How do you know if a head is “bad”

[rstoddard]

I pulled the head on the ‘75 2F I recently acquired. The head looks pretty nasty. Can any judgment be made about the condition of the head from a photo do I need to take it to a machinist to have it inspected for cracks, etc? I could trade it for another 61030 or 61031 if this one looks “bad” but I don’t know how to access it.

 

[rkymtnflyfisher]

Have it magnafluxxed.

 

[pb4ugo]

You can also clean up the surfaces and visually look for obvious cracks. Get a steel straight and a feeler gauge and check the deck for warpage. You can pour lacquer thinner or acetone in the combustion cambers and around the valves and see if they hold the liquid or if it leaks between the valves and seats. In the end magniflux is the best and what the machine shop will do after disassembly, cleanup and visual inspection.

 

[B y r o n]

I assume that since you pulled the head you are planning on doing work to the block. If that is the plan they can probably do the necessary inspection and advise you on any work that will need to be done.

 

[sogncab]

Usually if there's teeth involved.

*hat, coat, door

 

[Grayscale]

Now is the time to measure the diameter on the bore of the block with a pair of calipers. If it is slightly less than 3.701" then the cylinders are original size.

You have original valves, based on the Teq cast in the middle.

I'd be very careful cleaning up that gasket, don't gouge anything. I did and it will cost me a trip to the machinist. Try a brass or aluminum bar worked to a chisel shape? Use really soft steel for a scraper or whatever.

I'd go for an overall DIY refresh before sending it out. Something like new rings and bearings if you want longevity, fresh cross-hatch hone. You could do new valves if necessary, but, cleaning them up gets you pretty far in the game. Otherwise, just new valve stem seals and a head gasket. If it leaks, it will have cost you only time, some work, and a head gasket. If you have crank / block problems, then you'll pull the motor again and it might not be worth the work. Check for excessive pitting on the exhaust valves, otherwise this looks like a good motor.

 

[rstoddard]

Now is the time to measure the diameter on the bore of the block with a pair of calipers. If it is slightly less than 3.701" then the cylinders are original size.

You have original valves, based on the Teq cast in the middle.

I'd be very careful cleaning up that gasket, don't gouge anything. I did and it will cost me a trip to the machinist. Try a brass or aluminum bar worked to a chisel shape? Use really soft steel for a scraper or whatever.

I'd go for an overall DIY refresh before sending it out. Something like new rings and bearings if you want longevity, fresh cross-hatch hone. You could do new valves if necessary, but, cleaning them up gets you pretty far in the game. Otherwise, just new valve stem seals and a head gasket. …... Check for excessive pitting on the exhaust valves, otherwise this looks like a good motor.

That sounds good. I haven’t measured the bore yet, but there doesn’t seem to be much of a ring ridge, so (you may be right) it may be salvageable with a ring and valve job.

 

[rstoddard]

I pulled the head on the ‘75 2F I recently acquired. The head looks pretty nasty. Can any judgment be made about the condition of the head from a photo do I need to take it to a machinist to have it inspected for cracks, etc? I could trade it for another 61030 or 61031 if this one looks “bad” but I don’t know how to access it.

View attachment 3200236

I pulled the Oil Pan,,,
Not a pretty sight, but the Crankshaft looks to be in good condition.

 

[3_puppies]

until all the bering caps are removed, you will have no idea how the crank "looks"

does the rotating assembly, rotate?

 

[aztoyman]

I've seen worse looking engines get rebuilt.

It needs to come apart and be inspected. Things might be stuck together so don't break anything important taking it apart. If in doubt, let a shop do it.

The crank, block and heads can be rebuilt IF no fatal cracks and enough material available to machine to a usable over or under size.

Even a clean engine needs basically the same work if it's high mileage.

A machine shop should be able to inspect and advise for a reasonable price. They have to clean it to check it so they will have some time in it.

Good luck.

 

[sggoat]

This is ugly for sure--BUT it is not a show -stopper--do you have or have access to- a factory service manual for this engine?--if you do, just follow the steps--most of this ugliness looks to be surface, and not damaging--you could place it in the hands of a shop--but then you would not get to know your cruiser-It is not that hard to do--it's dirty and takes time, but the knowledge gained is invaluable--depends on your dedication, time, and the availability of the tools needed
I just had my '79 head redone--Cost was $230--(I had three sets of valve springs-the shop picked the best ones in spec, also had a new set of exhaust vlves{they used two of them}-had a new set of vlv guides-they didn't need them}--the head was resurfaced(no machining-didn't need it-just polished, spring keepers ok,--magnaflux ok-no cracks--
While the head was in process-filled the cylinders w/oil(~1") over the 6 days for the head work, there was no drop in cylinder oil level- so I figured the rings were ok) Cleaned the block surface(plug all the water/oil holes)--re-installed the head(new OEM gasket-get now before they are gone)), new Remflex manifold gasket) and---I got 22" vacuum at idle--I consider this to be a success!(and no, I am NOT going to re-torq the head bolts-been there-done that)
Suggest you get a new oil pan gasket from Toyota now(before they are gone)--the aftermarket 4 piece gaskets are junk--
As for checking the cylinders, I would not use such as lacquer thinner--it is thin, and will immediately begin dissolving any oil film present on the piston rings/cylinder walls--you will almost immediately get indications of leakage--even if the piston rings/cylinders are serviceable--the engine does not run with lacquer thinner in the crankcase-it uses ~30 wt oil-so that is what I believe should be used to determine if you have piston ring leakage(esp since this will be checked when the engine parts are as cold as they will ever be-whatever your ambient conditions are)Using this thinner may give you indications that you need to fix something that isn't broke.
Good luck-looking forward to your progress--

 

[rstoddard]

until all the bering caps are removed, you will have no idea how the crank "looks"

does the rotating assembly, rotate?

I've got it covered because we had rain. I'll look it over in a few days.

 

[clrussell]

Usually if there's teeth involved.

*hat, coat, door

I can’t believe no one bit on that one ^

 

[rstoddard]

I've seen worse looking engines get rebuilt.

It needs to come apart and be inspected. Things might be stuck together so don't break anything important taking it apart. If in doubt, let a shop do it.

The crank, block and heads can be rebuilt IF no fatal cracks and enough material available to machine to a usable over or under size.

Even a clean engine needs basically the same work if it's high mileage.

A machine shop should be able to inspect and advise for a reasonable price. They have to clean it to check it so they will have some time in it.

Good luck.

I found a great machine shop today. I knew I was in the right place when I say a photo of a '78 Land Cruiser on the wall! They have tons of F/2F experience and have worked on engines for shops around the Phoenix metro area. They have done work for me before and are old school guys. They are busy as hell so the recommended I tear it down and bring in the parts, carefully disassembled and marked for location. They will clean it up, inspect it, and do all the measurements and reassemble the crank and head to the right tolerances. Seems like the right way to go. I may need so advice on the teardown as I get to any spots where I am unsure how to proceed. It sounds like marking the piston, bearing caps positions and rods is critical, so marking everything and keeping them bagged and labeled by cylinder position seems to be a one of the key aspects.

Any advice on disassembly and removal of the bearing caps (i.e., sequence, turning the crank to remove, removal of the pistons from the cylinders, especially since they are dry, removal of the camshaft)- anything that you think is important that may not be covered in the FSM, is appreciated.

 

[rstoddard]

I can’t believe no one bit on that one ^

I don't know what it means.... must be dense.

 

[rstoddard]

Suggest you get a new oil pan gasket from Toyota now(before they are gone)--the aftermarket 4 piece gaskets are junk--

Do you know the PN for a '75-'80?

 

[sogncab]

I can’t believe no one bit on that one ^

LOL

 

[sogncab]

Any advice on disassembly and removal of the bearing caps (i.e., sequence, turning the crank to remove, removal of the pistons from the cylinders, especially since they are dry, removal of the camshaft)- anything that you think is important that may not be covered in the FSM, is appreciated.

There is a youtube channel. Jim's Automotive Machine Shop. None of it is specific or meant to be educational, but it does expose you to seeing how things are done in an auto specific machine shop. I enjoy watching them.

 

[rstoddard]

There is a youtube channel. Jim's Automotive Machine Shop. None of it is specific or meant to be educational, but it does expose you to seeing how things are done in an auto specific machine shop. I enjoy watching them.

Good video!