Small engine swap for my cruiser

Minimichael

Minimichael

Well-Known Member
#1
#1
Going from 2.75hp to a roaring 3HP!!!

Sorry it's hard to see what's going on in some of these pictures.

My old Ramrod's "built" Briggs 8B had a pinging problem, until it evolved into a clanking matter. So I'm swapping in a fresh antique (model 80232). It's a cross between a racing engine and a lawn edger, I guess. It came with a broken shroud bolt, which I failed to cleanly extract and finally decided to triage that disaster by tapping out for a smaller bolt.

Figured I'd share the whole fiasco. Looks like I'll only have to tap one hole in the block assembly to accommodate all the upgrades from one engine to the next (see highlighted pic of how I attached my diy fuel pump/primer bracket. I'm happy that's all that's involved in transferring this wig of components -- including Tecumseh tank, fuel pump, modified valve/breather cover and slide carb. I say all this tongue in cheek since I'm the original designer of the first hole.)

The engine mount plate is definitely not true. Gotta replace someday. Wondering now if that might have been part of my 8B's discontent...
 

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Minimichael

Minimichael

Well-Known Member
#2
#2
Okay I got everything moved over to the fresh 3hp. Just to recap, I moved my old mod package from the smaller 2.75hp Briggs model 8B, over to a 3hp model 80232.

This 3hp had burnt oil between the jug fins and along the gasket edge like the head had been blown or whatever. I cleaned and leveled the head and removed a decent amount of carbon deposits, too. Also I took a small file to the ports to soften the minimal casting edges. I'm very happy with the cylinder since it's super clean, but the head showed some battle scars so I'm thinking it may have been well maintained and even rebuilt in the past.

Sanding the head to level took some elbow grease, and I'd guess I shaved down a good 0.003" to give it a fresh deck. I did not touch the block though and I'm using the old gasket, too. So we'll see.

Right now, I gotta put oil in and get this quick-build back on the bike. And next up, the engine mount plate is an uneven welded mess so I'm going to try rubber and steel washers under the engine. So stay tuned?
 

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Minimichael

Minimichael

Well-Known Member
#3
#3
So I just got some regular rubber washers 1/8" thick, and steel ones about 1/16", to make the mount more uniform. I have my reservations about putting rubber under the engine – especially only a 1/8 inch layer – but I took it out for a long ride and it seems to have worked okay.
 

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Minimichael

Minimichael

Well-Known Member
#4
#4
Took my cruiser Ramrod out for an hour today. It was my first ride of the season and the new engine ran great. Especially after about the forty minute mark when I swear I felt it settling in. The hum of the cycles seemed to smooth out and the ride was feeling more stable and strong after that. It's not the color I wanted but I'm happy with this last minute engine swap :scooter:
 

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creia

creia

#5
#5
The old "rubber washers under the engine" technique has been discussed and tried before on this forum, however, it has been at least a few years since that conversation has been resurrected. While it was reported to cut down vibration somewhat, the downfall was that most reported that they could not get the engine to stay in position as the rubber washers allowed it to (eventually) move forward which would loosen the chain. Maybe you will have better luck and time will tell...
Michael
 
Minimichael

Minimichael

Well-Known Member
#7
#7
creia said:
The old "rubber washers under the engine" technique has been discussed and tried before on this forum, however, it has been at least a few years since that conversation has been resurrected. While it was reported to cut down vibration somewhat, the downfall was that most reported that they could not get the engine to stay in position as the rubber washers allowed it to (eventually) move forward which would loosen the chain. Maybe you will have better luck and time will tell...
Michael
Click to expand...
I knew there was gonna be a downside. Well, it might work in this case because these are mount holes (drilled by me) rather than slots. This of course brings chain adjustment headaches but that's another story...
 
Minimichael

Minimichael

Well-Known Member
#11
#11
creia said:
The old "rubber washers under the engine" technique has been discussed and tried before on this forum, however, it has been at least a few years since that conversation has been resurrected. While it was reported to cut down vibration somewhat, the downfall was that most reported that they could not get the engine to stay in position as the rubber washers allowed it to (eventually) move forward which would loosen the chain. Maybe you will have better luck and time will tell...
Michael
Click to expand...
As with most indepth discussions requiring multiple opinions before you can make your own informed decision..., ...hold on I forgot what I was going to say... Oh yeah, I can never remember what the consensus was!
 
Minimichael

Minimichael

Well-Known Member
#15
#15
The right way will be to cut off the old and weld on a new, for sure. It's all mangled because it used to have an angled metal mount for a slanted engine.
 
Minimichael

Minimichael

Well-Known Member
#16
#16
Took this bike out again today and the engine is running great. I haven't checked for loosened bolts or made other adjustments but I'm now getting a spinning grumble when I let off the accelerator and I'm pretty sure it's the clutch bearing and it feels all like tight metal-ly. So I oiled it and the problem slowly disappeared during yesterday's ride. Rode it again today and it only grumbled once, as I was pulling into the driveway after an hour.

Hey wouldn't it be something if the rubber washers were acting like a trampoline for the engine in such a way that concentrates the bouncing effect at or against a different locus of stability – like the point at which the rest of the bike is holding onto the spinning drive shaft?
 
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