Olga - 1971 FJ40

[Almill13]

After two years of ownership it is time to dig in and give Olga a refresh. A couple weeks ago she started to run poorly and missing at idle. After checking all the basics timing, fuel and spark to no avail I did a compression check and found two of the cylinders are dead. My plan is to take the head off and get it rebuilt and hopefully that is all she needs to get back on the road. While the head is off I'd like to do some other small upgrades and basic maintenance. In the past year I've installed a new fuel tank and a DUI distributor. My main goal with the 40 is to make it reliable and turn it into the family hiking and camping rig for weekend adventures. I started the teardown last night by going ahead and taking the intake manifold and headers off.

 

[Almill13]

Took off the bib then I pulled out the radiator, fan shroud and radiator housing along with the battery box. I plan to paint the shroud and housing before I put it back on the truck and get a new battery tray. My tray is for a dual battery set up but I only run one. Getting a little bit closer to pulling the head off.

 

[Green Bean]

Good looking truck. I hope that your job goes smoothly and that you are back on the road in no time.

 

[Almill13]

I got the head pulled yesterday thanks to the help of my favorite mechanic. It is easy to see where the head gasket failed between cylinders 2 and 3. I will check the flatness of the block and evaluate the cylinder walls later in the week. I am still trying to determine why cylinder 6 had such low numbers on my compression test. Before I started the tear down my wet compression numbers were
Cyl #1 155 psi
Cyl #2 0 psi
Cyl #3 0 psi
Cyl #4 100 psi
Cyl #5 110 psi
Cyl #6 30 psi

The rocker arm assembly was missing the retaining clip on the end by cylinder 6. I'm not sure if that could effect my compression test or not. Somehow the rocker was staying on the push rod and valve spring but I don't know how well it was actually working.

My understanding is the rocker arm assembly has a total of 4 retaining clips and is in two halves and comes together in the middle where the oiling coupler is. Please correct me if I am wrong about the rocker arm assembly.

 

[timmyisinthewell]

Sorry, all I can offer is pics off my old school microfiche reader. Notice p/n 13901C shows a quantity of four, and the shaft is in two pieces and has two different part numbers.

 

[Almill13]

Sorry, all I can offer is pics off my old school microfiche reader. Notice p/n 13901C shows a quantity of four, and the shaft is in two pieces and has two different part numbers.

View attachment 3602009

View attachment 3602011

Thank you, that is exactly what i was looking for. I found this by the end rocker it looks like item # 13901B from the diagram.

 

[Almill13]

Took some square tubing and made a spacer for the spare tire carrier. With the wider tires I was never able to fully inflate the spare and have the carrier close and lock.

 

[Living in the Past]

A number of items on your 40 would manufactured no later than 9/71. That chrome cover on the valve cover which I assume is to fill oil and the lack of one on the passenger side of the block does no make sense for a 71 FJ40. The oil fill on the valve cover was always on the front of the valve cover once it started 9/71. I would also question if you had the correct head gasket. The passages in the front do not line up with the openings in the block. Do the line up with the cylinder head?

 

[Almill13]

A number of items on your 40 would manufactured no later than 9/71. That chrome cover on the valve cover which I assume is to fill oil and the lack of one on the passenger side of the block does no make sense for a 71 FJ40. The oil fill on the valve cover was always on the front of the valve cover once it started 9/71. I would also question if you had the correct head gasket. The passages in the front do not line up with the openings in the block. Do the line up with the cylinder head?

I agree with you my engine is not a typical F something is strange about it. The block has the spot for the oil fill tube but it was never machined out. The oil cap filler on the valve cover was welded onto a F valve cover.

The head has F stamped into the corner. The old head gasket appears to line up with the head and the block.

 

[Almill13]

It's been a minute since I've been able to focus on the 40 project. Where does the time go?

These old heads are not light, I didn't expect to see it weigh in around 85 ibs.

I put some gas in each of the combustion chambers 4 , 5 & 6 all leaked through the exhaust valve. The exhaust valve on number 6 was severely pitted and possibly burnt.

Is it possible to clean up the valve seats and just lap in a new valve or is this machine shop territory? Does anyone have any experience doing this?

 

[Mark Jennings]

Yep, burnt valve…..I’d take her to a machine shop, all new valves, seals, valve springs and keepers…get ya a ‘hot rod’ 3 angle valve job….

However, the leaky exhaust valves don’t explain the loss on compression on the other cylinders.

 

[rlong]

Yup burned. When you get back together need to make sure it's not running to lean due to tuning OR vacuum leaks. The further a cylindar is from the carb (throttle body) the greater the likleyhood of a lean condition. All engines have unequal fuel distribution, #6 on a F/2F tends to be the most suseptable. It (lean condition and eventual damage) often occur due to vacuum leaks, i.e. the intake manifold gasket could have been leaking. All of these concerns are likley to be addressed when you put it together and tune it.. this is just what I was taught over the years. (I had this on happen to my 62' FJ40 from highscool in the early 80's)

 

[65swb45]

There is a lot going on there. That’s a 1974 head. You can see the bulge that marks the internal oil passage to the #4 rocker arm stand. And if the block doesn’t have the oil fill, that would make it newer than ‘71, which is what I assume your truck is, column shift and all.

#6 also has an increased chance of burning due to being next to the vacuum source for the booster. So you might want to have a look at that as well.

50 year old rocker arm shafts are not known for being in the best shape. Chances are that your rocker arm didn’t move because the shaft is deeply galled. I suggest disassembling the rockers completely for a thorough inspection.

To all who find this information useful, please consider hitting the like button.

 

[Mark Jennings]

There is a lot going on there. That’s a 1974 head. You can see the bulge that marks the internal oil passage to the #4 rocker arm stand. And if the block doesn’t have the oil fill, that would make it newer than ‘71, which is what I assume your truck is, column shift and all.

#6 also has an increased chance of burning due to being next to the vacuum source for the booster. So you might want to have a look at that as well.

50 year old rocker arm shafts are not known for being in the best shape. Chances are that your rocker arm didn’t move because the shaft is deeply galled. I suggest disassembling the rockers completely for a thorough inspection.

To all who find this information useful, please consider hitting the like button.

What I have done in some instance where you see ‘minimal’ galling on the split rocker shafts on these early rigs….AND the rocker bushings are still in good condition….is rotate the shafts 180 degrees. Because the valve train pushes the rockers UP, you get wear on the bottom of the shaft….so you rotate them 180, to allow them to run on a clean portion of the shaft. The oiling holes are symmetrical.

 

[Mark Jennings]

Hi

Yep, burnt valve…..I’d take her to a machine shop, all new valves, seals, valve springs and keepers…get ya a ‘hot rod’ 3 angle valve job….

However, the leaky exhaust valves don’t explain the loss on compression on the other cylinders.

Now I see it, head gasket leaked between cylinders 2 & 3……cool beens, valve job should get you back on the road.

Also, since you’ve got the head off, get the date code off of the block….under the TEQ on the drivers side.

 

[Almill13]

Hi

Now I see it, head gasket leaked between cylinders 2 & 3……cool beens, valve job should get you back on the road.

Also, since you’ve got the head off, get the date code off of the block….under the TEQ on the drivers side.

My Vin # on the frame matches the Vin plate on the drivers door FJ4098614
Above the starter my block serial # F374210
the casting number under the TEQ looks like 11108
My head has an F stamped on it

 

[Mark Jennings]

My Vin # on the frame matches the Vin plate on the drivers door FJ4098614
Above the starter my block serial # F374210
the casting number under the TEQ looks like 11108
My head has an F stamped on it

View attachment 3941447

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View attachment 3941451

So the Engine Casting date shows the block cast November 8th, 1971, which based on your build date of February 1971, tells me this was a replacement engine sometime in your rigs early life….the added oil cap, I bet dollars to donuts, was added to the original engine’s valve cover because of the missing oil fill pipe….it is quite a unique fix…it has a cool factor.

The question I have, was the head from the original engine, or part of the replacement engine? Your picture of the ‘F’ stamp also shows a bolt at the front of the engine holding the exhaust flange. On an original F head, this bolt wasn’t there, plus Mark’s comment above about the rocker oiling boss….Maybe an F.5 head?….hard to tell for sure.

 

[65swb45]

What I have done in some instance where you see ‘minimal’ galling on the split rocker shafts on these early rigs….AND the rocker bushings are still in good condition….is rotate the shafts 180 degrees. Because the valve train pushes the rockers UP, you get wear on the bottom of the shaft….so you rotate them 180, to allow them to run on a clean portion of the shaft. The oiling holes are symmetrical.

I have never tried this.

Assuming the oil holes are appropriate (having a hard time visualizing that at the moment*) you still have to account for the fact that the shafts are keyed specifically to ensure the proper oiling, so you would have to file a second set of notches into the shafts.

*At a party, under the influence

 

[Mark Jennings]

I have never tried this.

Assuming the oil holes are appropriate (having a hard time visualizing that at the moment*) you still have to account for the fact that the shafts are keyed specifically to ensure the proper oiling, so you would have to file a second set of notches into the shafts.

*At a party, under the influence

This is the split shaft, copper tube feeding oil to the center…..and to each of the rockers. Oil holes for the rockers are top and bottom. Orientation the notches you reference can be accounted for by moving the front shaft the back and the back to the front….e.g. shafts are flipped and rotated.