rod bearings - are these buggered?

[mikedsilva]

Chasing a slight knocking sound evident at idle.. new chain tensioner made no difference.
Thought I would go "all in"...

[faapgar]

The horizontal marks on the rod bearings would bother me.You have Loctite 574 orange between the main bearing webs and that is bothersome.Bearings do not look that old.Are there Mahle pistons or aftermarket ones in the motor?Did you check flywheel endplay?# 7 main has some different wear.Was the case bolted together and checked with a bore gauge?Were the bearings OEM from Porsche or Glyco aftermarket?Ciao Fred

[mikedsilva]

Originally Posted by faapgar

The horizontal marks on the rod bearings would bother me.You have Loctite 574 orange between the main bearing webs and that is bothersome.Bearings do not look that old.Are there Mahle pistons or aftermarket ones in the motor?Did you check flywheel endplay?# 7 main has some different wear.Was the case bolted together and checked with a bore gauge?Were the bearings OEM from Porsche or Glyco aftermarket?Ciao Fred

hi Fred
Pistons are CP.
Did not check flywheel endplay.
Case was bolted and checked with bore gauge.
Bearings are Generic glyco.

What do you make of the markings on the rod bearings? I've never seen that before.. Engine has only done a few thousand miles.

[dannobee]

In the other thread you said that the noise was more pronounced at idle when cold and gets less audible when warm. That's almost always a piston to cylinder wall clearance issue. Not necessarily a defect; it happens with some brands of pistons because of the aluminum alloy used during manufacturing. That is, assuming the piston to wall clearance was within specs.

[targa72e]

I had a set of Glyco rod bearings (2.4-2.7) that had horizontal marks fresh out of the box. I returned them and went with AA Cleveites.

john

[faapgar]

The marks are there as a high point to accumulate pockets of oil for better lubrication on the Mulsanne Straight at 400 kph.Ciao Fred

[bpu699]

Did your crank have ridges or wear?

Could some of those be scratches from mic’ing the bearing in the case?

[mikedsilva]

Wondering if this could be the source of the intermediate clicking sound...
Intermediate shaft gear.

https://youtu.be/vQ5jWb4AUHg

[Neil Harvey]

Those markings are typical of the housing bore too small. Too much bearing crush will show up as similar markings. Refit the caps, tighten the fasteners how you previously had and measure the housing bore.

[mikedsilva]

Originally Posted by Neil Harvey

Those markings are typical of the housing bore too small. Too much bearing crush will show up as similar markings. Refit the caps, tighten the fasteners how you previously had and measure the housing bore.

I did that today actually.. I measured my rod bearing clearances as between 0.04mm 0.05mm and one at 0.07mm...

[Neil Harvey]

Maybe you misunderstood my suggestion. You need to measure the housing bore of the rod (BE) without the bearing shells installed.

[VFR750]

Mike

The loose fit of the gear mesh does sound pretty loud. So that may be why you can hear it.

Also fits the data. As the engine warms up the aluminum gear grows more that the case because it is bathed in the hot oil and closes the clearances. Making the ticking sounds quieter.

[mikedsilva]

Originally Posted by VFR750

Mike

The loose fit of the gear mesh does sound pretty loud. So that may be why you can hear it.

Also fits the data. As the engine warms up the aluminum gear grows more that the case because it is bathed in the hot oil and closes the clearances. Making the ticking sounds quieter.

Thanks for the feedback.
I'm hoping this is the issue. What I found was that at initial cold start, it was quiet for a few minutes.. then the 'knock' occurred.. then as it got to operating temp, it would quieten down almost 100%.
I will get the rods checked by my machine shop and have them massaged if required. Have also ordered Clevite bearings for reassembly.

Still trying to figure out the whole 2 different size gears thing.. mine has a '1' stamped on it and from what I can tell, the replacements from Pelican, only come wiht a '0'...

[targa72e]

There is a chart of what size gears can go with what size case (don't have it handy). there are several options that work. In the end you just need a certain amount of clearance between gears.

john

[Flat6pac]

Mike. I have a 1 if you need it.
Bruce

[VFR750]

Here is the table

[mikedsilva]

Originally Posted by VFR750

Here is the table

OK, that answers another question I had about what the 0 and the 1 reference.. That table is VERY helpful and the first time I have seen it, thank you.
I will duck out to the garage to check my case, but pretty sure it has a '0' stamped on it. But I am not sure what my crank gear is stamped.. I don't think I can see a number on that one?
So reading the table, it seems that the ideal scenario for a 0 stamped case, is to also have a 0 stamped crank gear and 0 stamped IMS gear.
But it is permissable to have a bit of a mismatch so long as the backlash is within the limits shown.
Assuming my engines parts are original, and my case is a 0 and my IMS gear is a 1, then my crank gear should be a 0 too.
Gauging the table, it seems that the 1 ims gear is a 'tighter' fit.. but that I can also fit a 0 ims gear but it will likely not be as tight, but still within spec.
I'm tempted to buy a new 0 IMS gear as that is all I can find.. Is a 1 IMS gear available new?

Bruce, here is a photo of my current gear.. showing tooth wear..how does yours compare?

[Flat6pac]

Right now it’s late so there is no side pictures available before tomorrow
You can see the stamping on the gears.
Bruce

[kamyle ben]

7 main has some different wear.Was the case bolted tog filezilla uc browser rufus ether and checked with a bore gauge?Were the bearings OEM from Porsche or Glyco aftermarket?Ciao Fred

[dannobee]

Since you're homing in on the intermediate gear, did you happen to check the backlash? Was it within specs? From your video it looks a bit over spec.