10 or 12 inch is way too big. Bummer. No big deal I appreciate you taking the time to look. Thank you!!
Air compressor engine
- Thread starter stevehuckss396
- Start date
Help Support Home Model Engine Machinist Forum:
canadianhorsepower
Well-Known Member
- Joined
- Oct 22, 2011
- Messages
- 1,671
- Reaction score
- 324
Steve,
can you post a little bit more about the specs that would work
it's a shame not to see such a beautiful project sitting on the shelf
and there is enough person around this group finding the right thing
shouldn't be a problem:hDe:
cheers
The flywheel isnt the only hold up. I have to make a camshaft to reverse rotation on the engine if Im going to mount the starter inboard. I havent decided what I want to do. I have turned my focus to other things right now so I am not worried about it right now. Itll get finished sooner or later.
General Questions for Steve Huck, and other Forum Members.... sorry for these late questions...
I am going to do my best to be clear in asking for some additional information regarding the design of these fabricated heads which were used to convert the compressor into a gas engine:
Referring to post #15:
WHY was a 20 degree hole drilled into the head,/combustion chamber instead of a perpendicular hole, to locate the spark plug? Do spark plugs perform better when this hole is drilled at an angle? Would have a straight up spark plug worked just as well?
How much of a spark plug's electrode should protrude into the combustion chamber? What commercially available spark plug(s) would be a good choice for this application?
**********************************************************************************************************
Referring to post #40:
Is there a rule of thumb that will help in determining how long a rocker arm should be....and where the pivot should be located? The pivot point will affect valve lift, breathing, etc. Did I read that lift should be 1/4 of the valve diameter? HELP!
When a rocker arm uses a roller, should the roller be hardened...be left at the same hardness as the valve stem...be softer than the valve stem? My gut tells me that replacing a worn out roller, would be far easier than replacing a valve because the stem tip got chewed up.
****************************************************************************************************************
Referring to post # 46:
Lifter Guide Bushings....what's the best material for these bushings? Bearing Bronze....Oilite...Brass?
How strong/stiff should the valve springs be? I have no clue how you guys figure the spring specs.
******************************************************************************************************************
Apologies for the amateur-ish questions. It's best to go to experts for advice, than to search endlessly, and still be left with doubts. I could have sent a private message to Steve, but your collective answers, and opinions might help some other would-be engine makers.
I want to do my best in trying to fabricate, from bar-stock and weldments, a large, one-cylinder, (approx. 4,00" X 5.00" B/S) air-cooled, engine, using this "Huck Head" design. I like this particular head because it seems to be fairly simple to make by using Aluminum plate, and parts made from some cheapo bar-stock....no castings!...that's the best part. My skills are basic level, but I'll have guidance and help, when I get into trouble.
So....I'll need an to make an air-cooled cylinder/head combo...a built-up crankshaft, a crank-case with some bearings, get/make a carb. and find a very simple ignition system. I'm not too worried about the piston/rings/con-rod, or, crank-case... (I'll use either bar-stock for the piston, or use a commercially available piston/rings and use welded construction for the con-rod and crank-case). The carb...I have no clue what I need, or, what I will use....ditto...ignition system. I also have no idea what I'm in for with this engine-build, but I'm gonna give it a good try. Even a total failure can be fun...I think. I was inspired to make a large engine from following this Compressor-to-Gas Engine morph, and also by following the vintage, 1906 engine/motorcycle, and Vintage V-Twin engine builds on the MadModder Forum. It can be done.
Suggestions, please, and many thanks for any help.
Frank
I am going to do my best to be clear in asking for some additional information regarding the design of these fabricated heads which were used to convert the compressor into a gas engine:
Referring to post #15:
WHY was a 20 degree hole drilled into the head,/combustion chamber instead of a perpendicular hole, to locate the spark plug? Do spark plugs perform better when this hole is drilled at an angle? Would have a straight up spark plug worked just as well?
How much of a spark plug's electrode should protrude into the combustion chamber? What commercially available spark plug(s) would be a good choice for this application?
**********************************************************************************************************
Referring to post #40:
Is there a rule of thumb that will help in determining how long a rocker arm should be....and where the pivot should be located? The pivot point will affect valve lift, breathing, etc. Did I read that lift should be 1/4 of the valve diameter? HELP!
When a rocker arm uses a roller, should the roller be hardened...be left at the same hardness as the valve stem...be softer than the valve stem? My gut tells me that replacing a worn out roller, would be far easier than replacing a valve because the stem tip got chewed up.
****************************************************************************************************************
Referring to post # 46:
Lifter Guide Bushings....what's the best material for these bushings? Bearing Bronze....Oilite...Brass?
How strong/stiff should the valve springs be? I have no clue how you guys figure the spring specs.
******************************************************************************************************************
Apologies for the amateur-ish questions. It's best to go to experts for advice, than to search endlessly, and still be left with doubts. I could have sent a private message to Steve, but your collective answers, and opinions might help some other would-be engine makers.
I want to do my best in trying to fabricate, from bar-stock and weldments, a large, one-cylinder, (approx. 4,00" X 5.00" B/S) air-cooled, engine, using this "Huck Head" design. I like this particular head because it seems to be fairly simple to make by using Aluminum plate, and parts made from some cheapo bar-stock....no castings!...that's the best part. My skills are basic level, but I'll have guidance and help, when I get into trouble.
So....I'll need an to make an air-cooled cylinder/head combo...a built-up crankshaft, a crank-case with some bearings, get/make a carb. and find a very simple ignition system. I'm not too worried about the piston/rings/con-rod, or, crank-case... (I'll use either bar-stock for the piston, or use a commercially available piston/rings and use welded construction for the con-rod and crank-case). The carb...I have no clue what I need, or, what I will use....ditto...ignition system. I also have no idea what I'm in for with this engine-build, but I'm gonna give it a good try. Even a total failure can be fun...I think. I was inspired to make a large engine from following this Compressor-to-Gas Engine morph, and also by following the vintage, 1906 engine/motorcycle, and Vintage V-Twin engine builds on the MadModder Forum. It can be done.
Suggestions, please, and many thanks for any help.
Frank
The 20 degree angle is there to give greater clearance where the sparkplug wire attaches to the plug. Keeps the wiring away from the rockers.
The sparkplug's electrode doesn't even have to be in the combustion chamber to get a running engine. That being said, it is best to have it in the chamber for performance.
Plug choice is a crap shoot. Trial and error.
Personally I design rockers so the pushrod gives as straight a push as possible. The pivot is up to you depending on the lift you want. If the cam lifts .100 and you want .100 valve lift then you would go dead center. If you want .200 valve lift you would shift in the direction of the pushrod. The more you shift the more stress you put on that side of the valve train. Lifters, pushrods, and that side of the rocker is stressed more. I'm not an engineer so I cant help with the "how much"
Rule of thumb is 1/4 the valve size for lift is good for most engines.
As far as material goes, depending on how much you run it, hardening won't be needed. If you plan on doing actual work with the engine then I would harden both roller and valve. Material for the parts, Not an engineer.
Valve guides I use bronze. Brass would be too soft unless the valves are tiny. My V8 has 1/4 inch valves so I used brass. The compressor has 1.175? so bronze was used. Where the bronze/brass line is would be up to you.
I figured my springs by looking what is used in a similar engine. Briggs/Stratton engines had about the same bore, stroke, valve size, and cam lift as mine so I ended up with a spring that was just a hair stiffer than the stock Briggs spring.
Hope all that helps. These suggestions are just what I do in my garage. Don't think you have to stick to these suggestions. There is no engineering involved, just seat of the pants decisions.
Steve....
Thanks so much for taking the time to answer and explain some of your choices. The devil is always in the small details. I'll have to come close to duplicating what you do in your garage if I ever hope to make a spinning engine. Inspiration is not my problem, I got plenty of that. However, knowledge in respect to engine-building...not so much. But, I'm willing to try.
So...I ask questions, and I am very thankful that you guys are always willing to help, and give me some answers.
Frank
Thanks so much for taking the time to answer and explain some of your choices. The devil is always in the small details. I'll have to come close to duplicating what you do in your garage if I ever hope to make a spinning engine. Inspiration is not my problem, I got plenty of that. However, knowledge in respect to engine-building...not so much. But, I'm willing to try.
So...I ask questions, and I am very thankful that you guys are always willing to help, and give me some answers.
Frank
Questions:
This may be obvious to some, but not to me....
How are the valve guides installed into the head? Are they just pressed in, so they could be removed in the future, for whatever reason? Are the intake and exhaust passages located and drilled first, then are the valve guides installed and drilled for the intake and exhaust passages? Are the intake/exhaust passages the same size in diameter?
Re: Spark plugs in aluminum heads....will they/can they seize? Can thread-seizing in aluminum become a problem?
Thanks,
Frank
This may be obvious to some, but not to me....
How are the valve guides installed into the head? Are they just pressed in, so they could be removed in the future, for whatever reason? Are the intake and exhaust passages located and drilled first, then are the valve guides installed and drilled for the intake and exhaust passages? Are the intake/exhaust passages the same size in diameter?
Re: Spark plugs in aluminum heads....will they/can they seize? Can thread-seizing in aluminum become a problem?
Thanks,
Frank
digiex-chris
Well-Known Member
- Joined
- Dec 6, 2010
- Messages
- 263
- Reaction score
- 58
Very cool. Signing on to watch!
My valve guides are pressed into the head with a little green loc-tite on them. I drill the passages first and then press the valve cage in and then just redrill. It makes no difference what way you do it and it actually makes more sense to press first and then drill but i'm not all that bright.
Any sparkplug in an aluminum head should have a little no-ox grease on it to keep it from seizing and or corroding weather it be a model or the real thing.
Last edited:
Steve,
Do you have enough meat on the flywheel to cut teeth for the ring gear?
Several small mower engines have ring gears built into the flywheels,
or you could cut one out of plate.
With the high cranking resistance, I have to ask: what is the compression
ratio?
FYI, the max safe rim speed of cast sheaves is usually considered to be 6500 fpm.
I am interested in your engine build because I am using the same compressor in my shop. It always looked like engine material to me! A great build, I look forward to seeing it run. Do you have plans to put it on anything?
Thanks,
Tom Bowman
Do you have enough meat on the flywheel to cut teeth for the ring gear?
Several small mower engines have ring gears built into the flywheels,
or you could cut one out of plate.
With the high cranking resistance, I have to ask: what is the compression
ratio?
FYI, the max safe rim speed of cast sheaves is usually considered to be 6500 fpm.
I am interested in your engine build because I am using the same compressor in my shop. It always looked like engine material to me! A great build, I look forward to seeing it run. Do you have plans to put it on anything?
Thanks,
Tom Bowman
There is a spot where it could be done but it being cast I would never use it. Plate would be the safer way to go.
I think it calculated out to almost 9:1
