Connecting rod bearing size? (1 Viewer)

[40cruiserdad]

Well I have the pistons out to change the rings and noticed the rod bearings look like they should be replaced. I'm hoping someone can tell me if these are standard or oversized bearings. Also how to tell the diference.

Thanks!

 

[rkymtnflyfisher]

Looks oversized to me, .75mm

 

[40cruiserdad]

It that wierd? Seems like i read .010,.020,.030,.040 are standard oversized bearing sizes right?

 

[rkymtnflyfisher]

It that wierd? Seems like i read .010,.020,.030,.040 are standard oversized bearing sizes right?

SAE vs Metric



Don't quote me on any of that, I'm just thinking about going fishing.

 

[40cruiserdad]

Maybe....75mm is .0295" pretty close to .030".

 

[40cruiserdad]

Thanks for your help @rkymtnflyfisher hope you catch a hog!

 

[sggoat]

75 mm is 2.95 inches, not .0295--Even the crankshaft journals are not this large--
The other numbers you quote are typical UNDERSIZED (ie. .010 is ten thousandths UNDER the standard) same nomenclature as the pistons, but here you are talking OVERsized).
For example, my '77 (2F) lists three different undersized bearings available-----.05, .25, and .50. mm---the crank pin dia. is 53.98-54.0 mm--so if it was worn, the available undersized brgs would compensate for that particular wear. You need to measure the crank pin dia to figure out what undersize bearing you need(if any)
Same with the pistons but this is oversize--measure the cylinders/pistons to see if they are in spec My pistons are 93.97-94.02mm--if they get worn, the available oversizes are: 0.50, 1.0, and 1.50 mm
What year is the vehicle? does it have a 2F engine in it? mostly any 2F engine from 75 through 79 will be the same--

BYW Toyota still has the rod bearing set available for $99(in std and .25 under)---Hope all this helps---

 

[rkymtnflyfisher]

75 mm is 2.95 inches, not .0295--Even the crankshaft journals are not this large--
The other numbers you quote are typical UNDERSIZED (ie. .010 is ten thousandths UNDER the standard) same nomenclature as the pistons, but here you are talking OVERsized).
For example, my '77 (2F) lists three different undersized bearings available-----.05, .25, and .50. mm---the crank pin dia. is 53.98-54.0 mm--so if it was worn, the available undersized brgs would compensate for that particular wear. You need to measure the crank pin dia to figure out what undersize bearing you need(if any)
Same with the pistons but this is oversize--measure the cylinders/pistons to see if they are in spec My pistons are 93.97-94.02mm--if they get worn, the available oversizes are: 0.50, 1.0, and 1.50 mm
What year is the vehicle? does it have a 2F engine in it? mostly any 2F engine from 75 through 79 will be the same--

BYW Toyota still has the rod bearing set available for $99(in std and .25 under)

A little Google-fu research shows those bearings are Federal-Mogul .75mm oversize bearings for a Toyota engine.


TOYOF L6 3878cc 3.9L; TOYOF L6 3980cc 4.0L Diesel
Export; TOYOF L6 4230cc 4.2L; 1975-1954 TOYOT L/D
L6 3878cc 3.9L; 1987-1975 TOYOT L/D L6 4230cc 4.2

 

[40cruiserdad]

Thanks @sggoat I meant to type .75mm. Another question are .75mm and .030" undersized bearings compatible? Rock Auto has .030" ITM bearings available but not the .75mm.

The engine is a 1973 F engine.

 

[Living in the Past]

Before ordering anything would inspect and plastigauge all bearings.

 

[40cruiserdad]

Before ordering anything would inspect and plastigauge all bearings.

That's a good idea, I figured I would just replace like for like.

 

[Living in the Past]

That's a good idea, I figured I would just replace like for like.

If wear is only in the bearings you would be good. Crankshaft just replace bearings wouldn't solve an issue.

 

[40cruiserdad]

If wear is only in the bearings you would be good. Crankshaft just replace bearings wouldn't solve an issue.

Thanks! From what I've seen the crank looks good but I'll make sure to take a close look at it again.

 

[Living in the Past]

Thanks! From what I've seen the crank looks good but I'll make sure to take a close look at it again.

Would measure it to be sure it's not only smooth but round.

 

[40cruiserdad]

Would measure it to be sure it's not only smooth but round.

Anyone know what the std crank diameter is supposed to be for the F engine connecting rod.

 

[zerotreedelta]

This is the F and 2F, not sure which flavor you have...so there's both.

 

[40cruiserdad]

Perfect! Thank you @zerotreedelta .

 

[40cruiserdad]

This is the F and 2F, not sure which flavor you have...so there's both.

View attachment 2915741

View attachment 2915740

I haven't put a mic on it yet, but my dial caliper is reading about 2.094". Is that close enough to use the .030" undersize bearing set or do I have to get the crank turned to .040" under?

 

[zerotreedelta]

Edit: misread, still getting my morning coffee...does look like you're out the worn end.

Would be interesting to see how the old bearing plastigages out though...I'd assume it'd show wide/loose.