Slant Six Forum :: Shaving Head--increasing compression

Thanks for the orange box tip, D'idiot. Good to know. It doesn't make much sense to warm up your engine on propane. That's one of its beauties--it's already a gas and as warmed up as it needs to be when it hits the engine.

Joe

The only pros I see with propane is lower (almost non existent) emissions and the reduced amount of money needed to run the car. ?)

Quote:

It is generally accepted that 0.100" off the head is safe and that typically gets you about 11.5:1 compression. Of course that varies from one casting to another. I milled one 0.055" and got a 10.25:1 ratio. Unless you go "Charles Manson" with the "killer" cam, you should have no clearance issues, even with oversized valves. I have a power adder (turbo set-up) listed in the For Sale section right now. Still available. Propane injection is rarely used on gasoline engines. It's a diesel sort of thing.

That is incorrect.
There is no way you removed 0.055" from the head only and got 10.25:1 CR
It is generally accepted that removing 0.100" results in a CR of approximately 10:1 with a steel shim head gasket of 0.019"
I took 0.100" off the head in my car and there is now way I am over 10:1. I can still run 87 octane with an initial advance of 10*

Quote:

The only pros I see with propane is lower (almost non existent) emissions and the reduced amount of money needed to run the car. ?)

In my area, there is no reduction in the cost of fuel. Propane is just about the same price per gallon as 87 unleaded. Then when you figure the lower MPG of propane, there is no savings.

Quote:

The only pros I see with propane is lower (almost non existent) emissions and the reduced amount of money needed to run the car. ?)

In my area, there is no reduction in the cost of fuel. Propane is just about the same price per gallon as 87 unleaded. Then when you figure the lower MPG of propane, there is no savings.

here our LPG prices are at .56 a litre where as our cheapest petrol is at the moment $1.15 a litre. Most ppl get sucked into the whole *LPG gives you better mileage* routine. No it doesn't. Your pumping in twice as much LPG to get the same amount of mileage but it's the cheap cost that leads ppl to believe it's better. I have my LPG licence and work on these vehicles quite regularly(yes even in a Ford dealership, Ford out here produce just straight gas vehicles). Yeah it's ok if you know what your doing with gas but if you don't it can get nasty. And yes i too advise all family and friends to avoid putting LPg kitson their cars.
It really hates cylinder heads/valves.

Quote:

In my area, there is no reduction in the cost of fuel. Propane is just about the same price per gallon as 87 unleaded. Then when you figure the lower MPG of propane, there is no savings.

ditto.

BTW I see you also call gas to the propane and fuel to what guys here call gas... what a mess!

Quote:

ditto.

BTW I see you also call gas to the propane and fuel to what guys here call gas... what a mess!

indeed....aswell as what they call *vaporizers* we call them convertors
here. Propane is LPG here. Might i add another bad point about LPG. It's a really dirty fuel. I mean when you look at it the convertor really is just a carby. These things fill up with such contamination from the fuel it creats a lot of problems inside the convertor. Well maybe it might just be the LPG we have here?

Author:	Charrlie_S [ Sun Jan 14, 2007 12:37 pm ]
Post subject:
Quote: Thanks for the orange box tip, D'idiot. Good to know. It doesn't make much sense to warm up your engine on propane. That's one of its beauties--it's already a gas and as warmed up as it needs to be when it hits the engine. Joe MSD used to have a propane/dual fuel ign box. I don't know if it is still available. Check their website. Propane sucks on a cold engine in a cold climate. The propane comes from the tank as a liquid, and must be heated in the "vaporizer" before being transfered to the "mixer". The vaporizer is heated by engine coolant. If the coolant and therefor the vaporizer are not warm enough, the propane will not turn into a gas and the engine will die, when you open the throttle.

Author:	argentina-slantsixer [ Sun Jan 14, 2007 2:39 pm ]
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propane conversions are a everyday thing on every car down here due to gas prices. Performance on propane engines sucks, even the mills preapred to run on propane. The only pros I see with propane is lower (almost non existent) emissions and the reduced amount of money needed to run the car. Or are we talking mixed fuels here (gas-propane?)

Author:	Charrlie_S [ Sun Jan 14, 2007 4:19 pm ]
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Quote: The only pros I see with propane is lower (almost non existent) emissions and the reduced amount of money needed to run the car. ?) In my area, there is no reduction in the cost of fuel. Propane is just about the same price per gallon as 87 unleaded. Then when you figure the lower MPG of propane, there is no savings.

Author:	argentina-slantsixer [ Sun Jan 14, 2007 4:46 pm ]
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that's mainly my point, plus the engine suffers a lot when used with propane (higher temp operating range, "dry" combustion, etc) down here is a lot cheaper: premium 98 octane gas (93 octane in american octane rating) is $2 per liter, propane is $.90 per square meter (about the same amount of fuel, when converted). Used to be even cheaper.

Author:	mpgmike [ Sun Jan 14, 2007 6:22 pm ]
Post subject:
Quote: Quote: It is generally accepted that 0.100" off the head is safe and that typically gets you about 11.5:1 compression. Of course that varies from one casting to another. I milled one 0.055" and got a 10.25:1 ratio. Unless you go "Charles Manson" with the "killer" cam, you should have no clearance issues, even with oversized valves. I have a power adder (turbo set-up) listed in the For Sale section right now. Still available. Propane injection is rarely used on gasoline engines. It's a diesel sort of thing. That is incorrect. There is no way you removed 0.055" from the head only and got 10.25:1 CR It is generally accepted that removing 0.100" results in a CR of approximately 10:1 with a steel shim head gasket of 0.019" I took 0.100" off the head in my car and there is now way I am over 10:1. I can still run 87 octane with an initial advance of 10* I'm sorry, you're right. I went back and looked at some old notes and it was 9.25:1. Please forgive me. Sometimes I don't get enough sleep. Mike

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Shaving Head--increasing compression https://slantsix.org/forum/viewtopic.php?t=21408	Page 2 of 3

Author:	70valiant [ Sun Jan 14, 2007 7:56 pm ]
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Forget about it we all make mistakes.

Author:	benevolance [ Mon Jan 15, 2007 12:14 am ]
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It is no co-incidence that propane is the same cost as gasoline... 5 years ago it was half the price... It is also no small co-incidence that the proce of diesel is more than gasoline.... the government and detroit know how to get the max tax dollar out of us... They want to keep us driving gasoline vehicles...and inflating the cost of propane and diesel prevents a lot of people from exploring other fuels...Which prevents consumers from buying new cars that burn other fuels....Keeps the cycle going... Think about it...If we consumed less fuel overall...There would be less revenue collected from fuel taxes.... For this reason the government would always push for the use of dirty expensive and inefficient gasoline over everything else.

Author:	aussie_mopar [ Mon Jan 15, 2007 3:18 am ]
Post subject:
Quote: Quote: The only pros I see with propane is lower (almost non existent) emissions and the reduced amount of money needed to run the car. ?) In my area, there is no reduction in the cost of fuel. Propane is just about the same price per gallon as 87 unleaded. Then when you figure the lower MPG of propane, there is no savings. here our LPG prices are at .56 a litre where as our cheapest petrol is at the moment $1.15 a litre. Most ppl get sucked into the whole LPG gives you better mileage routine. No it doesn't. Your pumping in twice as much LPG to get the same amount of mileage but it's the cheap cost that leads ppl to believe it's better. I have my LPG licence and work on these vehicles quite regularly(yes even in a Ford dealership, Ford out here produce just straight gas vehicles). Yeah it's ok if you know what your doing with gas but if you don't it can get nasty. And yes i too advise all family and friends to avoid putting LPg kitson their cars. It really hates cylinder heads/valves.

Author:	argentina-slantsixer [ Mon Jan 15, 2007 3:30 am ]
Post subject:
Quote: Quote: Quote: The only pros I see with propane is lower (almost non existent) emissions and the reduced amount of money needed to run the car. ?) In my area, there is no reduction in the cost of fuel. Propane is just about the same price per gallon as 87 unleaded. Then when you figure the lower MPG of propane, there is no savings. here our LPG prices are at .56 a litre where as our cheapest petrol is at the moment $1.15 a litre. Most ppl get sucked into the whole LPG gives you better mileage routine. No it doesn't. Your pumping in twice as much LPG to get the same amount of mileage but it's the cheap cost that leads ppl to believe it's better. I have my LPG licence and work on these vehicles quite regularly(yes even in a Ford dealership, Ford out here produce just straight gas vehicles). Yeah it's ok if you know what your doing with gas but if you don't it can get nasty. And yes i too advise all family and friends to avoid putting LPg kitson their cars. It really hates cylinder heads/valves. ditto. BTW I see you also call gas to the propane and fuel to what guys here call gas... what a mess!

Author:	aussie_mopar [ Mon Jan 15, 2007 4:41 am ]
Post subject:
Quote: Quote: Quote: In my area, there is no reduction in the cost of fuel. Propane is just about the same price per gallon as 87 unleaded. Then when you figure the lower MPG of propane, there is no savings. here our LPG prices are at .56 a litre where as our cheapest petrol is at the moment $1.15 a litre. Most ppl get sucked into the whole LPG gives you better mileage routine. No it doesn't. Your pumping in twice as much LPG to get the same amount of mileage but it's the cheap cost that leads ppl to believe it's better. I have my LPG licence and work on these vehicles quite regularly(yes even in a Ford dealership, Ford out here produce just straight gas vehicles). Yeah it's ok if you know what your doing with gas but if you don't it can get nasty. And yes i too advise all family and friends to avoid putting LPg kitson their cars. It really hates cylinder heads/valves. ditto. BTW I see you also call gas to the propane and fuel to what guys here call gas... what a mess! indeed....aswell as what they call vaporizers we call them convertors here. Propane is LPG here. Might i add another bad point about LPG. It's a really dirty fuel. I mean when you look at it the convertor really is just a carby. These things fill up with such contamination from the fuel it creats a lot of problems inside the convertor. Well maybe it might just be the LPG we have here?

Author:	dakight [ Mon Jan 15, 2007 4:48 pm ]
Post subject:
CNG and LPG are two very different critters. LPG is "Liquified Petroleum Gas" and can be on of a couple of different animals, most commonly propane. But, butane is also an "LPG." Propane and butane are heavier than nutural gas and are more easily converted to a liquid. In addition to CNG there also exist LNG or "liquified Natural Gas" as well as blends of natural gas and hydrogen.

Author:	1969ronnie [ Sat Jan 20, 2007 6:36 am ]
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hi, .100 off my 69 head last month gave me 40 cc chambers. had 59 ccs before milling. also had some block milling to get pistons .070 in the hole and with with .040 gasket i figure on 10 to 10.5-1 comp . ron

Author:	FrankRaso [ Sun Jan 21, 2007 7:25 pm ]
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Author:	Daddiojoe [ Sun Jan 21, 2007 8:25 pm ]
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Frank-- Thanks for a most excellent post. So I take it you've done a conversion yourself? How'd it work out for you? Joe

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