How important is it to have a good .040 squish/quench?

After seeing the original 1970-1972 Buick BB dish pistons. It's difficult to see any squish/quench band?

Amazing how fast the 455 Stage 1 is. I wonder if adding modern pistons with a good .040 squish/quench, how much difference it would make?
Is this what most guys do to their 455 engines now?

I didn't realize that the original Buick pistons sat in the hole around .045 deep and then you add the head gasket thickness (can be of various thickness), and you get even a deeper in the hole situation.
Have to wonder HOW Buick managed to get 10.1 or 10.5 -1 CR's with dish pistons?
Guess they didn't know anything about squish/quench back in 1970.

 

Squish/Quench metrics were known since the early 1900s.

A lot of people toss the terms around without actually understanding what they mean and how they effect or negate power production and efficiency of the ICE.

There is a great deal of science involved in extracting the greatest amount of work from the effort that goes into each "power stroke" if the internal combustion engine.

All that goes into the most efficient "build up" of the compression/power, and the subsequent "exhaust" stroke to facilitate the next cycle, is a ballet of finesse. Get any one of the four strokes out of balance to the other three, and you pay dearly in efficient production of power.

One must understand what each of the four "strokes/cycles" brings or costs, in the production of power, vs the parasitic cost to create the production. Otherwise, one will chase a mean, and lose a great deal in the back end due to ignorance of the whole of the cycle of power production.

Too often, people fail to realize that those that created, tested, verified and adapted to the science of the ICE, traded the greatest amount of power and efficiency that could be realized, for the reality of fielding a reliable, salable and best cost to produce, massed produced commodity.

Many design iterations were short lived of only a few years. Subsequent design changes were implemented, but the overall was that money spent in the past on research, merely carried to the next iteration of producing more benefit, at a low cost to pay for the next iteration (wash, rinse, repeat).

The automotive (and other's) industry never was about bring the best for the most dollar available to spend on innovation. It was about bringing the next best saleable innovation, at he least cost, that the public could be convinced to throw the most money to obtain.

Engineers bringing innovation gets the "corporate heads" all hot an bothered, but a great deal of that gets relegated to the "back of the hanger" when the bean counters and sales force come in at 0900 hours and grab their first cup of coffee for the day.


FWIW
(I was not born a cynic, I just fast tracked and experienced a great deal in a short time in various fields and discipline, both civilian and military sectors. I'll happily discuss any and all of it, one on one, but no longer desire to play the game in public with people looking to dick dance for the sake of their own gratification.
If that offends anyone, that's for them to deal with.
I'm not the **s-hole some may think. But I am willing to share with people with true desire to know "stuff".
I just don't have time to waste on leg humpers... )

I'm really not an **s-hole, just ask Bill Burr, or Dennis Leary... No, on second thought, they'll both fight to the death, to throw me under the bus...

 

Gee, Mike, what the F#%@ was all that about?

I thought I was asking a simple question about Squish/Quench and piston design.

Interesting to know it was known in the early 1900's, unfortunately, I'm not that old. lol

 

I think Mike is talking about spending a ton of money on engineering and innovation, and then building a crappy product. I had a buddy that worked at Lockheed Martin. Boy could they spend money, and then end up with something that didn’t work. If I’m wrong I apologize Mike.

 

I used to work for the for the Federal Gov, I know all about Contactors spending tons of money on Projects that didn't work out.
Mike's reply is far from the questions I was asking. Vet (Navy)

 

My understanding is that the compression specs given out were some what optimistic. If Ford said 10.25 then Pontiac would say 10.5 even if it wasn't true it made the marketing department happy. Add to that the mass manufacturing issue and the factory specs were even more questionable. So, yes - more care and careful selection of parts when you rebuild one of these yields great benefits.

 

Thank you. I found out recently that the 70 GS & Stage 1 we're more like 9.5 CR. Buick like the rest (like you said) embellished their Car's
That said, no one has answered my Title question. Waiting to here from the engine experts. VET

 

Thank you sooo much Larry.
The posts you sent me explain a lot I didn't know.

I've done some study on the Kenne Bell pistons that someone installed (.040) in the hole. With the recommended head gasket for these pistons (.040) and I get .080 in the hole.
Wow, that is terrible. I have calculated my CR to be 9.4 to 1.

I believe this is was causing all the original dedonation issues the shop has been fighting along with high water temperatures. My Comp cam is in the 230 duration, which is not helping either.

Changes we've made.
(1) MSD ignition system.
(2) Adjustable vacuum canister.
(3) New HD radiator.
(4) New 160* High flow thermostat.
(5) TA High Performance water pump.
(6) New HD Thermostatic fan clutch.
(7) Evans Special Coolant.
(8) All new water hoses.
(9) All new belts.

We finally got reasonable water temperatures with A/C operating at full load/speed,
in stopped traffic or stop light, 210*/215* on a 97* day. Normal highway speeds, 185*-190*.

We have not had any dedonation issues to date.

If I had known about all these posts, I might have taken the new piston increased height adjustment route to get as close to zero deck as I could obtain.

I may still do this in the future.

This is what I like about this forum, there are a lot of smart and experienced people on board.

 

Fun stuff : Broaching, NOT Machining! Cutting the decks from the rough casting, Flint >

From an operator in 1990's:
"The broach uses a long series of carbide cutters to shave off metal. This process is quicker that milling but cruder. We used to have a .004 limit on flatness variation. The broach could run one hundred and fifty parts in a good hour. Chris Balog"

 

I did broaching as a machinist, but NOT on this scale!

The huge size of the machinery reminds me of the shipyard machines that made the 16 inch guns on WWll battle ships. VET (Navy)

 

Chris, I see you are a Sub teacher (bubble head) lol.
In what discipline/skill is your expertise?

I spent 7 years in the U.S. Navy.
68-72 active duty, Newport Rhode Island. 78-81 at the Naval Academy.
4 ships: USS Essex CVS-9, Birdfarm.
USS Milwaukee AOR-2, combo oiler, food & ammo supply ship. USS Grand Canyon AD-28, Destroyer Tender (repair shop).
USS Simon Lake AS-33, Sub Tender, Home port, Kings Bay, Ga.

I was a Machinery Repairman First class petty officer.
After 72, I worked in private industry for 8 years as a machinist and Tool & Die maker.
In 1980, I took a job/career with the CIA as a Technical Operations Officer. Spent a lot of time overseas and in the middle east in Counter Terrorist Operations.
Retired after 32 years of service and 36 years of Federal service.

Just got back into the Buick muscle car arena in 2021. Did a ton of upgrades to my 70 GS 455. Been in the shop for the past 22 months. Should be out in a week or two now. VET (Navy)

 

Sorry that I don't remember this in your post but have you tried running either AV gas or leaded race gas say 100 or so to see if your temps go away? I had a high compression motor that ran a tad hot on pump gas but ran nice and cool on AV gas.
Just a thought.

 

Thanks. We believe, the shop and I have the water temp is now under control.

As a dayly driver, neither AV or race gas is a good option.

The previous owner was using octane Booster to keep the dedonation in check.

 

Buick 3.8’s

 

Ive yet to this day have a zero deck buick...never once tried to actually....last engine i done was a 11.25 to 1.....52tho in the hole....40tho gasket.....ran 10.70s with 93 pump

One before that ran the same bottom end with a 100tho gasket....ran 11.60s on 93 pump

Understand the "science" behind zero deck...squish..whatever....i havent seen where they care toi much

 

The real reason to do anything is to keep it from detonating instead of combusting.

 

Yea i understand the reasoning....never experienced any detonation myself.....hell the 11.60 setup would run under load with mid grade..i think its got a little too much emphasis on it myself

 

Cam events play into it also tho

 

Have you seen a piston from a Buick Nail Head? All the engine sizes have a huge popup maby sticking out 3/8 of a inch over the deck of the block. Looks like its made for a deep breathing Hemi. The popup is there because of the design of the heads combustion chamber. Dished, flat or popup doesn't always determine comp ratio.

Also both 455's base and Stage 1 are still really "rated". at 10 to 1 according to alot of members. Many factory written specs are a mixed.
You seem to be chasing the Stage 1 motor specs. Larry linked alot of good threads and other than the TH400 being beefed up a little and the down shift to first coming in from a higher 35 mph or below the real big difference is what Jim W said was the use of 3:64 gears as standard instead of the 2:93's. The Stage 1 was a package of little things that worked well together.
I think the heads and cam difference was only around 16 hp. more.
Your base GS455 is still a stormer and many members say from stoplight to stoplight most wouldn't know the difference.