Z puller

[The B killer]

I'm looking for some ideas to make a good competitive Div.2 MM Z. Somewhere between 60-80hp. I was wondering what you guy's are doing to yours as far as bore, stroke, and fuel? Thanks in advance

 

[MM ZAck]

What weight class are you looking at? In order to get 60-80hp, you'll likely have to start with an overhead valve 206 out of a 445, Jet Star, etc. From what I've read, they breathe better and have more potential for modifications. From there you could bore it, find some LP heads, grind the cam, etc. I haven't rebuilt one of these engines myself. What do the Div 2 rules allow as far as engine and mph? As for the original side valve engine, I've got a '49 with Jahns 3.81 pistons, 10a2647 head, Berry cam, and runs on 111 octane that puts out 48hp at stock rpm. I pull it in 4000lbs and 5000lbs in 1st gear and have more than enough power to get to the top of the podium. You might try a post on the pulling forum too. There's a guy who uses the handle LW that knows about building Z's.

 

[The B killer]

We use NATPA rules so i have to use the flathead engine. 3mph speed limit. What is a Berry cam? And how did you bore those blocks? The last set i did my local machinist turned me away because he said his boring bar couldnt reach the bottom of the block. The only way I can think of is to put the blocks in a vertical mill. And did Moline make a LP head for the model Z? Thanks

 

[MM ZAck]

Berry Cam Service is a place that regrinds camshafts. They will set you up with a high torque grind, which is what you'll want for a 3mph class. (see link below) You are also limited to 1st gear at 3mph so you will be able to get the power you need out of the flathead engine. As for boring the blocks, I had a local machine shop do just what you describe - they used a vertical mill to be able to bore the blind depth. It's a little tricky, but it can be done. Yes, MM made LP heads for Z's. The 10a2648 head is a higher compression head and the 10a2647 head is the LP head. These are listed in the ZA and ZB parts books. The heads are a bit tough to find, but I was able to hunt one down for my tractor. It makes a difference as my tractor runs almost 9:1 compression ratio, and that's with the stock stroke. For a 3mph class, I'm not sure you need to go to that extreme though, as a stock ZA will have lots of lugging torque to begin with. Is your tractor a ZA, ZB or earlier red nosed ZT? The gearing is the same for ZA and ZB, but the ZT is a little different.
Berry Cam

 

[wnymolines]

ZAck do you what the low limit of octane you can use in your set up is?

 

[Mopower]

ZAck is right. I have the same setup. I also did some extensive port work. Drill the valve guides back flush with the combustion chamber. Use a ZT "straight-up" exhaust manifold and a ZA LP intake. Look at Manly valves with a neck down stem. This flathead needs all the help it can get. I was told Richard Kenyon made an adapt kit to instal a Pierce governor. The LP head is rare, but Welters Farm Supply modifies the gas head to give the compression lump a little more depth. Henderson Power in Grand Junction, MI can bore the blocks. Berry cams are great BTW. If you need contact numbers, give me a call.

Ethan Berry
The Mopower Ranch
Vermontville, MI
517-243-0617

 

[Dennis P]

Check with machine shops that rebuilds outboard motors. I found a feller to do mine there. Mine is bored .180 over with no other modes & I can pull 4500# in second gear & still slip the 13.6 x 38 tires. I also understand that if you set the cam up one tooth on the crank it seems to help.

 

[MM ZAck]

I don't know offhand. When I got the tractor running, I initially ran it on some 87 octane I had in a gas can. It pinged. I haven't run anything less than 111 since and it runs really nice on it.

 

[The B killer]

I have 2 ZTU'S I had a ZAU but my brother wanted it so I sold it to him. I currently have 2 heads sitting on the ground casting numbers RE-226C and RE-226D but I would like a high compression head. If anyone out there has one for sale let me know.

 

[Anonymous-0]

i have a 10A2648 head 300.00 plus shipping

 

[MM ZAck]

Wow, that's interesting. I've been wondering if mine would pull in 2nd gear on a soft track at 4000#. Is yours a ZA or ZT? 2nd gear between their transmissions is different. The ZA is almost 1mph faster at 3.6pmh vs. the ZT's 2.7mph. Can you spin the tires on a hard track? Also, I advanced my cam one tooth and it does help.

 

[Dennis P]

Mine is a ZTU. With 12 x 38 tires, I could slip them in 3rd gear, regardless of track. I can't pull in 3rd with 13.8x38 on 12"rims anymore.

 

[MM ZAck]

Wow, that's pretty interesting. You went to a slightly taller tire and it was just enough to take away 3rd gear in all conditions. That's good info. Can you still use 3rd on a soft track? 3rd gear in a ZT is virtually the same as 2nd in a ZA. My ZA has 12.4-38s on it so it should be able to handle 2nd gear.