2F health questions....what to do? (1 Viewer)

[Highrlr]

I purchased a used '78 2F to install in my '67. I purchased it in conjunction with some other parts, I've not heard it run, it was apparently rebuilt about 10 years ago, but has been out of the vehicle, and not ran in a few years. It appears to be really clean, inside and out. I ran a compression test on it, cold, since it's not installed in the truck. There seems to be quite a variance in the #'s. What would your next step be? Should I pull the head and inspect further? I've had a few people tell me to just install it, run it, and hope it comes around. But I would prefer to know everything is good, before install.
Debating now on if I use it at all, or rebuild the other 2f that was in my '67 originally.

 

[Highrlr]

Disregard the scribbled out #s, discovered my compression guage was leaking, had to tighten things up.

 

[RevISK]

So, did that fix the issue? The leaky gauge?
I’m no engine doctor but those numbers don’t seem crazy out of line. But again, I know little about this subject. Here to learn.

 

[Highrlr]

So, did that fix the issue? The leaky gauge?
I’m no engine doctor but those numbers don’t seem crazy out of line. But again, I know little about this subject. Here to learn.

The numbers were higher once I tightened up the gauge, but the variance in readings between the cyl's remained about the same.

 

[Highrlr]

Oh, and I did adjust the valves prior to running the test, again, on a cold engine, but adjusted none the less.

 

[CenTXFJ60]

Have you considered a cylinder leak down test. May expose some valve seat issues. Pulling the head is easiest at this point and gives you the chance to inspect the cylinders. Prior heat issues would typically impact the outer cylinders first. My bet is your lower end is fine and rebuilding the top end would be worthwhile maintenance while out of the truck. I’ve learned the hard way installing unknown used motors that a reseal & head rebuild results in a good piece of mind.

 

[Greenpiece]

Good data point for you: I recently (yesterday) did a cold then warm compression test on my 78 2F. Cold I got numbers as low as 95 and as high as 135 (a lot of variance). Warm I got 120 every cylinder except number 1 which read 130. So at least on my 78 having the engine warm made a lot of difference. Your numbers look pretty good for a cold engine. Also, for every 1000 feet altitude add 3% to your numbers when comparing to factory specs to correct for altitude. For example, I live at 3000 feet so 120 X 1.09=130.8 when altitude corrected.

 

[Highrlr]

Have you considered a cylinder leak down test. May expose some valve seat issues. Pulling the head is easiest at this point and gives you the chance to inspect the cylinders. Prior heat issues would typically impact the outer cylinders first. My bet is your lower end is fine and rebuilding the top end would be worthwhile maintenance while out of the truck. I’ve learned the hard way installing unknown used motors that a reseal & head rebuild results in a good piece of mind.

So, I actually purchased a leak down guage, but when I apply air pressure, the engine just turns over, I'm not quite sure how to prevent that? I re installed all the plugs, it helped a little, but still turns the engine, I am attempting to apply about 100 psi of air.

Also, I installed an oil pressure guage, and was seeing like 50 psi oil pressure just turning it over, on cold oil of course, but I thought that was pretty good!

 

[MDH33]

Big socket and breaker bar on the crank to keep it from rolling over from the air pressure during leak down. Easier with 2 people as connecting the tester s usually a 2 handed operation.

Those numbers don't seem bad on a cold engine, like mentioned above. I would stick it in and run it unless you're doing some sort of full rebuild nut and bolt restoration. Once it's warm, Oil is flowing and you burn the "cobwebs" out, it will most likely be fine. Rebuilds are expensive and time consuming. At least you'll have a running engine in it and you could rebuild your spare with no urgency.

 

[CenTXFJ60]

So, I actually purchased a leak down guage, but when I apply air pressure, the engine just turns over, I'm not quite sure how to prevent that? I re installed all the plugs, it helped a little, but still turns the engine, I am attempting to apply about 100 psi of air.

Also, I installed an oil pressure guage, and was seeing like 50 psi oil pressure just turning it over, on cold oil of course, but I thought that was pretty good!

Good call. No need to hit at 100 PSI. It’s a bit more difficult without the drivetrain in gear holding it back for you. 30-40 PSI is about as far as you should need to go to determine a valve seal issue. I may be wrong on that and others more knowledgeable can chime in. Here’s a video of my recent use of this tool

 

[Highrlr]

Big socket and breaker bar on the crank to keep it from rolling over from the air pressure during leak down. Easier with 2 people as connecting the tester s usually a 2 handed operation.

Those numbers don't seem bad on a cold engine, like mentioned above. I would stick it in and run it unless you're doing some sort of full rebuild nut and bolt restoration. Once it's warm, Oil is flowing and you burn the "cobwebs" out, it will most likely be fine. Rebuilds are expensive and time consuming. At least you'll have a running engine in it and you could rebuild your spare with no urgency.

That was my line of thinking with buying this used engine. I am doing a mechanical rebuild essentially. This 2f, rebuilt 4 spd, rebuilt 3spd t case, lots of new supporting parts, etc.

I will re try the leak down test. Does 100 psi sound about right for the leak down test?

 

[CenTXFJ60]

That was my line of thinking with buying this used engine. I am doing a mechanical rebuild essentially. This 2f, rebuilt 4 spd, rebuilt 3spd t case, lots of new supporting parts, etc.

I will re try the leak down test. Does 100 psi sound about right for the leak down test?

I think that’s high as I would only be looking for valve seal issues. If you’re doing the engine swap yourself then pulling the head and having a machine shop vet it is a no-brainer. Doing the work yourself you should be able to get away with a top end job for less than $750 including head rebuild gaskets etc.

I installed two used 12HT’s with unknown history (other than mileage). Both had to come back out within a short time with head issues and full rebuilds needed. Hindsight…doing a top end and motor reseal would have saved us a lot of time and $.

 

[Highrlr]

I think that’s high as I would only be looking for valve seal issues. If you’re doing the engine swap yourself then pulling the head and having a machine shop vet it is a no-brainer. Doing the work yourself you should be able to get away with a top end job for less than $750 including head rebuild gaskets etc.

I installed two used 12HT’s with unknown history (other than mileage). Both had to come back out within a short time with head issues and full rebuilds needed. Hindsight…doing a top end and motor reseal would have saved us a lot of time and $.

I agree, I think I like the idea of at least having the head checked out. I am doing all the work myself, and while I am certainly trying to watch cost, I just want to ensure this is all right, as I don't necessarily want to do this all again in the near future.

I will also be re sealing the oil pan, new rear main, probably drop the #1 and #4 main caps for a re seal. And I think I may dona new front crank seal as well, since there is some oil on the front pulled. The front cover looks dry, and I think I'll leave it in place, as it seems that can be a bear to re seal.

 

[lcwizard]

I picked up an 82 fj40 that had been stored for 15 years. It was sitting so long the water had evaporated in the block leaving nothing but a dry caked up powder
in the block. I replaced the thermostat housing, radiator, hoses and flushed the block a few times.
I cranked over the engine and got numbers as low as 65 in two cylinders, 120 in the best. Every day for a week I would put a dose of Marvel Mystery oil in each cylinder and crank it for a while with no plugs. In a week the lowest number was 125ish and the highest about 150. I put the plugs in, hooked it all up
and it fired right up. I would run it in 5 minute intervals for a few days, a couple times a day. In a few days every cylinder was up to or over 150.
That was 8 years ago. The person that bought it still driving it without issue.
If it hasn't been run in a while those numbers wouldn't scare me . Could be just gummed up rings

 

[pb4ugo]

I picked up an 82 fj40 that had been stored for 15 years. It was sitting so long the water had evaporated in the block leaving nothing but a dry caked up powder
in the block. I replaced the thermostat housing, radiator, hoses and flushed the block a few times.
I cranked over the engine and got numbers as low as 65 in two cylinders, 120 in the best. Every day for a week I would put a dose of Marvel Mystery oil in each cylinder and crank it for a while with no plugs. In a week the lowest number was 125ish and the highest about 150. I put the plugs in, hooked it all up
and it fired right up. I would run it in 5 minute intervals for a few days, a couple times a day. In a few days every cylinder was up to or over 150.
That was 8 years ago. The person that bought it still driving it without issue.
If it hasn't been run in a while those numbers wouldn't scare me . Could be just gummed up rings

^^^^^^This^^^^^^^

If the engine has been sitting for yrs, all your testing isn't going to give you any credible info until its been run for a while. Let go thru some heat cycles and oil changes. Your #'s are pretty good. Maybe Reseal it, maybe check a bearing or two. If there are no issues, stick it in.

 

[charliemeyer007]

The used engine I am running now was fired up on a pallet so I could hear it run.

I would put it in your rig and run it. Doesn't take much crud on valves to lower the numbers. Beating on the valves with a lead hammer while its running will clean them quickly. +1 for a dose of Marvel's in all cylinders an a spin with the starter while the plugs are still out to distribute it to the rings.

 

[pb4ugo]

How were you able to get compression #s? Can you rig it to run for a minute or so, at a time. Check for knocks and such.

 

[Highrlr]

How were you able to get compression #s? Can you rig it to run for a minute or so, at a time. Check for knocks and such.

I just installed a starter, and hooked a switch up. I could probably get it to a running state, but would have to install intake,carb,header, etc. And then remove all of that to put back into the 40. Maybe it would all be worth while....maybe not

 

[pb4ugo]

It may not be worth getting it running, but that's up to you. If in fact it had been rebuilt 10yrs ago and then in storage for yrs, it probably has minimal miles on it. During your reseal project you should be able to check some bearings and cylder walls from the bottom.

 

[lcwizard]

I just installed a starter, and hooked a switch up. I could probably get it to a running state, but would have to install intake,carb,header, etc. And then remove all of that to put back into the 40. Maybe it would all be worth while....maybe not

no need to rush things. spin in up a few times a day, check things in between. When your comfortable, for a minute then shut it down. Check things like plugs for oil or burn, temp and oil pressures. It's just a common sense thing. Run it for longer and longer periods and recheck compression now and then. Not knowing for sure the history, better to be conservative