Normal points type Ignition system seems to be all there and nothing hanging out side the block....all is good so far ! :wink:
Thinking about a thread that Markus did on the circular looking spacers under the valve springs ....and thought I would check this one. Sure enough it has one under each spring....doesn't seem to be a valve seal, maybe just a steel spacer to keep the aluminum from ware.
Kinda Impressed with with the valve size on this hs40, Int valve diameter is 1.079 or about 27mm, Exh valve diameter is .974 or about 24.7 mm.
So far ...so good , but here goes the side cover....:scared:
OK ..this is something that I wasn't expecting...what tha !?!? First look at a 1970 HS40 camshaft for me and this is what I see. Massive Int. lobe with a compression release ...
and a very normal looking exh. lobe.
Both lobes are cut on different base circles.....so really not much more lift than a regular cam. Sorry I didn't measure the lift....so it is what it is.
Heres the lifters, and not surprising that one is a whole lot shorter than the other one.
Int. lifter ( short one ) measures 1.321
Exh. lifter (longer one) measures 1.477
Not spots...just a paint marker...to help forget fullness ..:laugh:
Cylinder measures 2.623 at the top...piston measures 2.620 at the skirt.
Rod journal measures 1.000
Thinking about a thread that Markus did on the circular looking spacers under the valve springs ....and thought I would check this one. Sure enough it has one under each spring....doesn't seem to be a valve seal, maybe just a steel spacer to keep the aluminum from ware.
Kinda Impressed with with the valve size on this hs40, Int valve diameter is 1.079 or about 27mm, Exh valve diameter is .974 or about 24.7 mm.
So far ...so good , but here goes the side cover....:scared:
OK ..this is something that I wasn't expecting...what tha !?!? First look at a 1970 HS40 camshaft for me and this is what I see. Massive Int. lobe with a compression release ...
and a very normal looking exh. lobe.
Both lobes are cut on different base circles.....so really not much more lift than a regular cam. Sorry I didn't measure the lift....so it is what it is.
Heres the lifters, and not surprising that one is a whole lot shorter than the other one.
Int. lifter ( short one ) measures 1.321
Exh. lifter (longer one) measures 1.477
Not spots...just a paint marker...to help forget fullness ..:laugh:
Cylinder measures 2.623 at the top...piston measures 2.620 at the skirt.
Rod journal measures 1.000
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OK ..this is something that I wasn't expecting...what tha !?!? First look at a 1970 HS40 camshaft for me and this is what I see. Massive Int. lobe with a compression release ... and a very normal looking exh. lobe.
Both lobes are cut on different base circles.....so really not much more lift than a regular cam. Sorry I didn't measure the lift....so it is what it is.
Heres the lifters, and not surprising that one is a whole lot shorter than the other one.
Int. lifter ( short one ) measures 1.321
Exh. lifter (longer one) measures 1.477
and a very normal looking exh. lobe.
Both lobes are cut on different base circles.....so really not much more lift than a regular cam. Sorry I didn't measure the lift....so it is what it is.
Heres the lifters, and not surprising that one is a whole lot shorter than the other one.
Int. lifter ( short one ) measures 1.321
Exh. lifter (longer one) measures 1.477
Another thing that they were using on these most of these HS engines up into 1970 was a cam with a mechanical compression release on the intake side (compared here to a typical built into the exhaust lobe version after 1970, note the larger lobe and shorter lifter)
These are nice due to the fact that as soon as its spinning the flyweight pulls the little pin that raises the valve away and you go to full compression, where the built in always bumps the exhaust valve open as it pulls though the cycle. The bad is it seems pretty hokey and looks weak, and they did away with it for some reason, I would guess it was just way cheaper to go the fixed way more than anything.
These are nice due to the fact that as soon as its spinning the flyweight pulls the little pin that raises the valve away and you go to full compression, where the built in always bumps the exhaust valve open as it pulls though the cycle. The bad is it seems pretty hokey and looks weak, and they did away with it for some reason, I would guess it was just way cheaper to go the fixed way more than anything.
I have 3 of those HS40 engines (plus just sold one on a minibike). All run very, very good. I don't see the challenge in this thread. You have a great engine there and should be surprised with the power output of it. Just use some super fine sand paper and run it between the points a few times to clean them up. Set gap at 0.020", turn the coil counter clockwise in its mount to advance the timing and run it !
The cam is fine. Without the compression release, they get hard to pull start. My advice is to leave the cam alone. Set valve lash to spec (you'll have to look it up as I don't remember) not too wide as that reduces lift and duration, and enjoy the ride.
Danford1
The cam is fine. Without the compression release, they get hard to pull start. My advice is to leave the cam alone. Set valve lash to spec (you'll have to look it up as I don't remember) not too wide as that reduces lift and duration, and enjoy the ride.
Danford1
Those cams are the reason that really sketchy looking cut out on the crank is there.....to clear that ginormous lobe :laugh: They resorted back to mechanical over the fixed bump on the very late built engine, but it was a different setup that used equal length lifters. They are composite though and not steel. I want to try one on a stock rebuild soon, That little bit of grunt you gain with the full compression feels pretty good....but that kickback/hard start with the lobe ground off a fixed release cam is no fun.....Its really bad on an HS50!
Thanks Pete, just something this old guy does...ut::laugh:
Got a few parts in for this engine and still waiting on some. Also fabbed up an exhaust system for it. Thanks Markus that exhaust flange fits like a glove !:thumbsup: I bent the pipe on my old JD squared bender ...but couldn't get the bends close enough, but it close enough for me.
ut::laugh:Got a few parts in for this engine and still waiting on some. Also fabbed up an exhaust system for it. Thanks Markus that exhaust flange fits like a glove !:thumbsup: I bent the pipe on my old JD squared bender ...but couldn't get the bends close enough, but it close enough for me.
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