1641 with blown engine
 

I've got a 1641 with a blown engine that I'm trying to decide what to do with. The engine only has 460 hours on it, but the previous owner had abused it pretty bad. The blower housing and all under the tin was caked with a greasy mess. The engine had a rear seal leak and they just used it that way. It's got a broken connecting rod in one cylinder but it still runs somehow. I of course have not run it since I discovered the broken rod. Grill housing is also shattered.

I haven't opened up the engine yet but I would suspect the damage extends beyond the broken rod. Trying to decide if i should repower, buy a new rod and use, sell the whole thing for parts, or part it out myself. Anyone have any advice?

If you have use for it, then repower. Looks like the fender pan is clean, straight, has a 48" mower deck. Although I can't drive two at once, a reliable spare that takes the same accessories, is always useful. I vote to save.

I'd save that one. Open the engine and see how bad it is. Otherwise drop a new or good used engine in it. I've saved a lot worse. :beerchug:

If you have not opened it up how do you know it has a broken rod?

Thanks guys. I have another 1641 with 1800 hours so it's getting tired and a spare would be good.

Sam, I turned the crank and could see the piston not moving through the spark plug hole and I could just push the piston down with a screw driver

The piston seemed to be near TDC and it had spark and the plug was wet with gas. Don't know how that was happening.:bigthink:

Well for what it's worth I picked up a 1641 a couple years ago engine turned out to be bad, I put a new Vanguard 16 in it then patched up the old engine and put it in my pressure washer.

Keep an eye out for a Cub Cadet 2160 with a good engine and swap it over. I get Kohler CH18's pretty cheap from 2185's that way.

Good call. :beerchug:

Thanks for the tip. I didn't realize the 16 hp briggs was used in anything else except the 1641. I'll have to do some research for any other models to watch out for.

Confirmed my suspicions tonight. Blown up rod and the crank is junk too. It looks like the other rod is scored inside the end that attaches to the crank too. The guy ran it out of oil and sold it to me as needing some TLC.

It's a frustrating and humbling experience for me to know that I couldn't even identify a blown up engine. :bash: The guy was an @#$%#@ to deal with and I hope karma catches up with him in the future.

The 16 was used in the 2160, 2165 and some others 2180 has the 18HP Vanguard and probably others do. If you plan on keeping the tractor for a long time the extra $$ that a new engine with a warranty will cost may be $$ well spent.

I know how you feel, same thing happened to me on this one

I bought a new engine for it from Northern Tools
http://www.northerntool.com/shop/too...arch=6007-2851

Small Engine Warehouse also has a good price on them
http://www.smallenginewarehouse.com/...tegory=1710236

If you decide to repair your existing engine these guys are good to deal with
https://www.jackssmallengines.com/

This is the 1641 that I re-powered a couple years ago. :beerchug:

It happens... :bash2: But if you rebuild or repower it, you'll have a good tractor. :beerchug:

Thanks for the pics and advice, guys. Sam, my folks have a 1641 with the 46" deck like you've got. It does a pretty good job with the bagger. I bagged a lot of leaves with it in my younger years... Looks like you built a custom front end for yours. Was that out of necessity from bad plastic?

Sorner, thanks for the advice about lye via PM. I picked some up on the way home from work in case I got into it and decided I wanted to try to get the aluminum off the crank. I tore into it the rest of the way tonight.

Looks like the heat got to the crank and discolored it. Is it ruined even if I could get the aluminum off the journal?

The second pic is of the rod that isn't broken. It feels smooth but looks damaged. Salvagable?

Finally, the bore looks fine in the cylinder that the rod broke in. I can still see hatching and don't see any cracks or dents. I noticed what looked like marks from the casting or small cracks, though. They don't go through. Would that be alright if I rebuilt it?

Right now, at a minimum I'm thinking 1 new piston and rings, 2 new connecting rods, a new crank, and new gasket set to get it rebuilt. Probably at least $250. I need to think about it for a bit.

"V" twin Vanguard engines are to rebuild! The discoloration on the crankshaft is burned oil. Take it to machine shop and have the crank polished and inspected and the bores checked for size. Metal transfer typically occurs in a lack of lube situation. If you can reuse the crankshaft, make sure the oil passage ways in it are spotless! If you go with the repower, consider Sam Mac's suggestion.:beerchug:

I was in this exact position last year. Bought a clean 1641 "mechanics special" that ran on one cyl for $175. After finding that the motor was junk I was lucky enough to stumble across an ugly and beat up looking 1641 on cl for $200 that ran good. A motor swap later and we are mowing great!

That crank will clean up, I've used muriatic acid, it takes a bit of time but it will eat the aluminum off it.
Then you can see if it is scored, which I doubt.
Of course the engine will need complete dissembled washed/cleaned thoroughly to remove the debris/crud and a through inspection for other related damage, as is standard practice.:beerchug:

The front end was because the plastic was junk and I didn't care what it looked like just as long as it ran good. I've done two 1641's like that.

I was not able to clean up the crank. It is scored underneath the aluminum. I also tried polishing with some 1200 grit sandpaper with no luck.

So I'm still weighing options on rebuild or buy a new engine. I could buy a new 18hp for the same price as a new 16hp, around $1100. If I rebuilt it, it would be about $450 for two new pistons, new rods, used crank, gasket set, new filters and plugs, and a ball hone to deglaze the cylinders. I believe the heads are also warped and one of the head gaskets had blown. I suspect this because there was burned oil around where both heads bolted to the block. I read in the tech section how to flatten those out.

The 18hp should bolt right up from what I've seen. Will I be able to use the extra HP mowing thick grass or will it just burn more gas? Could I expect to run into other problems due to the overheating that it becomes more of a money pit?

As far as the crank goes.........................

If the crank is still round and the metal disturbance in and around the scored area is "down" not "up", I don't see why it wouldn't be usable. But that whole engine needs a good flush.

As far as the heat....................

I've put 3-4 Vanguards back in service that had suffered high heat, blown head gaskets, slipped valve guides, etc. Just fixed the obvious and put back in service with no further problem.

Your experience may vary.

ok,
before you pull the trigger on anything,
lets see some close ups of the crank.:bigthink:

I'd go for the 18, no reason it should over heat. If you are keeping this tractor let me know and I will move this thread to the CCC/MTD section. At one point you seemed ready to sell this one or part it out and asked what it was worth.

I took your and other members advice into consideration and decided I wanted a little project this winter so I think I'm going to keep it. I would appreciate if you could move the thread.

Also, I wasn't clear in my post. I was thinking out loud about if the engine that needs to be rebuilt could still have issues after the rebuild because it overheated.

I've attached a couple pictures of the crank. The one picture shows some minor scratches I put on the crank when I touched it with some 220 grit because I couldn't feel if what i was seeing was raised or cut into the crank. I can polish the back out.

If it mikes good and not tapered or out of round, I'd chance it.
Can you feel the groves with your finger nail?
It would be nice you went .010 under with new rods.
The last photo does concern me without having it in my hand to see/feel for sure.

Grind it.


Ten characters

George I think that is kind of the point. You aren't looking at it, and it isn't your tractor. I might consider running it too..... if I was holding the crank in my hand and putting it the motor for MY tractor. But it's not ours. It's the OP's. Who obviously doesn't know what to look for, how to rebuild a motor, or done enough of them to make a judgement call. The ONLY safe thing to recommend to him is to have it ground. It might cost $50 and guarantee him that it will not seize again. Personally, unless I'm willing to pay for a new set of rods and a crank, I wouldn't suggest he using it like it is. But that's just my opinion. I'm trying to politely disagree here.... it's not our machine to gamble with.

Sorry for my ignorance here, guys. I appreciate George trying to save me a little cash. I can run my fingernail over it and feel the grooves. I have read the specs and reject dimensions, but don't have a micrometer (yet, at least). I worry that the groove is near the edge of a rod, which could introduce a slight twisting. If it was right down the middle of the rod, I would feel better about it.

You're right, Jon, I've never rebuilt a motor. One thing that I'm not sure of is how I would find undersized rods if I ground the crank.

I appreciate the advice. I think we can consider this :beatdeadhorse:

Getting an undersized rod is as easy as getting a standard rod. Just like getting an oversized piston is as easy as getting a standard one.

If it has a groove you can feel, it needs ground. When rebuilding a motor, the crank isn't a place to try and save money. Use aftermarket parts to save money.

I agree with you Jon,
once and be done with that problem, and move on to another.
If it seized quick and it is a case hardened crank, sometimes you get lucky.
Other times why chance it to only have it fail and now your are out more money or it destroys the block.
We have BTDT and it only takes one time, to say I ain't going there again.
I'm hoping he finds a good donor motor, in the mean time this one is a good learning experience, seeing what makes them tick, also all reading, learn something. :beerchug:

Time for an update on this thread. I decided i wanted to keep this tractor and fix it. It's a little long but maybe the details could be useful to someone else someday.

First thing to deal with is the engine. I was going to half-@$$ rebuild it on the cheap. I got a different 16 hp engine that was also blown up but the crank was good, so I was planning to make a good engine out of the two using a piston and rod from each. Well, then I realized the rods that weren't broken were also bad. They had some aluminum from the rod that blew up melted on to them... In hindsight, now that I know what I'm looking at, it's obvious and makes sense given the trauma the engine experienced during a lack of oil situation... So then I decided if I was buying two new rods and a gasket set, new rings are obviously necessary. Briggs changed the pistons so I couldn't just buy new rings... A new piston was required. At that point, with everything else being new, some machining would be in order.

I didn't want to spend all that money and end up with something with problems because I've never done a rebuild. So, I found a new 16 hp vanguard on Amazon marketplace in very good condition for $700 after taxes. Bought that. Well, Amazon shipped it in the cardboard box with NO padding inside. It banged around in the brown truck and brown plane for a couple days and showed up at my house damaged. Key was bent, blower housing banged up, wiring frayed, air filter box bent up, etc. Amazon refunded my money and told me to keep it. Most of the stuff that was damaged I didn't need because I had from the old engine or it was already on the tractor, so I could work with it. I had to straighten the blower housing and repaint it. They changed the flywheel from the older Vanguards. Otherwise, new engine for free. Win.

Well, with a brand new engine, I decided to go through some other things. Pulled out the wiring harness to do a better job of cleaning up the tractor. Re-taped and replaced some of the split loom conduit that was melted to the engine. I replaced fuel lines and shut off valves (my valves were rusty and one wouldn't shut off). I adjusted the Ross steering box and greased the front end including the steering CV joint. I also cleaned up the driveshaft and will obviously re-grease when it goes back in. The old grease was black and came out in chunks.

Here's a couple pics of the damaged engine and where it stands now. I need to get things lined up and the engine tightened down yet, then electrical and fuel hooked up, air cleaner on, etc.

A couple questions related to start-up... I won't need this until next spring, but I want to get it running. Any thoughts on starting up a brand new engine, running it for 20 minutes, and then storing for the winter? Ultimately, I think I will run synthetic 5w-30 (briggs recommendations: https://www.vanguardengines.com/na/e...endations.html) but am thinking SAE-30 would be better for engine break in. The problem is it's cold here now, so don't know if cold starting a new engine with 30w oil is the best for it.

Wow, lucky break on the "free" engine. I would follow the recommendations in the Briggs manual to the letter. They know best what weight oil, amount of run time, etc. will give the results needed for break in.

Way to go. Do what the book says. I run Shell Rotella T 30 in my Vanguards and Kohlers

Go by the book as recommended.
If I had no book, I'd go with light break in oil, non detergent.
run it and play with it checking things over, adjusting linkages, alignment etc. You have a new toy and you want to play with it a little.
If it is really cold in the shop, you can put a 100W light bulb under the engine for a couple of hours before you start, just to make you feel better. :beerchug:

I guess I need to order an engine today and beat it up when it gets here so I can get it for free.:biggrin2:

Nice looking 1641. You are doing a great job on bringing it back. ��Engine ��
Looking at you pictures I noticed it has a plastic tunnel cover, mine has the metal one, I guess yours is a newer version.
David

Alright, I got the engine bolted down and all the wiring and linkages connected. I'm having an electrical issue though. Let me tell you guys what I've done.

When I turn on the key, I have no idiot lights on. Usually, there will be a low oil, and low amp at least. I found a wiring diagram and traced a few things. First, I found that I have 12 volts to the key switch on the black wire (comes from the solenoid through the fuse). Coming out of the switch, in the "run, lights" position, I have 3 volts to the voltage sensor. I thought this should be 12 volts.

I also checked the low oil pressure idiot light in the indicator harness with the key in the "run, lights" position and found that it also only had 3 volts.

I measured the voltage across the battery to be about 12.3 volts or so. Confused but thinking I may have a dead battery (it's a brand new 2660), I jumped the tractor to another battery, cranked it, and the engine fired right up. It was a beautiful sound, let me tell you. I let it run for about 5 minutes, thinking the battery was just low but figuring the tractor would keep running on its own now. It died immediately.

I'm pretty sure I have everything hooked up correctly, but I could use a few suggestions. I could post pics of specific wiring if need be.

Also, I was going to post wiring diagrams but to make them the right size the text wouldn't show up. If someone wants, I could email them if you contact me via PM.

After thinking about this more, I think it could be as simple as a dead battery. If the battery was dead, I think it would have closed the fuel solenoid when I disconnected the jumper cables.

I don't have a battery charger right now or I would just throw it on the charger. I asked Santa for one for Christmas already so don't want to go buy one right now. I'm going to swap in another good battery and I'll report back.

1641 wiring diagram. Make sure you have a good ground to the engine. I ground the Vanguards to one of the bolts just below the fuel pump

Well done with the free engine.

I would guess either bad ground, or ignition switch/plug issues. Or dead battery..... Or locusts... that should narrow it down a bit :biggrin2: