Head issues/MacGyver fixes? (2 Viewers)

[CUSailor]

7/'79 FJ40

So you may have seen other threads where I was asking about ignition and emissions issues. Here's a head issue.

One of the main reasons I started to work on the vehicle was I was getting significant oil/gas in my carb (Weber 2 Barrel) to the point it was smoking. Figured we'd pull the valve cover and see what we saw. Certainly saw a good bit of heat. All of the valve seals were cracked. Decided to go ahead and pull the head, clean the valves, maybe regrind, but nothing too extensive since I don't have the cash to go too far down the rabbit hole.

Could tell that the rear cylinders were burning very rich and a bit cool judging by the lack of discoloration on the valves and the significant build up. Everything cleaned up nicely but we couldn't figure out why the PO had used different types of bolts for the intake/exhaust manifold. When we started looking closer in the shop we realized that someone had rethreaded two of the holes and broke through to the oil galley (I think that's the right term). So we are brainstorming on how to go about fixing. It's not in my budget to replace the entire head (seems a CSB would cost about the same). We are considering putting a Helicoil in there with some high temp sealant, just a bare bolt with sealant, etc.

Any ideas would be appreciated! I'm not trying to get every HP out of this thing and I don't mind checking and topping off some oil from time to time, just want a reliable weekend vehicle.

 

[CUSailor]

Here's a few more photos. The cylinders and the mating surface actually cleaned up really nice. No cross-hatching, but also no lip at all on any of the cylinders. I'm going to pull the engine to replace the rear main seal and cam plug to stop a massive oil leak I have. While it's out I may go ahead and replace the piston rings as well.

 

[sproggy]

Hey Sailor, I can't answer your questions as I'm just not that smart but I'm wondering how you are keeping your head in such a great position to work on. What aren't I seeing in that last photo? I have mine off as we speak and have been working on it sideways as I don't want it to rest on the valve cover stems. What's the trick?

Thank you, Sproggy

 

[brian]

Not sure which holes.
But I believe two of the manifold holes do break into a pair of head bolt holes.

 

[Rusty 72]

Clean holes real good and use a good epoxy but use studs instead of bolts.

 

[DougAustinTx]

Don't forget, there are two (2) plugs in the rear of the block: the cam stop plug (which is not a regular freeze plug), and the oil galley plug which is the old style domed plug that you punch in the center to spread it out to seal.

 

[CUSailor]

Sproggy, It's resting on the thermostat casing (tried to get it off and started to strip a bolt so decided to leave it) a brass valve fitting that I'm not sure what it is though am curious if anyone would like to chime in, and then the entire back side is supported by a 2x4

Brian,
That's good to know that there are some that break through to the headbolts. The holes are the two that I have circled in this photo, though I really don't think they are supposed to be there as it looks like someone tapped these threads out to standard and the rest are metric. That being said, I'll shine a flashlight through and see if I see any light leak through there.

I think we're going to take Rocky's advice and put in a stud with epoxy. I need to make sure there won't be any issues with getting a nut on there, though I can't imagine it'd be much larger than the current bolt head that's there now.

Doug,
You mean on the back of the engine block itself right? I was planning on replacing all the freeze plugs on the block and did buy a set of cam plugs as well. Originally I thought my massive oil leak (liter every 20 miles or so) was from the main seal, but after doing a lot of reading in here it sounds like it could be one of several things so I figured I'd just redo it all once I had the engine out. I'm familiar with how to replace freeze plugs, but is there anything special about installing the cam stop plug? I'm also going to take care of the oil galley plug in the head while I'm at it, which looked like it was halfway out on its own already.

 

[sproggy]

Must be a lot of stress on the brass valve fitting...which incidentally I believe should have a thumb screw/valve in it/on it which turns off the coolant flow to the heater. That's how I remember it's function at least. I don't see the valve screw on yours.

I have all studs in my block for the manifold, no bolts. Which is stock I wonder?

 

[CUSailor]

Interesting, in that case I may try and pull it so the brass doesn't warp and replace it with a block of wood. Why would you manually want to adjust coolant flow to the heater? It just had a standard hose fitting on it for me.

Learn something new every day. I looked on SOR and here's what I found. Manifold Bolt - 4 Req, Manifold End Bolt - 2 Req, Manifold Stud - 2 Req.....or there's the manifold stud kit which comes with 6 studs and 2 manifold end bolts. Page 044 Land Cruiser 1968-8/87 Manifolds. Can anyone confirm the advantage of switching to full studs?

 

[CUSailor]

Sproggy, also figured out about the heater valve. So I'm a little slow and didn't realize that warm coolant going to heater = heat in your vehicle! It looks like mine is mounted on the firewall

 

[sproggy]

Yeah I think it's just so in the summer you can turn off the coolant flow and don't get any extra warmth in the cab.

Manifold: I wonder what the advantage is of studs and bolts mix?

 

[MoCoNative]

The early 2F's had that heater nipple off the head that resembled the older 1F nipples that did have the thumbscrew shutoff on them. Sadly they are no longer available. In dash control was nicer. Many times I've had to run out in a summer downpour to turn on the heat cause the windshield fogged up on my 1F equipped 40.

I was hoping someone more knowledgeable would chime in on the thread issues. As I recall only one of the front and one of the rear head bolts actually allow coolant flow into and out of the head. They are the two that have a hollow dowel of sorts that sticks up above the deck of the block. The only oil passage to the head on a 2F would be under the 4th upright that holds the rocker arms and has a matching hole in the top of the block. Again I could be wrong on the coolant passages, but that is what I remember. I think your thread issue doesn't matter on those two holes. Some pressurized air would confirm if things flow. Best repair if you have it at an engine shop is to have the holes cleaned and fix the two weird ones with helicoils.

 

[zebrabeefj40]

I was hoping someone more knowledgeable would chime in on the thread issues. As I recall only one of the front and one of the rear head bolts actually allow coolant flow into and out of the head. They are the two that have a hollow dowel of sorts that sticks up above the deck of the block. The only oil passage to the head on a 2F would be under the 4th upright that holds the rocker arms and has a matching hole in the top of the block. Again I could be wrong on the coolant passages, but that is what I remember. I think your thread issue doesn't matter on those two holes. Some pressurized air would confirm if things flow. Best repair if you have it at an engine shop is to have the holes cleaned and fix the two weird ones with helicoils.

Coolant flows between the head and the block through the coolant holes in the deck of the block and the matching holes in the head (note the green in some of the holes in the head photos above). I am aware of no head bolts that flow coolant (and I've torn into my share of Land Cruiser motors).

The supply side of the oil system comes up through the rocker towers; correct. The oil drains back to the pan through the push rod holes cast in the deck of the head and block. That draining oil also lubes the cam and lifters some on the way back to the pan (the crank tosses a lot of oil at the cam from the bottom to lube the cam lobes. There is pressurized oil for the cam bearings themselves). There is a diagram in the factory service manual detailing the path of the oil through the motor to help explain it better.

Nick

 

[CUSailor]

Thanks everyone,
What I'm wondering is if it originally had studs that needed to be removed for some reason that were drilled out and the holes re-threaded (thus the mix of metric and standard) someone went a little wide and broke through. Can anyone chime in on whether it's better to replace all (minus the two end caps) with studs? What was standard and why would SOR sell a stud kit if it wasn't a better fit?

 

[MoCoNative]

Yes studs were originally installed in the head. The two on the ends were bolts. They were added to the 2F to keep the exhaust manifold tight on the ends.

 

[bikersmurf]

Reinstalling the manifolds is much easier with studs. Slip on the gasket and then the manifolds... no need to try to hold it aligned with one hand while threaded bolts in with the other.

Studs fixed in the head are also much less likely to strip the cast iron than turning bolts under tension.

 

[DougAustinTx]

Doug,
You mean on the back of the engine block itself right? I was planning on replacing all the freeze plugs on the block and did buy a set of cam plugs as well. Originally I thought my massive oil leak (liter every 20 miles or so) was from the main seal, but after doing a lot of reading in here it sounds like it could be one of several things so I figured I'd just redo it all once I had the engine out. I'm familiar with how to replace freeze plugs, but is there anything special about installing the cam stop plug? I'm also going to take care of the oil galley plug in the head while I'm at it, which looked like it was halfway out on its own already.

There are 2 oil galley plugs in the block itself, one at the front and one at the rear inside the bell housing area. They are about 1" in diameter and start out domed. You punch the center of the dome to "set" them and seal. I also usually put a little non-hardening sealer under them before wacking the domes. I have heard that these Toyota specific mini-freeze plugs were hard to come by these days.
The cam stop plug looks much like a freeze plug, but it is thinner so it doesn't push the cam too far toward the front of the engine. If either one of the rear plugs start to leak, you will lose a ton of oil and it will make you think the main seal is leaking.

 

[brian]

Brian,
That's good to know that there are some that break through to the headbolts. The holes are the two that I have circled in this photo, though I really don't think they are supposed to be there as it looks like someone tapped these threads out to standard and the rest are metric. That being said, I'll shine a flashlight through and see if I see any light leak through there.

All 6 of the larger break into the headbolt passeng ways.