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radarme

Tecumseh H55D rebuild?

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radarme

Just got a Suburban 551 with orig H55D (spec 2113) engine. The carb was shot so I put on a cheap Ebay H60 carb on it to see how it sounds. It starts up pretty good and smokes a little. Pretty good knock to it. I'm sure it needs a rebuild and I'd like to do as much of it as I can (short of machining).

How available are parts for this engine? I know the engines are pretty rare. I've never done a rebuild... any pointer or words of advice?

regards,

David

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SPINJIM

I've rebuilt two Tecumsehs. Some parts are hard to find, but they're out there if you thrash around enough. I bought a few old Tecs at auctions just to get one or two parts from them. Get to know the serial numbers of the early ones so that the parts are compatible. Check on ebay. Also try Jacks Parts and Small Engine Parts Warehouse online. The early Tecs were good engines, as good as the Kohlers, and not like the stuff Tecumseh built in their later years. Also, I heard a rumor that a remnant of the old Lauson Engine company is now producing parts for the old Tecs. Go online and google "Tecumseh dealers". You'll get some old obsolete listings, but you can call those old Tec dealers to see if they have any parts left in old inventory. Good luck.

Just noticed that you're an experienced "Supporting Member" , so you probably already know most of the above. Sorry, I answered fast because I like old Tecumsehs.

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MarkPalmer

Unless the block is damaged beyond repair, any engine is rebuildable. It just comes down to patience in obtaining useable parts, and how much you want to spend getting machine work done. The cast iron "HH" Tecs with roller bearings were very similar to Kohler K engines and are usually worth rebuilding. The standard aluminum block H engines though are a tough call to decide if they are worth putting the money in to. I suppose if its for a really nice old tractor and you want to have an original or correct engine in it, you end up starting the hunt for parts. There is nothing really different to rebuilding the older Tecs than with any other small engine. I've had good luck mechanically with Tec engines, other than their carbs are terrible.

From the sounds in the video, I would say the crankpin bearing on the rod is definitely shot, and the piston is slapping against a well worn cylinder wall, throwing a lot of oil on the top end. Pretty much full rebuild required.

-Mark-

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sorekiwi

If I was in your shoes I'd rebuild the one you have. There's not many H55's around anymore, so you've gotta try and save one that runs. And there's not many tractors from that era arond still with their original engine.

Some of the H60 stuff will fit the H55. There are some people on this forum with more recent experiance than I, hopefully they will chime in.

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Fordiesel69

If you are going to keep the engine stop running it until you find the source of that knock. From the video I hope it is just a loose mount, or some loose accessories bolted to it. If that indeed is a rod / piston knock, the engine cannot be run any longer. As of now it is fully rebuildable, and quite cheap. If you run it and it blows, then it is just worth scrap. Not often do you get lucky when the rod breaks.

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Coadster32

Looks like you've found a good source there. I'd ask him (Randy) directly. Seems as though he should know.

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MarkPalmer

It looks like a several of the H50/60 parts will interchange with the H55. I know at least the head gasket, carb gasket, piston and rings do. I'm not sure about the other gaskets in the set, but good chance they will work.

-Mark-

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radarme

I think I'll give that guy a call... In addition to the gaskets, he may have some other parts I will eventually need. I pulled the engine last night, degreased it, and then cracked her open.

Lot's of carbon build up.

Flywheel has a few broken fins,

Piston is snug....

Cylinder walls look pretty good but they are oily.

When I took the breather cover off, it was pretty nasty underneath... and no gasket

Also, take a look at this video.... as I rotate the flywheel back and forth, you can hear something tapping....

http://youtu.be/p1XOKb_6xWw

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MarkPalmer

That is a common sound of rod bearing wear with the piston at the top of its travel. Quite a bit of oil and nasty carbon buildup on the piston crown and by the valves. It's all really nothing more than it being tired and in need of rebuild. It will most likely need oversize piston and undersize rod for machine work. You'll need to check the valve tappet clearances and condition to see if it needs valve work too, which is most likely and something best left to the engine shop also. Most common cause for missing flywheel fins is previous owners trying to use something to hold the engine from spinning to remove the flywheel nut. I always take them off with impact wrench, it doesn't give the engine time to spin.

-Mark-

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sorekiwi

Its been about 7 years since I did mine, so my memory is a little hazy. The one I did was an HT55C off a 502, so what I tell you may or may not apply to your motor.

I used H60 gaskets, and rings. I think I used H60 lifters as well, I would have liked to put new valves in mine but mine had a different style of keeper for the valve spring cap than what the H60 uses so I ended up refacing my old valves in the lathe and reusing them.

At the time I didnt have an H60 piston to compare to my HT55 one. I was told by several different people that the H60 piston was different. This was back in the pre Red Square days, the information probably came from one of the Yahoo groups. Good luck trying to find it now!!!

The connecting rod on the HT55 is different from an H60 one. The HT55 has an oil pump so the rod doesnt have a dipper on its big end. Im not sure if you could take an H60 one and cut off the dipper or not. Again I had no H60 bits to compae it to at the time. I ended up having my old rod crack checked and I reused it.

As I said above, there are people on here that know more about these things than I do, maybe PM them and ask your questions direct? Mitch (Puddlejumper) and SkyhawkTL spring to mind.

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radarme

Just a little update:

I've opened the crankcase and pulled the valves. There is some corrosion on the lifter related to the exhaust valve as well as the exhaust valve itself. I definetely want to replace the valves, springs, lifters... The question is do I need oversized valves... The current valve stems mic to .310 and I'm not sure if that is the std valve or the oversized one. Anyone know the diameter of the std valve stem?

Also, how do you know if you need to oversize your valves? What is the inspection procedure for the valve guides?

thanks

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Fordiesel69

Just a little update:

I've opened the crankcase and pulled the valves. There is some corrosion on the lifter related to the exhaust valve as well as the exhaust valve itself. I definetely want to replace the valves, springs, lifters... The question is do I need oversized valves... The current valve stems mic to .310 and I'm not sure if that is the std valve or the oversized one. Anyone know the diameter of the std valve stem?

Also, how do you know if you need to oversize your valves? What is the inspection procedure for the valve guides?

thanks

You can have the valves refaced, or if they are not GROOVED then just hand lap them in. If you feel the need to replace you should not need oversized valves, and I wouldn;t think they are avail anyways. If you think the old piston is snug and is std bore, a new one will be even better. And for the rod, find out if the rod is scored or if the crankpin is ovaled out. That knock was pretty nasty.

You will also need to get a new flyweel or have a shop balance that one.

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radarme

There is too much corrosion on these valves to put them back in.... Standard size valves are still avail at a decent cost. I'll pull the piston as soon as it gets below 100 degrees out there and see what the rest of it looks like. The face of the piston is stamped with a '5' so I won't know if it's std until I can mic it.... I'll be back with more questions later, I'm sure... Thanks for the help!

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sorekiwi

You can check wear on the valve stem by comparing the measurement in the worn part (where the valve runs in the guide) to the unworn part (the bit that never enters the guide)

What style of valve do you have? Does it have 2 small retainers to locate the spring cap? or does it have a hole through the valve stem that a pin goes through to locate the spring cap?

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radarme

It's got the hole with a keeper pin.... From what I've seen, the replacement valves don't have the pin anymore.

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sorekiwi

It's got the hole with a keeper pin.... From what I've seen, the replacement valves don't have the pin anymore.

Thats why I was asking. You will have to get the newer style spring cap and the keepers to suit your new valves as well.

Are you sure you cant just polish off the corrosion on a wire wheel?

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radarme

Did some measuring today with some rather clumsy tools... not sure how accurate I got... but here goes:

I'm planning on taking everything over to a machine shop to have them accurately measure everything to see what all needs to be done.

Edited by radarme

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Fordiesel69

The rod has some lid socring but nothing major. Looks like some debris entered it. Wrist pin has the two tan bands (stains) where no wear has taken place so we can assume there is some good wear overall on the pin / piston / rod. I am going to be curious what part is worn. The visual condition of those parts does not look all that terrible.

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radarme

I'm planning to have a machine shop:

1) check the cylinder dims and then deglaze it.

2) Check crank and cam shafts for wear and bends.

3) I plan to replace the valves and springs.... and I'll have them check the valve seats to see if they need to be reground and also check the valve guides for wear.

4) I'll have them check the piston and rod as well to see if they can be reused... will definitely get new rings.

What else? Should I go ahead and get the new valves so they can adjust the clearances or is this pretty simple to do with a bench grinder? I've never dealt with a machine shop before... Thanks!

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Fordiesel69

You *can* use a bench grinder, but it would be better to have the shop do it.

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MarkPalmer

I've ground the ends of the valve stems with the bench grinder to set clearances before and didn't have trouble with it- just be sure to stay as flat as possible and grind a little/take a lot of measurements. But if its in the machine shop anyway, let them resurface the seats and lap them in and set clearance. Your cylinder sleeve will most likely need to be rebored if its thick enough to do so, as I've rarely seen those old Tecumseh's come through measurement wise with just a deglazing.

You might need to explain to the machine shop your reasoning for wanting to rebuild your engine, as I'm sure most shops will tell you it would be cheaper to get a new engine than to do all the machine work on the vintage engine you have.

-Mark-

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radarme

I've got an update on the H55D... The crankshaft and conn rod has too much wear and will need to be replaced and the cylinder needs to be bored out to .020.

I'll need:

1) new crankshaft (part # 29522 or 30813)

2) new .020 oversized piston. (part # 28934 or 33314B)

3) new .020 oversized rings. (part # 28937 or 34856)

4) new connecting rod. (part # 27892 or 31295C)

5) new valves, springs, lifters

so I'm on the hunt! I'm guessing an affordable crankshaft will be the toughest thing to find. I have no interest in paying $200 for one. I'm also on the lookout for a K161 to use for the time being.... no telling how long it will be before I find that crankshaft.

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Coadster32

I beleive that a K161 won't fit under the hood...w/o modifacations. Looks like your plan is well underway. Good luck with it.

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radarme

I've located all of the parts and they on order... The crankshaft is a little suspect. I guess sitting in a warehouse for 50+ years would do it! It has some surface rust on it so I really won't know if it's useable until it gets here. I believe the only services I'll need from the machine shop is boring to .020 over and then redoing the valve seats. Any idea what I should expect this to cost?

thanks

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