TR2/3/3A TR3 connecting rod bearing replacement

[JR_Martin]

Hello forum. I'm brand new to this great source.
I have 1958 TR3 that was totally restored 16 years ago, but it only has 5000 miles on it. Obviously not a daily driver. Recently, after driving it long enough to warm it up, the sound coming from the bottom of the engine sounds like the connecting rods are trying to swap places. Local mechanic confirmed wear on the bearing, but said the shaft looked ok.

My question is, can you replace the bearings without pulling the engine, and how do you determine what size bearings to buy.

Thanks,
Je

 

[Geo Hahn]

Yes. Pretty simple -- in addition to the bearings you will likely want a set of locking tabs for the bolts.

In my (limited) experience if the bearings are other than standard they will be so marked.

 

[JR_Martin]

Thank you so much. What determines whether they should be standard or not?

 

[martx-5]

Have the mechanic mic all the journals on the shaft. Just because the shaft "looks OK", doesn't mean it is. He needs to measure it in various places to determine if the journal is out of round and/or tapered. Regardless of what size bearing shells are in there now, measuring is the only way to determine what needs to be in there.

Of course, if the journals are too far out of whack, then the crankshaft has to come out and get sent tot the machine shop.

If you need dimensional data, I can dig that out.

Edit: I'm digging it out...

Standard size Con rod journal diameter...

2.0860"-2.0866" --- Clearance --- 0.0016"-0.0035"

 

[JR_Martin]

Thank you, thank you, thank you. What a great forum this is.....

 

[hondo402000]

are you doing the work or the mechanic, make sure he or you check each bearing with plastigauge to confirm the clearance between the bearing and journal on the crankshaft. Hard to believe the engine only has 5000 miles and has a rod knock, you know you could have a piston wrist pin knocking too, usually to check for a piston pin knocking you run the engine, and pull the spark plug boot from each cylinder one at a time, that way the cylinder is not firing and it stops the load on the piston if the knock goes away you know which cylinder is the issue, if it keeps knocking then its a rod bearing knock

good luck

Hondo

 

[Jayplum]

Ok can attest to that.

 

[CJD]

It is far from normal for bearings to give out in 5000 miles. Although you can change the bearings with the engine in the car, it's usually a much better idea to pull it so you can figure out why the bearings failed.

 

[Sarastro]

John's comment was exactly what I was thinking as I read through this. If you have a knock after such a short amount of use, I would dig into the engine and figure out what's going on. In the long run, it might be easier just to remove the engine to work on it.

I'm assuming that this really is a knock, from inside the engine, and not something superficial. Good to rule out the simple things before digging into the engine itself.

 

[Jayplum]

John's comment was exactly what I was thinking as I read through this. If you have a knock after such a short amount of use, I would dig into the engine and figure out what's going on. In the long run, it might be easier just to remove the engine to work on it.

I'm assuming that this really is a knock, from inside the engine, and not something superficial. Good to rule out the simple things before digging into the engine itself.

John's comment was exactly what I was thinking as I read through this. If you have a knock after such a short amount of use, I would dig into the engine and figure out what's going on. In the long run, it might be easier just to remove the engine to work on it.

I'm assuming that this really is a knock, from inside the engine, and not something superficial. Good to rule out the simple things before digging into the engine itself.

I agree that there are times when an engine pull is required for a proper repair. In my case, once the diagnoses was complete, and u
I was able to affect repairs in place. Still an engine pull would be advantageous for other while you ‘re in there jobs. A proper job almost always will benefit from an engine out.

 

[CJD]

Good points from Jay and Steve. Other areas that can cause knocks are the distributor shaft, the timing chain tensioner, a badly worn rocker, or a loose crank extension.

 

[Jayplum]

Add crack in distributor cap.