Used Glyco rod bearings in my rebuild. Should I worry?

Tippy · 11-08-2016, 05:16 PM

As the title says, used Glyco rod bearings in my 3.2 (3.4) about 5 years ago.

I'm going to tear it down to replace rings and fix oil leaks, but didn't plan on removing rods from crank.

Do I need to inspect, or carry on?

Is the problem found early, or with some mileage?

Trackrash · Trackrash's Garage

If it were me, I would pull the rods and check the clearances and visually inspect the bearing shells. You are probably OK, but why not make sure?

How is your oil pressure?

Tippy · 11-08-2016, 06:26 PM

Quote:

Originally Posted by Trackrash

If it were me, I would pull the rods and check the clearances and visually inspect the bearing shells. You are probably OK, but why not make sure?

How is your oil pressure?

It's always been lower than I cared at idle, but pegs gauge cold

onevoice · 11-08-2016, 06:36 PM

I had a problem with Glyco bearings about 2 years ago. The ones I measured were incredibly out of spec. Others have had bearings that were fine. The bearings are manufactured in several different facilities, my bad ones came from S. Africa.

If your motor has been running fine for 5 years, I wouldn't be overly concerned. But then again, splitting the case isnt rocket science either.

Tippy · 11-08-2016, 06:40 PM

Yep, splitting the case is no problem. But, if I didn't have to, I rather not remove the rods.

stownsen914 · 11-09-2016, 06:17 AM

You don't even need to split the case to replace rod bearings. If it were me and I got the engine down that far and had even the slightest concern about my rod bearings, I'd be replacing them.

Tippy · 01:30 PM

Quote:

Originally Posted by stownsen914

You don't even need to split the case to replace rod bearings. If it were me and I got the engine down that far and had even the slightest concern about my rod bearings, I'd be replacing them.

Well, I'm tearing the case down to fix the parting line leaks.

If there's a history of Glyco's failing very early, then great, I'm in the clear.

If there's a history of Glyco's failing with time, well I'll 100% take it down to the crank again.

Needed that collective wisdom before doing.

I don't have a bolt stretch gauge anymore, so I WILL NOT torque only, hence reason for question.

m42racer · 11-09-2016, 11:22 AM

A couple of things to check. This should be done anytime an engine is built.

The crank journals need to be round and without any taper. The finish is critical as this helps the oil to flow through the clearances.

The rod BE also has to be round and without taper. This has to be checked with the bolts stretched.

The bearing shells need to be fitted, bolts re stretched and the vertical dimension checked. Then the clearances calculated and adjusted if need. The bearing sold today are a BI metal construction and are very hard so they will last thousands of miles. They are Ok for most but consideration should be given to add some extra clearance to help.

If you were to use a tri metal with the softer Babbitt layer, if the bearing was to "touch" the journal this soft layer is there to save the bearing from welding its self to the crank. If you use the stock bearing you do not have this safety built into the bearing so adding some extra clearance can help. Oil viscosity and pressure have to be considered here also.

You should consult an expert before doing this. They will know what is best.

Tippy · 11-09-2016, 01:34 PM

Quote:

Originally Posted by m42racer

A couple of things to check. This should be done anytime an engine is built.

The crank journals need to be round and without any taper. The finish is critical as this helps the oil to flow through the clearances.

The rod BE also has to be round and without taper. This has to be checked with the bolts stretched.

The bearing shells need to be fitted, bolts re stretched and the vertical dimension checked. Then the clearances calculated and adjusted if need. The bearing sold today are a BI metal construction and are very hard so they will last thousands of miles. They are Ok for most but consideration should be given to add some extra clearance to help.

If you were to use a tri metal with the softer Babbitt layer, if the bearing was to "touch" the journal this soft layer is there to save the bearing from welding its self to the crank. If you use the stock bearing you do not have this safety built into the bearing so adding some extra clearance can help. Oil viscosity and pressure have to be considered here also.

You should consult an expert before doing this. They will know what is best.

When you talk taper, can't help but think of American V8's. Taper on our 911 cranks I'd imagine is not commonplace?

My crank was perfect with many, many years around 500hp when I tore it down.

I almost reused the mains they were so perfect.

My BE's were resized during rebuild. I have ARP rod bolts.

Not scared to reuse rod bolts, but I rather not disturb them if I don't have to.