3212H Questions

[3212V 0]

Hi, I’m hoping someone can help answer a few tractor questions. I recently found a 3212H. The engine ran poorly (shook a lot and smoked some), but the hydro transmission appeared to be good. I already have a 3212V in good condition, but I don’t care for the vari-drive, since my yard requires a lot of reversing for mowing and snow removal. When I first saw the H, I thought, what the heck, worst case I could swap the hydro trans over to the V and have some spare parts. So I brought it home. But then I got curious, thinking, can I save this tractor? Aren’t two tractors better than one? So, I delved a little deeper. The carb appeared to be relatively new, but I took it apart and cleaned it anyway. I replaced the points, spark plug, and oil, repaired some bad wiring, and noted that someone had already converted it to battery/coil ignition. Unfortunately, it still ran poorly, and even worse, I noticed that a head bolt was loose. When I tried to tighten it, I found that the threads were stripped in the block. I repaired the threads with a helicoil, but also noticed some damage to the cylinder wall (I’ll follow with pics once I figure out how to post them). Well, I’d come this far, so I replaced the head gasket, put it back together, but no improvement. I’m not quite ready to give up on this one. I know as a minimum I would need to have the cylinder bored to repair the damage, but what is the largest oversize piston available? Is the only way to know if the damage can be removed to go ahead and keep boring to the maximum or until the damage is removed? Does anyone know a good machine shop in NH or MA who can do the work, and maybe even give me an opinion if it is a lost cause? Thanks!

[Taddy 0]

Hi Larry and welcome. In my opinion, a reputable machinist with cylinder boring experience will have guages or inside micrometers with pointed ends. With these, he would be able to give an educated guess as to how much material would need removed to clean up the damage in your cylinder. Be aware, though, that when you start hiring machine work to be done, it's gonna get expensive. Just be well informed. Good luck on your project. Todd

[3212V 0]

Here is a picture of the cylinder bore:

Taddy, thanks for the reply. I'm wondering if there is a machine shop within a reasonable distance who typically works on small engines?

[FastPaul 0]

Larry I have a few 12HP parts motors here with broken conecting rods, but the block are ok, I live close to you,Come take a look .

[MikeES 467]

Larry is the scuff on the cylinder wall rough or is it just visual? There is a long way to go as far as boring. Std 12hp (30ci) is 3.4365 and you can bore it out to the 32ci size of 3.5625 if needed. In my neighborhood you can a complete rebuild with boring, new piston and rod, valve job, and crank turn with all parts for around $300.

[Scott Salmons 7]

There is absolutely no way you can get by with just one tractor, at least that is what the wife thinks:D. Welcome

[D-17_Dave 12]

That doesn't look too bad. If it's not deep enough to feel with your finger then I'd scuff the cyl. and rering it and get some more life out of it till you dial it all in. This way you've improved it without getting exspensive till you see what you have. IMO

[PatRarick 1]

I agree with Dave. Doesn't look too bad. I'd hone it and re-ring it. It appears to be a score from a broken ring. If that's the case, you will only cause more damage by running it as it is.

[3212V 0]

I just got back in from throwing snow with the 3212V, and also experienced my first broken snowthrower drive belt.sm03 FastPaul, thank you for your offer to come look. The cylinder damage may be a case of "it feels worse than it looks". I can definitely feel a vertical groove running the length of the bore and another ~1/2" wide horizontal groove at the top. If I had to guess, an .060" oversize would probably take care of it, but is there an .060 piston available? MikeES, the 32ci piston is .125" larger, which is plenty, but is there any downside to this approach? For instance, is there enough block wall thickness, will the engine still balance, and will the carb work? Thanks to all for replying.

[MikeES 467]

As far as I know the blocks are the same. I have a 30ci B&S that has been bored out to accept the 32ci piston. And I know of 3 others. All run great with no problems. I used it as a pulling engine for a few years and now as a working engine. I swapped carbs with 16hp for a few pulls and saw no difference. I am now running it with the 12hp carb. I have heard of balance problems with the Kohlers when boring a 12hp out to accept a 14hp piston. But I do not see, nor heard of this with the Briggs.

[RayS 80]

quote:

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Originally posted by 3212V
I just got back in from throwing snow with the 3212V, and also experienced my first broken snowthrower drive belt.sm03 FastPaul, thank you for your offer to come look. The cylinder damage may be a case of "it feels worse than it looks". I can definitely feel a vertical groove running the length of the bore and another ~1/2" wide horizontal groove at the top. If I had to guess, an .060" oversize would probably take care of it, but is there an .060 piston available? MikeES, the 32ci piston is .125" larger, which is plenty, but is there any downside to this approach? For instance, is there enough block wall thickness, will the engine still balance, and will the carb work? Thanks to all for replying.

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The blocks are the same between the 12hp and the 16hp as far as I know the difference is the cylinder head. All internal parts are the same part numbers(crank, rod, valves, ect.) you can still get a .030 oversized piston.

[richp 0]

I don't think the blocks are the same. The 12 and 16 have different balancer set ups.

[PatRarick 1]

Blocks ARE the same. I've rebored two 30 cubic inch blocks to 32 cubic inch. On one I used only the block. All other components were from the 32 C.I. block. On the other, with the exception of the piston and the higher compression 16 horse head, I used all the 12 horse components. As to the balancers, all used a balancer on the flywheel side. Same balancer whether it's a 12 horse version or a 16 horse version. Most 12 horse engines had a balancer on the PTO side as well. Most 16 horse versions did not.

[3212V 0]

Like car engines, it seems less confusing to talk about cubic inches than horsepower. For reference, I’ll call the 12hp “30ci” (3-7/16” bore) and the 14-16hp “32ci” (3-9/16” bore), and compare engines of similar age. The engine in the 3212 was a 30ci, B&S model 320421. The next year, the 3314 had the 32ci model 320421. When I compare the parts list for these two engines, the part numbers differ for the block, head, head gasket, piston, and valves. Assuming that I could bore out the 30ci block to accept the 32ci piston, can I still use all of the other 30ci parts, including the head and head gasket? On a side note, the 32ci piston (p/n 390364) appears to be lot less expensive than the 30ci (299688). So if an overbore is required anyway, it would seem like the least expensive rebuild is to go to the 32ci piston, unless other parts aren’t compatible? Thanks again!

[PatRarick 1]

You can rebore the 30 C.I. block to 32 C.I. and use all of the 30 C.I. components. The difference in the heads is the size of the combustion chamber, which affects compression ratio. I am going to assume that the larger rebore with the lower compression 12 horse head will give you a 14 horse engine. Getting the piston from Briggs, you are probably correct in the cost being lower in reboring to 32 C.I. For the 30 C.I., the std piston lists for $106.55, while the std 32 C.I. piston lists for $61.50. The .010 oversize piston is $103.20 for the 30 C.I., and NLA for the 32 C.I. The .020 oversize piston is $103.20 for the 30 C.I., and $73.50 for the 32 C.I. The .030 oversize piston is $142.70 for the 30 C.I., and NLA for the 32 C.I. If time is on your side, you may want to wait and watch e-bay. I picked up two NOS Briggs pistons for the 32 C.I. last year. One std and one .030, for less than $25 each.

[PeppyDan 3]

quote:

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If I had to guess, an .060" oversize would probably take care of it, but is there an .060 piston available?

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That sounds like a big scratch, .060 is 1/16 inches deep. I'm not saying that it can't be that deep but it just doesn't look it. Sometimes they can appear deep until you step back and look at things in different perspective. Dan

[3212V 0]

PeppyDan, I thought the same way at first, but then I got to thinking about what overboring means. If I understand it correctly, an .060 larger diameter "circle" (cylinder bore) is only .030" wider on each side. If so, this would mean the damage needs to be less than .030 or ~1/32"?

[PeppyDan 3]

You are correct, I guess I had a brain fade momentsm008O)!! Dan

[PatRarick 1]

Unless you are experienced, looks and feel can be very deceiving. I've seen scores that I swore could not be removed with a .030 overbore that have cleaned up with a .010 overbore. I've likewise seen some that I didn't think were too bad that couldn't be removed with the .030 overbore.

[3212V 0]

In case anyone was curious, I took the engine apart today and found this:

The loose fragments were found in the oil pan. Since the engine had some heavy vibration, I'm wondering if the missing pieces made the piston lighter, causing engine imbalance? The middle compression and oil control rings were broken, but this could have occurred when I removed the piston. On the other hand, it would explain the blue exhaust smoke and lack of power. Also, the flywheel key was sheared. A previous owner had converted the engine to battery coil ignition, presumably to address this issue. The original Briggs magneto ignition was missing. I'm guessing the cost to replace the magneto means that I'll be keeping the battery ignition. Although I haven't measured anything yet, the rest of the engine parts look pretty good. My only concern is that the ball bearing in the PTO side cover felt kind of rough. I don't see this bearing in the parts illustration. Does this mean the bearing is not replaceable?

[gregc 3]

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I don't see this bearing in the parts illustration.

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Should be #17 in your parts list.

[3212V 0]

Greg, This bearing isn't the one on the crankshaft, but further out, inside the front cover itself (# 747). As far as I can tell, this bearing is for a counterweight with a gear attached to it. I'm guessing it is part of the synchro-balance.

[gregc 3]

According to the manual the counterweights and ball bearings are an integral part of the covers and cannot be removed.