Walter

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Master Yota
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Re: Walter

Post by Master Yota »

Are you certain it is a ZF transmission? I only ask because I've never seen a ZF mated up to an NP208. Now I haven't seen everything, but most of the ZF's up here in the frozen north were mated up to the BW 44-? series of tcase. Is the NP208 a fixed yoke version? If so, they are somewhat sought after in off road circles, so you shouldn't have any issues selling it.

I used two transfer cases in my setup, the married Ford tcase was intended to act as the pto output, while the divorced Dodge NP205 did regular driving duty behind it. With the additional length of the ZF and 208 you might not have enough room to accommodate a similar setup if you wanted to operate anything with pseudo-pto setup...
Ray
1953 CDN. M37
1954 CDN. M152
tbone1004
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Re: Walter

Post by tbone1004 »

Don't think I'll run anything PTO on there, will just sit as a dummy box since I can't find anything other than the ford ebrake that bolts to the 4x4. Will see how this all ends up, but worst case scenario I have a relatively sought after transmission for the cummins boys and might be able to find a 2wd down the road. I would love to keep the 4x4 and find a reasonable Ebrake setup so when I do end up swapping axles I can keep the driveline brake which I do like much better than an axle brake and then use a divorced np205. Now that I have a transmission, I have no excuse not to put the engine in there so hopefully my buddy will come over and help me remove the front clip and pull the engine sooner rather than later. Still have to get a carb and I could use the existing vbelt if I wanted to get it running fast. Scary stuff now

Haven't seen it, but the guy said he had bought it for a jeep project and the tranny is out of a '91 f350 so that would a ZF5 and he said the 208 was out of an 84 that was originally mated to a C6. He ended up using the C6 for the jeep and used a 205, so the 208 was just on there and he wants to get rid of it.
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Re: Walter

Post by tbone1004 »

picked it up. Looks great, couldn't argue for the price either. Also got a 4bbl Holley 600cfm in great shape for $50 so that was pretty slick. I think I'm just going to leave the 208 on there for now and use a really short stub shaft. Will be in my jeep until Wed when I can pull it out and clean it up properly. Now I need to buck up and order the ARP dress kit and decide if I'm going to convert to hanging pedals since this has a hydraulic clutch
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Re: Walter

Post by JimC »

I recommend an extension on the bottom side of the stock clutch pedal to reverse the direction of travel, driving a clutch master cylinder mounted beside the stock brake master cylinder.
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Re: Walter

Post by Master Yota »

You may not be aware, but its very easy to swap the factory ebrake from the NP200 to an NP205. The two tcase's share the same rear cover, and with a simple groove machined into the M37 cover, and a dual pattern yoke from Tom Woods Driveline you can mount the parking brake onto the NP205.

Also, If you manage to find an NP205 from an 87 (IMS) or newer Gm truck (preferably a fixed rear yoke so you can swap the parking brake on) it will have the same 6 bolt round mounting pattern as all the ford transfer cases. This means that if you swap out the 32 spline GM input shaft, for the Ford 31 spline shaft, that you can (with some fiddling) bolt the passenger side drop tcase onto your ZF transmission.

Mind blown yet? :mrgreen:
Ray
1953 CDN. M37
1954 CDN. M152
tbone1004
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Re: Walter

Post by tbone1004 »

no, I've looked through all of this before, but I think I'll bolt it in as is for the time being and I'll deal with removing it when I swap axles. At that point I'll go to a regular divorced NP205 with a centered rear diff and potentially be living down south where the odds of finding a 2wd zf5 are much better than in New England. In the mean time, I'm going to be on the hunt for a 2wd F450 with the stick shift and try to score one of the ebrake assemblies on the cheap. Still a bit overwhelmed with having to fab the crossmember, motor mounts, and all of the linkages though.

Jim, thanks for the heads up on the pedals. I'm 6'4" so I was thinking about going to hanging pedals to give me a bit more leg room. Will have to look at that once I have all of the parts before I start plumbing. Maybe I'll leave the original pedals and since this is a hydraulic clutch I might be able to have it partially down and put a short throw clutch on it... Will have to look at different master cylinders.

I'm very much looking forward to 2100rpm at 50mph though. 2500rpm at 60 is going to be tolerable for short bursts where I need it, but 50mph and being able to maintain it is going to be quite nice. Being able to downshift to 4th if I have to at 50mph is going to be something I've been missing.

I'm going to update the fuel system to be ready for EFI if I go that route which will be good, so high pressure ready lines and what not. Going to hold off on any brake or steering updates until the new axles come in and I'll just keep it under 65 when unloaded and try to keep it under 55 whenever possible. Stll have to find a bloody serpentine system before the engine can go back together
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Re: Walter

Post by JimC »

I used a Plymouth brake master cylinder because they were plentiful and cheap, but they might be hard to find now. Pretty much anything will work. How about a second M37 brake master cylinder?

My 37 tops out at a little over 111 mph with stock gearing and tires. How fast are you wanting to go that you need taller gearing?

Do I understand you correctly that you are converting from 4wd to 2wd?
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Re: Walter

Post by Master Yota »

Jim, Tbone wants the 2wd transmission so that he can stick with a divorced transfer case.

Willwood will have the best master cyl. from a price and modification standpoint. IMS I used a single line Willwood MC with a 7/8ths bore and it cost be about $50.00...super easy to mount and install.

Hanging pedals are awesome. 8)
Ray
1953 CDN. M37
1954 CDN. M152
tbone1004
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Re: Walter

Post by tbone1004 »

Mine will top out somewhere around 120mph as well, but your final drive ratios are optimized for a certain engine cruise rpm. By going with CUCV axles and HMMWV tires, that puts me at .76 transmission, 37" tires, 4.56 diffs, and about 2000rpm at 65mph instead of the 2750 that it will be doing with stock axles. That's a much happier speed for the engine and the CUCV axles will give me cheaper locker options, much cheaper disc brake options ,and gets me to the standard 8 bolt lug pattern which is nice if I ever want to change rim diameters but also getting to tubeless tires.

What is the one drawback of the smallblock ford in this case is this is the only ZF5 with an internal slave, all of the other ones have an external slave cylinder. Oh well....


Here's the speed for cruising at 2000rpm which I've read is the happy number for this engine, with the stock axles, and with the CUCV axles/hmmwv tires. You can see that the CUCV setup has a much more road friendly speed with 4th hanging out right around 50mph and 5th just shy of 65. The stock will give me a good setup to hang out around 50 which is what the speed limit is on most of the roads where I am now
Stock Axles Speed
1st 5.72 6.24
2nd 2.94 12.15
3rd 1.81 19.74
4th 1 35.72
5th 0.76 47.00
rev 5.24 6.82
Shift RPM 2000
Axle 5.83
Tire 35


CUCV Axles Speed
1st 5.72 8.44
2nd 2.94 16.42
3rd 1.81 26.67
4th 1 48.28
5th 0.76 63.52
rev 5.24 9.21
Shift RPM 2000
Axle 4.56
Tire 37

Dana 60's with 4.10's Speed
1st 5.72 9.39
2nd 2.94 18.26
3rd 1.81 29.67
4th 1 53.70
5th 0.76 70.65
rev 5.24 10.25
Shift RPM 2000
Axle 4.10
Tire 37
Last edited by tbone1004 on Tue Feb 11, 2014 10:42 am, edited 2 times in total.
JimC
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Re: Walter

Post by JimC »

I've never been concerned about optimizing cruise rpm. Don't spend enough time on roads for it to be a significant factor to me personally. I can see how it would be a concern for a highway truck though.
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Re: Walter

Post by tbone1004 »

it's not really a highway truck, but since I want to use it as a daily driver, having good cruise rpm's is certainly high on the priority list. If it was an offroad truck only I'd be less concerned but reliable daily drivability is priority #1 with the drivetrain. The gap between 3rd and 4th is still really big with a lower diff ratio, but we'll see

I just edited the post to include the 4.10 ratios commonly found in Dana 60's and even that would be a good number for this truck with cruising ratios. Axle hunt ensues, but engine has to go in first...
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Re: Walter

Post by JimC »

I wasn't knocking your choice. Mine just never spent enough time on roads for me to worry about cruise, and I liked the low crawl speed.
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Re: Walter

Post by Master Yota »

An optimum cruising rpm is subjective at best, as the gear calculators don't generally factor in cam choice, tire rolling resistance, and a host of other factors. Any cruising speed near 60 that allows for an rpm under 3000 is ok for a small block, and about 2400 for a big block. Prior to overdrive transmission, most trucks with a 1:1 final drive, 4.10 gears and a typical 30-31" tall tire did 60 mph at 2500 rpm and the engines lasted for decades performing at that speed every day.

An overdrive is a bonus at best, but its hardly an engine saver. Any truck operated in hilly terrain won't use 5th gear enough to see any benefit regarding engine life.
Ray
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tbone1004
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Re: Walter

Post by tbone1004 »

that was an optimal rpm for fuel economy according to the guys on the bronco forums running this engine with the RV style cam that I have.

What is exciting is that even with the stock axles, in 4th I get 35 to 55 in 4th gear from 2k to 3k which will be good, but still have to this thing shoehorned in
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Re: Walter

Post by JimC »

Doesn't optimal rpm also depend upon manifold pressure?
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