Ohio Red 1978 FJ40 (1 Viewer)

[Chestcutter]

After having a lot of fun driving the truck and teaching my son to love 4 on the floor, I got tired of breathing exhaust fumes in the cab and knowing that intake leak was making it impossible to tune properly. @Dianna's Post re: exhaust manifold replacement inspired me to stop procrastinating and get to it.

Many thanks to @fjc-man for the suggestion to take the left fender off. Which made a painful project less so.

First time in the garage with the hood up in a couple weeks:

Taking off the Vac switching valve, which isn't doing anything with the desmog. With the wire harness out and half the grille disconnected I might as well do the headlight upgrade while I'm waiting for parts

Fender off - much easier access. Nice to be able to sit on the tire and work

Carb off and evaporating residual gas into the cool spring air

Manifold looks good so far with no cracks

Reaching the rear exhaust bolt is a huge pain. Took the heater hose off and debating removing the fitting, but managed to get them out

Exhaust flange nuts remarkably came out with no fanfare, so ready to pull

And it is pretty obvious where the exhaust leaks are.

Off and ready for disassembly

 

[fjc-man]

What’s your plan? Mill flanges as one and spot face the mounting points?

 

[Chestcutter]

To be determined at this point. Before separating, the manifolds look fairly true with no real warping and the depth of both flanges to the washers are similar. Issue appears to be that other than the 2 center studs, all the bolt holes in the head have issues. The two below the gasket were coarse thread of a smaller size which don't look to be helicoiled but both were stripped. So I think the main problem was inadequate torque on the manifold to head bolts. Lots of other problems as well. See below.
These are the two lower manifold to head bolt holes.

Both had small coarse thread non OEM bolts but don't look like they were helicoiled
Upper bolts were OEM M12x 1.25 but threads in the head are beat. Center studs are OK. The below shot shows the non-standard bolts.

Also there was a leak in the heat riser gasket as was evident around the one heat riser bolt that was black. Heat riser bolts are non-OEM and coarse thread with helicoils in the manifold which look reasonable. I would like to go back to OEM bolts if possible. Anyone know the size of the OEM heat riser bolts?

Another issue - I had a clear exhaust leak between the parts of the manifold.

The part that leaks separated easily, the other one is very stuck, but doesn't leak. My original plan was to separate, clean, and install new springs and rings on both sides. Given one side is very stuck and doesn't leak, best to leave this alone?

Final question for now... I have a big exhaust leak around the flapper valve shaft. Thinking I will replace this with a block-off plate.

I have heard the remflex gaskets are too thick for this purpose. Fel-pro? Other option?

Given bushings are not available for this, will likely block off with bolts on both sides. Open to suggestion.

 

[Chestcutter]

So questions for the experts based on this plan

1. Time-sert the 12 mm holes in the head and replace the bolts with studs. Keep the center studs which look OK.
2. Leave the manifold surface as is as long as it checks true with a straightedge after reassembly. Any advice for cleaning this up?
3. Cap the holes from the flapper valve with bolts. Tap these and use flanged bolts - I saw this in another thread but can't remember the size.
4. Either re-use existing heat riser bolts with helicoils or time-sert these to OEM bolt size - again anyone know the size?
5. Use Fel-Pro gaskets for the heat riser with block-off plate and either the Remflex (what I have) or Fel-Pro for the manifolds.
6. Any reason to separate the part of the exhaust manifold that seems rusted together? I have new springs and rings for the other side.

Appreciate all the advice from those more experienced.

 

[Chestcutter]

@TheHardWay promised you pics. Get out the popcorn and there will be more.

@Dianna hope your disassembly is smooth

@Jdc1 I may be hitting you up for the best machine shop...

 

[TheHardWay]

Most excellent photos - thank you sir. About how long did it take to get the fender off, and how high on the PITA scale? UPDATE: Just read @Dianna thread - not long at all and pretty low on PITA scale, sound about right?

 

[Chestcutter]

agree 20 min job to get the fender off and well worth it

 

[fjc-man]

I discovered the ease of working on the left side of the engine by taking the fender off I exchanged my air pump( seized) for a rebuilt one. I didn’t have to touch the P/S going at it this way.

 

[tstepp920]

To be determined at this point. Before separating, the manifolds look fairly true with no real warping and the depth of both flanges to the washers are similar. Issue appears to be that other than the 2 center studs, all the bolt holes in the head have issues. The two below the gasket were coarse thread of a smaller size which don't look to be helicoiled but both were stripped. So I think the main problem was inadequate torque on the manifold to head bolts. Lots of other problems as well. See below.
These are the two lower manifold to head bolt holes.
View attachment 2648400
Both had small coarse thread non OEM bolts but don't look like they were helicoiled
Upper bolts were OEM M12x 1.25 but threads in the head are beat. Center studs are OK. The below shot shows the non-standard bolts.
View attachment 2648401
Also there was a leak in the heat riser gasket as was evident around the one heat riser bolt that was black. Heat riser bolts are non-OEM and coarse thread with helicoils in the manifold which look reasonable. I would like to go back to OEM bolts if possible. Anyone know the size of the OEM heat riser bolts?
View attachment 2648412
Another issue - I had a clear exhaust leak between the parts of the manifold. View attachment 2648416

The part that leaks separated easily, the other one is very stuck, but doesn't leak. My original plan was to separate, clean, and install new springs and rings on both sides. Given one side is very stuck and doesn't leak, best to leave this alone?

Final question for now... I have a big exhaust leak around the flapper valve shaft. Thinking I will replace this with a block-off plate.

I have heard the remflex gaskets are too thick for this purpose. Fel-pro? Other option?
View attachment 2648420

Given bushings are not available for this, will likely block off with bolts on both sides. Open to suggestion.

I just took my manifolds off. I am looking at the flapper(?) assembly wondering how to get it apart without destroying it. Any guidance would be appreciated.

 

[Chestcutter]

I was able to unscrew one of the bolts holding the flapper, and the other was broken so ground out with a dremel. With the flapper free the shaft should slide out. My bushings were very loose - not sure if it would need some "help" in some cases.

 

[Chestcutter]

Started cleaning up the manifolds and the intake looks in good shape. Exhaust has some areas of pitting on the mating surfaces.

Hoping a Remflex gasket will be enough to fill some of these holes, or I'll be headed to the machine shop soon.
Also not sure how well the end piece of the exhaust manifold is going to seal given the condition of the surfaces. Which have a fair amount of pitting. This makes me think I don't want to try to separate the other side.

 

[Chestcutter]

Took care of a couple minor projects while cleaning parts and waiting for others to arrive. Grab handles - thanks to @Goldbug for the inspiration - from SOR though I would have ordered the Toyota ones from @Racer65 had I known these were coming.

Was about to install my spiffy new inner boot for the transfer shift lever from cityracer, - part of my "track down smells and noise in the cab" project, and found the outer boot is not in such great shape. Luckily still available OEM from Toyota
.

 

[Jdc1]

@TheHardWay promised you pics. Get out the popcorn and there will be more.

@Dianna hope your disassembly is smooth

@Jdc1 I may be hitting you up for the best machine shop...

We have a few decent ones that i’ve used in the Akron area. PM me and i’ll let you know who.

 

[Goldbug]

Took care of a couple minor projects while cleaning parts and waiting for others to arrive. Grab handles - thanks to @Goldbug for the inspiration - from SOR though I would have ordered the Toyota ones from @Racer65 had I known these were coming.

Was about to install my spiffy new inner boot for the transfer shift lever from cityracer, - part of my "track down smells and noise in the cab" project, and found the outer boot is not in such great shape. Luckily still available OEM from Toyota
.View attachment 2649157

Looking good. And outdoing us all with these fancy pictures too!

 

[greenbeasty]

Following along while collecting parts for my 78, thanks for the excellent photos!
Good thing you bought a “ recently restored “ truck, and “ running” at that. Imagine how much work you’d be doing otherwise!

 

[Chestcutter]

Good thing you bought a “ recently restored “ truck, and “ running” at that. Imagine how much work you’d be doing otherwise!

Many lessons learned in the process, though I am not sure how I could have discovered some of this stuff prior to purchase short of tearing the engine apart.

I think about it every time I look at a credit card statement! It has forced me to learn a lot about the truck though, and the MUD community is a huge help.

 

[Chestcutter]

A month goes by, parts arrive, and sit and eventually there is time to work again. While I gather pics for the great half baked manifold refresh, a couple of smaller projects in the interim.

1. Toyota / Koito Headlight relay harness - absolute best value for money of anything I have done. A one hour job except for the ring connectors which were far too small for the 5/16 battery terminals - I ended up replacing these with new heat shrink connectors. All else as direct from Mr Toyota and they are seriously brighter. I mounted the relays to the right fender similar to others.

Debated this as I am looking for a spot to add a Bussman relay block somewhere and it seemed right to have all the relays in the same spot? Right fender is crowded, so this will probably go on the left in the space vacated by the vacuum switching valve which is no longer in use. New stainless screws from Overland Metric make it pretty.

2. I've been looking for a distributor air filter since mine came without, and my original dissy was a rusted mess with no vac hoses or filter. I know some have had luck finding used ones, but late one night searching I came across a later Toyota replacement that looked like it might fit with some modification. Thus the hack shown below. Filter assembly from a 1995-2000 Toyota Dyna 200 LPG, bent, cut and drilled, fits perfectly and looks almost like the original. In any case it makes me happier than the plastic Mcmaster car filter I had in place.

On the right is the part that arrived from Japan

After some mods with the dremel and belt sander and new holes drilled for the 6 mm bolts (LL)
At right is after I figured out how to remove the heater intake and the carb fan timer. 20 minutes to head scratch, 5 min job.

And finally in the engine compartment looks (almost) stock, and connected to the dissy with a new VCV.

 

[Goldbug]

A month goes by, parts arrive, and sit and eventually there is time to work again. While I gather pics for the great half baked manifold refresh, a couple of smaller projects in the interim.

1. Toyota / Koito Headlight relay harness - absolute best value for money of anything I have done. A one hour job except for the ring connectors which were far too small for the 5/16 battery terminals - I ended up replacing these with new heat shrink connectors. All else as direct from Mr Toyota and they are seriously brighter. I mounted the relays to the right fender similar to others.

Debated this as I am looking for a spot to add a Bussman relay block somewhere and it seemed right to have all the relays in the same spot? Right fender is crowded, so this will probably go on the left in the space vacated by the vacuum switching valve which is no longer in use. New stainless screws from Overland Metric make it pretty.
View attachment 2683432

2. I've been looking for a distributor air filter since mine came without, and my original dissy was a rusted mess with no vac hoses or filter. I know some have had luck finding used ones, but late one night searching I came across a later Toyota replacement that looked like it might fit with some modification. Thus the hack shown below. Filter assembly from a 1995-2000 Toyota Dyna 200 LPG, bent, cut and drilled, fits perfectly and looks almost like the original. In any case it makes me happier than the plastic Mcmaster car filter I had in place.

On the right is the part that arrived from Japan
View attachment 2683439
After some mods with the dremel and belt sander and new holes drilled for the 6 mm bolts (LL)
At right is after I figured out how to remove the heater intake and the carb fan timer. 20 minutes to head scratch, 5 min job.
View attachment 2683440
And finally in the engine compartment looks (almost) stock, and connected to the dissy with a new VCV.
View attachment 2683445

Nice job! I agree the Koito headlight upgrade is an insane value for money. What did you do with all the excess wiring? Cut it out and re-splice or zip tie it all up?

 

[Chestcutter]

What did you do with all the excess wiring? Cut it out and re-splice or zip tie it all up?

I just zip tied it on the front of the left fender. Strange that the instructions say to mount the relays inside the cab, but the excess length is not on the relay side but in between the headlight connectors. Doesn't make a lot of sense.

 

[Chestcutter]

Follow up on the never ending manifold project: @TheHardWay time for some more popcorn

After cleaning up the manifold and talking with the experts - many thanks to Mark @65swb45, @Jdc1, @Miloslavich and many others for guiding this newbie on the way - I elected to skip the machining and see if I could get away with fixing the known problems with wrong bolt sizes, bad helicoils, etc, reassemble with new hardware and gaskets.

Both the intake and exhaust manifolds had coarse thread bolts into helicoils, some of which were completely beat. So I ground down the removal tool at right, which allowed me to get a good bite and with a few taps of the hammer to get started, remove even the ones with the tangs broken off.

2 of the exhaust holes were in good enough shape for M10 x 1.25 TIME-SERT. The others were too beat and needed BIG-SERT to be secure. Since these are blind holes with not a lot of room I got a couple of extra thread insert taps and ground them off as bottoming taps to bring the threads all the way down to the bottom of the holes. Rigged a jig with some wood and clamps to ensure allignment with the drill press. The kits are pricey but the quality is very good and they seem much more secure than the helicoils. Need to be sure the insert length is right and the insertion tool doesn't bottom out before they are seated, which necessitated shorter inserts.

Once drilled, couterbored, tapped, chased with bottom tap and blown out with air - insertion is quick. I used high heat JB Weld on the threads.

Flapper valve shaft holes were filled with M12 flanged bolts and nuts, with copper crush washers inside and out, and Permatex copper sealant for good measure. These should be able to be removed and the flapper replaced later if desired. Reassembled the intake to the exhaust after 2 coats of POR-15 manifold grey on the exhaust - I just couldn't stand looking at the rust, though I know it won't last. I used the heat riser block-off plate (Cruiser outfitters or SOR) on the intake side and a single Remflex on the exhaust side with no sealant. Reassembled the forward exhaust horn rings and springs and a coat of Anaerobic gasket maker on the advice of a very experienced local race mechanic to help deal with the rust pits Let's see if it stays sealed.