Hi, Any one know of a site that will tell me what parts will interchange with what engines? I have a great running 8HP with a tapered output shaft. I want to use it to replace a tired 7HP that has a key shaft. So I have to replace the existing tapered shaft in the 8HP with a keyed shaft that matches the 7HP. Changing the cranks is no problem. Finding the correct crank, for the replacement, is proving difficult.
The older, (valve in block), 7 and 8 HP B&S engines are very similar. I think the stroke was the same, but the bore was different. (maybe the other way around??) The crankshaft should swap over, but you may need to swap connecting rod and piston too. I forget if it was the bore or the stroke that was different, but I do know you should be able to do the swap with the parts from each engine. I have a manual around somewhere so I could get more specific if you want me to. Greg
Have you considered getting an adapter to fit over the tapered shaft to make it straight? Only thing is, it will increase the shaft OD.
Ok, I got out my manual. Bore is the same on the two models you have, so that makes the crank different, and I checked, the pistons are the same, the connecting rod is different.
Thanks for the quick reply. If the strokes are the same I am good to go. I could just order a new crank for the model/type 7HP and put it in the 8? Is there a listing of what cranks were used in what engine.
8HP is model 190412 type 3129 7HP is model 170452 type 2351 (this has a gear reduction unit that I will remove and rebolt to the 8HP)replying to Greg O, John Turgeon wrote: Sorry to Jack thread, but in my case I need a block. I have a 8hp on a big trike that ran until I cracked mounting ear for intake off of block. Will a
7hp block work if I switch the guts? Buddy has a 7hp but the shaft is tappered so that won't work me. And I don't want to get an ohv motor cause I'm trying to stay period correct. Any help?
Check spec for both engines. Ist the bore the same? If so measure deck height from base to gasket surface. Is it the same? If so put 8HP crank (with rod and pin) in 7HP block and you are good. Cam MAY also be different but not likely.
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