450 LP head again

Blackland Dan · Feb 21, 2010

WOO HOO!! I removed the valve cover and sure enough it's a 364586 head. It looked like 384586, but it had some oil on it so I'm guessing the first 6 looked like an 8. With it now determined which head I have, can anyone tell me what my compression is with an all stock engine?
Some had made comments about having an M manifold. Would the original manifold give me better performance? I just want to pull it in farm stock but I want to keep the tractor all original. Y'all have been a great help to me, as usual. Thanks again. Dan

sflem849 · Feb 21, 2010

Yes, the manifold will give you better performance on a gas engine. I think they use it on an LP engine so you don't blow up. Maybe it just has to do with keeping the fuel cooler so it doesn't vaporize in the pipe. I am sure somebody will chime in.

Wardner · Feb 21, 2010

These are Nebraska test results.

450D 48.78 hp
450LP 54.12 hp
450G 55.28 hp

As for using the proper manifold, one would have to say it should improve performance. But will it be cost effective? IH thought so as they came out with special LP manifold before producing the LP head. I guess they figured "more bang for the buck".

sflem849 · Feb 21, 2010

(quoted from post at 12:17:02 02/21/10) These are Nebraska test results.

450D 48.78 hp
450LP 54.12 hp
450G 55.28 hp

As for using the proper manifold, one would have to say it should improve performance. But will it be cost effective? IH thought so as they came out with special LP manifold before producing the LP head. I guess they figured "more bang for the buck".

No bang from predetonation in the manifold?

Blackland Dan · Feb 21, 2010

Thanks, guys. I'm thinking that predetonation wasn't a real problem because the previous owner ran it like this for the last 20 years. I think Wardner's statement about being cost effective is my deciding factor. I'll just stick with what I have.
Does anyone know what the compression ratio is?

Thanks again. Dan

randy hall · Feb 21, 2010

as taken from the blue ribbon serviceman's handbook a gasoline 450 has 138 lbs. compression at cranking speed, a distillate engine 89 lbs., c-281 with firecrater pistons 135lbs. and your 450 lp has 186 lbs. compression. every series ih improved the manifolds. m, super m, 400, and 450 all used different manifolds on the gas tractors.horse power at rated speed on the pto is 52.1 for the gas and propane models, 37.4 for the distillate and 47.4 for the diesel model 450.

sflem849 · Feb 21, 2010

(quoted from post at 16:28:51 02/21/10) Thanks, guys. I'm thinking that predetonation wasn't a real problem because the previous owner ran it like this for the last 20 years. I think Wardner's statement about being cost effective is my deciding factor. I'll just stick with what I have.
Does anyone know what the compression ratio is?

Thanks again. Dan

Something scares me about running propand through a red hot manifold. What did the PO use the tractor for? Not many are used for plowing hard like they used to. Not too many other uses out there to work them long and hard like that.

randy hall · Feb 21, 2010

what makes you think that the propane vapor mixture would be more explosive than the gasoline air mixture.

sflem849 · Feb 22, 2010

(quoted from post at 20:28:50 02/21/10) what makes you think that the propane vapor mixture would be more explosive than the gasoline air mixture.

It has a greater Stoichiometric ratio and a lower ignition point.

D Slater · Feb 22, 2010

Dan they did use the manifold you have on the 450 now on SM LP tractors below serial # 25931 under part # 357049 R91. That part # was just a 8035 DD manifold with a tee fitting already installed. Above that serial # they changed to manifold 358308 R1 or R11 with tee, the same manifold that would be original to a 450.
If you run across a used 358308 check for cracks. Common place is toward engine below the outlet pipe.
Reason IH give for the manifold type change was for more satisfactory performance in high temperatures.

Blackland Dan · Feb 22, 2010

sflem, you threw some stuff out there that got me to scrambling to see what they mean. I already understand flash point but the stoichiometric ratios got me going. You're right about the lower flash point of propane vs gasoline, -45 for gasoline and -156 for propane. However, the stoich values are 14.7 for gasoline and 15.7 for propane. I don't know if that 1 % is substantial or not. Thank you for the lesson. I always learn neat stuff on here. Dan

sflem849 · Feb 22, 2010

(quoted from post at 16:06:33 02/22/10) sflem, you threw some stuff out there that got me to scrambling to see what they mean. I already understand flash point but the stoichiometric ratios got me going. You're right about the lower flash point of propane vs gasoline, -45 for gasoline and -156 for propane. However, the stoich values are 14.7 for gasoline and 15.7 for propane. I don't know if that 1 % is substantial or not. Thank you for the lesson. I always learn neat stuff on here. Dan

I learned it in Haz Mat Tech training for the FD. Basically Stoich Ratio amounts to how soon and how often you will blow up. Probably doesn't even apply to this bc you are playing with all of it in the carb to make it work perfectly. We used it with LEL (Lower Explosive Limits) to determine if we could go in.

Blackland Dan · Feb 22, 2010

I'm a 20 year retiree of the El Paso Fire Dept. and I know about LELs and UELs and that stuff. But, even though I understand the stoiochiometric
ratio, I never knew what it was called. crazy, huh?

450 LP head again

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