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Post by rideslikenacho on Sept 11, 2023 6:08:34 GMT -5
Yeah the case halves are near that bolt area as well. Tightening the cylinder bolt nuts made the leak worse so I’m leaning towards base gasket but also cannot rule out case seal either. Used honda bond when putting the case halves together but yeah that’s possible the leak is from there. Probably best to try a new gasket first along with some sort of sealant, and see if that resolves it. I torqued everything to spec in the manual so it was definitely done to manual spec. Also could be the cylinder body not sitting entirely flush with the engine case.
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Post by GrumpyUnk on Sept 11, 2023 8:50:33 GMT -5
What he said. Most times where one surface has a joint, such as the case split line, manufacturers will specify a dab of RTV sealant right where the 3 parts come together. In the case of a split crankcase, it would be at either side of the cylinder, where the case halves come together. The case gasket may be shaved to match the surface level to form a better seal. If the case gasket protrudes, it may cause leakage.
When I have dry 'paper' gaskets, or O-ring gaskets, I will smear some RTV on the surface of the gasket, almost enough that you could see the color of the RTV, IOW, a very THIN smear. Only enough to take up any imperfections in the gasket surface of the machined parts. Some are pitted or rough, and the thin smear will fill those tiny bumps and crevasses. Not enough that the RTV is forced out the edges when the fasteners are tightened. When re-using O-ring gaskets on 4T, or on CVT cases, a thin smear will allow sealing, AND give a good surfact that allows removal without tearing. O-rings on carburetor mating or mounting plates insures a decent seal even with tired O-rings. Yeah, belt AND suspenders...
tom
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Post by rideslikenacho on Sept 11, 2023 12:09:07 GMT -5
Ok thanks, I’ll try a thin smear of rtv with the base gasket next time. Any recommendations for a good rtv sealant? Would be great to only do this one more time. 😂 Nothing like having to redo everything after a build.
Hopefully not a leak from the case where it comes together. It may get a thin layer of rtv along the seams while Im in there.
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Post by GrumpyUnk on Sept 12, 2023 10:32:12 GMT -5
I do not know if you are the first post manufacture to fiddle with the cylinder. I do not know about yours but most have a couple ferrules poked in diagonally to align the cylinder. Be sure they are replaced and in the correct position.
I just used some blue RTV that was designed for gasket sealing. The tube was blue and it was made by Permatex, I think. They are an old company, so must be doing at least one or two things right. There are multiple versions o the market. I ignored what they said, and used it on base gaskets, rocker cover gaskets, CVT gaskets, O-ring seals on a 3.0 V6 intake, upper & lower and about anything else where a slight seal was needed. I think it will fill small scratches that could lead to seepage, and it did help semi-hardened O-ring seals on 4T cam covers to remain pretty leak free.
Honestly I think you could use RTV from a tube sold to fit into a caulking gun. The 12" long, 2" dia tubes.
Thing is to keep it from 'curing'(vulcanizing) in the tube. I refrigerate mine. Less HOH in the air, and chilly. It actually keeps the RTV pretty well. Mom does not know as it is in the basement reefer.
tom
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Post by rideslikenacho on Sept 13, 2023 5:49:23 GMT -5
Definitely made sure the ferrules were in place and aligned correctly and pretty sure nobody had ever opened it up before me. I’ll get a new base gasket and some rtv permatex, maybe the ultra black stuff and redo it. I believe that lower left area is where one of the ferrules is, maybe it didn’t area correctly who knows.
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Post by GrumpyUnk on Sept 13, 2023 8:40:16 GMT -5
The base gasket does 99.99% of the sealing normally. The RTV will just fill small imperfections in the metal machined surfaces of the block and bottom of the cylinder. The 4T engines have a oil passage coming up from the block on the left side, between two studs. It will travel across the bottom of the cylinder to go around the top left stud up to the cylinder head, and then within the head to the cam & rocker arm/followers.
A 2T would have oil from the fuel mix collect in the sump. It should not be a lot, but there will be some. I think it helps lube the bearings/cylinder wall a bit, but you don't really want it wandering around on the outer surfaces. A water cooled would have ... more stuff, and possibly a coolant mix leak.
If you have a 4T be sure any RTV/sealant used does NOT get into the oil passage area on the block or bottom of the cylinder. It can clog oil flow if too much is present. The amount used should be very minimal, a smear. Not a blob.
tom
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