Poll on line-boring with heads/torque plate installed vs. without

[Intercooler]

The bit of information I got from Merkel's over the weekend has me thinking seriously of whether to even do my 4.1 with caps. From what I gathered you can run into problems with #3 and #4 mains going out of round if the line-bore isn't done with a torque plate or the heads being torqued on while line-boring it. Of the two I had done previous I didn't have the heads or a torque plate bolted on when they were done. Both lived okay while I had them but I didn't have a bunch of passes or miles on them. Fact or myth here?

 

[bruce]

Originally posted by Intercooler
The bit of information I got from Merkel's over the weekend has me thinking seriously of whether to even do my 4.1 with caps. From what I gathered you can run into problems with #3 and #4 mains going out of round if the line-bore isn't done with a torque plate or the heads being torqued on while line-boring it. Of the two I had done previous I didn't have the heads or a torque plate bolted on when they were done. Both lived okay while I had them but I didn't have a bunch of passes or miles on them. Fact or myth here?

If you want to get serious,
you have the girdle on
heads and intake
and circulate hot coolant thru the block.

Or just sit down and see how picky you really can afford to be.
At tiimes I just wonder about doing a girdle, and leaving it at that. Without the mains wondering around with a girdle in place that might be a good plan, dunno if anyone's tried this

 

[JToups386]

Any longtime, experienced, reputable machinist I've talked to or dealt with, always recommends using the torque plate, etc! Why would you want to try and line bore something as it sits free standing, as opposed to mocking it up into the "load" it will be subjected to when all bolted together? IMO, it is an absolute must to do! I think any machinist that does not do it, is either really lazy, or just doesn't have the proper equipment, which then would make me ask myself why I took my motor there to begin with.
My theory behind doing this is similar to why I insist on retorquing the headbolts after initially heating them up. It's just all good insurance and worth any additional time or money spent to do things right. But,,, this all comes from having grown tired over the years of fixing things that I originally took shortcuts on. I think there's something about a "learning curve" in here somewhere......

 

[Tow Man]

ALWAYS machine with torque plate installed! This goes for ANY performance engine of ANY make/model! PERIOD

 

[tyndago]

For a performance motor ...always with a torque plate....

I have seen pics of the differences of having a plate installed and not installed. The head bolts and having the heads torqued down actually change the shape of the bore.

 

[PEACHS]

Torque Plates?

I wonder if GM used these torgue plates when they machined all of the turbo motors for our cars? Every local machine shop i had contacted did not have torque plates for the Buick. Also the way GM torgued the heads on our motors would be very hard to simulate with just a single torgue wrench. I wonder why when ever a head gasket is replaced when ported heads are installed they alway tend to reblow on the intake side? I would think that when boosting 25-30# into a motor would tend to distort the cylinders roundness. Add some detonation, the heads cupping ,and head gaskets blowing out. Will torgue plate honing keep the cylinders in roundness? Just my thoughts on the subject.
Peachs

 

[tyndago]

Re: Torque Plates?

Originally posted by PEACHS
Every local machine shop i had contacted did not have torque plates for the Buick. Will torgue plate honing keep the cylinders in roundness?

If they dont have them - then get them to make them. Any competent machine shop should be able to make a set of torque plates.

If you read any of the SA Design books on building motors you will find that they say that you are giving up power and ring sealing if you dont use torque plates.

Since its going in a GN /T I would imagine that you want to make all the power you can.

Ever wonder why it seems some cars , some guys ,some teams just do better.... its a combination of little things that make a big difference in the end. 20 hp in the hone , less rotating weight , etc , etc... that all add up to one good tune and a good running motor and car.

 

[KendallF]

I am betting that most of the respondents in this thread don't know we're talking about boring/honing the main bearing bores, not the cylinders. I would venture to guess that the majority of shops do not use a torque plate or heads for this. I personally have never seen anyone use them. For one thing, many times a shop only has one torque plate and uses it on the bank being honed.

The data I have seen on bore concentricity differences with a torque plate installed show that the cylinders are affected for 2-3" down the bore. I would like to see anyone show, via measurements of any sort, that the main bores move significantly when the heads are bolted down.

 

[Intercooler]

Originally posted by KendallF
I am betting that most of the respondents in this thread don't know we're talking about boring/honing the main bearing bores, not the cylinders. I would venture to guess that the majority of shops do not use a torque plate or heads for this. I personally have never seen anyone use them. For one thing, many times a shop only has one torque plate and uses it on the bank being honed.

The data I have seen on bore concentricity differences with a torque plate installed show that the cylinders are affected for 2-3" down the bore. I would like to see anyone show, via measurements of any sort, that the main bores move significantly when the heads are bolted down.

Excellent points!

 

[The Radius Kid]

Kendall's right.They aren't going to matter that much.
Bruce is also right.It all comes down to how picky you want to be.
You could do a Gene Fleury style polishing job on the block,do the crank and rods,but is it going to matter when all is said and done.
Your "main" [pun intended] concern is to keep the bores in alignment with the cam bores and the decks.I've heard of guys who don't level the bar very well and wind up screwing things up with respect to deck heights as referenced off of the crank C/L.
Kendall just went through this not too long ago,and to do what he did,takes some saavy.Nice work Kendall,I may have sounded a tad sarcastic then,but I really was proud of you.
BTW,I'm a machinist with 20+ years experience.