Inliners International Forums General Discussion Hi Performance Boring & honing inline 6 with torque plate.

Hey guys,

eventually I need to get my 250 block bored & honed with a torque plate.

Does anyone have a shop they recommend to do this in So-Cal?

I do not think Mike Kirby is in business anymore.

Thank you

MBHD

Hank, Good to hear from you!

I think tlowe used to have a torque plate that he rented or loaned. Don't know what shipping would be. The club should have a loaner that would be a good perk.

At one time Tom had a loaner program for his plates. Just hit him up and see.

Is there an easy way to make one? Using a section cut from another block? How thick should one be? Could it be made from aluminum? Could you use a gasket for a pattern/template?

I've seen people take old cylinder heads and cut the center out over the bores. A gasket can be used as a template as well. The material should be the same as the head being used to provide the same distortion characteristics and best results. But, use what you have and what's easiest to handle.

Is it required to use a torque plate? What if there is none to be had, can the boring and honing be done successfully without one?

Below is a link to a video that discusses this question. The host of the show admits to NOT using a torque plate, and that it's not ideal. He then measures the results from honing without a torque plate. The results he ends up with are WAY out of tolerance for someone like me. Both of the 292 blocks I have here will be final honed with a torque plate.

Fast forward to 4:10 in the video to start:

292 Engine Build

Hope this helps

Here is a link for the one Tom at 12bolt.com seems to have for rent:

Torque Plate Rental

Millions of rebuilds have been done without them and all the engines that have rolled out of Detroit since the beginning of time didn't either. But a torque plate can be a huge benefit. One way to look at it is if a block is not finished honed with a plate, when the head it torqued on every place a head bolt is close to the bore, the cylinders will have tight spots. So the rings will only contact the cylinder walls at those tight spots until sufficient wear occurs to wear those spots down to begin full contact so they can do their job properly.

Thanks, to all. Lots of information there.

I can definitely see the benefit of using torque plates. I contacted the machinist that is machining my block and head, and he said I don't need to use the torque plate. I agree with you, so many engines out there that were built without using the torque plates and they had no issues.

We rebuilt a 350 in '85 for my '56 Chevy 210. We mic'd everything, cut the ridges, used the ball-style hones for the bores, no align hone, no torque plates, reused everything except the bearings and rings, and after 194k miles on that rebuild I pulled the heads to have Pop do a valve job. It really didn't need one, I just asked him if it would be a good idea, and he said it wouldn't hurt, and to bring it in to the shop. No ridge in any cylinder. The engine never used oil or burned oil, never overheated, and ran like a top. After Pop finished the heads it had much better throttle response, and still didn't use or burn oil. I thought he ported and gasket-matched the heads, he did not.

So I will be moving forward without using a torque plate on my 292. I trust my machinist and his expertise, as he does excellent work.

Heavens, I have built innumerable 235 motors over the years, boring and honing, without a torque plate. Did the same for the 261 I built for myself a couple of years ago. Try finding a torque plate for those motors. Would a torque plate have been nice and give a more accurate build, absolutely. Is a torque plate an absolute necessity, absolutely not, lol. But I agree, if possible, better to use one if available then not.

On the other issue, does anyone know definitively if Mike Kirby retired or gave up the shop?

Nothing conclusive but have heard he's not in the shop much if any due to health. I know people have left messages and have tried to call without response. But maybe he has other numbers he monitors more frequently....

The last time I saw info about this was torque plate helped manage the distortion caused by the head bolts, but having the water jackets full of hot water made almost as much of a difference. Appears that there is a lot of distortion once the engine heats up/

On a racing motor, yes. On a low rpm motor with cast pistons and original ring package, probably not. Nice street rod motor, my problem is finding a machine shop I trust, then I would think about if the piston / ring package required the higher precision.

Another thing besides a torque plate many also Bolt the water pump to the block.

D13, the benefits are many and you need to decide if the added costs justify your plans and budget. No 6 cylinder ever rolled of the assembly line in Detroit that was honed with a torque plate, and most ran well and provided good service. But even on a stock type rebuild it can be beneficial.

[quote=CNC-Dude #5585] "No 6 cylinder ever rolled of the assembly line in Detroit that was honed with a torque plate"

But they hadn't been bored .060 over either.

I think it's a good idea as is the water pump.
The only guy (in my area) I knew who had a torque plate for a 6 cyl passed away and I don't know where it went.

Bore size doesn't really matter. The torquing will stress the bores regardless of their size or thickness. A Bowtie race V8 block is still close to .300" thick and it pulls them in at the head bolts. Much stronger blocks and thicker decks also with a lot higher nickel content as well than these factory blocks.

OK,
makes sense.

Question 1: Is it better to bolt the torque plate down or use studs and nuts?
Question 2: Assemble engine with head bolts or studs to match how plate was fastened down for boring?

So many questions come up.
I'm not likely to build a full race engine so maybe I shouldn't over think this stuff.

Thanks.

The original fasteners should be used, installed to their original depth.

My understanding of the "best practice" from the V8 world, which I would guess applies to the inline 6 world:

You use the fasteners that will be used in the final assembly of the engine. If you have purchased studs for the engine, use those studs when final honing with the torque plate. If you have purchased new head bolts for the engine, use those bolts when final honing. You also need to use the same head gasket you will be using in the final assembly. Yes, this means you need to buy two head gaskets, saving the unused one for the final assembly.

If I am incorrect, someone please step in and correct me.

Yes David and Chevelle292Wagon, the block should be machined using the same fasteners it will be assembled with. Same goes for main studs also, the block will need to be align honed when converting to studs.