RTH: rear main seal journal diameter of 2F/3FE

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I have seen in other threads the spec for the rear main seal of 2F and 3FE engines. the 2F seal is 100mm inner diameter, while the 3FE is 105mm inner diameter; both with 120mm outer. this was the spec for the seal, FWIU, and I am not certain if it is the spec for the journal itself...

I have a Toyota reman 3FE that I am rebuilding. it has some miles on it. It has .50mm over slugs, and .25mm under mains and rods. The mains and rod are going to be turned to .50mm under, and the block will grow to take some new(er) fatter pistons. I believe the rear main journal has been turned and sleeved. I forgot to hit it with my calipers this morning, but the 4" mic was to shy, and by more than a couple mm, so I'm inclined to think it is larger than the 105mm diameter that the seal is specd for.

In lieu of measuring it this afternoon, has anyone got a stock 3FE crank they can measure for me, or confirmation that the seal spec correlates to the journal diameter? I'd also take the spec for a 2F rear main journal if anyone knows that.

Thanks, Mud.
 
Some crankshaft specs are in the back of the engine FSMs. Not sure if those are the specs you're looking for though.
 
BTRT not found in the appendices
 
Calipers claim it is 105.23mm...about 4 3/32". regardless, I still would like to know what a known good journal measures to....

I am thinking about having it turned down to the spec of a 2F journal, however, just because I am certain that this one is worn from where it was when it was new.

SO, if anyone has a good 2F crankshaft they could measure and post up about, I'd be grateful. I don't want to assume it is anything based upon conjecture, as it would be a shame to have to resleeve it...Planning on taking it in for the grind soon, which is why I ask for the real-time-help. Thanks again!
 
I have a 3FE crank on the floor I can measure if you still need it. I need to pull the pilot bearing out of it too..
 
YES please. would you say the rear main journal of your crank is in good condition? Good enough to let the rear main seal do its job? Thanks, Matt.
 
Well this one leaked but that was probably user error lol. I'll get that measurement in a sec.
 
My seal surface has some nice racetracks on it, but looks original. My measurements were 4.1395", or 105.15mm.

image.jpeg
 
Thank You Matt! so it seems that the 2F seal fits in a 3F block, but would have a smaller ID than the 3F- which means>>> if we can find the spec for a good 2F rear main seal journal, we can have our old worn down 3F rear main seal journals turned DOWN to fit a 2F rear main seal like a BRAND NEW CRANK is supposed to fit...



SO,


Anyone care to post up the spec for a GOOD 2F journal diameter?
 
Ooooohhhhh I see what you're getting at. I like that.
 
Yes, Please, Godwin. The leaking of a 2F rear main seal in a 3F(E) is due to the fact that the 3F rear main seal journal is 5mm bigger than the 2F- according to the seal specs.....



I learned something today, thanks Godwin!

Catalog shows 2F & 3F RMS are both 120mm OD, but the 2F seal is 100mm ID, 3F seal is 105mm ID.
 
That sounds small...
 
By about .7mm
 
makes you wonder what toyota thought the limit here was....we might be too optomistic thinking we can turn the crank down 5mm...grrr...


By about .7mm


difference between mics...that's why all precision tools have standards to set zero, and why you should use the same tool and standard for all precision work on any given project- Godwins 99.43 could be Mr. Ts 100 straight up...but that does seem pretty far from 105.23...If I knew what a new crank specd to, I'd be all over finding a guy to fit a sleeve...


Please keep the pool going- Anyone with a crank out and the tools to mic it, please post up!
 
PAGING @FJ40Jim ...what does the master say regarding rear main seal journal specs???
 
difference between mics...that's why all precision tools have standards to set zero, and why you should use the same tool and standard for all precision work on any given project- Godwins 99.43 could be Mr. Ts 100 straight up...but that does seem pretty far from 105.23...If I knew what a new crank specd to, I'd be all over finding a guy to fit a sleeve...

Calipers I used are Mitutoyo digital and I ensured that they were zeroed before measuring and rechecked the zeroing afterward. These may not be precise enough due to wear or dirt since they've been carried up and down rivers measuring turtles and other critters but they are what I have on hand.

Plenty of opportunity to introduce error into this process :lol:
 
exactly. this should be covered somewhere, I'd think...
 
PAGING @FJ40Jim ...what does the master say regarding rear main seal journal specs???
Can't find it in the FSM's with a quick search.
My "made in EU" caliper is showing 99.45 on the clean '76 crank that just came back from machining and polishing at machine shop, that has previously been machined & polished.
99.50 on an untouched '82 crank.
Other cranks are bagged & shelved with big ends at the back, not digging them out & unwrapping just to measure...

Clearly it's not 100mm OD. Maybe the stock size is 99.5mm, and these are polished down to ~99.45?
Polishing can easily remove .01-.05mm or .001-.002inch.
 

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