Torque Plate

[dspillman]

Hi Guys,
I'm having a 280 block bored out for my "low budget" stroker in Shelby,North Carolina. I know its hard to find a torque plate in my local machine shops for the L-series engines. If anyone is interested, Plate will be at the shop for a least a couple of weeks. Welcome to use.

BTW, I have a 240 block bored 40 over free to any takers...Several years old, torque plate not used for this over bore.

David

[preith]

I'm a little confused by your post, are you offering one, or in need of it??

With that said, I feel there's a popular misconception with torque plates. The torque plate does NOT need to be used for the actual over boring, but only for the final honing. Also I wonder just how important they are for the 'ole L-series. IMHO, the reinforced skirts on the blocks make them much more stout than a Chevy or Ford small block. My last road race block was prepped sans torque plate, with no issues.

[dspillman]

I'm a little confused by your post, are you offering one, or in need of it??

With that said, I feel there's a popular misconception with torque plates. My last road race block was prepped sans torque plate, with no issues.

Hi,
I used to feel the same way.

Having measured cylinder walls with plate installed and remeasuring without, quite a difference.

Sorry to have confused you with my post. I have the plate, thought someone could benefit, if close by.

David

[ZSaint]

For normal street driving, boring w/o a torque plate is fine. However, if you want to maximize your power, you need a torque plate. I had one built back in the late 70's. We got leakdown results in the 99% range with total seal rings. Round is round! I went back to the engine builder's shop and my plate was still there in 2005. Everett Hatch has passed on but the new owners still had and used the torque plate. I had my F54 block bored and honed at this shop. (Along with balancing, lightening, headwork, etc) It was kinda like going back in history having this Z engine built by the same shop that used to build my race engines. But I digress...!

[preith]

dspillman, no offense, but I kind of feel like I'm dealing with the media here; your reply twists my post a bit. I should have left the last part out, my main point, which seemed to slip past Zsaint too, was when to use the torque plate during machining. It is not needed for the boring, the final hone will compensate for any differences.

[dspillman]

dspillman, no offense, but I kind of feel like I'm dealing with the media here; your reply twists my post a bit. I should have left the last part out, my main point, which seemed to slip past Zsaint too, was when to use the torque plate during machining. It is not needed for the boring, the final hone will compensate for any differences.

No offense taken, I need to place more smiles in my posts to help with my abrupt typing.
I had a engine "built" couple years back that didn't really come out the way I planned as far as power concerned, but was Bored/honed with torque plate...After dissassembling the entire engine to start over, a fellow racer and I checked bore diameters, with and without torque plate installed, seems hard to believe, but we had 2-3 thousands difference ".002-.003 inch" at same points measured.
Like Zsaint mentioned, the extra power "lost" on the street not important, but on the track leaving Horsies on the table if not used.
I have always assumed that plate was used for all steps of overbore and cylinder prep, I don't really know.

david

[240ZX]

If you want the job done correctly, use the torque plate for the entire process. This ensures that both the boring and honing steps are done in the same plain. I just doesn't make good sense to not use it! One might say its not necessary for a street engine.....isn't that similar to saying its OK to do a half arsed job. One has to ask themself, how much more trouble is it to use the torque plate for both steps as opposed to one??? Basically, the more correct the tolerances are in an engine, the more efficient it will be and certainly live longer. As they say......its your money and your engine....you make the call!

[preith]

If you want the job done correctly, use the torque plate for the entire process. This ensures that both the boring and honing steps are done in the same plain. I just doesn't make good sense to not use it! One might say its not necessary for a street engine.....isn't that similar to saying its OK to do a half arsed job. One has to ask themself, how much more trouble is it to use the torque plate for both steps as opposed to one??? Basically, the more correct the tolerances are in an engine, the more efficient it will be and certainly live longer. As they say......its your money and your engine....you make the call!

I see your point, but speaking hypothetically, if the end result would be the same, or the cylinders would exact dimensions either way, I still don't see what difference it would make? As for how much more trouble would it be to leave it on, I have no idea, but perhaps it is.

[dspillman]

I see your point, but speaking hypothetically, if the end result would be the same, or the cylinders would exact dimensions either way, I still don't see what difference it would make? As for how much more trouble would it be to leave it on, I have no idea, but perhaps it is.

.............
Check a block bored with a torque plate without head or plate attached, its not round.
The end result isn't the same....with or without head bolted on. Edit edit


Reread the above post, you're talking about end result with Plate used only for final Honing vs. Boring and Honing....
david

[240ZX]

I see your point, but speaking hypothetically, if the end result would be the same, or the cylinders would exact dimensions either way, I still don't see what difference it would make? As for how much more trouble would it be to leave it on, I have no idea, but perhaps it is.

Without any disrespect, it is pointless to discuss a hypothetical situations! However, as you may or may not know, a cylinder bore in a block will actually change demensions when a head is installed and torqued properly. So, if one is to bore/hone a cylinder without the use of a torque plate installed, the end result will be a distorted bore, after the head is installed and torqued. Basically, the torque plate induces the same loads on the block as does the head. Hence the use of a torque plate......you wouldn't need one if you could bore/hone the cylider with the head installed! Hope this explanation helps you understand.

Tom

[ZSaint]

Preith: I guess you will never know what difference the torque plate would have made. If you are racin' you need every 1/10th HP you can get, IMHO. Most people just bore and hone their L6 blocks and go about their business. 240ZX said it correctly. We saw a chance to gain a bit and we took it... Glad we did! As long as we are all having fun, that's all that matters.

[MikeW]

I read somewhere that for an even smaller improvement you have to bolt on all of the engine accessories like the water pump as they have a similar effect on the block.

To be fair, it seems to me that Preith was wondering if using the torque plate only for honing was good enough, not whether using it at all was good. If the torque plate only moves things a 1/100000th then the honing process might cover that.

[preith]

Without any disrespect, it is pointless to discuss a hypothetical situations! However, as you may or may not know, a cylinder bore in a block will actually change demensions when a head is installed and torqued properly. So, if one is to bore/hone a cylinder without the use of a torque plate installed, the end result will be a distorted bore, after the head is installed and torqued.

Ok one last time...and I'll speak theoretically this time. I'm not denying the bore will be different after the head has been installed, that we can agree upon. My point from the beginning, as dspillman eluded to in his edit, is the argument of final honing with a plate vs boring and honing with a plate. "Theoretically" the final bore could be the same, but I don't know, I never been able to compare the two.

[240ZX]

Phillip,

Sure, you can use the torque plate for honing only. I quess the point I'm trying to make is, if you have a cylinder that is measureably round and then is distorted from external forces.....it will not be round anymore. I suppose that honing a cylinder, with a torque plate attached, that was bored without a torque plate may bring the cylinder into roundness....although you may have to hone more material away as opposed to the amount of honing required when using a torque plate to bore. As a suggestion....measure your bore before and after you install the torque plate (be sure you take the measurements in the same locations). These measurements will provide you with just how much the cylinder has distorted after installing the torque plate. I would say go ahead and use the toque plate to hone....it certainly won't hurt to do it that way! As mentioned by MikeW, attaching components to the block, that also stress the block, is a good idea as there will be nothing left to chance by doing so. You will likely only find very serious engine builders going to this length for that extra margin in reliability and performance.

[240ZX]

One additional thought to ponder........boring is the process for reshaping the cylinder bore and honing is the process for prepping the cylinder wall surface. The grit of the hone stones and the cross-hatch pattern you do is dictated by the rings you will be using.

[Stubby]

If you bore without the plate, then install the plate, you must leave extra material for the honing process. When you torque the plate on the block, it distorts the cylinders .003 to .004 and it's tough to straighten the cylinders with a hone. Even on a Sunnen CK10 hone, it still adds time and effort to the job. Can it be done? Yes. Will it cost more? Yes.

I have built thousands of engines with and without plates. I will always use plates on anything I build for myself.

Once someone sees the difference with their own eyes they usualy feel the same way.

[Dtsnlvrs]

David, PM sent...also might be interested in the L-24..will send another PM