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johnmonkey

Engine replace in a Gravely

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johnmonkey
Hello all, I have a question about my Gravely Tractor. I have a 1963 7.6 convertible with the old style engine (Studebaker, I think??). The crankcase of the engine is shared with the transmission. Question: is there a plate that I can bolt on and separate the transmission and replace the motor with a new motor?. I really like the Gravely but it is a beast to start and keep running. Thanks. JH

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Chris727
I used to have a couple of those, never really used them though. The engines were true "gravely" engines, I think Studebaker owned gravely at the time. At some point, I think in the late 60's or early '70s they began using Kohler engines, I'm not sure how they mounted them or what differences there were in the transmissions.

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powerking_one
John, The only engine that Gravely used which could be somewhat retro-fitted on the classic L 2-wheeler tractor was the very limited production Commercial 10 one. It was a K241AS Kohler with a special machined crank and planetary input gear which matched the original L series Gravely manufactured T-head engine. Still, if you found this engine, it would not mate to the transmission housing. The Commercial 10 up through the last manufactured 2-wheeler tractors all had a 4 flange engine mounting transmission casting meant for the non-Gravely engine. There were posts on the Yahoo Gravely club group from a guy in New Zealand who did adapt a 13HP Honda engine to fit on a classic "L" model; but in my opinion it was false investment good judgement. Tom (PK)

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HubbardRA
John, If you could adapt a later model engine and bolt it on, it would turn too fast. Those old "T" head engines ran much slower than the current engines. That is probably why the planetary gear is on the one Tom was talking about. From memory (been over 30 years) the Gravelys didn't turn but 1500-1800 rpm or so at WOT. That would only be half of the 3600 rpm that todays engines turn. Without some sort of gear-down the tractor would be too fast to use if you changed engines. If your only problem with the original engine is hard starting, then why not put a starter-generator on it. We put a starter on the last Gravely that my Grandpa had when I was in my teens. The Gravely kit had a ratchet that went on where the strap now wraps so the starter did not turn all the time, but if you use a starter-generator all you need is a pulley since that can turn the whole time the tractor is running. The battery would mount up front just behind the PTO engagement. You could either cut off the hood, or find one of the later model hoods for a tractor that came with a starter. You can probably still find parts to re-ring that orignial engine if that would we a suitable way of going. That and a valve grinding and you should be set.

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UCD
My friend just rebuilt one of those old gravely engines for one of his customers. The parts are NLA but he used a piston that was the same and still avail. and adapted a set of rings. It runs like it was new

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DBork
John, Good advice above on the Kohler 10hp retrofit - especially about the difference in engine rpm between the Gravely T-head engine (about 1800 rpm max) and the kohler engines (3600 rpm). When Gravely first switched to Kohler engines with the Commercial 10, they found the tractors moved too fast from the higher revving Kohler engine. So, they quickly came out with the Comercail 10A - which had a reduction gear on the input shaft to slow things down. I think your best bet is to repair the original engine if possible. If you really want to do an engine swap, there were also kits to fit Wisconsin engines to the Gravely tractor. These are not too common. Another option I have seen is to remove the Gravely engine cylinder jug, head, rod and piston. Then make a plate to bolt over the top of the crankcase. Bolt your replacement engine to the plate, with new engine output shaft aligned over the snout of the Gravely engine crankshaft. Use a belt and proper size pulleys (about 2:1 ratio) to slow down the speed of the input to the Gravely. You use the new engine to drive the crank of the old engine. Make any sense? I have seen a couple of these type of retrofits. One used a small diesel (hatz or lombardini - don't remember) engine. The only complaint from one guy was a higher center of gravity that made tractor tippy when working over field furows. Anyway, good luck with your project. You could get more info from the Yahoo Gravely group - as mentioned in the other posts.

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John_RI
There's a guy named Richard in West Va that probably has most anything you'd need. He specializes in model L's but probably has convertible parts as well. Real nice guy and I've always found him very helpful. http://www.gravelyparts.com/ Those old gravely tractors were built even a little tougher than Simplicitys.

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