Car Conversion

Ron 10/99

Bearcat 55 Conversion to Car Engine Jim What has to be done to convert the 55hp boat engine so that it can be used in a car?? Ron

Jim_Bollman 10/3/99 9:11 pm

Ron, I have never done a conversion myself, so what I'm telling you is second hand and only the highlights. The Bearcat 55 (55hp) is a vertical outboard boat engine built on the design of the original Crosley. It is bored and or stroked out to 55 CI from the original 44 CI Crosley. I believe the valves are larger and it has a more radical cam. It ran with dual carbs. The biggest problem, since the flywheel was up in the air and the boat stuff was driven off what is normally the front of the engine, the flywheel is held on to a taper with a large nut. If you want to use this very nice steel crank, you have to adapt a flange to the crank so a regular Crosley flywheel can be used including the pilot bearing for the front of the transmission. This has to be welded on. The alignment pins for the fly wheel need to be properly positioned so you don't loose balance. You obviously strip all the water cooled manifolds off and put on stock Crosley manifold or some Braje stuff. If you want the full 55hp you will need good manifolds and carburetors. Flats are still in most all the right places to machine holes and tape for mounting all the standard things. The big missing flats are where the water pump and generator go. One possible solution is to use the Bearcat water pump that mounts where the fan normally would. A good machinist can probably fabricate brackets for the stock one. I have also heard that a stock Crosley crankcase can be substituted. I don't know if this is true. I have also heard a Crosley crank can be used, if so it better be a good steel crank. You will have to rework the oil pick up since you are rotating the engine. I think that's the high points. If anyone reading this actually did a conversion please give more complete details. The 49 Wagon I drove with the conversion could accelerate up hills in 3rd that I had to take in 2nd with my stock 49 Wagon. Jim...


More Conversion Notes

rsrendfeld 12/29/00 10:20 am

On the CAC site there is a like to a site about Homelite boat motors. The 55 hp Homelite motor is based on the 26 hp engine used in the Crosley Car. Is the boat motor a bolt in swap??? OR Would it be easier to hot rod a Crosley motor to get 50hp?? Ron in Indy

Jim_Bollman 1/2/01 10:40 pm

Ron, I have seen several conversions of Homelite/Bearcat engines back into car engines. I even drove a 49 wagon with a complete stock Homelite installed, it was very impressive. Most of the flats on the crankcase and block that need to be machined and/or tapped for mounting accessories are present. The oil pump and carbs needs to be modified to work laying down. The big problem is the crank, it has a taper with a nut where a car engine has a flange. The one I drove had the taper cut shorter and was fitted with a flange welded on. Do have the whole thing balanced if you go this way. Not sure what other approaches can be used on the crank. If 55 HP is not enough you can always start souping up the engine from there, you are starting at a higher point so it should be easier. Jim...

speedoo51 1/5/01 5:10 pm

Crofton 53 ci with 45 hp was the same as the 44 except bore was 2.75, same as Homelite, keeping the 2.25 stroke. Don't know if was left-hand ports or standard right or if came either way. I have Crofton sales pamphlets listing the engine for boat applications. The Homelite I looked at had more material on outside of block, between the water jacket covers and the mounting flange. There is not enough room for the hold down nuts so they drilled and tapped from flange face side and screwed in studs that were long enough to go all the way through to main caps! I imagine that the Crofton 53 was done the same way. The Homelite also had a camshaft that was twice the size of a Crosley but kept the same gear drive.


And More

myronhwhite 6/27/01 2:06 pm

I found one. Does anyone here know how hard it is to put one in a Crosley ? Looks like clutch and cooling are the hardest problems. Thanks, myron white Portland, OR

crosley19 6/27/01 6:26 pm

First you have to have a machine shop make an adapter to mount the Crosley flywheel to the tapered Homelite crank, then using the drive coupling from the lower unit, and have that machined to a Crosley crank pulley. Then the crankcase must be machined for the Crosley distributor ( there is a machined dead end hole already there for it). Then you have to drill, tap, and plug the water outlets by the exhaust ports (you don't need to have the water shooting out into your exhaust system. Then I suggest using one of Braje's log intakes, and headers, because the Homelite ports are much larger than the stock Crosley intake and exhaust. (you will restrict it too much using stock intake and exhaust manifolds. Then tap the generator, and water pump mounting holes, and definitely use a 4 blade water pump impeller, and larger radiator. Then have the front hole in the Homelite oil pan welded shut,remove the bolted in baffles from the pan and remove the pickup tube extension from the Homelite pump, and put the Homelite pump back in without the pickup tube. That all. Barry


More Details

crosley19 May 12, 2002 9:37:25 PM

I have a local machinist that specializes in racing automotive work. He cut the flange off of an old Crosley crank right at the rear seal flange, drilled it and tapped it, then machined down the Homelite crank and threaded it, and screwed the flange on, and then drilled and pinned the flange so it wouldn't unscrew. Then I milled out the crankcase for the larger pistons to clear the webs. You have to remove the studs for the main bearings for the Crosley block and drill them over size to accept the Homelite cylinder mounting studs. Drilled and tapped the water outlet holes for the water cooled exhaust manifold in the cylinder head, and installed flush pipe plugs. Then drilled the back of the block for the water temp gauge, and installed a special pipe plug (John Deere part) to accept the temp bulb. Don't have to do anything for the water flow around the cylinders. The water flows freely if you use a military 4 blade water pump. The front pulley was made by machining the crank shaft coupler from the Homelite, and machine a 3 inch Crosley pulley. The crank is hardened in the nose of the Homelite, so you cannot tap it. I cut off .015 inch off the front of the Homelite crank. Had to cut down the front so I could get a good fit on the tower gears and welded a stud into the crank to hold the pulley on. An adapter had to be machined to mount the fan pulley also. The stock Crosley carb delivers enough fuel for the Homelite, had to open up the screw 3 turns.

Alot of machining to do this, I would not suggest you try it yourself unless you are a master mechanic- master machinist, or get good help. You must use the heavy duty military crankcase, and aluminum oil pan to take the extra stress from the increased H.P. A local racer tried this years ago using a stock Crosley crankcase, and tin oil pan, it split the crankcase right up the middle after 10 miles of hard driving.