alright...yall double check me

im trying to calculate compression ratio for my motor, and ive tried 3 calculators and keep coming out around 13.1-13.2:1

its a 8 cyl
3.85" stroke
4.42"bore
75cc comb. chamber
.040" head gasket compressed
4.5" head gasket bore size
12.1cc dome on piston
.025" piston deck clearance


comes out around 13.16:1 compression

im too lazy to cc the heads myself, but every i look says 75 cc for dove-a's

who thinks this will be too much for a 472 on propane? supposedly it has a 105+ octane rating?

I hope its alright because i already have 4 slugs in the motor

with my head flow #'s and my lunati custom grind solid lifter cam and approx 550 cfm(thats what propane guy said the x-450 flows)

it says 457 hp@5000 569 ft lbs @ 3500.

it shows over 530 ft lbs from 2000-4500

what do you all think??? Tear my idea apart:mr-t:

you need 2 ohgs to feed that
how big is the cam? figure out the dynamic compression ratio

cam is 264 272 advertised 232 238 @.050 .542 .559 lift

114 lobe seperation

im not running dual mixers, i just want one and ive already accepted the motor wont be to its full potential...but the way i look at it....look what the winston cup cars do with their restrictor plate motors

im thinking of running a thicker head gasket....i will figure out the dynamic compression ratio if i can find a calulator....whats the difference in dynamic and static?

Whats your top ring distance? Thats a volume that seems to be forgotten alot, but you need that too. Came out to 13.16:1, but with the top ring volume it could go down to about 13:1

came out to 10.952 using this

http://www.kb-silvolite.com/calc.php?action=comp

how do i figuyre the top ring volume?


my intake closing point is 43 degrees but the calculator says to add 15 degrees? to that so i get 58 and used that #

Top of the first ring to the top of the piston.

hang on ill go get the measurement real quick

its .275"

and my head gaskets are .041" compressed, not that it changes it much

found a gasket i could pick up tomorrow with bore of 4.54" and .0595 thick

changes it to 12.39 and 10.32.....maybe that woudl be more workable?

do i need to be running copper gaskets with this compression?

12.98:1.

cant leave that shit alone can ya? if it werent for that we'd be going to riverrock next weekend :smokin:

ahh well, reckon we will make it to june jam... hell maybe by then i will havw my beadlocks, cromo shafts/joints, slugs, and GLO diff cover all installed!!!



hey... a man can dream :flipoff2:

-cutts-

think it would be worth changing to the thicker gasket i stated above?

is the 12.98 the comp ratio with my curretn gaskets and the piston top ring volume?

i talked to propane guy(cary) and he said hes heard of 12.5 or so successfully but couldnt remeber if he has ever heard of 13:1 being done? lunati cams tech guy said go for it???


are there any other dangers of running 13:1 on a trail motor??



i hear ya cutts, you know me i cant leave shit alone...

think it would be worth changing to the thicker gasket i stated above?

is the 12.98 the comp ratio with my curretn gaskets and the piston top ring volume?

i talked to propane guy(cary) and he said hes heard of 12.5 or so successfully but couldnt remeber if he has ever heard of 13:1 being done? lunati cams tech guy said go for it???


are there any other dangers of running 13:1 on a trail motor??



i hear ya cutts, you know me i cant leave shit alone...

That was with a .040" head gasket thickness. If people get away with 12.5 and youve got a "big" cam, id say it will be ok.

im not too much of an engine guru...im leaning towards the "thick" head gasket just to be on the safe side and have 12.39
i still dont know whats what when it comes to the dynamic comp ratio and ive done alot of reading on it....i guess it comes down to me running propane

run it and see if it detonates
if it doesnt I am building mine to that compression
if it does try the head gaskets

god damnit being the test mule sucks....anyone else have any input?

I would run the thick head gasket personally... Whats your dynamic ratio or what is it that you dont know... Is the thick one .052"? Why are you against running them?

dynamic with thick gaskets is 10.32 with current gaskets its 10.952

i just want as much power as possible, thats why im debating the comp ratio...but theres not much info to be found on what you can do on a propane powered motor, its all wishy washy

i think im going to swap out gaskets at summit tomorrow and go witht he thick ones to give me a static of 12.39 and dynamic of 10.32 (thats without using that top ring calc you spoke of)

dynamic with thick gaskets is 10.32 with current gaskets its 10.952

i just want as much power as possible, thats why im debating the comp ratio...but theres not much info to be found on what you can do on a propane powered motor, its all wishy washy

i think im going to swap out gaskets at summit tomorrow and go witht he thick ones to give me a static of 12.39 and dynamic of 10.32 (thats without using that top ring calc you spoke of) Without calculating that volume, your not getting an effective compression ratio. After all it is part of the combustion chamber. www.diamondracing.net is that calc I am using.

Chris I say bigger gasket! But that's just me.


Shut up and fininsh that shit and lets see some pics!

10-4, im headed to summit to swap gaskets

i saw a jeep with an sbc and he said it was running 13.4:1 with everything in pairs on the pane system.

ur silly to not run dual

dont run a thicker gasket, you will lose quench and will probably have worse detonation issues than if you didnt. how is your deck right now?? zero?? out of the hole?? you are better off changing the cam or just pulling a little timing. personally i think you will be fine at 13:1 if the propane is actually 105 octane, im running over 11:1 on 91 pump gas in my 521 with .040 quench and flat tops, A-460 head and 34 degrees of timing, no detonation. Also, keep it cool and that will go along way as far as detonation goes. this isnt a fucking chevy with big shitty chambers that dont burn worth a shit and ping like a bastard.

can someone explain the basics of quench to me? ive done alot of reading about it but ive never been able to quite grasp it

When you say how is my deck...do you mean how is the piston in relation to the deck of the block??

if so its a little out of the hole...i havent measured anything...the flat part of the piston is .025 below the deck and the dome is .4" i think??

keeping my junk cool has never been a problem, i run a large horsepower robbing mechanical fan with clutch and fan shroud....never had a problem

thats part of the deal, some people say propane has 100, some people say 104, some say more, i havent been able to find a clear answer on the "octane" rating

can someone explain the basics of quench to me? ive done alot of reading about it but ive never been able to quite grasp it

When you say how is my deck...do you mean how is the piston in relation to the deck of the block??

if so its a little out of the hole...i havent measured anything...the flat part of the piston is .025 below the deck and the dome is .4" i think??

keeping my junk cool has never been a problem, i run a large horsepower robbing mechanical fan with clutch and fan shroud....never had a problem

thats part of the deal, some people say propane has 100, some people say 104, some say more, i havent been able to find a clear answer on the "octane" rating
Squish clearance has to do with creating turbulence and allows for a more complete combustion. Thats what I have read, I would like to know more about it though for those who know... If I had to guess the tighter the squish band, the more spread out the mixture becomes, allowing for a more complete and balanced combustion...I read that in a race engine the closer the squish clearance the better, and at high rpm you want it as close as possible. You have to factor in rod stretch and all that though.. crazy

editing in progress***


quench (or squish) is the distance from piston at TDC to head.
it's the perfect size air bubble in your compression chamber. when you squish that air bubble JUSSSST RIGHT it sends a shockwave (think of the *NOISE* of a balloon popping) down the combustion chamber that helps even the temperature of the block. i believe it has to do with resonance (like VRIS in an intake manifold)

BUT!!!

you are getting WAY too involved in engine building specifics for what you are actually considering doing. if you are seriously going to run one OHGX450... then you're not building a frickin race motor. so as long as your compression ratio is north of 10:1 you don't need to concern yourself too much with all that effective ratio stuff.


1:accepted optimal CR for LPG is around 11:1

2: squish, swirl, valve steps, shrouding, wet-flow, and turbulence can pretty much be thrown out the freakin window... you don't need to vaporize your gasoline between the float bowl and the piston. your Pane IS vaporized, and at 11:1 your mixer *tuning* and spark advance will control detonation very well.

3: you should be most concerned with a complete combustion event and opt for dished pistons to facilitate. i STRONGLY suggest having your (hypertectec) pistons, chambers and valves pollished. all those reflective surfaces will bounce that heat right out your exhaust. *side note- polishing all these things averages a 6% increase in HP.

4: 160* thermostat at the highest... make sure you have a glycol%, radiator, and enough CFM from your fan(s). some things (besides all the polishing) to help keep your temp down : eliminate EGR. use an aluminum intake like performer RPM that has eliminated the heat cross-over.




here's some clear answers for your pane questions...

the effective octane rating of LPG is 103 and you will get similar *performance* using LPG vs. gasoline
BUT it has a lower energy content (Propane contains about 84,000 Btu/gallon and regular gasoline averages 114,000 Btu/gallon)
so your *mpg* will drop, depending on load. at optimal load you will lose .08% MPG... but, once you put that pedal down to pass a blue-hair, or climb an obstacle, your MPG is going to drop much faster than .08%

if you're running forklift tanks, you are choosing between 10 and 16 gallon tanks. you're not getting very far with that. those tanks cost you between 100-200$ each.... how many do you want to buy and carry around?

but i keep coming back to the initial remark i made...
why on earth would you run ONE X-450 on a 472 when most% of people aren't happy with ONE X-450 on a 350 with decent HP #s!?!?!?

the ohgx450 is rated at 435CFM... can you IMAGINE putting a carb like that on a bigblock? granted, cfm means different things for gasoline/lpg...

you need to figure out your engines cfm demand at a given rpm... if it's ever OVER 435, then you are going to SUFERRRRRRRR anywhere faster than that RPM. do that, and i'm sure you'll see why you should go with a dual mixer setup. they will of course be smaller mixers, probably giving you ~300cfm each.

i just want as much power as possible, thats why im debating the comp ratio...but theres not much info to be found on what you can do on a propane powered motor, its all wishy washy

go to a propane forum! why are you asking questions about pane performance on a rockcrawling board?!?! :flipoff2:

go to a propane forum! why are you asking questions about pane performance on a rockcrawling board?!?! :flipoff2:

that was a retarded post! MAYBE bc its going on his rockcrawling truck, dumbass!

thats like complaining someone asked about rockwell axles and then tellin them to go post on a military truck forum :shaking:

-cutts-

ummmm yeah... except there are some good pane forums with gurus that have as much knowledge in building for pane performance as the gurus on pirate4x have in rockcrawling.

i would have given him the same advice if he was strapping the motor to a red-ryder to compete in some backwoods-beer-blitzed-wagon-race.

for basic questions: http://fuelsforum.rasoenterprises.com/viewforum.php?f=5

Really? Guys aren't happy with one x450 on their small block? Who?
I've got a ton of customers running some pretty hot motors on one mixer. 383 strokers, a 350 that runs over 7000rpm all day, big blocks over 500 cubes, etc.. They will make 500hp and short bursts even higher. AK Miller, the one who designed this mixer, used to run one mixer on top of a supercharged 350 until he passed away.

ummmm yeah... except there are some good pane forums with gurus that have as much knowledge in building for pane performance as the gurus on pirate4x have in rockcrawling.

i would have given him the same advice if he was strapping the motor to a red-ryder to compete in some backwoods-beer-blitzed-wagon-race.

for basic questions: http://fuelsforum.rasoenterprises.com/viewforum.php?f=5

I was a member of that forum
very little useful info there
all you have is Franz telling you it cant be done
better info here on P4x4

Lets see some pics of that Glo cover, and 1 mixer should be just fine.......


cant leave that shit alone can ya? if it werent for that we'd be going to riverrock next weekend :smokin:

ahh well, reckon we will make it to june jam... hell maybe by then i will havw my beadlocks, cromo shafts/joints, slugs, and GLO diff cover all installed!!!



hey... a man can dream :flipoff2:

-cutts-

Really? Guys aren't happy with one x450 on their small block? Who?
I've got a ton of customers running some pretty hot motors on one mixer. 383 strokers, a 350 that runs over 7000rpm all day, big blocks over 500 cubes, etc.. They will make 500hp and short bursts even higher. AK Miller, the one who designed this mixer, used to run one mixer on top of a supercharged 350 until he passed away.

just stating what i've heard from guys running 400+hp smallblocks. most of them aren't happy.

and supercharging or turboing totally changes the ballgame when you are talking about mixers...

i respect your company and what you are trying to do... but it's a simple question of cfm that a 472 is going to demand. without calculating for his specifin engine, i'd speculate it's going to fade HARD around 3500-3750RPM

that's only based on #s i recall for a 400ci needing the maximum cfm of an X450 at just 4000rpm

I guess my point was it can flow enough air to do it. It was a draw through setup. (carb on top of blower).

I would be shocked if you can get 350hp out of 435 cfm. look at the circle track guyswith their 500cfm holley 2bbl (more like 375 cfm because they are rated at more pressure than a 4bbl) they are elated to get 375 out of their small block chebby at 7000rpm, and they put one hell of alot more effort into tuning than i wager you/me/we are willing to. short bursts over 500hp?? why would a short burst take any less air??? if we were talking fuel starvation issues in a gas burner and the float bowls making it up for a second, then maybe, but propane doesnt work that way. if you want to learn, heres some guys to talk to, same rules apply search first. www.460ford.com. if they cant tell you, no-one can, the knowledge base there is incredible.

a huffer would pull a lot of air through the mixer but you would still see a vacuum reading under the mixer I bet

ive learned alot from a guy named darren on fte....also 460ford.com and i did some reading on reincarnation automotive as well

heres my plan....im polishing the chambers and ports...running the thick gaskets fresh plugs with about .030" gap and im going to run the motor and see how i like it...also definitly swapping to a 160 t-stat...i have a big stock power robbing mechanical clutch fan and shroud on there, so keeping cool shouldnt be a problem, as it never has been

if i end up thinking i could use another mixer....i will but another intake and put another mixer on it.....

i dont see what the big damn deal is wanting to get all of you can out of what you have in a motor....i think of it as a challenge and i thought this would be a good place to ask about pane because alot of people on this board run it...ive searched and searched on google and havent come up with any good info.


i appreciate everyones input!!

oh yea, i already have a performer rpm intake, l&l chassis exit headers roller rockers with chromo pushrods 2.19 1.76 SS valves, hardened seats and bowl blending with exhaust porting. This was all done on the last build....im just trying to milk all the power i can out of this motor while on propane and one carb and see if one carb satisfies my needs...if i end up needing two...so be it

for those telling me to go with dual mixers... how would you suggest going about this??

after doing some searching, the only dual carb intakes i can find for the 460 are high rpm tunnel ram designs...

are there any adapters that adapt two square bore carbs to one????

Blue Thunder makes a nice looking low rise dual quad for the 460, the downside is they go for around $500.00 if I remember correctly.

anyone see any dangers of running aluminum heads on this motor???

anyone see any dangers of running aluminum heads on this motor???
You can get away with a higher C/R on gas with aluminum :D

Do you plan on re-curving your distributor for propane? I dont know what exactly is involved as far as the advance curve, but it would be a good idea to find out before you run the motor on the trail.

Did you post this question on 460ford.com? Those guys do know their shit, i've lurked there for many moons.

IF you dont want to spend money on a duel 4 intake you could
look at a technocarb , big one they say it can flow 700 CFM .
Not many supplyers , Propane Guy mite have some .

IF you dont want to spend money on a duel 4 intake you could
look at a technocarb , big one they say it can flow 700 CFM .
Not many supplyers , Propane Guy mite have some .

will that thing run without the computer box?

i got to porting/polishing my stock dove-a's and i dont have time for it....my time is worth more than my $$

i hate to post this up on 460ford.com....but i guess i need to, it just seems like a nebie ass question for that place

i dont want the technocarb....too damn complicated


my dizzy has some lighter than stock springs from my last build...i will play with it like i did with the last build and get all i can out of it

it was my understanding that it didnt box to run a technocarb
just ran better , just like MSD box for the OHG

went with edelbrock heads after some research

http://i203.photobucket.com/albums/aa294/kubotaorange76/Cam%20swap%202007/P5150045.jpg
http://i203.photobucket.com/albums/aa294/kubotaorange76/Cam%20swap%202007/P5150046.jpg
http://i203.photobucket.com/albums/aa294/kubotaorange76/Cam%20swap%202007/P5060038.jpg
http://i203.photobucket.com/albums/aa294/kubotaorange76/IMG_3104.jpg

So what intake are you running? I am building a 472 for propane also, I am considering the Weiand Stealth and a 700 cfm Technocarb. I would like to see what you end up using and how well it works.

i am runner a performer rpm intake, because thats what i had before....for some reason i got a wild hair and went and bought the rpm heads at summit...heck originallly i was just going to slap this propane kit on the motor like it was, then i tore it down to raise the compression, then i decdied to change the cam, then the heads. haha

the 450 ohg mixer flows 550-575 cfm, and dd says my combo with 12.1:1 compression and these heads will make 444hp@5000 rpm, 555 ft lbs @3500

torque is over 540 ft lbs from 2k-4k...im anxious to get this thing together and see what kind of drivetrain parts i will break

i also was the superintendant at a high end car performance place so i can get a couple chassis dyno pulls for free...so i may do that and see how she does with the 44's and stock tires

Keep us posted as this is well needed info. Try it with one mixer and see how it is. I'm pretty hopeful that it will be just fine:beer::beer:

i definitly will cary...i noticed when i raise the cfm up to 8-900 cfm the horsepower only increases about 20 at the peak, leass the lower you go...same with the torque

Damn dude I just seen this post, you need to send some of your $$$ to me so I can get my junk up an running again!

Can't wait to hear her roar when you get 'er slapped back together! I'll be waiting for a vid of you a cutts tearing shit up!

any progress? I am gonna be in the same boat as you soon.

*edit*

found this on ebay:

http://cgi.ebay.com/ebaymotors/Ford-429-460-BT-CJ-SCJ-DUAL-QUAD-INTAKE_W0QQitemZ110160856410QQihZ001QQcategoryZ460 98QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

in case you decide you want dual mixers.

i'm doing this http://store.summitracing.com/partdetail.asp?part=WND%2D1993&autoview=sku with 2 impco 425 and model e vaporizor with electric cutoffs and have one on a switch so i don't burn so much pane.

switching one off isnt going to save any propane but it will make tuning real hard
the motor only draws enough fuel to run.
if it needs 6lbs per hour of fuel it will draw that much from what ever source it has be it 1 or 2 regs
the switch seems like a waste of time

hmmm... i never thought about it that way, a guy in NC has a cj-5 with an electrical switch that opens a valve. He turns it off when going slow then turns it on when he wants to hit the gas.

i'm doing this http://store.summitracing.com/partdetail.asp?part=WND%2D1993&autoview=sku with 2 impco 425 and model e vaporizor with electric cutoffs and have one on a switch so i don't burn so much pane.

There is a high rise intake on ebay right now...but I dont wanna go through the hood.

Not to hijack, but anybody know what an Impco 425 on a 2 barrell baseplate flows???

just stating what i've heard from guys running 400+hp smallblocks. most of them aren't happy.

and supercharging or turboing totally changes the ballgame when you are talking about mixers...

i respect your company and what you are trying to do... but it's a simple question of cfm that a 472 is going to demand. without calculating for his specifin engine, i'd speculate it's going to fade HARD around 3500-3750RPM

that's only based on #s i recall for a 400ci needing the maximum cfm of an X450 at just 4000rpm


She starts running out of breath around 35-3700 like you predicted!

Dont get me wrong it will still pull 5 grand...but it sort of feels like a governor starting to ease in around 3500 and come in stronger and stronger. I bult a house and sold the rig to bad 80 cj-7 on here...hopefully after he finishes linking / caging I can help set him up with another mixer:smokin:

I have a built 408w in my Bronco and am putting dual 450x carbs on and hoping to get about 7000rpm out of it, we will see. The motor only spins about 4500rpm with the single 450x not so much fun in the sand.