Checking compression before installing a new to me 86 2f. (1 Viewer)

[40cruiserdad]

I picked up a used 2f from an 1986 fj60 a few months ago. I have gotten it all cleaned up but I want to check the compression before installing it. Is there a way to hook up a battery to the starter to crank it over?

 

[40cruiserdad]

I picked up a used 2f from an 1986 fj60 a few months ago. I have gotten it all cleaned up but I want to check the compression before installing it. Is there a way to hook up a battery to the starter to crank it over?

I picked up a used 2f from an 1986 fj60 a few months ago. I have gotten it all cleaned up but I want to check the compression before installing it. Is there a way to hook up a battery to the starter to crank it over?

Does it even make sense to try and check the compression before installing the engine? Seemed logical to me in case I get poor compression numbers I can work on it outside the engine bay.

 

[3_puppies]

very easy to do
+ to starter
- to the engine block or starter mounting bolt
use a remote start button or similar to go from + to the signal wire to engage the bendix
may need to strap the engine down so it stays upright
these will be cold #'s so they will be lower than warm #'s

 

[40cruiserdad]

Thanks @3_puppies guess ill pick up a remote start button tomorrow.

 

[fjc-man]

What he said, assuming it still has oil in it

 

[cruisermatt]

We do it all the time with engine hanging on chain from the forklift.
2 bolts in the bellhousing, 2 bolts in a leftover 3FE flexplate (lightweight and worthless), and one bolt in the shop test starter. Use the jumper cables off the forklift battery

 

[DougAustinTx]

If the motor hasn't been run in a long while, fog some oil in each cylinder before cranking it. It's easy to score cylinders when they are dry. Don't actually start it during the cranking. After you have spun it over and gotten the compression numbers on all the cylinders, it should have developed enough oil pressure to make it safe to actually start it. You will be looking for 145-150 psi on each cylinder, although anything 125 and over will be ok.

 

[OSS]

The ‘standard’ compression specification for that engine out of the 2F FSM is 149 psi (lower limit 114 psi) but that’s only when the engine is warmed up prior to testing. Manual states to warm up the engine prior to doing a compression test so I suspect a cold engine would pump at lower pressure.

I had a ‘86 2F engine for 30 years in my FJ60. The compression was below 149 psi for maybe 25 years and 220,000 miles - and engine ran fine.

 

[40cruiserdad]

Compression test done...1 through six numbers on a cold engine that hasn't run in about 5 years are; 120, 110, 110, 110, 95, 120. Good/bad? The number 5 cylinder seems to be climbing a little each time i run through. Bore scope shows a a couple streaks of surface rust on the cylinder walls maybe from condensation? Should I go ahead and drop it in so I can get it running and test it warm?

 

[bikersmurf]

Were those numbers wet or dry?

I’d consider soaking the rings in Marvels Mystery Oil for a few days and then testing again. A few tablespoons through each plug hole should do the job. I’m guessing that the rings may be sticking and not sealing well.

 

[40cruiserdad]

Were those numbers wet or dry?

I’d consider soaking the rings in Marvels Mystery Oil for a few days and then testing again. A few tablespoons through each plug hole should do the job. I’m guessing that the rings may be sticking and not sealing well.

I did squirt about a tsp or so of engine oil down each plug hole and let it sit overnight. It could be a sticky ring in that cylinder.

 

[40cruiserdad]

For the curious here is how she looks cleaned up and painted.