Cub 1641 B&S 16 V-twin top end rebuild
 

Decided to make this a new thread... and add a bit with progress.
I should have most of the parts tomorrow "monday 5-20" to put back together.

Note: I know I could have rebuilt the head. Put new bushing in etc. There are ways to keep the guide in place. Punch marks around bushing into the aluminium, etc, I have even heard of guys using flux core weld and welding it in from bottom or through port. I didn't want to have any of that in my engine so I opted for new heads.

Update to my 1641. Okay so I figured out why it felt sluggish. The relief valve lever was stuck and not going down all the way. Got that down and felt much more powerful!

I started to run it a bit and cut some grass. All seemed fine until I started to hear a valve tapping. I idled it down and shut it off. Opened the hood and knew right away from the heat off it something was not right. I decided to pull the engine and have a look. Most of the members here will all know what happened as soon as you see pics. For the less experienced guys I will continue because this is really important maintenance if you dont want to have a big issue one day.

The previous owner let the grease, mouse house, nest, and whatever else was in here packed the cooling fins to the point that the engine overheated. The overheating caused the valve guide "bushing" to slip. I had put a new pushrod in and adjusted it but when I started cutting grass the first time it got hot again and dropped. The head gasket was bad in a spot as well surprisingly it ran pretty well anyway.

I decided to go with new heads. Only one side was really bad but I am doing both. Also a bunch of new gaskets, a new starter " starter works but my luck it would stop half way through summer and as you guys know, its way easier to change now" also installing new coils, and stator for same reason.

So, the moral is. CLEAN UNDER YOUR TINS! or spend a lot of money later....

OMG ----- :bigeyes:

But then again, I have seen those situations.

Good write up. For the less experienced and newbies, keep us updated along the way.

:IH Trusted Hand:

Will do Roland, BTW.. It really ran great with the new pushrod LOL.. Only lasted about an hour but hey. I gave it a shot.

Heads arrived today. Along with starter and wrong push rods:angry:

Bolted the heads down. Will do a little more cleaning while I wait for other parts to arrive

Okay, call me crazy. But I already do not like the quality of the new stamped rockers vs the original machined ones. The parts I ordered are B&S OEM. Our countries quality is going to crap!

The "new" stamped ones are fine. The "machined" ones you speak of were first design and superceded long ago with the stamped ones.

I've taken a hammer and tapped bent pushrods straight and used them with no problem. Once the reason they bent in the first place was taken care of.

Bent push rods straight huh?? Okay. I will not be doing that no matter how well its worked for you. The reason I wont. Is why take the chance on having a weakened rod rebending and ending up down in the cam or lower? The rods are 5 bucks a piece

I know the stamped ones are fine. But in no way of the same quality. Just cheaper to make

Okay, fine with me.

Sorry man,, But this is what bent rods from a Briggs look like if they enter the cam area. There is no "straitening" these.. And I dont want to own one like this.

How is the camshaft?

Lew,

Those are not my push rods. Mine didnt hit the cam. All measurements I got lead to my cam being fine. My point was I would not try to straighten a bent rod and have it wind up hitting my cam

Great picture you posted there. Nice and scary. I wouldn't straighten them either. Maybe the one on the right?

But I wouldn't have put a bunch of expensive brand new parts on an old, overheated engine either.:biggrin2:

Fast to judgment. The cylinder walls are fine, crank, bearings, end play fine. Since you are so proficient in B&S then you know this is a common issue and often fixed exactly how I am fixing it. Expense is relative. They are a lot cheaper than buying an engine, which is what you could end up doing if you straighten push rods.

By the way, which ones would you straighten? Intakes? Exhausts? Both? Just curious

"Proficient" isn't the best way to describe my association(s) with Briggs/Stratton small engines. Seasoned/frugal is more accurate. The first B&S engine I souped up was over 65 years ago. I've hauled in about a dozen junker 1440/1641 CC's in the last several years. Parted out three that were too rusty to mess with. The rest, I got running and cut grass with them. Or, just look at them. I think I have close to 20 Cyclops CC's. Several 1864's, 1862's, 2082, couple of 2084's. So, I've experienced most of the typical B&S problems including Command issues.

Is this your first Vanguard or just your first Cyclops?

The only thing common about bent push rods that I know of is they bend when the engine is overheated and a guide comes loose and slides up in the bore and binds the spring retainer which bends the push rod.

I'm curious as well. Which push rod do you think goes on which valve intake/exhaust valve? Steel or aluminum? The exhaust guide seems to be the one that slips. Also seems like it is usually the left side.

The early shaft mounted rockers were good. Just expensive. The first edition stamped rocker replacement was a little wimpy. It was replaced by a second design with an indentation behind the rocker tip and they are robust.

It's no sin to save a buck or two. I had a guide slip in one of my Vanguard's heads. Bent the pushrod. First one I had seen. I smacked the valve with a hammer and knocked the guide back down where it belonged, straightened the push rod. It ran for several hours without a load. After about a half hour cutting grass and same thing happened again. Guide slipped again.

I went to my stack and got another head off one that had a broken rod. Straightened the push rod again and put it back together. That engine has been mowing about an acre of grass for two years without a problem.

If you don't like my methods, that's fine. There are others here that don't fix things by just writing a check. Some, because they don't have a check. Some because they like to see what they can fix rather than replace and others, are just plain cheap. I have a check book so just put me in the latter two categories.

My first cyclops. No where near my first vanguard, v-twin, 100's of full engine rebuilds from 3 hp to 2000 hp gas and diesel engines.

The aluminium rod is intake. the steel is exhaust. This aint rocket science...


The overheating on these engines typically resides at the heads. They are the first part to overheat and the bushing moves then the rod bends. So typically the heat issue stops at the head since the block is inherently cooler by nature anyway.

Once the bushing or guide slips the damage has been done. You might get lucky by "smacking it back into place" or it could move again the first time you run it. Of course that's if the guide slips upward which is usually not the case. They tend to slip down which means your removing the head anyway, which means your pulling the engine anyway.

As I stated in my first post. I could repair the head. It would be a simple fix to install new guide, use a punch to indent the area on top around the bushing to give it a tighter fit, install new rods, and roll with it.

I do not "flip" many tractors. But I have no idea what the future holds for this one. I may end up selling it at some point. If I do, I will have the clear conscience of knowing it was fixed correctly.
I do not know if you are a "flipper" or not. But I am glad you offered the information you did.

This is not a matter of writing a check or not. I rebuild equipment for a living. Fixing things most times means spending money. Its just the nature of the beast. Yeah, sometimes there are band aids or cheap fixes that can be done. In this case I want to have a trouble free tractor for many hours of use. I don't want to have it drop dead on me in the middle of mowing. So yeah. I spent 280$ on heads. I spent 20$ on push rods. I could have stopped there. Bit for an extra 140$ I am installing a new starter, new coils, new stater, and a new seal. All the things that would force me to pull the engine again.

Call it what you want.

BTW.. you answered your own question in your response.
Bent the pushrod. First one I had seen. I smacked the valve with a hammer and knocked the guide back down where it belonged, straightened the push rod. It ran for several hours without a load. After about a half hour cutting grass and same thing happened again. Guide slipped again.

Depends on who you ask. Even B&S is confused.

[/QUOTE]

BTW.. you answered your own question in your response.
Bent the pushrod. First one I had seen. I smacked the valve with a hammer and knocked the guide back down where it belonged, straightened the push rod. It ran for several hours without a load. After about a half hour cutting grass and same thing happened again. Guide slipped again.[/QUOTE]


This wasn't a question. It was a statement.

I'm not a flipper. I buy and keep.

Have a good day.

BTW.. you answered your own question in your response.
Bent the pushrod. First one I had seen. I smacked the valve with a hammer and knocked the guide back down where it belonged, straightened the push rod. It ran for several hours without a load. After about a half hour cutting grass and same thing happened again. Guide slipped again.[/QUOTE]


This wasn't a question. It was a statement.

I'm not a flipper. I buy and keep.

Have a good day.[/QUOTE]

I know that was not a question. Your question or statement, whatever, "why install new heads and why not straighten push rods?". You yourself stated why that was not really an option. You tried what you suggested then wound up changing the head. Just like I am doing. The difference is, You had a spare. I didn't. And I didnt trust the used ones I saw on ebay. So I bought new ones.

Good day!:beerchug:

This wasn't a question. It was a statement.

I'm not a flipper. I buy and keep.

Have a good day.[/QUOTE]

I know that was not a question. Your question or statement, whatever, "why install new heads and why not straighten push rods?". You yourself stated why that was not really an option. You tried what you suggested then wound up changing the head. Just like I am doing. The difference is, You had a spare. I didn't. And I didnt trust the used ones I saw on ebay. So I bought new ones.

Good day!:beerchug:[/QUOTE]


The other difference which you missed, or didn't mention is, I straightened the push rod twice and it's still running two years later, cutting an acre a week.

I know that was not a question. Your question or statement, whatever, "why install new heads and why not straighten push rods?". You yourself stated why that was not really an option. You tried what you suggested then wound up changing the head. Just like I am doing. The difference is, You had a spare. I didn't. And I didnt trust the used ones I saw on ebay. So I bought new ones.

Good day!:beerchug:[/QUOTE]


The other difference which you missed, or didn't mention is, I straightened the push rod twice and it's still running two years later, cutting an acre a week.[/QUOTE]

Oh. I didnt miss it :biggrin2:
That was after you put a different head on it. Mike, seriously? What is your issue with me using new push rods with my new heads? Like I said the push rods are 5 dollars each. Are you saying I should have straightened the old one out and put it in my new head? I am really confused by all of this.

So what, I spent a few bucks, according to you maybe for nothing. But I have piece of mind for 5$ push rods. I am glad your straightened push rods held up in your engine, Good job and congrats..:beerchug:

Can we move on now?

[QUOTE=cooperino;482665

What is your issue with me using new push rods with my new heads?
Can we move on now?[/QUOTE]

I don't/didn't have an issue with you spending your money. I simply suggested that bent push rods could be straightened by tapping them (reasonably) straight with a hammer and you chose to take it to another level. If you didn't want to heed that tip, just ignore it.

You're the one that had the issue first with my "tip". So, go ahead and move on if you'd like. No sense beating a dead horse.

OK let's get back to the repair. :beerchug:

You know it Sam.. Just waitin on the parts.

UPDATE !
Okay, she is all back together again. It took a little more time than expected. Heres why.
As I said. Ordered new heads, coils, starter, seals, yadda yadda. I had also ordered a new kill wire assy. I installed everything, double checks clearances, air gap etc. The engine fired right up..ok great I thought. Well, still no power. First thing I thought of was "oh crap! Lew asked me about the cam" but I measured it and I had both cylinders the first time I put the new push rod in it. The pto ran and all. So, I started checking spark. Had good spark. I pulled plugs. Uh oh! One wet one dry. What could this be??? Pulled then engine again. Took off blower housing. Air gap still good. Not sure why I thought to do this but I pulled the kill wire and ohmed it out. One side "while connected to coils" showed open. The other side. Closed. Brand new kill wire from briggs with one defective diode. So anyway. I got her all back together. Fired up! BOTH CYLINDERS! YAY. So I cut the front grass hood still off just in case. Ran terrific. Lots of power. Very very happy!

PS, I should add. the thing that brought me to the kill wire was that when I shut off the key the tractor hesitated to shut down. The fuel solenoid is what was shutting it down. The kill wire had worked before all the work was done.

Yeah,I get it George. Trust me, very familiar with stamped rockers. I was just sayin Briggs did this to go cheap. Also the prior design was nice because it had a piece between the 2 rockers that aided in adjusting. The new ones are separated so when you go to adjust them, they twist almost to the point that the rod can and has fallen out of the rocker. The old rocker type had much less twist.

In any event I did get them adjusted obviously and should be fine for many years. It was a fun project and I am happy with the results. Now that everything is running correctly the new to me 1641 will get much seat time as it will now be my go to cutter. This will give the 126 a break and it will be coming into the shop for refurbishment once the 100 is finished. :beerchug:

sorry coop, I shouldn't of derailed your repair post, It has been deleted.:bash2:

No worries at all bud. Didnt bother me in the least:beerchug: