the oil pressure go up when the spark plug wire is shorted to ground? then you found a con rod shell that has a large gap in thickness. The big worry is, is the crank con journal scored? if it is micrometer out of limits, then a machine shop with equipment that buildings up the steel needs to be done.

 

[The Analyst]

Is there another bearing inside all the flywheel/clutch stuff? Like a roller or needle bearing? Maybe something in there isn’t right and the rotating stuff has just enough wiggle room to slap around.

no there is not. The crank has what is called Babbit lead/Tin Shell caps. Take a cross section of ABS tube, cut one inche off the end then cut it in half. Each half has locking teeth that lock into the top and bottom of the connecting rod and cap.