Torque plate

Has anyone measured the distortion of an 058 block when under the use of a torque plate?

I know the impacts .003" can have on a big block chevy with regards to blowby near TDC... BTDT

I had my block bored under the promise of using a torque plate. I showed up early and the engine machinist was finish honing the block and the torque plate was 10 ft. away. It was dry and I am even having serious doubts as to whether or not he even used it during the cutting process... which is less important to the honing. I asked about it and he said he used it...

Not to mention... not one piston was marked as to which hole it went into...

This was a big bore to BHW's to clean up a cylinder... I am seriously considering taking it to another machine shop on Monday to verify clearances because the one gauge I don't own is a bore gauge...

Needless to say I am really irked over this...

they're unnecessary on these motors, but he'd be using it during honing if he used it at all, unless he was just going at it with a dingleball hone in a drill to shine it up, then in that case no big deal as that style of hone is not used vigorously enough to change any dimension.

Also, best to use the old gasket in there too, as you'll get a little more clamp load around the cylinders than around the bolt holes with the extra wrinkles in the gasket around the cylinders. Some MLS gaskets actually have a few thousandths step in one of the layers to provide even more clamping right where it's needed. My OEM ALH head gasket didn't have that.

As I went over in the other thread, you'll likely have no issues whatsoever, but if he's lying to you then from that alone you have every right to be fuming mad.

I always use torque plate
And i have measured several times to see the difference
A diesel block with 12mm bolts/studs and 81.50mm bore was 0,02mm too big one direction and 0,03mm too tight the other direction after plate was taken off

You also notice it when you try to install the pistons,it is REALLY tight to get the pistons in there since the diesels don't use much piston/wall clearance

On gasoline engines with bigger bores the distortion will be even slightly higher even if they use smaller 10 or 11mm bolts/studs

Distortion is ofcourse worst at the top of the cylinder,but that is also where ring seal is most critical

Thanks that was what I was looking for. I have a spare head I'm going to bolt on and a trip to my uncles machine shop where he has 40 years and the experience of measuring tolerances much smaller than what we are looking at... Plus he has all the exotic gauges!

I'll measure the bores near the deck in a bunch of directions from the crank cavity. If its out of round it will be clear the difference without a torque plate.

I'll then remove the head and see if its completely round as I suspect it to be, seeing as I walked in on him as he was doing the final hone without the plate.

I am curious as how close he even set the tolerances.

Sadly if it wasn't done properly it will be a block destined for scrap and I am out a lot of money.

Didn't we talk about this on the phone some time ago?

The bigger the bore and the bigger the torque, the more likely you will have the top 1" or so, out of round from torque-plating. Not only should you torque plate, but you should torque spec to the bolts you intend to use. If you are going to use ARP studs, we apply more torque load than if it is a standard block build.

Some machinists think that the torque plate should be used with the type of bolt that is going to be installed. I.E; if you are going to use TTY bolts, torque plate with the TTY's. A used set of tty's is what one very excellent machinist we know suggests. The other opinion is that torque is torque. Our techie machinist will disagree, saying that the method of torque is not the same if using stretch bolts compared to chrome moly bolts. It may not matter. But applying the correct amount of torque for the type of bolt used, does matter. The ARP's definitely add clamping force and will distort the block more.

The whole point of the torque plate is to get the distortion into the block so you can hone it correctly. If your uncle measures no distortion in the block, static, it is wrong. Also agree that a head gasket should be used.

The other choice you might make, assuming you have 81mm pistons, go one step more and get 81mm +.5.. O.S. I may still have a set. If not, I can get them. I'm sure you could get your money's worth out of the other set. It would be cheaper than a block.

Also, are you aware of the limitations for head gaskets with the choice an AHU head? Deck height for the pistons will have to be done carefully. You have but one choice of head gasket for the AHU block when using 81mm pistons.

Let me know if I can help you out.

We have never actually spoken on the phone. An emails or two here and there..

I am in complete agreement on the bolt specs. I am well versed on the plates, just not the 058 style block specifically when it comes to its idiosyncrasies.

The oversize option was proposed to me this morning. One good thing is the owner of the shop is now involved and he himself had that same sunken stomach feeling I got when I saw the final hone without the plate. Needless to say they want to make it right. Going to the 81.0mm was already a .060" cut..81.5 is another .020". That's a total of .080 off these bores.... on what at first glance looks to be a Siamese block (guess I should go out in the cold snow and check in the coolant passages). The real question is how much metal is there and how much is really needed? I am told the gas guys bore these tdi blocks to 83mm and make 600+hp. But that's also using rpm in their favor and that helps keep the PCP's in check. I intend to compound this block (<50psi), and its already half been built.

So is the 81.5mm a reasonable safe bet on the AHU block?

lol.. I bet its great for spool though..

On the HG.. I already have the one and only MLS option (G60) sitting on the bench waiting. I just need to set protrusion to fit it.

The deck was cleaned up at .003".

Which brings up another point. I understand its either the ARL or ASV pistons that in the .5mm OS the piston top height is modified to the assumption of the block being decked. Is this also the case with the Nural 81.5mm?

All Stock said:

I intend to compound this block (<50psi), and its already half been built.

Click to expand...

cut your piston bowls while they're out

I was talking to a couple local machine shops before I sent my block to Frank. I kept insisting that it's not just a smallblock and you cant just "drill it out and send it".

I told them ahead of time that it's gotta be done a specific way. They told me that nobody has a torque plate, but if I wanted to they could be persuaded into using it and I would have to have one made or sent to them, for close to $1000 to use it one time.

After speaking to Frank and Matt Whitbread, i opted out from any and all local machine shops. Definitely go with somebody who knows YOUR specific block. ESPECIALLY if you go compound.

Votblindub said:

ESPECIALLY if you go compound.

Click to expand...

whoops
did mine with a black and decker drill and a lisle rigid hone, plopped over a 5 gallon bucket to catch the kerosene splashed in periodically to lube the stones

dunno if the main caps were on or not

Remember to shoot for more piston/wall clearance than stock when building for over 150hp/liter, I did mine to .004" clearance, but less would probably work okay.

So far I have taken a step back, a deep breath... I believe giving them the opportunity to make this right is the best thing to do. So I'll be heading back to meet with them for a torque plate re-measure to see what we have to do in order to ensure we have the proper tolerances and the best ring seal possible.

I have to say the referrals to Whitbread and Frank are well placed. They are two people who day in and day out do TDI's and the experience gained there is worth its weight in Gold when it comes to dealing with the specifics of the TDI.

As for the tolerances, those are on the table when we measure this out torqued. Maybe there will be enough room.. maybe not. The other option is a new block or go 81.5mm.
The problem with 81.5mm is I have half built a compound setup already and I question if it will have been weakened too much to handle it. That was a question I had to overcome to consider 81mm pistons.... now another .020" is on the table.

Well in any case.. whatever is done it just needs to be done the proper way.

A torque plate is only possibly 100% accurate if it simulates similar/exact forces on the block as the intended cylinder head/fasteners when torqued and with the exact head gasket being used.

I won't bother going into detail of why I feel that using a torque plate is unnecessary.

andy2 said:

A torque plate is only possibly 100% accurate if it simulates similar/exact forces on the block as the intended cylinder head/fasteners when torqued and with the exact head gasket being used.

I won't bother going into detail of why I feel that using a torque plate is unnecessary.

Click to expand...

I agree, everything helps but you can pull things in the opposite way.

Fit a head and see how it looks at the top and then fit the crank and see how it is at the bottom of the bore. I dont thing you could ever get things perfect. We are also measuring when cold, when things get REALLY hot i doubt the bore and piston remain perfectly round so making things perfect at one temperature seems a bit silly.

There is no perfect. I am not going to do, as some I know, heat the block and stand in a spray of 200 degree cutting oil coming out of a cylinder block, just to get a few more tenths of accurate. Perhaps some of you can claim that is what ring wear-in is for.

However, it doesn't take much of a genius to follow some common sense. There are pistons we install with a torque plate because the things won't fit past the skirt if the block isn't pulled into shape. Remember, the top of the block is where the distortion happens and at that point, the piston is a lot smaller, so once the piston skirt gets past the top of the bore, no problem.

Then, I will give this bit of reason. Someone who is building like Andy2; by the time the block is hot, the race has been over for a while. Another example, what difference does a vertical stripe in a cylinder make, that loses a quart of oil in 1,000 miles, if you are traveling 1/4 mile at a time? For you guys, if the cylinder bore is off by a few thou, so what? Maybe you should consider more squared pistons, instead of a piston that is .020" smaller at the top... It might compress better in that grand total of 10 seconds you intend to use it.

On the contrary, if you are putting an engine together with the intent of making it something that heat soaks, the rules change. There is a local guy that sets up NASCAR engines you all could learn a thing or two from. The rule is, the closer to race-operating situation you can make the engine, the more accurate the job you do, the better and more likely the engine will go 500 miles.

Our goal is to make a concentric hole, for the length of the bore, as best as possible. I don't think anyone will argue that is goal worth attempting. It's not 'silly'.

Those without torque plates, it won't show up on your dynos. It's shows up in life expectancy. The way I see those big dynos, it does not correlate to life-expectancy when you are doing big numbers like that. In your case, maybe you don't need that torque plate.

As for me, I think the most common thing to dissuade someone from using a torque plate is if you don't happen to have one.

Looks like it will 81.5mm With the torque plate on it comes too close to factory service limit specifications if we try to correct it.

I had a novel of a response to the why or why not of a torque plate.. Everything from the 30+ years of experience I have and the some of the names who taught me along the way.. To the business case of OEMS and why they don't use them. You can't grow up in Detroit as a hardcore car guy and not learn a few things. But I thought it best to play stupid seeing as I have been accused before of not knowing what I am talking about..

I started this thread not to seek the answer to do I or don't I.... but to get specifics about the TDI block and its distortion from someone who has measured it.

I will say I like the discussion and I will say I have been in shops, race shops, factories... places most car guys have never seen. I have seen R&D prototypes of all kinds of things. In doing so I have seen the case for why we need torque plates on many occasions outside of my own experiences. Yes the variables change... yes you can further simulate the exacting conditions, but single handedly the plate does the most to simulate a precise reenactment of the operating conditions the block will see during operation.

In engine building when you have the opportunity to further accurately control tolerances you take them. Period. Its not just the difference in 1st place or DNF ... its also your Reputation. Its the little things that separate the crowds and if they didn't matter competition wouldn't exist. If your not worried about exacting tolerances your not the one I want building anything for me. Like most, slapping parts together can and will work, but its all about maximizing what you have and in the world of racing....NEVER EVER leave a potential advantage on the table!!

Funny thing about this argument... I have seen proof time and time again as to why you should be using a plate for your customers...aside from giving them your best that you possibly can.... no customer deserves just good enough.

But... I have NEVER once seen valid proof other than an defensive ego as to why you shouldn't use one.

i think if you have one use it. We chase 0.02g tolerances on pistons and rods and dont need to!