Piston / Cylinder clearance - 2F - is 0.004 too much? (2 Viewers)

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Joined
Apr 20, 2006
Threads
3
Messages
115
Location
Four Corners Area - Farmington
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
 
I would use the bores and the pistons as they are. Hand fit the new rings to get the gaps you want. I would be more interested in why the engine lost oil and seized, Did you replace the cam bearings in the earlier overhaul? I can't remember now if the oiling in a 2F requires the cam bearings to be in a certain position for that engine. Some engines' cam bearings need to be clocked to align oiling holes to feed the rods and mains, but not sure on the 2F. It's been a while. I would say it is very unusual for one of these oil pumps to completely fail.
 
Thanks for the reply. Don't think its the clocking of the cam bearings given the top end was oiling before and the mileage since the rebuild, but I will check. I don't recall seeing any issues with the cam bearings when I pulled the camshaft.

I'll have to do a post mortem on the oil pump. Unusual, yep. But I kept reading in posts hear about week oil pressure relief valves and springs. We'll find out when I take her apart I guess. I would think that, if I screwed up and used the original pump, after 44 years maybe the relief spring gave out and just dumped the oil pressure.

Anyone else have an oil pump failure on a 2F?
 
A common mistake on the 2f motor is putting HG on backwards. You end up covering one of the oil galleys that feed the head.
I don't believe the cam has anything to do with oiling the engine.
 
This is not the issue. Oiling on the head/valve train was great prior to failure. Head was wet with oil when cover removed. This after thousand of miles and servicing. She was squirting oil nicely when valve adjustment made previously. Oil from crank flows to the cam through the galleries and up. Head gasket flip won't take out mains - it'll trash your valve train, but not the lower end. (hmmm, just thought of this - too much oil to the top end? Need a restrictor? Nah - this ain't a Cleveland)

Still thinking oil pump failed, but will disassemble. Could be a bad bearing from the start, making a leak. They were checked by me with plastigage and were in spec though. (that was a long time ago). Could be one failed and made a leak but that seems less likely than the pump.

Guess we'll see - still would like to know if anyone ever experienced an oil pump failure and how they determined? Out of spec on the gears & cover? Squishy relief spring?
 
Not many miles before pulled off duty (maybe 10k max.)

If you were able to drive this many miles on the rebuild before it was parked, then it could not have been an assembly error.

My guess is the same as yours, oil pump failure of some kind. The only other remote possibility is the bearings were so dry when you restarted after sitting that they immediately spun.
 
@rflegal

I don't know about oil pump failures, but I had a Chevy Malibu wagon ('80's?) that wiped the main bearings when the oil pump pickup screen plugged up. The mechanic said the screen was small in diameter and sludge was covering it up.
 
Thanks, but no, fresh oil & filter (changed with virtually no miles), screen nice and clean as well as pan save for shiny bits of bearing. Should have mentioned that. I had just done a front seal cause she was dripping from deform from sitting so long, so fresh pan gasket, seal, etc. - full pan, nice and clean. All that new oil gone to waste.


If you were able to drive this many miles on the rebuild before it was parked, then it could not have been an assembly error.

My guess is the same as yours, oil pump failure of some kind. The only other remote possibility is the bearings were so dry when you restarted after sitting that they immediately spun.

Yep, that's how I got to the pump. She had probably 2+ tanks full of gas idling and running while I swapped in the Sniper and tuned. I don't think she was dry on the bearings. I did the front main seal sometime in January cause she was dripping from a deformed seal from sitting (probably same issue with rear seal) and replaced the used pump with new on the hydroboost; I think that was March? Ran really good too, dang it. One thing for sure, once fixed she'll have a real oil pressure gauge.

After the install in November - Running good. Was doing balance of upgrades (cage, seats lights, etc) up till April.

Sniper install back in November...


Pics from tear down (blue tarp coverin' parts in the bed).

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What make of oil filter?
 
Motorcraft FL-1 - been running those for the last 15 years.
 
No dirt/sludge/water/etc in the pan when I dropped it for the seal back in March (?). Lots of hours in the driveway running since. Clean oil in the pan save for the shinies from the bearings after the seize. All of this points to catastrophic failure.
 
Which puts me back to my original question - has anyone here actually had first hand experience with 2F oil pump failure and been able to be sure of the cause conclusively? I have a new Aisin pump going in, but want to make sure.
 
Oh, and of course the question about 0.004 piston/cylinder clearance.
 
Which puts me back to my original question - has anyone here actually had first hand experience with 2F oil pump failure and been able to be sure of the cause conclusively?

Nope, not I. They seem to be very simple and bulletproof. Only thing close is the failure to seat the dizzy shaft all the way in.
I have heard, recently, of bearing failure due to bad oil filters, but I forget which ones...
 
You wrote this in your first post:
" 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."

So you had low oil pressure for some time before this event? That low oil pressure is not normal. Mine goes straight to 58-60 psi when I start it, and never drops more than 5 psi as the oil heats up. It sounds to me like your bearings were going out for some time, and they got progressively worse. Were these bearings tri-metal, or some sort of aluminum replacements? As the bearings got more and more clearance, I can see the oil pressure dropping, but I can't figure out stopping the engine (seizing). Usually when the bearings are oil-starved, they start knocking as they shred, but that doesn't lock the engine up. Lock-up usually happens when the pistons are oil starved and start to expand in the cylinders as they heat up..... or you throw a rod (yeah, that can lock the engine up real quick).
 
I have heard, recently, of bearing failure due to bad oil filters, but I forget which ones...

Wix / Napa, several 1FZFE engine deaths have been discussed in the 80 section.
 
You wrote this in your first post:
" 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."

So you had low oil pressure for some time before this event? That low oil pressure is not normal. Mine goes straight to 58-60 psi when I start it, and never drops more than 5 psi as the oil heats up. It sounds to me like your bearings were going out for some time, and they got progressively worse. Were these bearings tri-metal, or some sort of aluminum replacements? As the bearings got more and more clearance, I can see the oil pressure dropping, but I can't figure out stopping the engine (seizing). Usually when the bearings are oil-starved, they start knocking as they shred, but that doesn't lock the engine up. Lock-up usually happens when the pistons are oil starved and start to expand in the cylinders as they heat up..... or you throw a rod (yeah, that can lock the engine up real quick).

Well, the pressure was never shown good on the stock gauge, even before the first rebuild so... that thing just sucked. Should have put in a real gauge long ago.
No knocking, nice operation before hand. Cylinders and rings all look great thus far (need to finish micin' them all) I suppose it could be a long time fail on the bearing. I don't recall the source but I can read the #s on the back, rods are -25.

Pistons and rods good too. I will drop the crank and inspect as well as take the straight edge and feeler gauges to the pump internal over this long weekend.

Do-do happens, especially when it's been sittin' so long, but I want to finish this up and be sure it won't happen again.
 
Also there was no metal in the oil drained when I did the front seal this spring. Since then, nothing but several miles around the property (maybe...) and maybe 40-80 hrs idling and tuning.
 
Also there was no metal in the oil drained when I did the front seal this spring. Since then, nothing but several miles around the property (maybe...) and maybe 40-80 hrs idling and tuning.

Well, the crank is down. Mains aren't that bad. Rear's not great and journal scored but not near as totaled as the rods. About a 3:1 comparison WRT damage, rods:mains.
Clean up the new (used) crank, new bearing, etc. Need to check cam bearing, likely renew. Picked up 1.00 os pistons & rings, domed. Will keep posted.
 

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