View Full Version : torque plate for ka24det (deck plate)

04-09-2003, 02:19 AM
is it necessary to have a torque plate used when honing out the block for JE 8.5:1 compression pistons? I dont know where I can get one of these torque plates. Does anybody know where I can get one made cheaply? Please help me out since I'm getting ready to install pistons and rods and have machining done. I live in NC/SC range.
What could be the worst thing that could happen if I dont use a torque plate when honing out cylinders?

Rembrandt Q. Einstein
04-09-2003, 12:38 PM
Possibly, Sunbelt or Jim Wolf Technology might have/use them. JWT has VG30 deck plates, so they might have more Nissan deck plates.

I don't know if Sunbelt has a web site, but JWT is www.jimwolftechnology.com (http://www.jimwolftechnology.com)

Most domestic honing plates are made by BHJ, and in their products section they only list Nissan V-6 torque plates.

I think that the optimum, most realistic honing plate would be a factory cylinder head (get one from a dead engine) with the valvtrain removed, with bore-size holes cut into them. I don't think anyone knows for sure, but obviously with a large chunk of metal out of the head the stress won't be 100% realistic, but it would be better than a straight hone job for sure. A billet honing plate would be less realistic than a cut-up head, but I think that it is "over-realistic" (which is not necessarily bad) in that it distorts more than it needs to since the billet plate will be more rigid than an aluminum casting full of ports and passages, and more stress will be in the bores than the head's deck. Maybe being "over realistic" makes initial break-in tighter than it needs to be, and keeps the bores better for a longer time after break-in.

Of course, given the exact same setup, a stress-plate honed block is going to have better ring seal and less friction, which makes more power. The worst thing? I don't know.

If you can find a dead KA24D head, it may be cheaper to have holes cut into it than to buy a piece of bar stock aluminum (or steel, whatever) and have holes cut into it not only for the bores but also the right height holes for the individual bolts.

04-09-2003, 01:03 PM
I think a torque plate made from an old head would be too flexy to be used as a torque plate. The head has all sorts of cooling channels, ports, webbing, etc and it would end up being very weak if you removed all the solid material that forms the roof of the combustion chamber.

But hey, who knows. Maybe I'll try it anyway.


Rembrandt Q. Einstein
04-09-2003, 03:51 PM
That's what I was thinking.

Maybe if you filled the ports and passages with block filler (do they make block filler for aluminum alloys?), and welded braces over the intake and exhaust ports to stiffen it up. That adds too many variables though.

By that time though the head plate wouldn't be as realistic and if you were gonna do all that you might as well machine your own plate from scratch.

It's pretty cool how far they go in NASCAR to simulate running conditions. They circulate hot coolant through the block, bolt up engine mounts, bell housings...etc.

04-09-2003, 04:03 PM
Maybe if you filled the ports and passages with block filler (do they make block filler for aluminum alloys?), and welded braces over the intake and exhaust ports to stiffen it up. That adds too many variables though.

Don't really need "aluminum" block filler per se since the torque plate isn't going to experience thermal expansion and contraction. Just a whole bunch of block filler in the cooling passages and ports might make it worthwhile. Who knows.


Rembrandt Q. Einstein
04-09-2003, 04:21 PM
If the honing machines didn't go through such a long stroke and the block's main bearing webs were wide enough apart, the best way to do it would be to hone the block from the bottom, upside down with the head bolted on and the valves out so the fluid could flush out.

Rembrandt Q. Einstein
04-09-2003, 04:26 PM
Has anyone ever done that?

Do they put a bar through all the mains when they conventionally hone a block? If they do I don't see what good it does B/C cranks can turn free with caps torqued and it shouldn't contribute to the static stiffness of the block.

04-09-2003, 06:48 PM
From what I've read, most places have the bearing caps bolted on and torqued to spec, but nothing through the bearings.

One problem I can see with doing it "upside down" with a head on (assuming the boring head fits between the mains) is that you might either end up cutting into the head, or not cutting through the bore enough. Although I suppose if you have a headgasket in there, that gives you about 1mm or so to work with where you wouldn't be cutting anything. Hmm...


04-09-2003, 09:30 PM
whats a torque plate used for when honing?

Rembrandt Q. Einstein
04-09-2003, 10:06 PM
It is used to simulate the distortion of the bores when a cylinder head and its bolts/studs are attached. If the bore is distorted, it isn't round, and when it heats up, it will be even more distorted. The rings won't seal as well, and torque-producing cylinder pressure will be wasted in blow-by.

Called torque plates, stress plates, deck plates, honing plates, they all do the same thing.

Say you have 5 head bolts per cylinder. When you torque the head down, there will be little tiny slivers of a gap in a pentagon shape.

Torque plate honed engines make more power and are more efficient.