New Engine for a 1975 FJ40 Named "Sandy"

[Grayscale]

I can't remember what it took to get the transfer shifter cane removed. However, I know it was removed when I reinstalled the gear boxes independent of the motor.

The existing studs/nuts on the old engine are M12. So I don't think I'll need to change the studs. SOR does have the nuts and washers, so that is a huge help. Since we're talking about the specs on the manifold, is there some tell-tail that would indicate this manifold is designed for 10mm and not 12? I think previously someone said the firing order indicated that this was a 1F manifold.

The stud size dictates washer and nut size. Also, there will be 2mm of less space to sandwich between the far ears of the intake manifold.
If the hardware is actually finger-tight, it wasn't checked and didn't need it, or it is coming loose. I certainly think that this manifold needs the correct size hardware, if it is to hold torque over a few bumps, and heat cycles.

Or, instead of the correct hardware, have it professionally machined to the 2F manifold dimensions, for M12 studs, and the larger M12-diameter hardware. You could try grinding the face of the manifold to match the larger washer or nut diameter, but, I don't think it would be produce a satisfactory result. That counterbored face on the tabs of the manifold need to be flat, and distribute the compressive force from that M10 or M12 nut over a greater bite of aluminum, just to avoid abusing the part, or breaking off a tab.

 

[Grayscale]

So, this is my '70 (ish) F manifold, and the 2F head on the bench.

I was only able to install it this far without forcing it. That is because the 2F stud is over-sized for the F-manifold.

 

[MatthewMcD]

So, this is my '70 (ish) F manifold, and the 2F head on the bench.

I was only able to install it this far without forcing it. That is because the 2F stud is over-sized for the F-manifold.
View attachment 3817056

I can't tell if it's been machined, but it is sitting on M12 studs on the old engine. I'll order the manifold nut and washer kit from SOR as it has the end bolts as well. If they don't fit (because the PO didn't go this far.) I'll have the machine shop do the work.

 

[MatthewMcD]

OK, big reset/reboot on manifold info. I was wrong.
I decided to unpacked my tools and pulled the manifold nut and measured it. It is an M10 like you all said it was. I contacted the machine shop that's going to do my flywheel and he agreed to machine the manifold. I have not removed the manifold, yet.
So what I am planning now is to pull the manifold and measure it before deciding on either the "step down" option or machining the manifold and staying with the M12s that are on the new engine.

My question is what is the "best" approach? Leave the manifold as is and step down or machine it to support the M12 studs that are in place on the new engine?

 

[charliemeyer007]

I made my own brass stepped washers for my intake and header. It was like 1/4" thickness difference between the aluminum intake and the steel header flange. I made longer "studs" to accommodate the stepped washers and a doubled man-a-fre header gasket that was installed wet. Has been on for years and at least 2 engine and has never failed/leaked.

IIRC its like 28#' for the torque 10mm 12mm who cares, the goal is evenly applied to both units that are flat.

 

[MatthewMcD]

I made my own brass stepped washers for my intake and header. It was like 1/4" thickness difference between the aluminum intake and the steel header flange. I made longer "studs" to accommodate the stepped washers and a doubled man-a-fre header gasket that was installed wet. Has been on for years and at least 2 engine and has never failed/leaked.

IIRC its like 28#' for the torque 10mm 12mm who cares, the goal is evenly applied to both units that are flat.

Thanks Charlie, At this point I have to dig in and see what I've got. I figure if the manifold face needs machining, I'll have them do the work. If it doesn't then I'll have to decide.

When you say "stepped" you mean that the actual two halves of the "hole" made by each piece of the manifold were out by as much as 1/4"? That's crazy.

 

[charliemeyer007]

I can't find my pic's. I made the stepped washers from 50 Cal BMG brass. Cut the spent case off with a hacksaw just ahead of the web say 3/16 from the extractor groove. Punched out the primer and drilled out the primer pocket /flash hole to the next size up from stud size 7/16. Used a big file to plane down the hacksaw cut flat/square - maybe 1/8 from the extractor groove. Next filed half the hole down to the other side of the extractor groove. This left me a one piece washer that was say 3/8 long to fit on the aluminium intake and 1/8 to fit on the steel header.

 

[Grayscale]

It is possible that the M12 studs fit, but the washers don't. So, take an M12 washer and mark a desired diameter circle with a sharpie, and grind them on the outside to fit the smaller diameter manifold face. Then add a steel lockwasher between the modified flat washer and M12 nut. A steel lockwasher shouldn't be next to the aluminum intake, it will gall it all up. That will probably give you clearance without making any additional modifications? Depending on what the previous tech did on this motor. You just need some steel in that gap that I pointed out with the green arrow in post #170

 

[77mustard40]

Matt irrespective of the stud sizes, I’d measure the manifold depths at every shared fastener location and record them by location. When I was converting to a stock carburetor I was also chasing a manifold vacuum leak. My flat machine washers were purchased to accommodate the existing manifold machined openings. I filed one-half of each washer to customize it for the measured difference in the respective intake manifold and header at each stud/bolt location. I marked the opposing side of the washer with a sharpie so I could see the proper orientation of the washer as I assembled everything. The end result eliminates any depth variance, so when you torque the nuts/bolts you know that the torque is being applied equally to each manifold. Yes my header was ‘machined to match’ the intake but there are still going to be differences at different shared fastener locations. IIRC the great JimC told me that .010”was the max tolerance and all mine were below that but I did the extra work anyway and it turned out great.

I don’t think I’d worry too much about the stud diameters as long as you can assemble the manifolds, and I would not machine the manifolds to accommodate a washer. I’d go after washer and leave the manifold as is.

I’m an OEM gasket guy, dry, torqued to spec; which as pointed out above is quite low for the size of the fasteners. I did recheck torque after several runs just to make sure.

 

[MatthewMcD]

I can't find my pic's. I made the stepped washers from 50 Cal BMG brass. Cut the spent case off with a hacksaw just ahead of the web say 3/16 from the extractor groove. Punched out the primer and drilled out the primer pocket /flash hole to the next size up from stud size 7/16. Used a big file to plane down the hacksaw cut flat/square - maybe 1/8 from the extractor groove. Next filed half the hole down to the other side of the extractor groove. This left me a one piece washer that was say 3/8 long to fit on the aluminium intake and 1/8 to fit on the steel header.

Most importantly, can you still read the headstamp on the .50 cal cases?

 

[MatthewMcD]

Matt irrespective of the stud sizes, I’d measure the manifold depths at every shared fastener location and record them by location. When I was converting to a stock carburetor I was also chasing a manifold vacuum leak. My flat machine washers were purchased to accommodate the existing manifold machined openings. I filed one-half of each washer to customize it for the measured difference in the respective intake manifold and header at each stud/bolt location. I marked the opposing side of the washer with a sharpie so I could see the proper orientation of the washer as I assembled everything. The end result eliminates any depth variance, so when you torque the nuts/bolts you know that the torque is being applied equally to each manifold. Yes my header was ‘machined to match’ the intake but there are still going to be differences at different shared fastener locations. IIRC the great JimC told me that .010”was the max tolerance and all mine were below that but I did the extra work anyway and it turned out great.

I don’t think I’d worry too much about the stud diameters as long as you can assemble the manifolds, and I would not machine the manifolds to accommodate a washer. I’d go after washer and leave the manifold as is.

I’m an OEM gasket guy, dry, torqued to spec; which as pointed out above is quite low for the size of the fasteners. I did recheck torque after several runs just to make sure.

Great advice thanks!

Well, tomorrow we're making the drive to the shop where I'll be doing the work. It'll be the longest drive to date at about 100 miles. Then next weekend is disassembly (and removal) and the following weekend (hopefully) assembly.

 

[77mustard40]

Great advice thanks!

Well, tomorrow we're making the drive to the shop where I'll be doing the work. It'll be the longest drive to date at about 100 miles. Then next weekend is disassembly (and removal) and the following weekend (hopefully) assembly.

Good luck man, I'm sure you will make the drive just fine. Looking forward to how this project turns out!

 

[Pighead]

It is an M10 like you all said it was.

Of course it is, we all knew this would happen. You should listen to us more.
Don't panic. It will all fit.
Don't do the "step-down" studs, they are weak and won't hold the torque you want. Just open up the half-circles in the manifolds where the stud goes. I used an angle grinder and Dremel and "hand-crafted" it to fit. A real machine shop would do a better job. My cylinder head is a Late F and came with the M10 manifold studs. I had the M12s installed the first time I rebuilt this head (2004). Your intake manifold, same as mine, will fit just fine on the M12 studs.

 

[Grayscale]

I've never assembled a married exhaust manifold and intake manifold to the head. I've disassembled the assembled manifolds, but, never put them back without a header. Removal of them took more effort than I expected, and the 2F cast iron exhaust manifold chewed up the bottoms of the stud threads.

It is a bad photo, but, the intake tab and the exhaust manifold tab on the right show how much the paired manifolds barely fit on my '75 2F. Under that nut on the right, the exhaust is sitting up much higher on the engine than the intake manifold.

The exhaust manifold is much weaker than a header. I have one split in two. Could have been age / use, but, it failed in its structure between the downpipe area and where an arm meets. These castings can't even take welds without being shocked by the thermal expansion and contraction. I thought that a reputable professional engine builder skipped all but two head studs, just to avoid the carnage of using big screwdrivers and pry bars to remove it after the nuts are loose and the washers are removed. In other words, the coordinated assembly alignment of all these studs can be skipped if you install screws (with a fixed head, just washers, no nuts) or the proper length, one at a time. The disassembly is made easier because you pull screws, leaving the plenums only hanging on two factory studs, no struggle with antique, hard to source, exhaust parts.

If I was to enlarge the intake manifold for diameter of stud, I'd probably use a round file. The grinder is not really shaped like a stud. Aluminum is a soft metal it will take easily to a hand tool.

 

[RevISK]

Best of luck Matthew, you’ll do great.

Just remember my mantra, “Don’t let perfect get in the way of good enough”

 

[MatthewMcD]

Best of luck Matthew, you’ll do great.

Just remember my mantra, “Don’t let perfect get in the way of good enough”

Amen!

 

[MatthewMcD]

The trip was a success, and the old engine did surprisingly well. 96 miles in 2 hours. Max speed was 68mph, but mostly we cruised around 50-55mph. I don't have the data yet, but I think the new carburetor is significantly more fuel efficient. It certainly feels better driving the truck.

My wife followed in the chase vehicle and got some great dash cam video. I'll post that in a bit. This shot is a traffic jam minutes after a serious wreck on 290. We caught the aftermath on the dash cam.

Celebratory beverages and ribs may have been consumed before the drive back home.

 

[MatthewMcD]

...and here's a couple clips from the trip. It's not Tunisia, but I think historic Texas and the hill country are very pretty, even when we're bracing for another artic blast.

 

[RevISK]

Nice lil spot to arrive at the end there.

 

[MatthewMcD]

Nice lil spot to arrive at the end there.

It is. All of our dogs through the years have loved staying there. I have a photo of my buddy carrying my golden to the car because she just stayed on the porch and silently protested our departure.

We bought 10 acres nearby.