WANTED-TECUMSEH DYNO or ISKY CAM
- Thread starter Havasu Dave
- Start date
Yes, but the grind cost is still significantly more than the $45 Ugly Chicken was charging on Ebay. She's all out of them. Since we've sort of turned this thread into a conversation section, (breaking the rules for classifieds) I'm moving it to the Tecumseh section. Meanwhile, if someone has a 245 cam, I need one. If you are interested in having one ground, Dyno will do them for about three times what they went for on Ebay. Less if there are more wanting one. They need a core, and want the Bump type of HS compression release. So if you want one, and have a core, I'll make a list, and see what we can do. But I'm not going to sit on this for very long, so don't wait.
255 cam is a strong little cam for a 3.5hp motor and it will pull easy 7000+ rpm's in a flathead built right and it will pull hard if you don't watch it. I know only one person that ran a 255 in s 5hp block and that was david wulf. he had a big bore hs-50 with electronic ignition/hot coil ...etc...
great setup if you where looking go really fast. but maybe to much for a 3.5hp? I ran the same cam in my ohh motor on my thunderbolt. work great with a lot of gearing. last year I built a ohh motor for my drag bike and use that same cam with 1.3 rockers and that engine was awesome. pulled 8200rpm's at 125ft. just can't say enough how great that 255 cam can be in the right motor.
i too plan on building a side popper ,but it will have to wait till next fall. i have a newer style block that takes the billet rod. also has the roller bearing cover,steel sleeve. my plains where to just use a stock ohh steel cam with the compression release with a hot coil and maybe modify the cast flywheel little.
something to think about and you may know this from the pass from my postings. i tried to have tim weld up one of my ohh compression release cams and he could not do it. welding was not working good for him on that type of casting.
now ole4 had him weld one years ago and had no problems?
maybe dynocams might have better luck welding a comp-release cam and you can still get the 245 cam profile. just remember you have to weld in the area on the side cover where the cam bearing is. basically enclose it so the mechanical arm does not get damage and take the chance of damaging the whole engine.
depending on what you want to do and type of block you have? you can still go pretty damn fast with a stock steel ohh comp-release cam.
last time I talk to someone at dynocams about making a cam it was way over $100. I believe $150
not trying to rub it into you dave,but I do still have one more 245 cam. just the perfect cam for a hotrod Tecumseh flathead. ever if I had to pay dyno the $150 bucks.
it would be nice if they can weld up a ohh-cam...
great setup if you where looking go really fast. but maybe to much for a 3.5hp? I ran the same cam in my ohh motor on my thunderbolt. work great with a lot of gearing. last year I built a ohh motor for my drag bike and use that same cam with 1.3 rockers and that engine was awesome. pulled 8200rpm's at 125ft. just can't say enough how great that 255 cam can be in the right motor.
i too plan on building a side popper ,but it will have to wait till next fall. i have a newer style block that takes the billet rod. also has the roller bearing cover,steel sleeve. my plains where to just use a stock ohh steel cam with the compression release with a hot coil and maybe modify the cast flywheel little.
something to think about and you may know this from the pass from my postings. i tried to have tim weld up one of my ohh compression release cams and he could not do it. welding was not working good for him on that type of casting.
now ole4 had him weld one years ago and had no problems?
maybe dynocams might have better luck welding a comp-release cam and you can still get the 245 cam profile. just remember you have to weld in the area on the side cover where the cam bearing is. basically enclose it so the mechanical arm does not get damage and take the chance of damaging the whole engine.
depending on what you want to do and type of block you have? you can still go pretty damn fast with a stock steel ohh comp-release cam.
last time I talk to someone at dynocams about making a cam it was way over $100. I believe $150
not trying to rub it into you dave,but I do still have one more 245 cam. just the perfect cam for a hotrod Tecumseh flathead. ever if I had to pay dyno the $150 bucks.
it would be nice if they can weld up a ohh-cam...
just wanted to post little more info on modifying you vintage side cover so you can run a ohh steel compression release cam in it.
here is a vintage cover of the cam bearing area. note the top part is open. this is the area that will need to be welded up and enclosed.
unfortunately i can not find that picture i took after welding it. i basically just enclosed it and remachine it out and drill a small hole on top for the oil to lube the bearing surface.
as you can see in this picture of a ohh cover that area is almost enclosed.
what Tecumseh did was to run a small thrust washer that would run up against that area.
and then a small area on the compression level would ride up against the thrust washer.
if that area was not welded up you could push the washer into that opening and damage some things.
here is a vintage cover of the cam bearing area. note the top part is open. this is the area that will need to be welded up and enclosed.
unfortunately i can not find that picture i took after welding it. i basically just enclosed it and remachine it out and drill a small hole on top for the oil to lube the bearing surface.
as you can see in this picture of a ohh cover that area is almost enclosed.
what Tecumseh did was to run a small thrust washer that would run up against that area.
and then a small area on the compression level would ride up against the thrust washer.
if that area was not welded up you could push the washer into that opening and damage some things.
you will need to also shorten your flathead vintage lifters just little or I believe you might be able to find the newer flathead lifters that the engine came with this cam...?. markus might of found that part number? I personally never look into that. I just machine my lifters to the proper valve clearance. if I am correct the base circle on the ohh cam is about .037 larger? so you really don't want to machine that much off the end of you valve to get the proper clearance. that's just my opinion.
there is little bit of work to make it all happen,but it's not hard to do.
I did help a friend last year with a hs-40 engine and we intstalled the ohh-cam ,modified timing,ported the block,rupp header,adjustable jet19mm dellorto carb,billet rod,16 pound animal springs,factory torque converter. all this went on a black widow bike of his.
this bike was so fast and had no problems spinning 4700 rpm's at 125ft. I was very impressed how well this bike perform with mostly stock parts.
there is little bit of work to make it all happen,but it's not hard to do.
I did help a friend last year with a hs-40 engine and we intstalled the ohh-cam ,modified timing,ported the block,rupp header,adjustable jet19mm dellorto carb,billet rod,16 pound animal springs,factory torque converter. all this went on a black widow bike of his.
this bike was so fast and had no problems spinning 4700 rpm's at 125ft. I was very impressed how well this bike perform with mostly stock parts.
All good info. I am not building a fire breathing monster (or what passes for one in flat-head land) 
but if I could get better performance out of the OHH without the expense of machining a replacement cam, that would be good. What I need to do, is get both of those OHH and HS MCR cams into the block with a degree wheel and set a base from there, and "then" decide where to go with the cam.
One other thing, is that I intend to use another 22mm round slide carb. I see no reason why an H35 can't handle the air, as long as it's flowed- and the (now) intake side for sure has a nice, straight shot at the valve.
Good information on the cam making contact with the sump where the release is at.
but if I could get better performance out of the OHH without the expense of machining a replacement cam, that would be good. What I need to do, is get both of those OHH and HS MCR cams into the block with a degree wheel and set a base from there, and "then" decide where to go with the cam. One other thing, is that I intend to use another 22mm round slide carb. I see no reason why an H35 can't handle the air, as long as it's flowed- and the (now) intake side for sure has a nice, straight shot at the valve.
Good information on the cam making contact with the sump where the release is at.
yes, that 22mm carb should still work good even with a stock cam with all the correct mod's done to it. I would guess it would run good with a jet some where between 110-120. just a ball park figure. my opinon with the intake port now coming into the side and some porting done. it should run good. not real big fan of the old style compression release setup from 1970 with one lobe large and the other small. first thing I would be checking is that large lobe to see if it will hit anything. also how much of it will be worn down. that would effect the lift. most of the use ones you will find will have a lot of run time on them. also I think if they where such a great cam setup back in the day. why is there no one using that setup today in small engines. I like the ohh cams. they work. but there is some mod's that need to be done first.
also wondering how well that cam would perform at higher rpm's with one side lobe being heavier then the other side. would it create a unbalance effect at higher rpm's? would it take more energy to make it spin or I should say are you creating more drag with one lobe being extra large. does it effect extra stress on the lifter bore? bigevilone2 you see tim a lot, ask him what he thinks of that cam design that was short live back in the day or Charles on JMBR Podcast. it would be interesting to see what kind of problems they think could happen with that cam design used in a performance application.
Well, here it is back from Dyno. @delray @ole4 They were concerned with doing this and preserving the holes for the MCR gear. I did not get a timing sheet with it, but I'll run a wheel on it. I asked them to do the same spec. as the OHH 245. It took me far too long to reassemble that MCR! I'd taken several photos before hand though. Close to $200 with shipping. HS 40 .245 lift. Going on an H35. 
