The importance of a torque plate

Max1196

Well-Known Member
Joined
May 12, 2016
Messages
1,287
Reaction score
1,224
Location
Swift Current SK
I've been well aware of the need to use a torque plate on a 440, that's why I have one. So being that it was 440 day again, I photo'd finished size with plate tight AND finished size with the plate loosened. The bore size, 2 inches from the deck, can, and has been in the past, been observed to change as much as 1.8 thou, just by loosening the plate. This one I'm showing moved about 1.4 thou.
100_3845.JPG
100_3842.JPG
100_3835.JPG
 

K.O. SWINGER

Meeting in the alley since 1976
Joined
Nov 18, 2010
Messages
2,808
Reaction score
2,769
Location
oregon
So it seems those numbers would only increase as the motor got hotter correct?
 

MoparMike1974

FABO Gold Member
FABO Gold Member
Joined
Jun 16, 2017
Messages
4,087
Reaction score
3,625
Location
Maryland
Its amazing how much metal moves, even a big chunk like an engine block.
Why dont you hone with the plate torqued?
 

66fs

FABO Gold Member
FABO Gold Member
Joined
Sep 9, 2009
Messages
7,420
Reaction score
2,527
Location
Greenwood, South Carolina
Don't forget the mains, torqued to spec for the fasteners used, or not torqued at all. No numbers here, But it can be huge, relatively speaking.
 

MOPAROFFICIAL

Well-Known Member
Joined
Jun 1, 2016
Messages
12,040
Reaction score
15,348
Location
Hiatus
And a torque plate still does not completely simulate the effect/presence of a head bolted down.

...and if you run aluminum heads and use an iron torque plate... you again are not doing what you think you are doing and you're even doing it wrong/worse now.


Just see yourself...Use a torque plate during the honing...then bolt a head on you're using, assembled, and then flip the motor over on the stand and measure the bore....its not round! The head pulls it out more than the plate! Anyone can buy a bore gauge and find this out.
Better than nothing, I guess.
That's the reality of it.
 

harrisonm

Well-Known Member
Joined
Jan 16, 2005
Messages
4,704
Reaction score
6,037
Location
Topeka, KS
Thanks for the post. I have certainly heard about the importance of a torque plate, but I've never actually seen the proof.
 

66fs

FABO Gold Member
FABO Gold Member
Joined
Sep 9, 2009
Messages
7,420
Reaction score
2,527
Location
Greenwood, South Carolina
And a torque plate still does not completely simulate the effect/presence of a head bolted down.

...and if you run aluminum heads and use an iron torque plate... you again are not doing what you think you are doing and you're even doing it wrong/worse now.


Just see yourself...Use a torque plate during the honing...then bolt a head on you're using, assembled, and then flip the motor over on the stand and measure the bore....its not round! The head pulls it out more than the plate! Anyone can buy a bore gauge and find this out.
Better than nothing, I guess.
That's the reality of it.

Fastener engagement, same gasket as in the final build, and torque in the same increments and torque all play a part. As you said, it is still an approximation that can be verified if one takes the time and has the proper equipment.
 

MopaR&D

Nerd Member
Joined
Jan 4, 2008
Messages
4,857
Reaction score
1,845
Location
Loveland, CO
Dang I just had my 440 block bored and honed .030" over, forgot to ask if they used a torque plate or not. The shop I go to routinely builds quad-digit-HP drag engines (high-budget BBC and LS are their bread-and-butter) so whichever route they took I trust their judgement. I will ask them about it though when I bring in my 440Source Stealth heads to be checked over, shop owner claims just with their valve job on those heads they will pick up 10-20 cfm of low-lift flow. I feel pretty lucky to have access to a machine shop with racing experience like that.
 

CNC-Dude

Well-Known Member
Joined
Apr 6, 2019
Messages
150
Reaction score
113
Location
North Georgia
So it seems those numbers would only increase as the motor got hotter correct?
Winston Cup teams for over 20 years now have a system that pumps water heated to operating temps through the water jackets of their blocks while they are final honed. They also have used torque plates bolted to the bell housing to hone the cylinders as well. We used a bell housing plate torqued to our H/MP 6 cylinder blocks because we found that after bolting the bell housing to the engine pulled #6 out of round. We did that on the advice of the head engine builder for Bobby and Donnie Allison that used the same machine shop as we did back in the late 70's.
 

Ceedawg

Well-Known Member
Joined
Aug 2, 2016
Messages
735
Reaction score
500
Location
Va
And to think of the millions of engines that came down Chrysler’s assembly line that never used a plate. That 5-10 HP could’ve helped
 

MopaR&D

Nerd Member
Joined
Jan 4, 2008
Messages
4,857
Reaction score
1,845
Location
Loveland, CO
And to think of the millions of engines that came down Chrysler’s assembly line that never used a plate. That 5-10 HP could’ve helped

No way in hell lol they were soo cheap when it came to manufacturing, they could have started by tightening up their tolerances by even just 30% and their engines would have made WAY more power. There was another thread where someone posted tolerance specs from one of the Chrysler factories back in the late 60s and the allowable variance in compression ratio for a HP 440 was something like 9.3-10.2!! There's a 20+ HP difference right there. Explains why many classic Mopars either ran super strong or unexplainably weak when new. And why blueprinting Mopar engines can give such huge gains even without other mods. Same goes for rotating assembly balancing, deck machining, cylinder head casting, you name it if they could cheap out and save a cent they'd do it.
 

Ceedawg

Well-Known Member
Joined
Aug 2, 2016
Messages
735
Reaction score
500
Location
Va
No way in hell lol they were soo cheap when it came to manufacturing, they could have started by tightening up their tolerances by even just 30% and their engines would have made WAY more power. There was another thread where someone posted tolerance specs from one of the Chrysler factories back in the late 60s and the allowable variance in compression ratio for a HP 440 was something like 9.3-10.2!! There's a 20+ HP difference right there. Explains why many classic Mopars either ran super strong or unexplainably weak when new. And why blueprinting Mopar engines can give such huge gains even without other mods. Same goes for rotating assembly balancing, deck machining, cylinder head casting, you name it if they could cheap out and save a cent they'd do it.
Wasn’t just Chrysler, the all did it, do all what you said and cars would of been to pricy for the average guy or gal. Besides they were making cars to get from a to b not racing machines even though some were promoted as such. They gave you a rough jewel, you polished it.
 

MopaR&D

Nerd Member
Joined
Jan 4, 2008
Messages
4,857
Reaction score
1,845
Location
Loveland, CO
Wasn’t just Chrysler, the all did it, do all what you said and cars would of been to pricy for the average guy or gal. Besides they were making cars to get from a to b not racing machines even though some were promoted as such. They gave you a rough jewel, you polished it.

Very true, Chrysler was arguably the worst about it though. Other makes like Buick for instance had much better tolerances and QA/QC for mechanical parts. I get the cost aspect but there wasn't much of an excuse for the quality to be that low though especially when you look at how import manufacturers later came in and dominated with cars that were built really well but still affordable. But that's a whole other discussion lol they had completely different philosophies from the top-down on how to build things.

I guess my point was for the really high cost of using torque plates in a high-volume machining operation you could get similar or better results just tightening up already-existing tolerance specs on already-existing procedures which were pretty awful for Chrysler at that time.
 

Ceedawg

Well-Known Member
Joined
Aug 2, 2016
Messages
735
Reaction score
500
Location
Va
Very true, Chrysler was arguably the worst about it though. Other makes like Buick for instance had much better tolerances and QA/QC for mechanical parts. I get the cost aspect but there wasn't much of an excuse for the quality to be that low though especially when you look at how import manufacturers later came in and dominated with cars that were built really well but still affordable. But that's a whole other discussion lol they had completely different philosophies from the top-down on how to build things.

I guess my point was for the really high cost of using torque plates in a high-volume machining operation you could get similar or better results just tightening up already-existing tolerance specs on already-existing procedures which were pretty awful for Chrysler at that time.
I understand, on my 07 Mustang GT 500 the engine was put together by one man, had his signature on it. It can be done, for a cost. But $2800 Road Runners didn’t fit that bill then.
 

Sr4440

Active Member
Joined
Oct 4, 2021
Messages
37
Reaction score
42
Location
killeen Texas
When you file fit piston rings, you should also have a torque plate bolted in place. Never underestimate the power of having straight round cylinders to making power.
 

oldkimmer

FABO Gold Member
FABO Gold Member
Joined
Nov 11, 2006
Messages
22,571
Reaction score
6,362
Location
Kindersley, Saskatchewan,
Don't forget the mains, torqued to spec for the fasteners used, or not torqued at all. No numbers here, But it can be huge, relatively speaking.
Max1196 checked the mains on my 440 block that another machine shop did 4 or 5 years ago. Up and down was good but side to side it was out .005 thou. So no bearing crush. This block was line bored with billet main caps. Needless to say I was/am pretty disappointed. The bore job on the cylinders was crap also. Time to do a different block. Kim
 

66fs

FABO Gold Member
FABO Gold Member
Joined
Sep 9, 2009
Messages
7,420
Reaction score
2,527
Location
Greenwood, South Carolina
Max1196 checked the mains on my 440 block that another machine shop did 4 or 5 years ago. Up and down was good but side to side it was out .005 thou. So no bearing crush. This block was line bored with billet main caps. Needless to say I was/am pretty disappointed. The bore job on the cylinders was crap also. Time to do a different block. Kim

It is amazing how bad some machine work can be. Sounds like you would have better off leaving the block stock.
 
Top