Bent valve cover

[JimRB]

If that was mine and I could not find a cheap replacement I would be drilling a few stop holes, grooving out the crack, propane torch pre-warming and tigging away. My lawn mower deck had all kinds of cracks and pieces missing and it welded up just fine. Even if it warped a bit in the process, a few minutes on the mill and it would be good as used.

 

[Tinhack]

Call Circle G and see if they can get one. Otherwise, fix what you have. Looking at your photo close-up indicates that the problem may have been mechanic-induced. The crack goes all the way through the bolt hole on the left. I suspect the crack continues to the bolt hole on the far right as well (not shown). Whoever did the work on your engine over tightened the valve cover bolts. Perhaps to stop an oil leak.

 

[quicksandfarmer]

Call Circle G and see if they can get one. Otherwise, fix what you have. Looking at your photo close-up indicates that the problem may have been mechanic-induced. The crack goes all the way through the bolt hole on the left. I suspect the crack continues to the bolt hole on the far right as well (not shown). Whoever did the work on your engine over tightened the valve cover bolts. Perhaps to stop an oil leak.

The only one who's ever worked on this engine is me!

The last time I adjusted the valves I had a hard time getting the cover off, I whacked it with a block of wood. I'm thinking that might have cracked it. I put those bolts back on with a torque wrench so I don't think I overtightened it.

 

[piper184]

Looking closely at the picture it would appear that the webbing in the casting is not sufficient to transfer the loads from the hold down bolts to the edges of the cover. If a new one has the same design, it is likely to fail in the same manor.
That being said, you did get quite a few years worth out of it and how ever many hours it lasted.

If you can't get a new one, this one could probably be made serviceable by a couple of different methods.

My ideas would be to find a shop willing to give welding a try. Then see if there is room on the inside to have some re-enforcing gussets welded into it. Then I would look into making some sort of plate to put over the top on the outside so that the clamping forces were spread across the top to the edges and take some of the stress off of the center line running along the crack.

Then I would definitely use an RTV product to seal a new gasket to both the head and the cover. That way the only force that the hold down bolts need to exert is enough to hold the cover in place. The RTV will aid in gluing the cover down and in sealing the surfaces.

It wouldn't be pretty and it might not work, but at least you might get the use of your tractor back.

Another option might be to see if you can find a foundry that would be able to cast a new cover using the existing one to make a mold.

Hope you find a solution

 

[quicksandfarmer]

Looking closely at the picture it would appear that the webbing in the casting is not sufficient to transfer the loads from the hold down bolts to the edges of the cover. If a new one has the same design, it is likely to fail in the same manor.
That being said, you did get quite a few years worth out of it and how ever many hours it lasted.

If you can't get a new one, this one could probably be made serviceable by a couple of different methods.

My ideas would be to find a shop willing to give welding a try. Then see if there is room on the inside to have some re-enforcing gussets welded into it. Then I would look into making some sort of plate to put over the top on the outside so that the clamping forces were spread across the top to the edges and take some of the stress off of the center line running along the crack.

Then I would definitely use an RTV product to seal a new gasket to both the head and the cover. That way the only force that the hold down bolts need to exert is enough to hold the cover in place. The RTV will aid in gluing the cover down and in sealing the surfaces.

It wouldn't be pretty and it might not work, but at least you might get the use of your tractor back.

Another option might be to see if you can find a foundry that would be able to cast a new cover using the existing one to make a mold.

Hope you find a solution

Thanks.
Since it doesn't leak through the crack, but around the edges when the cover distorts, I'm thinking of something similar if I can't find a replacement: seal it with RTV and replace the nuts with lock nuts, and tighten them just barely tight enough to hold the cover on.

 

[5030]

I TIG weld alloys all the time and the issue is: It's oil soaked and aluminum alloy tends to soak up the oil and so you cannot TIG it unless you remove all the oil from the 'pores' of the alloy and that can be pretty complex and time consuming as in repeated 'baths' in various non contaminating solvents, followed by a good washing in hot water and even then, if any oil is left in the casting, the weld won't take and be porous. If it was mine, I'd be perusing various salvage sites to see if I could find one. The length of the crack is what really precludes TIG welding and it has to be done by a very competent weldor as well. It won't be cheap by a long shot. Just the prep will be expensive time wise. Problem with older units is parts availability.

Good luck. You are gonna need it.

 

[piper184]

I wonder if they ever used a stamped steel cover on that same head design? Perhaps try searching for a different year. With my luck they wouldn't be interchangeable but it might be worth some searching.

Another option is to make a new cover from scratch. If I did it, it would likely be rectangular and ugly as sin, but I bet I could fab up something that would seal. A welder, a torch or plasma cutter, some plate, some angle and some time.

The salvage yard idea is a good one. Take the old cover along and shop for something close that could be modified. You might not find anything, but desperate times and all that....

 

[etpm]

You could try JB Weld or similar on that crack. Or, if you don't want to spend the money getting it TIG welded, then try aluminum solder. They sell aluminum solder at decent hardware stores. Out of curiosity I decided to test the strength of aluminum solder and found it to be quite strong. It is easy to use. You just need to get the aluminum clean. A propane torch would provide enough heat if the valve cover was first wrapped in something insulating.
Eric

 

[quicksandfarmer]

So an update on this:

I talked to Tommy at Affordable Tractor, he had a cover for a YD480. I have a YD485, but since they use the same gasket I thought I'd give it a try. Well, I tried it today, it doesn't work, it's not quite deep enough for the rocker valves.

I used the tractor today for the first time in a while, I lost about a quart of oil in about an hour. So the tractor is almost unusable as-is.

I'm thinking my best bet now is to try and glue the cover on with RTV. I'm thinking of leaving the gasket in, but putting a layer of RTV on each side. I'm also considering only gluing on the bottom, hoping that the thickness of the gasket would create a dam to hold the oil in. That would have the benefit that it would still be possible to get the cover off.

Any recommendations for a specific type/brand of RTV? Any ideas for getting the surfaces clean?

Thanks.

 

[etpm]

So an update on this:

I talked to Tommy at Affordable Tractor, he had a cover for a YD480. I have a YD485, but since they use the same gasket I thought I'd give it a try. Well, I tried it today, it doesn't work, it's not quite deep enough for the rocker valves.

I used the tractor today for the first time in a while, I lost about a quart of oil in about an hour. So the tractor is almost unusable as-is.

I'm thinking my best bet now is to try and glue the cover on with RTV. I'm thinking of leaving the gasket in, but putting a layer of RTV on each side. I'm also considering only gluing on the bottom, hoping that the thickness of the gasket would create a dam to hold the oil in. That would have the benefit that it would still be possible to get the cover off.

Any recommendations for a specific type/brand of RTV? Any ideas for getting the surfaces clean?

Thanks.

I'm gonna repeat myself and suggest aluminum solder again. Really. If you have a decent propane torch you can do it. Vee out the crack some, clean the area real well with brake cleaner, let it dry, and solder away. And also apply solder to the outside of the valve cover along the line of the crack. Or, if you don't like this solution, get a piece of aluminum plate that will make up the thickness difference between the different model valve covers. Then use a band saw or a jig saw or whatever you have and cut the plate to resemble the gasket. Drill any necessary holes. And use two gaskets instead of one. Or, you could just use several gaskets to make up the difference. But really, it is easy to solder aluminum with the aluminum solder rods that are sold at any good hardware store. I tested the stuff and it is not only easy to use it is quite strong. You just need enough heat. Pre-heating in an oven or with a weed burner is acceptable. Be careful with a weed burner though because it could melt the cover. It only needs to be just a little too hot to touch, like 250 degrees F. Then solder away. My opinion is to repair the valve cover so that it can be used in perpetuity without any extra gaskets, or sealant, or spacers. Even though I am a good TIG welder, and have two TIG machines, I would be sorely tempted to use aluminum solder just because my tests show that it is actually good stuff and quite strong.
Eric