So after running out of OS piston's for the HS40's I had started searching some old resources hoping I could at least come up with a spare 1 or 2 for customer rebuilds. Well I ended up finding quite a few again! The blocks I have on hand are all either new tear downs or low run time with where they all pull very low numbers for piston ring gaps and measure straight down the bores. So I was thinking I'll just pick up some used blocks off ebay and bore them. ANy other time I've been forced to buy a replacment block off ebay It was usually whipped, So I bought three blocks in past couple of months one bare, and 2 short blocks.
Well, the bare block and one of the short blocks I had inspected, and much to my surprise both were tight, smooth and clean bores Talking like .014-.015" on a set of rings Ones so nice it does not even have .0005 of variation in the center typical wear area of the bore. What the hell, where were all these blocks a couple of years ago!!!!! I have not torn into the third short block I bought, it still has a head on it and I just tossed that in the pile for later....maybe I will get to bore that one (probably when I get to it, I wont have a piston available to use )
So I knocked out some prep work on both I have torn down......basic rebuild stuff that needs addressed in all engines. One I did have to go oversize on the intake valve, that sucks only because those valves are pretty pricey on their own, guide was only showing .001 over ( a "+1" pilot fit tight midpoint) but for some reason even with another valve I felt worse than that and the valve itself had damage from the keeper making me thing something was not centered well and all that could be corrected when going oversize. I would have liked to have seen the tappet, but that one was purchased a bare block with just the valves in it, the cam bore and tappet bores all look good so I am not sure what was happening.
Ate up intake valve on engine 2
OG valves on engine 1 (right) and exhaust on engine 2 Refaced nicely, Engine 1 got a 4 angle recut to the seat last week, engine 2 is ready to get the deck surfaced trued to get rid of the "good enough" job that Tecumseh did on these as well as the always present low spot around the exhaust.
I got to cut something at least! Taking the Intake guide to OS:
With the Guide cut its time for a valve job, Technically they all need a true valve job.......just measure the seats and compare to the measurements in the book.....or not, ignorance is bliss A seat recut has to be preformed with any guide work anyway to make sure everything centers out. tecumseh does reccomend a 3 angle recut to be done. I was pretty happy with this one, and achieved the .035 seat width That is recommended in the book for this particular engine size. Exhaust is next, that should be .045......
Test spin with marker only and I am pretty happy with the results.
I am off to work now, More on these later,.....
Well, the bare block and one of the short blocks I had inspected, and much to my surprise both were tight, smooth and clean bores Talking like .014-.015" on a set of rings Ones so nice it does not even have .0005 of variation in the center typical wear area of the bore. What the hell, where were all these blocks a couple of years ago!!!!! I have not torn into the third short block I bought, it still has a head on it and I just tossed that in the pile for later....maybe I will get to bore that one (probably when I get to it, I wont have a piston available to use )
So I knocked out some prep work on both I have torn down......basic rebuild stuff that needs addressed in all engines. One I did have to go oversize on the intake valve, that sucks only because those valves are pretty pricey on their own, guide was only showing .001 over ( a "+1" pilot fit tight midpoint) but for some reason even with another valve I felt worse than that and the valve itself had damage from the keeper making me thing something was not centered well and all that could be corrected when going oversize. I would have liked to have seen the tappet, but that one was purchased a bare block with just the valves in it, the cam bore and tappet bores all look good so I am not sure what was happening.
Ate up intake valve on engine 2
OG valves on engine 1 (right) and exhaust on engine 2 Refaced nicely, Engine 1 got a 4 angle recut to the seat last week, engine 2 is ready to get the deck surfaced trued to get rid of the "good enough" job that Tecumseh did on these as well as the always present low spot around the exhaust.
I got to cut something at least! Taking the Intake guide to OS:
With the Guide cut its time for a valve job, Technically they all need a true valve job.......just measure the seats and compare to the measurements in the book.....or not, ignorance is bliss A seat recut has to be preformed with any guide work anyway to make sure everything centers out. tecumseh does reccomend a 3 angle recut to be done. I was pretty happy with this one, and achieved the .035 seat width That is recommended in the book for this particular engine size. Exhaust is next, that should be .045......
Test spin with marker only and I am pretty happy with the results.
I am off to work now, More on these later,.....