Bent valve cover

quicksandfarmer · Aug 9, 2024

Has anyone experienced a bent valve cover on their inma?

Background: I checked the oil before starting and it was very low. Looking under the hood, there was oil all over the right side of the engine compartment. So I topped it up and started it and looked, and oil was leaking out under the valve cover. I stopped the engine and inspected it closer, and the valve cover gasket had slipped out sideways and oil was leaking out under it. So I loosened the nuts, pushed the gasket back in, tightened the nuts and started it up again, seemed to work.

Then a few days later it slipped out again. Upon closer inspection this time, I noticed that the valve cover was not even with the edge of the engine block, it bulges out in the middle. You can kind of see it in this picture:

So I'm trying to figure out what to do. I've ordered a new gasket to see if that helps. It could be that the cover has always been like that and I never noticed it. But I'm trying to think forward if the bend cover is the problem. Could I bend it back into shape? It's case aluminum about a quarter inch thick. I worry that it will never bend quite into shape and there will always be irregularity that keeps it from sealing.

Or should I try sealing it with liquid gasket? I think that would do a better job of adapting to the irregularity.

Other thoughts?

alexpops · Aug 9, 2024

take it off/clean it up/& see what's going on. Is it deformed like from under excess pressure? like something hit it from inside? or is it a bad casting/press job? from the pic, it looks like you got way more than a gasket issue going on. there's oil all over the valve cover like it's coming from somewhere higher up. you won't be able to tell till you get it clean.

CliffordK · Aug 9, 2024

1/4" thick would be mighty thick aluminum.

Can you tell if the valve cover was cast, or forged/extruded?

If it was cast, it will be tough to do much with it.

If I saw obvious signs of a previous bend (and no cracks), I might try bending it back. However, it might also be a manufacturing defect.

Can you locate a new valve cover?

I like to add a gasket sealant to my gaskets. Yet, I fear this may be a losing battle.

2515R Dude · Aug 9, 2024

Can you clean the cover and post a picture of it?
I highly doubt it is bent for two reasons: 1- If it is a manufacturer's defect, why it did not leak for 17 years you own the tractor?
2. if it is bent indeed, so, it is something recent because you just noticed it, meaning there is a much, much bigger problem.

5030 · Aug 9, 2024

If it's a Jinma, the valve cover is pressed steel btw.

piper184 · Aug 9, 2024

It is perfectly acceptable to use RTV in place of a low pressure gasket. The down side is that it is harder to remove the next time.

BUT, you have to figure out what went wrong before attempting any repairs.

I am not familiar with your particular engine but can definitely tell you that the 284 with the Y85 engine uses a stamped sheet metal cover and a fairly thick and stiff gasket. I had mine off for the valve adjust and the gasket was good enough to re-use. I did however clean it well and give it a very thin coating of high temp RTV (what I had on hand at the time) to aid in sealing.

I would suggest cleaning the exterior of the engine.
Removing the valve cover and gasket and clean them separately.
Inspect bowed out area for anything out of "whack". Think loose rocker or rocker shaft. Perhaps a broken valve spring.
If all is well, do the valve adjust, since it is open anyway
Use a small hammer and gently do some sheet metal work to reshape the cover.
Install with new gasket. Use RTV if you think it is needed.
Let set overnight and do a test run.

Please report back with pictures if possible.

Best of luck

quicksandfarmer · Sep 12, 2024

I had a chance to look at it today. It turns out the valve cover is cracked:

When the bolts are tightened down it flexes along the crack and bulges out.

I have to see if I can get a replacement.

piper184 · Sep 12, 2024

Well, that sucks!

Find the data plate on the engine and have a go at the search engines. Odds are one of the online dealers can help you.

Affordable tractors and Circle G come to the top of my mind, but there are others that are worthy too.

A really good weld shop may be able to fix it for you if you can't find a replacement. Welding dirty, oily cast aluminum of unknown alloy would not be in my wheelhouse to even try. Last resort kind of thing.

Good luck and let us know how it turns out

5030 · Sep 12, 2024

Too big of a crack to TIG. Replace it.

quicksandfarmer · Sep 12, 2024

So far the only site I've found that even has it listed is Circle G, but it's out of stock:

Valve Cover-YD485

Bin 11

www.circlegtractorparts.com

I was hoping they'd have a part number that I could Google but they have the SKU as "Valve Cover-YD485."

AliBaba has this, which is close but not right:

Valve Cover For Yangdong 4cyl Engine - Buy Cylinder Sleeve seal Liner shelf Liner Product on Alibaba.com

www.alibaba.com

JimRB · Sep 12, 2024

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 · Sep 12, 2024

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 · Sep 12, 2024

Tinhack said:
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 · Sep 12, 2024

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 · Sep 12, 2024

piper184 said:
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 · Sep 13, 2024

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 · Sep 13, 2024

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 · Sep 15, 2024

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 · Feb 10, 2025

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 · Feb 10, 2025

quicksandfarmer said:
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