Need some advice - low compression (1 Viewer)

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Joined
May 13, 2015
Threads
3
Messages
31
Location
Billings, Mt
Hello mudders,
I have a 77'FJ40 that up till a couple weeks ago ran great, now it seems like to have hardly any power at all. i have checked several things but nothing really stands out. After alot of reading on this forum I came to the conclusion I may have a blown headgasket. i have done a dry compression test, followed by a wet test. With the throttle open, here are my numbers:
1. 42/57
2. 47/48
3. 90/97
4. 90/91
5. 91/100
6. 90/105
After I did the dry/wet test, I adjusted the valves and got these numbers:
1.58
2. 55
3. 96
4. 98
5. 102
6. 108
I know that even the higher numbers are pretty low. Also all the compression tests were done with the motor warmed up. I am seeing no bubbles in the radiator with cap off, no emulsion on the valve cover or oil fill cap, and no anti-freeze in the oil.
I guess my question is, should I pull the head and have it looked at and change the headgasket, or should I be thinking about rebuilding the motor?

Thanks for any suggestions
 
Imho with the two cylinders being that far off from the others you could have a blown gasket between 1&2 cyl ... the space between them is small (if memory serves me)

The water jackets aren't really too near the center where it's blown .
... so... you will see nothing more
 
Thanks JohnnyC,
So do you think I should pull the head and have it looked at, and replace the head gasket? what about the low compression numbers in theremaining cylinders?

Thanks
 
Sounds like the head is coming off. Get it magnafluxed at a machine shop when you pull it to check for cracks. Replace the HG and give it a shot.

The low compression numbers could be from a lot of stuff, maybe you just need a valve job.

Maybe not.
 
Thanks Rkymtnflyfisher,

Sounds like thats the way to go then, i will pull the head and have it looked at and magnafluxed.
I have one more question, just out of curiosity, how much trouble would it be to replace my motor with a 2F from a 1987 FJ60?
Asking because I found one locally for decent price.

Thanks
 
Thanks Rkymtnflyfisher,

Sounds like thats the way to go then, i will pull the head and have it looked at and magnafluxed.
I have one more question, just out of curiosity, how much trouble would it be to replace my motor with a 2F from a 1987 FJ60?
Asking because I found one locally for decent price.

Thanks

Youll be able to inspect your cylinder walls with the head off and determine what next steps should be.

'87 2f- If you are able to hear it run and get compression numbers, that's not a bad way to go. Plenty of detailed write ups if you search through mud. There are a few ways to do it. I am running an 84 FJ60 2F but with 1f exhaust/intake/carb and 78ish water pump in my 72 build.
 
How does it run,idle?
 
Allenman,
it runs like crap, no power. It will idle, but its pretty rough
 
Many have adviced in the past just to swap in another used 2F....once in a while they pop up in the classified section
For as low as 400 up to 1200.

Post up in the wanted section.
 
allan man,

I believe thats the routeI will take, once I get the head off and get a good look at the damage.

Thanks
 
Yeah by all means do whatever you can for first without investing to much... When you take that head off you should have a good idea and the oil pan...wrenching is free and fun.


For Sale - 2F and 4 speed


Not affiliated...
 
Follow up,I pulled the head and low and behold, the head gasked was separated between number 1 & 2 cylinders. I have had the head looked at. He magnafluxed and hot dipped it. the head was pretty warped, so it took quite a bit of machining to make it right. The valves were good, he did a vacuum test on them. getting ready to put it back together!
 
even with the gasket out between the 2 cylinders, that doesn't explain the low #'s on the other cylinders.

I'm not too far away and have a 2F if needed.

you can also check in here: MT- 406 Cruisers
 
3_puppies,
I was thinking that the warped head may have something to do with the low compression #s? I will keep you in mind for a replacement 2F if needed. I didn't realize there was a Toyota Club in MT. Do you guys ever do anything near Billings? I'm not sure my FJ40 to make it Bozeman.
 

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