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Briggs Intek V-Twin(s) Blowing Sump Gaskets....

Posted by BriggsGalaxieman 10 (My Page) on
Wed, Dec 12, 12 at 9:07

Engine: Briggs Intek V-Twin 26 hp 446777-0244-E1


I am having a problem with blowing out sump gaskets on this model engine. Twice it has happened on two different engines:

1. My original factory 446777, purchased in 2004, developed the sump gasket leak after about 8 years use. I replaced that gasket using RTV Blue as a sealer and it does not leak (so far).

2. I rebuilt a second 446777 for another tractor, about two years ago. This engine developed the exact same leak last summer. The picture below shows this engine that I just now disassembled. The picture shows the damaged gasket exactly as it appeared when I opened the sump.

In both engines the leak was in exactly the same place (directly below #2 cylinder). The original 2002 factory engine did not have any sealer on the gasket (as I used on both gaskets I replaced), but it did fail in exactly the same place.

Any ideas?

Thanks....

Photobucket


Follow-Up Postings:

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RE: Briggs Intek V-Twin(s) Blowing Sump Gaskets....

I personally would not use silicone. When I do these, they get a light amount of high tack on the gasket before it is installed. Do both sides if you wish. Any signs of loosening on the fasteners, use loctite- or maybe use it anyways.


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RE: Briggs Intek V-Twin(s) Blowing Sump Gaskets....

tomplum...

I don't think the problem is with the silicone because I had the same leak...same place with the factory no gasket setup...and I have another engine that I did with silicone that does not leak....

The first thing I have checked when leak started was the bolts. Never found one untight. I used a torque wrench on all sump bolts when assembling....


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RE: Briggs Intek V-Twin(s) Blowing Sump Gaskets....

did the gasket blow out - or was it sucked into the crankcase?


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RE: Briggs Intek V-Twin(s) Blowing Sump Gaskets....

bluemower,

The gasket was exactly as you see in the photo. The one small piece was hanging outside of the engine before I took it apart. I did not touch that area of the gasket when removing the sump. But, the other 'half' of the gasket was inside the sump as seen in the photo.

It actually appears to have been 'blown out' AND been 'sucked in'....


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RE: Briggs Intek V-Twin(s) Blowing Sump Gaskets....

A certain brand of forklift transmission where I work will have a control valve gasket failure (blow out) of the OEM gasket at the main pressure galley which will result in transmission slippage upon takeoff.
The reason the gasket fails is due to the ultra smooth surfaces of both the trans case (cast iron) and the control valve (cast aluminum alloy). The aluminum casting process used by the OEM produces such a perfectly smooth gasket surface that they don't even machine the gasket perimeter at all. And the "too smooth" surface is what leads to the failure of the OEM gasket after about 10,000 hours on the clock (approx. 3 years in our operation) because there is no "tooth" on the metal surface to bite into the gasket surface and hold it in place.
My fix which I learned years ago working in a motorcycle shop (where we had a similar problem on engine valve covers) is to first clean off all oil using a shop towel wet with spray carb cleaner (or other volatile solvent) and lightly scuff the entire gasket perimeter with a Scotchbrite pad.
Next, using an automatic center punch I make a line of punch upsets at about the centerline of the gasket perimeter about 3/8" to 1/2" apart around the entire gasket line.
Lastly, after marking which side of the new gasket will be in contact with the punched surface, I spray that surface of the GASKET with Permatex High Tack gasket sealer/adhesive. Then while the High Tack is still wet, I flip the gasket over and lower it into position on the valve body. Get all the bolt holes aligned and press the gasket down evenly. Then I install the valve to the trans case and torque to specs.
Have not had a repeat failure in 12 years of doing this.
I am having to resort to using 3 separate posts for the photos as the forum does not seem to want multiple image uploads (er else I ain't figgered it out yit).


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Gaskets....2

Photo 2


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Gaskets....3

Photo 3


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Gaskets....follow up

Galaxyman, I believe if you use my technique you will have success in holding the gasket in place.
And silicone RTV is not the preferred sealant to use on aluminum surfaces unless it is especially formulated for aluminum.
And even when you use RTV that is compatible with aluminum (the Permatex ULTRA line in any color)) you must clean the surfaces well with an evaporating type solvent.
The last (and maybe most significant in your failures here) is that some GASKETS will not bond to ANY formula of RTV.
I always use High Tack when I go with a gasket.
RTV of the correct type can often be used INSTEAD OF a gasket in certain applications, but a sump gasket is not one of those places because the thickness of the gasket is accounted for in the end spacing clearance of the crankshaft bearings.


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RE: Briggs Intek V-Twin(s) Blowing Sump Gaskets....

mownie,

As usual...really good information!

Yes, the gasket surfaces are both aluminum, very smooth and shiny!

Your suggestion to 'rough up' the surfaces makes a lot of sense. After that, I will follow up with a lacquer thinner cleaning and High Tack sealant with the gasket.

I suspect that the failure of the gasket in that particular place, on this engine, is caused by heat.

If you look again at my picture you can see that the problem area for the gasket on this engine is right below #2 cylinder bore. The #2 cylinder bore is within about 1/2 inch of the gasket failure. That, it seems to me, would be a place that gets extra hot. The #1 cylinder bore is offset vertically and 1 1/2 inches from the gasket surface. The 'extra' heat on the gasket area may cause just a 'little bit extra' expansion of the joint between the surfaces and thus allow the gasket to 'slip' on the smooth surfaces. Since the sump is under positive pressure it would tend to push the gasket outward, which did happen here.

Thanks for your help,

Galaxieman


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RE: Briggs Intek V-Twin(s) Blowing Sump Gaskets....

BGM, that is entirely possible. By the way, Permatex has a "brush in can" version of High Tack which I have used at home. Mainly I like the brush/can because there is no overspray with it, and I can tell you that the spray type will make some pretty spider webby looking red overspray if ya ain't real careful. That is why I spray it on the gasket at work instead of the metal surface. I can put the gasket on a scrap piece of cardboard and spray away without painting everything nearby. :^)


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RE: Briggs Intek V-Twin(s) Blowing Sump Gaskets....

mownie,

I had planned to pick up some Permatex High Tack (brush in the can style) at my local parts store. I just noticed that I do have Permatex Super 300 Form-A-Gasket 'in stock'. Would that be OK for the sump gasket or should I get the Permatex High Tack?

Thank again,

Galaxieman


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RE: Briggs Intek V-Twin(s) Blowing Sump Gaskets....

Well, I'm gonna be opinionated on that one. I went to the Permatex website and reviewed the corporate blurbs. While the 300 and the High Tack do read very similar.....only the High Tack had any verbage about "holding a gasket in place".
Both products purport to "seal" but only the High Tack mentioned "holding", and even THAT might mean "during assembly".
Possibly either of the products could provide a decent and dependable bond given the metal surfaces are prepared properly by scuffing and de-oiling with an evaporating solvent prior to assembly.


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RE: Briggs Intek V-Twin(s) Blowing Sump Gaskets....

I thought I would tie up this thread by showing what I did for the sump assembly:

First, I roughed up the gasket surface on both the sump and block with a small wire brush in a drill. The 'scratching' is just enough so that I can feel it with a fingernail.

Photobucket

Then, I punched slightly raised marks onto the gasket surface of the sump with a punch and hammer.

Photobucket

Then, I finshed the assmebly using Permatex High Tack Gasket Sealant:

Photobucket

Hopefully this will finally solve my gasket blowout problems. Thanks for the suggestions....

Galaxieamn


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RE: Briggs Intek V-Twin(s) Blowing Sump Gaskets....

Well sir, I believe that will do the trick. :^)


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RE: Briggs Intek V-Twin(s) Blowing Sump Gaskets....

I am just catching up with the various comments and the job may be completed, but here are more comments.

In the original picture, my impression is the gasket was crushed at the bolt hole. Perhaps the factory overtorqued and part of the gasket was pushed in and part of the gasket was pushed out. i don't know if extreme engine heat may have caused this. Another possibility is full torque may have been applied to the one bolt before the other bolts were screwed down.

When evaluating this type of problem, a straight edge should be placed across the bolt holes to see if there is any warpage. This type of damage would apply excessive pressure to the gasket around the bolt holes. The space between the bolt holes may not apply enought pressure to hold the gasket in place. Since the crankcase is supposed to operate with slightly negative pressure, a gasket that is not securely held in place would most likely be sucked into the crankcase.

hopefully the suggested repairs will solve the problem. After assembling and starting the engine, consider performing a crankcase vacuum check.


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