I bet the compression was good due to the fact that the "grand canyon" trenches in the cylinder walls are on the lower 3rd of the stroke. Lets lots of oil in, but gets good compression.
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How NOT to restore the FJ40
- Thread starter FJ40Jim
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cruiserkev
3 decades in the same FJ40
Thanks for sharing Jim.
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Correct. Remember that the intake valve remains open as the crank swings past BDC and begins throwing the piston up the bore. real compression is built in the top half of the bore. As soon as the top ring got above the trench, it was compressing. But at the bottom, the trench was a conduit for crankcase oil & vapor pressure to get sucked into the chamber on the intake (vacuum) downstroke.
Did you read the thread?
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With a little head mill and .75mm overbore, it shoulda been 165-175.
It was a matching set of good quality .75mm OS pistons. The cylinders were bored to fit, maybe even a little toot tight (we'll get to that shortly).
It's reasonable assumption that there was a problem in at least one cyl that required overboring the block. IOW, there's no reason to bore a good running engine.
Dunno, haven't measured thickness yet. It's been run through the tank & oven so far. Now it can be magnafluxed & measured & built.
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OK, the engine & trans is out of the truck. Let's continue our brief sidetrip into the clutch, tranny & transfer.
The note said something about the tranny & transfer case being completely rebuilt.
By the looks of this, it was rebuilt, then disguised by reapplying 30 years of grime to all the fasteners. That is dedication.
The rear output bearing is loose, allowing the brake drum to orbit and beat up the rear seal, allowing most of the 90wt to exit through the P-brake. Note the shiny wet brake shoes that are completely saturated. When the t-case was drained, it had about one cup of oil in it. Lucky it didn't melt down.
Edit: yes, the lower return spring is missing. Remnants were found rattling around inside the drum. A new one will be sourced from Toyota with the brake shoes.
Pulled off the trans, clutch, flywheel, bellhousing. Underneath the BH is found an american standard cup plug in place of the special, very shallow metric cam plug. This plug was beat forward until it was running up inside of the rear cam bearing. Now the plug is occupying space that should be occupied by the camshaft itself.
So if the cam can't fit all the way to the back of the block, what happens?
Well Timmy, if the cam is prevented from going all the way to the back, then when the thrust plate is bolted to the front of the block, instead of the plate pushing the cam to the rear, the cam is going to bow the heck out of the plate and ride forward. Sorry, no pics of that.
So now the cam lobes that normally ride just a little off center of the lifters to encourage lifter rotation are centered under the lifters, allowing the lifters to "stall" i.e. not spin. A stalled lifter tears the surface hardening off the cam lobe in short order, which then begins to destroy the lifter face. And so with only a thousand miles on it, the new cam & lifters and thrust plate are garbage.
But we do get to keep the new all metal timing gear set.
The note said something about the tranny & transfer case being completely rebuilt.
By the looks of this, it was rebuilt, then disguised by reapplying 30 years of grime to all the fasteners. That is dedication.
The rear output bearing is loose, allowing the brake drum to orbit and beat up the rear seal, allowing most of the 90wt to exit through the P-brake. Note the shiny wet brake shoes that are completely saturated. When the t-case was drained, it had about one cup of oil in it. Lucky it didn't melt down.
Edit: yes, the lower return spring is missing. Remnants were found rattling around inside the drum. A new one will be sourced from Toyota with the brake shoes.
Pulled off the trans, clutch, flywheel, bellhousing. Underneath the BH is found an american standard cup plug in place of the special, very shallow metric cam plug. This plug was beat forward until it was running up inside of the rear cam bearing. Now the plug is occupying space that should be occupied by the camshaft itself.
So if the cam can't fit all the way to the back of the block, what happens?
Well Timmy, if the cam is prevented from going all the way to the back, then when the thrust plate is bolted to the front of the block, instead of the plate pushing the cam to the rear, the cam is going to bow the heck out of the plate and ride forward. Sorry, no pics of that.
So now the cam lobes that normally ride just a little off center of the lifters to encourage lifter rotation are centered under the lifters, allowing the lifters to "stall" i.e. not spin. A stalled lifter tears the surface hardening off the cam lobe in short order, which then begins to destroy the lifter face. And so with only a thousand miles on it, the new cam & lifters and thrust plate are garbage.
But we do get to keep the new all metal timing gear set.
Last edited:
Phares
Mostly Useless
Holy amazing!
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Pistons & stuff
With the tranny out of the way, the block is picked up and oil pan removed.
There is an interesting collection of aluminum & carbon flakes at the bottom of the pan, underneath the oil pickup.
Where would the aluminum shavings come from?
Perhaps these piston skirts:
Note also in the above picture the location of the wristpin. It should be centered inside the piston. That's how it came out of the engine.
Here's the full set. 3 were heavily scuffed and 3 still looked like new. They were a matching set, but because of the top quality bore job, some cylinders were a little too tight, which smeared the pistons. Because the aluminum was torn off by being squeezed in the bore, those pistons are .005" too small now, too damaged to re-use.
The crank had been turned undersize. But the machine operator leaned on the polisher belt too hard and turned the bearing surface into a trough. So the rod bearings were worn on the outside edges, but untouched in the center. The crank will have to be re-machined, no big deal. But the undersize machined seal surface will probably preclude re-using the crank. Whatever, cranks are not hard to come by. Easier than pistons.
The main bearings have a maker's mark on the back I have not seen before.
Anybody have an idea?
That brings us up to the present.
The engine bay score stands at...
Garbage:
1 block
1 camshaft
12 lifters
12 valves
1 cam thrust plate
1 cam plug
1 front timing plate
1 timing cover
3 pistons
1 crank
1 thermostat housing
1 water pump
1 manifold insulator plate
salvageable:
manifolds
head
Good:
clutch
flywheel
timing gear set
6 rods
oil pump
fuel pump
ignition system
Back to work. The great piston hunt continues...
With the tranny out of the way, the block is picked up and oil pan removed.
There is an interesting collection of aluminum & carbon flakes at the bottom of the pan, underneath the oil pickup.
Where would the aluminum shavings come from?
Perhaps these piston skirts:
Note also in the above picture the location of the wristpin. It should be centered inside the piston. That's how it came out of the engine.
Here's the full set. 3 were heavily scuffed and 3 still looked like new. They were a matching set, but because of the top quality bore job, some cylinders were a little too tight, which smeared the pistons. Because the aluminum was torn off by being squeezed in the bore, those pistons are .005" too small now, too damaged to re-use.
The crank had been turned undersize. But the machine operator leaned on the polisher belt too hard and turned the bearing surface into a trough. So the rod bearings were worn on the outside edges, but untouched in the center. The crank will have to be re-machined, no big deal. But the undersize machined seal surface will probably preclude re-using the crank. Whatever, cranks are not hard to come by. Easier than pistons.
The main bearings have a maker's mark on the back I have not seen before.
Anybody have an idea?
That brings us up to the present.
The engine bay score stands at...
Garbage:
1 block
1 camshaft
12 lifters
12 valves
1 cam thrust plate
1 cam plug
1 front timing plate
1 timing cover
3 pistons
1 crank
1 thermostat housing
1 water pump
1 manifold insulator plate
salvageable:
manifolds
head
Good:
clutch
flywheel
timing gear set
6 rods
oil pump
fuel pump
ignition system
Back to work. The great piston hunt continues...
Last edited:
I'm surprised pistons are so hard to source, is that just the way it is? I would think something like the crank/block would be a lot harder to come by? I always thought there were quality after-market options for pistons? Does Toyota still have the camshaft, etc.?
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Wow, you're good.
King bearings. I thought they only made USA race car parts.
They list a 429AM part number for F & 2F main bearings.
They also have a listing for rod bearings.
That's good to know.
If I were the buyer, I'd tell the "restoration" company I purchased from to lawyer up, and fast!
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The dome top 75-80 pistons seem to be extinct. There were only two factories on the planet producing them recently. Now both of those factories have stopped.
There is a chance that the ITM source somewhere in Chicomm could restart production, but I was told that the factory was not seeing orders, so there was no planned re-intro date. But the same rep also said they are not seeing orders because people don't bother ordering when they are told the part is on indefinite hiatus. It's a death spiral of reduced demand/ reduced availability.
Cruiserdrew
On the way there
Very bad news. So we now have to drive them until they die and then scrap? What about 3FE pistons?
Kind of a newb question, but if one wanted to try to salvage the block and make it workable with pistons that might still be available (ie. less oversize) could you sleeve the cylinders like they to with diesels? Or is that just way too much work and expense given the availability and price for 'rebuild-able' short blocks, especially since so much of the rest of the motor needs to be replaced anyway?
3F-E pistons are still available Andy. Just got a set 2 months ago for Robbie on a 3F-E he was building.
The 75-80 ones are Gone Johnson.
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Yes, it is do-able.
And yes, it costs a lot of money to resleeve all 6 holes.
If it comes down to that, we will start using pistons for the GMC 270 (which the 2F is copied from). Same rods, crank, .990 wristpins but a 3.781 bore instead of 3.70 bore.
Or if we are gonna sleeve the blocks, might as well bore to water, then sleeve back down to 4.030 bore and install GMC 302 +.030 pistons for a 305CID engine.
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You might as well ask "what about 22RE pistons?"
Other than being round and aluminum, they share no dimensions.
Coolerman
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Yes, it is do-able.
And yes, it costs a lot of money to resleeve all 6 holes.
If it comes down to that, we will start using pistons for the GMC 270 (which the 2F is copied from). Same rods, crank, .990 wristpins but a 3.781 bore instead of 3.70 bore.
Or if we are gonna sleeve the blocks, might as well bore to water, then sleeve back down to 4.030 bore and install GMC 302 +.030 pistons for a 305CID engine.
Very interesting thread for sure. Jim have you ever built one of those 305CID engines for anyone?
