1F Engines; 3 -> 1 or ? (1 Viewer)

[LakeLaurashawn]

Good Morning - I have a May-72 FJ40 with what appears to be an original engine based on the serial number. I have owned it for about 13 years and at some point in the future would need to be rebuilt.

Over the years I have acquired 3 complete long blocks, two of which are complete from the water pump back to the parking brake shaft. Each has a history of unique issues - one was a smoker, one had low compression and the other had an overheat issue than a knock. All three of these were obtained via the classifieds and I have no compression information and never saw any of them running.

My goal is to tear into them and send the best parts to a machine shop for a rebuild, making a single new rebuilt unit. At the same time, I would rebuild one of the two transfer cases and transmissions for a complete assembly using Georg, @orangefj45 The idea here was that I could continue to drive my FJ40 around while taking time to rebuild a replacement drivetrain.

However, these have been in my shop for years and as time has elapsed, so too have the available parts. My initial path was to swap out my 1F for a new rebuilt 1F. The current motor, transfer case and transmission all work well, just planning ahead for what will likely need to take place. This path would avoid me a 1F -> 2F conversion.

Here is my dilemma - rebuild three old long blocks into one or head down the 2F path conversion . . ? For my wheeling use, I am fine with a 3spd and 1F. As I read more and more, 2F parts seem to be getting harder to obtain, based on year. I could grab one from the classifieds, but I'd want to rebuild it and the associated transmission before installing.

Everyone love pictures and data, here are both:

Donor 1 is F392802
Donor 2 is F376855
Donar 3 is F389970

Suggestions & Thanks
Lake

 

[JohnnyC]

what is wrong with your current engine? imho i would do a check over of the current engine ... compression? leak down?

youd be surprised how many miles you can get from one

 

[LakeLaurashawn]

Nothing is glaring at this point with the Engine, Transmission or Transfer Case.

Last time I did a compression test, which was about 2-years ago, the numbers were all relatively even and in the 125-135 range. I have not completed a leak down test, but check and adjust the valves about once a year or so.

I am surprised how many miles she has given me over the last 13-years and hope for many more. My thought was to be prepared as she fails rather than waiting until she fails, before parts are completely NLA, and/or no machine shop will touch the older engines.

 

[Skreddy]

Hook a battery up to the starters and do compression tests as they are; I’ve done that on lots of engines.

As for what I’d do: I’d avoid the one that developed the knock. Between the smoker and low compression one, I’d do a comp test, then a leak down or at least put air to each cylinder at TDC with both valves closed. That can help determine if you’ve got a bad valve or head gasket issues. May not help much to determine rings since they’ve been sitting so long. But at this point, it’s just a guide to see if one is drastically better (or worse) than the other. If there’s no glaring differences, I’d send them both to the machine shop and let them pick the best bits.

 

[Pighead]

you need to disassemble your extra blocks and see what you have, see if you actually can make one out of three and what parts you'll need to do it.

 

[firemanj92]

I'd like to mention the build costs will add up. I had my F motor rebuilt in 2020 by a Toyota motor builder that @orangefj45 uses/recommended. At that time it was approx $6000 with Toyota parts including heads, resurfacing the flywheel and machining the manifolds as preventive measures (motor only had 36k miles but at 55 years old). I spoke to 4 LC motor rebuilders (CruiserCorps, Mosley's, BTB and Yota1) and they were all about the same $$ back then, not including shipping which was an additional $1000 each way to some of the specialists. Btw, Mosley does not necessarily rebuild 1F's but may if you sweet talk him