old school HS bumpstick

[markus]

Looks like the old style regrind "3/4" style cam maybe where they would add material to the valve stems to make up for the grind. I remember a batch of old stock wiseco pistons and some actual HS40/50 billet rods from back in the day etc, years ago there were some valves that were pre welded/extended that came with the batch that were still in stock Tec boxes and just marked with a sharpie like this one is...looks like I will have to break out the 'ol degree wheel and see what whats going on when it comes in!

 

[delray]

wow base circle looks really small and the the lift too. don't see how it's going to to have much performance gains? need to mic it. some of the briggs stuff when it comes to valves have the same ball park dimensions. i wonder if there lifters are longer and grind one down to fit? next time i go up north to my friend house i will take a picture of a machine he has that is design to grind lifters down. you also can make a V-block on your bench grinder to hold the lifter some what square and grind it and then i touch it off on my lathe with a less aggressive flat round stone in my tailstock and the valve is chuck up in the 3 jaw chuck. takes some time but the lifter tip comes out square every time.

 

[ole4]

Measure the minium and max lift with a calipers that will tell you what the lift is and you can see if it is more than a stock cam. Is there a compression bump on the exhaust?

 

[markus]

Measure the minium and max lift with a calipers that will tell you what the lift is and you can see if it is more than a stock cam. Is there a compression bump on the exhaust?

I'll let you know when it comes in, Just saw it offered up and grabbed it early today becuase I knew it was the old style regrind like Rons offered, I went back to see if my pics still existed of the modified valves I had from that buyout and noted they were from Wiseco, but they showed and talked about extending them in some of the Tweak the teke writeups which is how they made up for the reduced lobe circle. this one would have been done Post 1970, with the cam design, I seriously doubt there is a bump for the release left. In some of my old articles the cam they show for rons is the 1968-70 mechanical release but with the release parts knocked of the big lobe cut way down since the article print dates are like from mid 1971 they probably would not have had too many of the new style available at the time for regrind......They (Ron's) had a $3 buy back for core cams back then.

I still have one of those Valves here, which is how it came and you cut to fit. of course wont do me any good, becuase this one is for the H25-35 intake. Someone one here bought the HS Intake I had on here years ago, oh well:

 

[markus]

@ole4 that camshaft showed up today. With calipers I am getting .243 at the intake and .257 at the exhaust-bump is ground off so I could measure with the calipers. I had the camshaft box out and went ahead and measured some other HS camshafts at the same time for reference as well.
I don’t have time right now to setup a degree wheel, I have to get cracking on some small H engines for some people before I can get out some HS blocks.

 

[delray]

I'll let you know when it comes in, Just saw it offered up and grabbed it early today becuase I knew it was the old style regrind like Rons offered, I went back to see if my pics still existed of the modified valves I had from that buyout and noted they were from Wiseco, but they showed and talked about extending them in some of the Tweak the teke writeups which is how they made up for the reduced lobe circle. this one would have been done Post 1970, with the cam design, I seriously doubt there is a bump for the release left. In some of my old articles the cam they show for rons is the 1968-70 mechanical release but with the release parts knocked of the big lobe cut way down since the article print dates are like from mid 1971 they probably would not have had too many of the new style available at the time for regrind......They (Ron's) had a $3 buy back for core cams back then.

I still have one of those Valves here, which is how it came and you cut to fit. of course wont do me any good, becuase this one is for the H25-35 intake. Someone one here bought the HS Intake I had on here years ago, oh well:

View attachment 271830

i wonder if that cam was made by the same person that made a cam for that little H build article on the yellowjacket. they too had done some valve tip mod and reground to make up for a smaller base circle cam?

 

[delray]

Measure the minium and max lift with a calipers that will tell you what the lift is and you can see if it is more than a stock cam. Is there a compression bump on the exhaust?

@ole4 , you think when they ground that cam down possible to change the lobe separate angles or not. i see from what pictures posted of the cam it still has the raw castings on the sides and from his measurements he posted it would be kind of hard to move the center point lobes around alot without welding on the lobes and regrinding the side also. lobes also don't appear to look wide. just tall narrow. would that make that cam a good midrange torque cam. 6000+ range?

 

[ole4]

Depends on how big the original lobe base circle was but even with a large base circle you would be limited to a few degrees. While I have never had one in my hands some of the pics you have posted of cams with one gigantic lobe then you probably could. Isky had degreed my original MCR cam but I cannot find that data. Here are some pics of stock vs Isky and the timing sheet for it.

 

[markus]

I was digging in my boxes of Briggs & scrapiron parts looking for the old heavy duty valve rotator retainers for another project and spotted some 5hp sized lifters which reminded me of this camshaft. Since the way they ground these I needed either longer lifter or longer valves ( even dropping the seat down I am thinking will not give me enough without welding)

the Briggs are longer but too wide of a foot so I wanted to see how cooperative it would be to turn it down....it was pretty easy. This should give me more than enough to work with and just cut down at the top during setup.

Left to right new style LH, standard Small frame H/HS, modified Briggs, standard briggs

Now to find some time to get an HS block out and see if it’s gonna work! And if so I will order some new ones to use. This has been one busy winter down here!!! The Snowbirds are keeping me very busy fixing their toys and cars etc...

 

[massacre]

@ole4 , you think when they ground that cam down possible to change the lobe separate angles or not. i see from what pictures posted of the cam it still has the raw castings on the sides and from his measurements he posted it would be kind of hard to move the center point lobes around alot without welding on the lobes and regrinding the side also. lobes also don't appear to look wide. just tall narrow. would that make that cam a good midrange torque cam. 6000+ range?

The only way to really tell is to use a degree wheel and measure the LSA and duration between the 2.

 

[delray]

nice markus,think some guy mention about briggs lifters earlier post..lol. i wonder how long the small blocks are? might be to short. 5hp looks like they will work good after grinding or machining the stems down. funny how much briggs parts can work in a tecumseh and people say they can't find any performance parts for a tecumseh....
i'm thinking a 20mm dellorto,good header on a old school bike frame for starters .........

 

[markus]

The small block ones are too short, but the foot size would have worked.