There Are Sealants...And There Are Sealants
It was a rather balmy spring afternoon. Dr. Crankshaft was just finishing up after working at preparing his garden for spring planting when Dabney drove up on his vintage 1969 Triumph motorcycle.
"Hey, Doc, whaddya think?" he said as he shut the bike off. He was obviously proud that he got his motorcycle back on the road. "Not bad for a winter's work, huh, Doc? I restored the entire thing over the winter. Took everything apart and polished the aluminum castings, wheel spokes and anything that could be made shiny. And I painted the frame and fenders. I think this British Racing Green really sets it off"
"Impressive, Dabney," said the Doctor sincerely, "but it looks to me like you got a bit of a problem." The Doctor was pointing to the oil leaking from the seam between the engine block and aluminum case on the kickstart side. It was also leaking from the oil strainer on the bottom of the engine. "How does it run?"
"Well, this is the first real test outside. I've test-fired the motor with a little gas, but only for a few seconds," said Dabney. "It seems to run ok, except for these oil leaks. There's also a little gas seepage from the bottom of the carburetor."
"So I see," said the Doctor. A drop of gasoline was forming at the bottom of the carburetor where a brass nut was fastened. "Of course, there's the old joke about British cars; I guess it could apply to British motorcycles: you only worry about them when they stop leaking oil," said Dr. Crankshaft, "but there's really no reason for all those leaks."
"I really don't understand it, Doc, I used all new gaskets and put sealants on everything, and after all that, it still leaks," said Dabney.
"What kind of sealants did you use?" asked the Doctor.
"Oh, the usual stuff. I used a tube of Permatex, just like I've always done. I've been using the stuff for years," replied Dabney.
"Holy hemorrhage!" exclaimed Doc. "It's no wonder all these leaks are happening. Let me explain a bit about sealants... Let's go over to the bench." Doc had a bench next to his garden, along with a table that held his iced tea. With that, Dabney put down the kickstand, leaned the bike, and walked over to the bench and sat down. Sometimes (most of the time) Dabney felt that the Doctor was being critical of him. This time he didn't feel that way so he was eager to hear one of Doctor Crankshaft's lengthy lectures, hoping he could learn something.
"Time was, gaskets used in engines and fuel systems were primitive, usually made of cardboard or cork. As oils and fuels changed, new and improved materials had to be created that resisted leakage. Since most gaskets themselves couldn't seal all leakage, sealants were developed to help the process along. These liquids - or semi-liquids - would be sprayed, brushed or spread on the gasket surface," said the Doctor.
"Dabney, when your motorcycle was manufactured, they might have used something like that Permatex on the gasket surfaces. But time has conspired to slightly warp the engine's metal parts and modern oils and gasoline no longer are kept from leaking by a 'one-size-fits-all' sealant. In fact, if you notice the Permatex display at the auto parts store you will see that the Form-A-Gasket brand now comes in many different mixtures, numbered from one on up. Each of these has a specific purpose, degree of hardness when dry and resistance to certain materials. You have to choose the right one for the job. On top of that you have the silicone sealants too. These also come in different formulations to resist regular and synthetic oils, antifreezes, greases, transmission fluids and gasoline. Some resist vibration and some don't. In fact, today's car engines generally contain 23 different sealants in their assemblies," the Doctor expounded.
Doc continued, "There are new products out there that can go a long way to making your life better. Unfortunately, now you're going to have to do a little disassembly on your motorcycle and use the correct sealants. You gotta keep up with the times, my boy."
"You're right, Doc. I guess I'll go back to the garage and start tearing 'er down."
"Yeah, Dabney, looks like that's what you need to do. By the way, I'm supposed to meet the Missus at Nelda's Diner in a few minutes. Can you give me a lift into town?
"Sure," said Dabney.
"Great! Wait a minute, and I'll get my helmet."
Doc disappeared into his garage and came back out wearing a vintage '40s helmet left over from his dad's racing days. "Like I said, Dabney, you gotta keep up with the times."
Dabney could hear the Doctor behind him chuckling to himself as they drove off.