Inliners International Forums General Discussion Engines Using a 153 torque plate on a 250

Hi All,

I have access to a 153CI torque plate. Could it be used on one of the 153's inline 6 brethren by bolting it down to the front or back 4 cylinders and boring the front/back 3 cylinders at a time?

Thanks,
Rick

Yes you can!

Perfect!

In general, they seem to be more plentiful.

Do you really think that is a good idea as it would not be torqueing the block like it should be. Even adding the water pump like many do when adding the torque plate. When I did my fresh 250 I had the torque plate water pump and Main caps in the block when bored and honed.

AFAIK best practice (when possible) is to install and torque every fastener that attaches to the block, including motor mounts

Sure, ideally a six-holer plate would be best. But let's look at what happens when a torque plate is bolted on a block:

The head bolts draw the cylinders outwards causing a squarish distortion at the deck surface. As you move down in the cylinder bore this distortion diminishes and the bore is rounder towards its bottom. Of course, cylinder pressures are highest at or near TDC (actually peak pressure is about 70 degrees after TDC, more-or-less, depending on the burn rate of the engine in question.) so near the top is where it is most important to have good round bores. Any deck plate to simulate this distortion is good - the square bore will be eliminated. Since the hone works on only one cylinder at a time a four cylinder plate should do an adequate job, particularly if the plate is overlapping in the adjacent nearest neighbor holes.

When I worked for Headrick years ago, we had several customers that made their own from old cylinder heads. They bored all the way through the head so the honing head would fit through it. One other guy made one that just did one cylinder at a time. They won races and never complained about any issues.

There is a problem that I see coming. The bolt pattern will not be correct. GM did not put the bolt holes right inline, they are all over the place.
So I will say NO. A 6 cyl TQ plate will work on a 4cyl but not the other way around. 4 to 6 no.

Isn't the 153 just a 230 with 2 rear cylinders missing. I looked at the layout and from the top of the block the 153 looks like the 230/250 with the last 2 cylinders not cast.

I'm getting the 153 plate from a forklift shop. Evidently the 153 was a pretty popular engine for that vertical market. I have the head off one of my 292s and I can throw it on there and see if there are any irregularities?!

Since you have such easy access to it go ahead and do a comparison to see.
Also, the 153 was in production a full year or more before the 230 was. So, to say the 153 was patterned after the 230 may not be accurate since it came before the 230. It does however share the same bore and has other similarities to the 6 cylinder.

I will try and pick up the TP on Friday. Other than lining it up and then bolting it on, is there anything you want me to try? I will torque it down on 1-2-3-4,2-3-4-5, and 3-4-5-6 just to see if it lines up on all possibilities.

Also note that all of the engines I'll be building are gonna' be for street use. I want them to 'live long and prosper'. Two will probably have turbos so I would like at least those two to have cylinders be a bit more true.

Make sure the bores in the plate are concentric with the bores in the block. Like tlowe mentioned, the bolt holes may be suspect because of loose production tolerances of the day back then. So the torque plate was likely machined to much more precision tolerances we see today.

Will do.

The TP is relatively new. The 292 is a later Goodwrench engine (hencho en Mexico) that was put into a state vehicle and then surplus'd (no cylinder ridge). So that will be a best case scenario.

I have a 230 but that one is buttoned up. That will be the one I actually try it on. It's going into a Camaro as a 250.

Couldn't you just use two head gaskets?

For a visual, I would think so. But I want to play with my new toy. If I can find my bore gauge (not likely in a timely manner), I can rotate the crank and maybe get some top round measurements.

Thanks to all that have posted.

Could a torque plate be made from an old head?

Per Leo's book, yes. See page 532.

That page may be wrong because I'm using Kindle. So it's in chapter 4 'Machining Operations'.

I read an interesting thing...

A person cut the top of a bad inline 6 block and turned it into a torque plate.

I'm not looking to go that direction but I thought it a creative use for an, otherwise, piece of junk.

his books do not go that high in pages The Hybrid head chapter starts at 125. The cylinder Head key Element is chapter 10 which starts on page 95 ( sec edition book) The first book it starts on 103 (11) and pg 83 cylinder key Element.

So I contacted the manufacturer of the torque plate, regarding using the 153ci TP on an inline 6 of the same family, and this was the response, "Sounds like a reasonable proposal. I can't think of a specific reason not to try it."

Not sure if you know this. 12Bolt has TQ plates for 194-230-250-292 that can be rented.

Hi TL,

I do and I certainly believe what 12B offers is far better than my solution. But free is hard to pass up and in my case, other than the 2 turbo'd ones, right now, it's not as important. I have several engines to build in the next couple of years and will need a 'real' TP for some of the builds.

12Bolt also has a couple extra TQ plates to sell.
Not knocking you for trying to save money. Email if interested. tom@12bolt.com

I do not think the 4 cyl TQ plate is going to work. The 6 cyl plate does work on 4 cyl, been there and done that. But not the other way around.

"Try it" means nothing except the bolt holes line up.
The thickness of the head, depth of the bolt thread may be different.
Do they both use the same bolts, or just the same thread?

I don't doubt that. The answer was very vague.

It's the same bolts. Also,the TP has all the hardware that came with it from the manufacturer...including wooden box and oil paper it came in. I know it is recommended that you use the hw that is supposed to go on the engine but heck, I'm using a torque plate that is 2 ports shy of an inline 6.

I just want round hone under torque for street use. I would imagine I could use a one hole TP for my needs. I've read people have done just that. But my question is to the board...if anyone has done this and if so, was it successful within the scope of street use with a turbo.

Thanks to all that have responded.

I can't get there today...so either he'll drop it off this weekend or I'll pick it up Monday. If anyone wants me to, I'll send pics of it before test fit.

Yes, if it will bolt on, it will work for your intended purpose.