4 cylinder ohv engine plans

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I have found 2 omissions on the plans for my 4 cylinder OHV engine. I am posting a picture of the additions for those who bought a set of drawings. I appologize for any inconvenience this might have caused. I don't have everyones mailing address that purchased these plans so if you contact me I will be more than happy to mail you out the new sheet.
Thanks,
gbritnell
CYLHEADCHANGE-1.jpg


 
Steve, I have your address so I will be sending you out a sheet with the new dimensions on it.
gbritnell
 
I got the copies printed up today so they'll go out in Monday's mail. I have 6 names and addresses so if anyone else reads this forum and bought a set of drawings at NAMES just let me know and I'll send you the drawings with the additions.
gbritnell
 
I wonder if someone can explain. Looking at the crankshaft of a 4 cylinder engine like this one, the same as the normal full size ones, why are there always 2 pistons TDC and the other 2 "BDC"? Wouldn't it be better to "space" them 90º of each other? In this way one could have a power stroke at 90º intervals probably making the engine run more smoothly. At least it's what I think. Maybe it's easier to build them the way they do.
If they are spaced at 90 degrees it's called a 'crossplane' crankshaft. Yamaha use this configuration for their MotoGP 4-cylinder, 4-stroke, across the frame, engines. The sound is pleasant compared to the awful sound of a Harley. Best sounding engine of all times is the 1.5 litre supercharged, V16 BRM, closely followed by the V12 Rolls Royce Merlin.
DickG
 
I wonder if someone can explain. Looking at the crankshaft of a 4 cylinder engine like this one, the same as the normal full size ones, why are there always 2 pistons TDC and the other 2 "BDC"? Wouldn't it be better to "space" them 90º of each other? In this way one could have a power stroke at 90º intervals probably making the engine run more smoothly. At least it's what I think. Maybe it's easier to build them the way they do.
The reason is simple, it is to balance the rotating motion two pistons going up balanced by two going down
 
Yamaha builds one. Here's a video;



Do yourself a favor and turn off the crappy music for the first minute and a half or so.
 
Interesting video, and thanks for the noise warning. Unfortunately I was a bit slow turning it off. Horrible!
 
Hi Meyers,
Yes the plans are still available. Send me a personal email.
gbritnell
 
Ok. I just upgraded my membership today. Not sure how to send you a personal email....
 
I'm interested in a set of plans, but live in the uk. Do you have them in pdf format to save on the postage etc ?
 

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