Hi all. I truly appreciate the expertise on this board, lots of experience here and am in need of some that sagely advise.
So, here's the scenario ( apologies in advance for the long story).
'76 FJ40, 2F (the one in my avatar) has been sitting for a while (last reg 2015). Full rebuild way back in 2004-ish with 1.00 mm OS pistons, turned crank, resized rods, etc. Not many miles before pulled off duty (maybe 10k max.) Wanted to make some alterations - project stutter makes months turn into years.
After some major upgrades, put back on the road a couple weeks ago. I was so excited!
Less than 10 miles into its first cruise out, total loss of oil pressure (had been idling fine and running test circles in the driveway while tuning the Holley sniper prior to re registering). Always showed low oil pressure on the gauge, but would surge with rpms and, after checking this board, didn't worry too much about it.
Well, tooling down the test drive, the engine locked up, chirped the tires in fact. Coast home (thank goodness we were uphill). Once cool, engine would spin with plugs out but would lock up once warm again.
You know what I'm thinkin'.....trashed mains from a failed oil pump ( BWT, how can you tell if it's bad post mortem? - you can put her in oil and spin per TOY-manual pg. 4-7, but no way to really check pressure - is there a length for the relief valve spring length? How can I be sure it was the oil pump?)
OIL PUMP. The only thing I can't recall if it was replaced or not way back when. Dang, I know those receipts are somewhere.
Tear her down.....
Shinies in the oil pan, not good. Keep goin. Out comes the transfer and tranny (rebuild it since it's out, I never touched it before). Now those nice new seats are out and interior is gutted again.
Clutch is OK, rear main seal leaks a bit, but NBD. Sitting a long time is hard on both front and rear mains - ask me how I know. By the way, checked the dizzy drive, cam gear to the dizzy, all was as expected. Hold down was tight and clamped down.
Strip it all off, ancillaries, all that work you just completed. argh - off with her head. Removing the header is a real PITA.
Block is still in the rig now, all that remains is the pistons, crank and flywheel. Out come the pistons. Look good on top, almost like new. Bores look good. Rings look really good, almost clean. Oil ring is loose and free, not solid and buggered like others I've rebuilt. All rings are nice and springy. On the bottom end... argh... bearings are trashed. Yep - barely there. Oil starved.
They're 0.25 under. Pins look OK but.....No worries though, I found a good STD crank on EBAY with rods and pistons (anyone need some STD pistons?) I picked it up, mic'ed it, yep STD, very nice. Mine was working on the old balancer death wobble anyway and the keyway was questionable. This one looks like new, I'll have it polished or maybe trimmed to 0.25 probably and she'll be good as new.
Still haven't seen the mains yet but I'm sure they're as trashed as the rods. The mains are fed by the main gallery and then feed the rods, so if the rods are starved then I'm sure the mains are toast.
Annnnyyyywwwaaayyy, here's the REAL question. I started checking pistons today. Can't recall brand or supplier, but I had a chance to clean and inspect the #3. Mic'ing piston and bore gage shows a 3.7428 bore with a 3.7388 piston - 0.004 clearance. T-manual is 0.0020....hmmmm.
Bore wear limit is 0.008" on pg. 10-9, which would give me a max bore of 3.7429" for the 1.00 mm over.
3.7428 - ooooooh, that's close.
Remember, this is not a hot rod. I seem to recall using 0.005 for clearance on my OS 5-litre with forged pistons way back when. I'm not sure the shop didn't use a similar number on the 2F as well. The pistons are marked 62641 but I can't find the specs or manufacturer to check producer's clearances. I wouldn't be surprised if it was 0.005". I didn't notice any rocking when I pulled 'em out and there was no rattling... until the bearings let go of coarse - then they slapped pretty good after that.
Looking for opinions, suggestions, thoughts. Anyone recall the manufacturer's # (Manefre?) I'd rather not do much to the pistons and rods other than a new set of rings if I can. I'll put up a pic if it helps. I'd rather just clean up the new-to-me crank, new balancer to take care of the wobble and button her up. So far the bores all check to same +/- 0.001" roughly so the closest I think I'd get is a new set of 1.00 OS pistons and rings (3.7402" vs. 3.7388" - woohoo, pick up 1.5 thousandths). But even so...
I mean, I'll obviously check the remaining pistons against the bores, but is 0.002" really worth a rebore to 1.50mm over and a new set of pistons and rings. I strugglin' with this one on a 2F that does weekend offroad duty.
Sorry for the long story. Just can't seem to find a solid place to land on this one....... please help.
Thanks for any of your thoughts. - Bob
So, here's the scenario ( apologies in advance for the long story).
'76 FJ40, 2F (the one in my avatar) has been sitting for a while (last reg 2015). Full rebuild way back in 2004-ish with 1.00 mm OS pistons, turned crank, resized rods, etc. Not many miles before pulled off duty (maybe 10k max.) Wanted to make some alterations - project stutter makes months turn into years.
After some major upgrades, put back on the road a couple weeks ago. I was so excited!
Less than 10 miles into its first cruise out, total loss of oil pressure (had been idling fine and running test circles in the driveway while tuning the Holley sniper prior to re registering). Always showed low oil pressure on the gauge, but would surge with rpms and, after checking this board, didn't worry too much about it.
Well, tooling down the test drive, the engine locked up, chirped the tires in fact. Coast home (thank goodness we were uphill). Once cool, engine would spin with plugs out but would lock up once warm again.
You know what I'm thinkin'.....trashed mains from a failed oil pump ( BWT, how can you tell if it's bad post mortem? - you can put her in oil and spin per TOY-manual pg. 4-7, but no way to really check pressure - is there a length for the relief valve spring length? How can I be sure it was the oil pump?)
OIL PUMP. The only thing I can't recall if it was replaced or not way back when. Dang, I know those receipts are somewhere.
Tear her down.....
Shinies in the oil pan, not good. Keep goin. Out comes the transfer and tranny (rebuild it since it's out, I never touched it before). Now those nice new seats are out and interior is gutted again.
Clutch is OK, rear main seal leaks a bit, but NBD. Sitting a long time is hard on both front and rear mains - ask me how I know. By the way, checked the dizzy drive, cam gear to the dizzy, all was as expected. Hold down was tight and clamped down.
Strip it all off, ancillaries, all that work you just completed. argh - off with her head. Removing the header is a real PITA.
Block is still in the rig now, all that remains is the pistons, crank and flywheel. Out come the pistons. Look good on top, almost like new. Bores look good. Rings look really good, almost clean. Oil ring is loose and free, not solid and buggered like others I've rebuilt. All rings are nice and springy. On the bottom end... argh... bearings are trashed. Yep - barely there. Oil starved.
They're 0.25 under. Pins look OK but.....No worries though, I found a good STD crank on EBAY with rods and pistons (anyone need some STD pistons?) I picked it up, mic'ed it, yep STD, very nice. Mine was working on the old balancer death wobble anyway and the keyway was questionable. This one looks like new, I'll have it polished or maybe trimmed to 0.25 probably and she'll be good as new.
Still haven't seen the mains yet but I'm sure they're as trashed as the rods. The mains are fed by the main gallery and then feed the rods, so if the rods are starved then I'm sure the mains are toast.
Annnnyyyywwwaaayyy, here's the REAL question. I started checking pistons today. Can't recall brand or supplier, but I had a chance to clean and inspect the #3. Mic'ing piston and bore gage shows a 3.7428 bore with a 3.7388 piston - 0.004 clearance. T-manual is 0.0020....hmmmm.
Bore wear limit is 0.008" on pg. 10-9, which would give me a max bore of 3.7429" for the 1.00 mm over.
3.7428 - ooooooh, that's close.
Remember, this is not a hot rod. I seem to recall using 0.005 for clearance on my OS 5-litre with forged pistons way back when. I'm not sure the shop didn't use a similar number on the 2F as well. The pistons are marked 62641 but I can't find the specs or manufacturer to check producer's clearances. I wouldn't be surprised if it was 0.005". I didn't notice any rocking when I pulled 'em out and there was no rattling... until the bearings let go of coarse - then they slapped pretty good after that.
Looking for opinions, suggestions, thoughts. Anyone recall the manufacturer's # (Manefre?) I'd rather not do much to the pistons and rods other than a new set of rings if I can. I'll put up a pic if it helps. I'd rather just clean up the new-to-me crank, new balancer to take care of the wobble and button her up. So far the bores all check to same +/- 0.001" roughly so the closest I think I'd get is a new set of 1.00 OS pistons and rings (3.7402" vs. 3.7388" - woohoo, pick up 1.5 thousandths). But even so...
I mean, I'll obviously check the remaining pistons against the bores, but is 0.002" really worth a rebore to 1.50mm over and a new set of pistons and rings. I strugglin' with this one on a 2F that does weekend offroad duty.
Sorry for the long story. Just can't seem to find a solid place to land on this one....... please help.
Thanks for any of your thoughts. - Bob