Rough idle, compression test... head gasket at 3 and 4? (1 Viewer)

DFXR

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Got a rough idle the other day, just minutes after I was reflecting on how well the 2F was running (aside from a little exhaust leak). Jinx in effect.

Vacuum was down from a steady 20 to a vibrating 16-18.

Started pulling plug wires at idle, and got no change on cylinders 3 and 4. So I skipped past any carb/intake/EGR troubleshooting.

Borrowed a compression tester (thanks @joebattle1 ) and got these numbers. For reference, this is a 235K mile truck with maybe 50-60K miles on a home rebuild by the previous-previous owner:

1: 130
2: 135
3: 40
4: 40
5: 140
6: 140

Dry test, engine warm. I did not bother with a wet test.

I am thinking, based on reading here, that I have a head gasket leak between 3 and 4. Fairly common, right?

The good news is that this happened a couple miles from home. I did not overheat or even run hot. Oil and coolant are level and clean. I'm hoping that the head did not suffer much in the run up to this.

So I will be pulling the head. The only heads I have pulled have been on dirt bikes. In terms of weight and complexity they almost don't count. They definitely did not have a smog octopus attached.

There are some good HG / head removal threads out there (thanks @lcolon). I'm sure I will still have some questions going forward. I will try to avoid the "while I am in there" variety because I am trying to stay away from that rabbit hole.

Here's a question for way down the road: has anyone out there assembled their head and manifold together on the bench, and then flown it in as a single unit with a little rolling shop crane? Or should I stop thinking about that? I can see it being straightforward with an actual hoist or gantry (esp on a desmogged 2F). But this would be a budget version, on a smogged 2F. Obviously the hood would have to get folded back.

Stay tuned-
 

OSS

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For one last futile try, you could check the valve lash on 3 & 4 to be sure that they aren't just too tight.

The head weighs 82 lbs and is awkward to maneuver inside the engine bay. The manifold comes off before removing it and gets bolted on after installing it. Don't attempt to handle them as a single unit - there's nothing to gain from it and more to lose. Removing the manifold while it's still in the truck is straightforward, same with bolting it back on.

A hoist can be used to pull the head out without removing the hood. It just squeaks by.
 

DFXR

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Thanks. I have replaced the manifold once. I was just thinking about the rear bolt and whatnot. By the time I am ready to put it all back together, the manifold part will probably seem easy and the crane idea will seem ridiculous.

I did a valve adjustment about 1K miles ago, and re-checked maybe 500 ago, but since the valve cover is coming off anyway, I'll take a look.
 

DFXR

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For one last futile try, you could check the valve lash on 3 & 4 to be sure that they aren't just too tight.

Checked the valves, nothing tight in there unfortunately. A couple loose but nothing crazy. I'll keep taking stuff off.
 

Spike Strip

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If you have a pair of helping hands, mark the hood on the lift helper things and remove it. Makes it waaaaaaaaaaaay easier. As OSS says, doing the Head/Manifold together is possible, but you also have to align with the downpipe so just asking for addt'l issues.

Be prepared to replace all the studs and fasteners for the manifold, if you haven't done it recently.

It's most likely the HG though the common spot is btwn 5 and 6.

Head is phooking heavy, and is sometimes stuck, so a crane is a good way to go.
 

NeverGiveUpYota

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3 & 4 are more common.... feel free to correct me but that’s where the cylinders meet at their most narrow point. It’s always said to listen for air/bubbling between 3 & 4 also.... AND if the head wasn’t checked for flatness it’s most often to be off in the middle as well which again is between 3 & 4...

16C0B078-0B5D-425E-AD64-99559D64F5E8.jpeg

It’s much more obvious on the head than the block.... if I can find a shot in my thread I’ll add it.
Underside of the head. Not as obvious as I recall. The HG itsel tho is very thin between those two also.

Also both those pixs are my trucks parts.

A77C69AD-9108-4852-BBA5-A241D507F0B3.jpeg
 
Last edited:

DFXR

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All the manifold bolts and studs, including the downpipe connections, busted loose this afternoon without too much fight. Last time around with the manifold I used a ton of Never-Seez on @Spike Strip 's suggestion. It works!
 

Spike Strip

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Yup. Makes the 2nd time (unfortunately, there sometimes is one) much much easier.

Any idea what HG was used on the rebuild? ...
 

DFXR

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Yup. Makes the 2nd time (unfortunately, there sometimes is one) much much easier.

Any idea what HG was used on the rebuild? ...
No idea. I'll let you know when I get there. Not tonight though!

If I was just doing the manifold I'd be feeling pretty good right now.
 

lcolon

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The worst thing about pulling the head - messing with the manifolds on re-install and getting the j-pipe / exhaust pipe lined up, the weight of the head itself which takes 2 people to remove. Other than that, it is straight forward.

Check the intake manifold for cracks below the carb. I would also have the manifold checked for straightness / decked.

As for while you are in there - do change out any coolant hoses that are older. It is much easier to do with the head out so I would take advantage of that opportunity. It would also be a good time to switch to the SOR stainless J-Pipe if yours is in poor condition. When my head was out the last time, I also did the saginaw power steering conversion, also much easier with all the stuff out of the way.
 

DFXR

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The worst thing about pulling the head - messing with the manifolds on re-install and getting the j-pipe / exhaust pipe lined up, the weight of the head itself which takes 2 people to remove. Other than that, it is straight forward.

Check the intake manifold for cracks below the carb. I would also have the manifold checked for straightness / decked.

As for while you are in there - do change out any coolant hoses that are older. It is much easier to do with the head out so I would take advantage of that opportunity. It would also be a good time to switch to the SOR stainless J-Pipe if yours is in poor condition. When my head was out the last time, I also did the saginaw power steering conversion, also much easier with all the stuff out of the way.

Thanks. I have been reading your recent head removal thread - very helpful. Will be getting into the real head removal today or tomorrow. I am confident that I can get the thing off, but putting it back together may be another story.

I did the stainless j-pipe a couple years ago when I replaced my original manifold. The stainless one definitely sealed better than the old one. Sad that it has to come off because that is one gasket that is not leaking. I also have a pretty new Toyota PS pump on there so I am keeping that.

Had a look at the intake and no cracks. I would love to put a heat shield between the intake and exhaust, but I really don't want to get into the drama of separating the sections. This manifold was NOS when I put it on 3 years ago and is still in good shape (aside from a leak from one of the horn rings).

I am about to order all the related gaskets for this, is there something blindingly obvious that I am missing? I'm not including all the hardware here.

Head gasket: 11115-61010
Ex manifold gasket: 17172-61041
Valve cover gasket: 11213-61011
Manifold to ex downpipe: 90917-06056
Manifold to J-pipe: Remflex 7009-C

Here's where I stopped last night. All the manifold bolts and studs are free. Just have to wrestle it off the downpipe and then get on with the head. The smog stuff really does take the fun out of this.

IMG_1968.JPG
 

DFXR

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3 & 4 are more common.... feel free to correct me but that’s where the cylinders meet at their most narrow point. It’s always said to listen for air/bubbling between 3 & 4 also.... AND if the head wasn’t checked for flatness it’s most often to be off in the middle as well which again is between 3 & 4...


It’s much more obvious on the head than the block.... if I can find a shot in my thread I’ll add it.
Underside of the head. Not as obvious as I recall. The HG itsel tho is very thin between those two also.

Also both those pixs are my trucks parts.
Thanks for posting that head shot. Looks really great. It's pretty narrow in there between 3 and 4, but it's not something I would have thought about on my own. What all did the shop do to that head besides milling it?
 

lcolon

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For gaskets - I sourced my head gasket from cityracer - good price compared to the dealer. For the other gaskets - Manifod, EGR, J-Pipe I used the remflex kit. Some like the OEM gaskets, but even with a freshly milled manifold, I still opted for remflex. The remflex kit comes with the other manifold related gaskets (not the donut for the downpipe).

Ask any questions you have along the way.
 

lcolon

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Since you are in the bay area - I recommend Yota1 out in Riverbank for your machine shop work. They only do Toyotas and have extensive experience with the 2F. A bit of a drive to get everything out there, but they did a great job with my stuff at a very reasonable price.

At least have the head cleaned / magnafluxed (if nothing else is required) as a part of the job
 

DFXR

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I pulled this out as a single unit this afternoon. I do not see it going back in that way. Will take some Advil and tackle the head tomorrow.

Looks like something was happening, or starting to happen, at port #5 from the left. Otherwise the manifold is looking OK.

Is there any way to lock the heat riser plate in the "hot" position without welding? I have the SOR heat shield from my other manifold, but I don't want to separate this one here.

IMG_1980.jpg
 

DFXR

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Since you are in the bay area - I recommend Yota1 out in Riverbank for your machine shop work. They only do Toyotas and have extensive experience with the 2F. A bit of a drive to get everything out there, but they did a great job with my stuff at a very reasonable price.

I actually saw Yota1 referenced in your head removal post and exchanged some emails with Nick. He got back to me right away, and definitely sounds like he knows the 2F pretty well. He even has rebuilt heads and rocker arm assemblies ready to go. Not that I will need that, I hope. I am also looking at a couple machine shops here in the East Bay.
 

DFXR

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Got the head off without any drama. A neighbor was walking by and I said "What are you doing right now?" and he just jumped right in (in flip flops!). I lifted the front of the head up and we slid a piece of plywood under it. Then the two of us just pulled the head forward onto the ply.

Between 3 and 4. I think I see the problem.

Otherwise it looks OK, I guess. What do I know? Open to any and all evaluation.

IMG_1992.JPG


IMG_1991.JPG
 

OSS

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Its customary to machine the head flat when it is removed. Especially with a blown HG.
The EGR stuff should be removed from the manifold before installing it in the cruiser. Normally its removed before pulling the manifold too.
Replacing all the valve stem oil seals is usually a given any time the head comes off too.
 

NeverGiveUpYota

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Ask for the head to be magnafluxed and check flatness as stated above. And they won’t typically pressure test it as well but ask regardless if they have the equipment and can, it’s a pretty cool process. You can find videos on YouTube.
Stem seals definetly. Guides not so much. Your valves all appear pretty equal in color, they prob are fine. If you do have them rebuild it it might be worth have the seats recut.
 

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