Not being too smart about this stuff yet, (but learning!) what is quench, zero decking, deck height etc.?

 

beeboy, you can find all kinds of info on those subjects by searching for them here. You can also get a book called "Ford Performance" at the online store here that will explain it all in detail.

 

The most comprehensive information I've ever seen about head & piston design/quench characteristics was on the Keith Black/Silvolite pistons site. (Unfortunately it's no longer there because the site is being renovated.) However the point here is that quench has nothing to do with how modern an engine is or whther it has knock sensors, it's simply physics. I figure the folks at Keith Black ought to know a bit about the physics inside a combustion chamber.

 

Ok, then you experts tell me why my 68 10.5 to 1 compression 390 runs fine on regular unleaded, 12 degrees initial timing, stock distributor the car came with? No pinging what so-ever. This motor has iron heads aslo. 67 cc chambers ( C8AE-H castings) untouched. They were pulled last year and all they needed after 34 years was new seals. Stock bore, the original cast flattop pistons. Cam was swapped for a Crane 272 degree Energizer ( .523 lift) The cam in that built 400 with 9.7 to 1 comp was a CompCams 280H grind. I had this 400 running properly, it would run rings around whatever you want. Nothing wrong with a 9.5 + to 1 comp ratio, you just can't run this high a comp without sufficient quench. Which is exactly what you have with the open chambered 2 bbl heads, even with a zero deck. Running dished pistons isn't the same as dropping the pistons down the hole with a flattop. The higher tops of the piston surrounding the dish, will give you some quench with the proper heads And that CAr Craft test where they stacked head gaskets on that 440 mopar, was done using race gas on a dyno. Not hardly a valid comparison with a vehicle running pump gas. And if y'all still insist that Ford never admitted "goofing with the 400's design need to go back and study your history.

 

frankly i am ford people (old ford anyway) maybe in 30 years i will get one of these new-fangled cars lol , and may i note i aint looking foward to it

now blending old and new is sweet

ok if ya are a person who whishes to ingore quench effect there are other routes first off is engine coating. having a ceramic or thermal coating applyied to you pistons and combustion chambers
WILL ELEMINATE DETIONATION PERIOD
detionation is / or is caused by not heads or pistons igiting air/fuel mixture prematurely wich as it is compressed becomes more volitile and the more it is compressed the more volite it will become inturn creating more power

aluminum heads will detonate less because they "wick" more heat away faster than cast iron heads

where as ceramic coating blocks the head and piston from getting hot in the first place ELIMANATING DETIONATION along with expanding pistons that require you to run higher clearances piston to clynd wall wasting energy and having pistons rocking in the bores causing more wear ,also the metal no longer asorbs gas

if you go to hpc coatings website the tested a sb and (even tho its is a intr comb engine) they coated the engine thermal and friction coatings and they got it up to 106% volumetric efficncy could of been better if they tuned it but it was a "direct compareasion, and here i thought that you couldn't do that huh

btw does spped-pro have there coated pistons for the 400 or 351c ?? i can't recall and s1 else may remember... they sell pistons all ready coated with thermal and friction on the skirts to keep scuffing to a min

 

Quote from baddad457:
===========================
"Nothing wrong with a 9.5 + to 1 comp ratio, you just can't run this high a comp without sufficient quench. Which is exactly what you have with the open chambered 2 bbl heads, even with a zero deck."
===========================

I think you meant to say "what you don't have...

In that case what you said there was correct.

If you want quench you have to run 4V heads etc etc with the proper reverse dome pistons which aren't available (unless custom). Then you can run 9.5 or even sometimes 10:1 depending on altitude, gas availability, and how far you want to push it without doing monthly teardowns. The aussie head and piston designs have been discussed here ad nauseam so I won't go into them (homework time).

9.0:1 or 9.2:1 are about as far as you want to push the open chamber heads with the few flat top pistons that are available on ebay etc. They are not made anymore. The open chamber design has fewer HC emissions than the quench design which is why it was designed to be that way (no design error). Later on with the advent of cats the HC problem went away but the engine was near the end of it's design life due to the built in emission system ports in the heads and manifold so the engine was not redesigned. The same head chamber design was used in the 460 for many more years.

The 390 has a quench head with a different combustion chamber shape and would not meet HC emission standards which is one of the reasons it was phased out. Many engines were phased out since the 70's for emissions, mileage, or production cost reasons etc.

You just need to do your homework b4 you go out and spend the big $$ on fancy engine parts and expect them to work together. Comparing compression and fuel requirements across engine families is fruitless. Look at the new engine designs, some of them are using very high compression with computer designs and electronic controls.

-Edit- The thermal coatings will improve things but I have not heard anything about long term durability. The OEM's AFAIK are not using them which leads me to suspect that they are short term solutions.

 

Comparing compression and fuel requirements across engine families is not fruitless. And if you'll look at the newer engine's combustion chamber designs, you will find them not all that different from the older "dinosaur engines" they replaced. They've moved back the the "quench"designs which allows them to run higher comp ratios which results in more powerful engines. The reduced emissions and tolerance to cheaper grades of fuel can be mostly credited to the EFI controls. I'd like to see what an old tech FE series motor would do with EFI. I didn't go out and spend $$$ on fancy engine parts to build that 400. The pistons were used 1980's Speed pro's that came from a 351C that we'd built back then for my brother. The machine work to open the pin bosses cost some extra, but not what I'd have spent on new ones. That 400 performed as intended but the cost of having to run it on the grade of gas it required, was more than my 17 yr old kid wanted to spend on gas. Retarding the timing to allow it to run on pump gas only resulted in lack luster performance. Now he's happier driving my 68 Merc with the 10.5 to 1 390 that runs on cheaper gas and has the power that the 400 had running on expensive fuel.

 

When you have to detune them like that it's the pits

The combustion chambers look similar, but there are subtle differences that the computer modeling has helped with.

Lots of guys build huge engines with desktop dyno and then when they enter the real world and have to detune them they run worse than if they had been built for the real world in the first place. You can find all kinds of examples here with the search function.

What is your 68 mercury?

I had a 63 with a 390 and 12.5:1 compression. I don't know if you could even get it to run on pump gas now. I used 115 octane Phillips flight fuel (ultra premium) or 130 octane aviation fuel in it. I parked it when I couldn't get good gas. It ran great at 150mph but in normal driving 8mpg was the best I could get with a weekly tuneup, -4 mpg without...

 

The Merc is a 2 ddor fastback Monterey. Picked it up awhile back for $1000 with 58K miles on it. Crappy repainted green paint job. I overhauled the 390 after my other kid ran it hot ( 300 degrees) didn't hurt the heads, they just needed new seals. pistons are the originals, crank is still std/std. Honed it and re-ringed it along with new bearings, Crane cam, 428PI intake, Holley 750, and Ford Powertrain Applications headers. Car runs mid 14's with the untouched C-6, and a 3.70 geared detroit locker 9 inch. I also have a 63 Merc out back with a 390. This car also sat for years, but motor fired up after a little tinkering. Purrs like a kitten. I used to also have a 67 fastback Stang with a 427 4 speed that had 12.0 to 1 comp , it liked Avgas mixed with reg leaded.

 

I wish I still had my 63 galaxie 4dr hardtop. There were only 100 of them made with the bucket seats and floor shift. I sold it when I bought my 68 Plymouth. At the time I was newly married and I needed transportation not HP.

I think this thread is probably far enuf off topic now... -hehe

 

Yea, I wish I hadn't a sold the 67 Stang and 427 for $3000 either in 89 so I could come up with the down payment on the 89 Ranger that I'm playing with now ( aluminum headed 302 roller motor and Toploader 4 speed, it's almost as fast as the Stang was in the 1/4)

 

This rocks!
.030 over block
fordged alum. pistons (aprox. 9.4- 1)
Mainley severe duty stainless valves
heads mechined for studs and triple springs
Comp Cams hydr roller cam
(224 duration at .050/ 110 lobe separation/ .566 lift)
chromoly pushrods
guideplates
Comp Cams 1.7 alum rolled rockers
titanium retiners and locks
high volume oil pum
Holly street dominater single plane intake- gasket matched
(the edelbrock dual plane and 600 carb went to the 4x4)
Demon 800cfm carb
every thing balanced

This little jem resides in my '69 stepside now. Traction is a real issue
QUESTION...
I feel that the heads are the limiting force hear. They have been pocket ported and gasket matched to the intake gasket/valley pan but power drops off at about 5500rpm. I thought that the intake and carb swap would cure this. The cating #is D5AEA-2-A. What heads have I already done too much work on? What heads would breath better? you all know more on this than I. Thanks

 

and buy the way...

talk to a good mechine shop about an offset grind on the crank and connecting rods out of a Toyota I think

I think it takes displacement to about 430something. Later

 

The M engines couldn't meet emissions without losing compression and retarding the cam. Emissions controls and de-tuning to meet emissions standards (whether this is viewed as Fords goof or not), caused much of the detination woes this engine has. A 4-6 degree camshaft retard, coupled with the undersized exhaust ports on a 400 will cause exhaust gases (heat) to remain far too long in the combustion chamber. A dual pattern cam with quench heads and you will lower combustion volume temperatures signifigantly. But you can't do one or the other, they either both work together, or not so much

 

ford was too buzy pouring money into the winsor ontario plant to deal with the clevland/michigan plants and to them(imo) winsor couldn't handle putting out 2 different engine designs.so they stop-gapped the 351m/400 long enough to phase it out.

in 71/72 it was ment to be the now aging 360/390 power plant. in 75 the 351m was made specificaly to be a stop gap until winsor plant could keep up with demand.

in fact they should of if was down to discounitueing they should of shipped the tooling to the Lima plant

by the way what is going on with the Lima plant..what is being cast there?

by the way you always use a dual pattern cam on ANY 335 series to improve exaust flow and scavanging