OHH60 rod specs

[J.S.@SMS]

Is there anyone out there who knows the rod specs for a Tecumseh OHH60 from around 2006, or if an OHH60 shares the same rod with an OHH50?

I found this rod on arc racing's website
https://www.arcracing.com/6282-arc-billet-rod-tecumseh-5-5-ohv-3-484/
The description says the rod specs are "3.484" center to center with a 1.0023" crank pin bore and a .5637" wrist pin bore"

If anyone knows if this rod will work, please, let me know. I have an OHH60 that's running subpar, and I figured that if I am going to rebuild it, I might as well see about putting some performance in it.

Also, at some point I think that I heard of a slide carb that would just about right bolt on. If anyone knows what carb this is could you let me know.

 

[JTSpeedDemon]

That "slide carb" you are talking about is probably a Mikuni 22mm carburetor.

 

[J.S.@SMS]

Not quite but close. An OHH60s carburetor has a 46mm center to center mounting pattern. A Mikuni 22 has a 48mm

 

[Tpdingo]

That "slide carb" you are talking about is probably a Mikuni 22mm carburetor.

Contrary to popular belief there are more kart parts in the world than what is on GoPowerSports.com. Not many more...but more .

 

[JTSpeedDemon]

Meh, I wasn't saying I know what carb it is, but whatever.
I stand corrected.

 

[65ShelbyClone]

I had always heard that the only difference between OHH50/55/60/65 engines was the carburetor. My suggestion would be to look at the parts lists to see if they have the same part number on the connecting rod.

And Tillotson HL carbs have the same 1.8 inch bolt spread as a Tec.

 

[kevbo22]

I had always heard that the only difference between OHH50/55/60/65 engines was the carburetor. My suggestion would be to look at the parts lists to see if they have the same part number on the connecting rod.

And Tillotson HL carbs have the same 1.8 inch bolt spread as a Tec.

Thats a good call. according to jacksmallengines diagrams and part list the rod for both the ohh50 and ohh60 are the same.

But you know, you could call arc racing and ask if that rod for the ohh50 will fit a ohh60.

 

[J.S.@SMS]

Just did some looking around on this forum and I found this.
http://www.diygokarts.com/vb/showthread.php?t=40502
which led to this.
https://www.ebay.com/itm/PZ22-XR50-CRF50-Carburetor-For-Honda-XR50-CRF50-CRF70-With-22MM-Carb-New/351600058071?epid=1760604668&hash=item51dcff1ed7:g:OCsAAOSwaNBUfSFc:sc:USPSPriorityFlatRateEnvelope!75022!US!-1:rk:11f:0

However I'm confused. In the post Kartfab said that it will bolt on, but the Mikuni has a 2mm larger bolt pattern. Would would it be probable to use smaller bolts to bolt the Mikuni to the manifold?


I also checked and Jacks small engines lists the same rod part number for the OH50 and 60 so the rod should work.

 

[KartFab]

It just bolted on mine.. you do need to modify the bolt on one side to get it to clear the intake casting but that’s no big deal. If you can’t get it to fit just right you can drill out the existing holes. It’s not super precision work.

The rod fits, I’ve done it

I put it a dynocams 245!cam in mine as well.

You can use the stock briggs animal 20 lb springs and use a .030” spacer for correct spring install height.

Overall I wouldn’t recommend going all out on these tecumseh engines. They have a really poor design, and you can get more horsepower from a predator 212 with the same mods.

So for jetting what I did was put the clip in the top position. Idle mixture screw 1.5 turns from bottomed out, and drilled the main to .035”. If I had to do it again, I’d go with .034” on the main. If you do not drill the main out it will run super lean or not at all.

 

[J.S.@SMS]

Thanks for the advice on the carburetor, and the rod. But I do still have a few questions.
Exactly which cam did you use, because I cant seem to find a 245 grind on their website? And what would you recommend about the flywheel? I know that on a Briggs 5 hp flathead a 3 hp flywheel can be used, but what about ohv Tecumseh's. I do have a 2.5 or 3 horse Tecumseh flathead that I can get the model number off of.

And I am aware that these aren't the best engines to mod. And I'm only planning on doing the basic mods: rod, flywheel, cam, valve springs a carb swap and a governor removal.

 

[JTSpeedDemon]

(*giggle)
Basic mods.
Rod, flywheel, cam, valve springs, carb swap, and governor removal.
I classify those as advanced mods.
Basic is more like header, high flow air filter, and drilled out carb jet.

 

[J.S.@SMS]

To me those are basic and, for performance purposes, necessary mods (especially in this engine). However I consider advanced mods to be more in the neighborhood of (in order of most practical to least practical): major head work (oversize valves, port and polish and knock off 60 thousandths), EFI, boring the block 30-60 thousandths, stroker crank, and either nitrous, a turbo, or a supercharger. Sadly, half of those mods don't exist for this engine afaik, and even if they did the engine likely wouldn't hold up. Even though the nitrous might not be a bad idea.

 

[Tpdingo]

Sadly, half of those mods don't exist for this engine afaik, and even if they did the engine likely wouldn't hold up. Even though the nitrous might not be a bad idea.

Its an OHH60....there really isn't much I'd want to do to that engine. I really don't like that motor...at all. Nitro...well that would be fun to see. 3600....3600...7500RPM!!!!! *engine screams*

 

[JTSpeedDemon]

...I consider advanced mods to be more in the neighborhood of (in order of most practical to least practical): major head work (oversize valves, port and polish and knock off 60 thousandths), EFI, boring the block 30-60 thousandths, stroker crank, and either nitrous, a turbo, or a supercharger.

Well, everyone's got their own views of what advanced and what's basic, but I don't think it's worth it to even do basic mods on a Tecumseh.

 

[KartFab]

theuglychicken on ebay sells those cams, but it looks like he sold out. Only has the 356 cams left :-( Might have to call dynocams to see if they will grind you a tecumseh cam. the 255 is pretty slick. but i coudlnt get my hands on it, which is why i went with the 245.

i used the stock flywheel, but i don't condone it. Im not sure what fits this thing as far as flywheels go.

 

[J.S.@SMS]

Tpdingo:
These engines do have their flaws, but at least I haven't had to rebuild one that only had 20 hours on it, like one of my clones.

JTSpeedDemon:
The only reason that I'm considering modding this engine is because it is showing signs that it needs a rebuild. Its power is down, it sputters, the governor's a little screwy, and it smokes slightly. Both oil and gas. So, really, the deciding factor is the condition of the crank, piston, and valvetrain. I'm pretty sure that its going to need a new set of rings, and a good honing, but that's easy enough. I did it to the clone mentioned above.

Also, I like to stand out from the pack. So, I figured that while everyone else is building clone engines, I might as well see about building something different. So I had three options, a Tecumseh h25 or h30 Flathead (not sure which), an OHC Honda GC160, or an OHV Tecumseh OHH60. So I chose the one that has some upgrade parts.

Kartfab:
Thanks, I'll have to look into that. I didn't think that they would grind a Tecumseh cam.

 

[JTSpeedDemon]

Well, that's perfectly fine, I like to stand out a bit too with ma' '85 Briggs!
But not enough to work on a Tecumseh...
The Honda 160 cammer sounds very interesting, it would probably be butter-smooth.

 

[J.S.@SMS]

The Honda 160 cammer sounds very interesting, it would probably be butter-smooth.

A few problems with the Honda are that no hop up parts exist, and I haven’t seen any performance cams. And welding the cam won’t work, because it’s plastic. Also I wouldn’t trust a belt to keep the correct timing at high rpm.

And yes, the GC160 is pretty smooth.

 

[65ShelbyClone]

The GC's head and block are also cast as one piece.

 

[J.S.@SMS]

Yeah, I forgot about that.

Would a GC190 cam fit in a GC160?