grove cutting tool

[Frank S]

this is another of those sometimes I hate it when I am always right things.
The whole reason I made my transmission jack was to change a rear main seal on a friends Mack truck
I had been telling him for a year or more that he had an iol leack between the flywheel housing and the engine block.
Every Mack service center in country that he has had some repairs done on his truck while out on the road has said the rear main seal was leaking.
Finally he took it to a shop to get another related issue taken care of on the transmission they kept the truck for 2 weeks then claimed the only thing wrong was the throw out bearing was dry and greased it. The issue was the clutch arm bushings were worn They were supposed to pull the transmission and replace them but they didn't Saying OH they are not bad enough to need replacing at this time
Anyway I told him that if I was to drop the tranny I wanted to replace the clutch since he had 400,000 miles on it already. and I was not going to do a job twice.
He said he wanted the rear main seal replaced anyway OF COARSE YOU DO I thought. And I'm going to have the flywheel ground as well and pull the housing off to FIX the leak
In all the years that truck manufactures have been in business they still haven't learned that when they assemble the flywheel housing to the engine the only thing that keeps the oil from leaking is a microscopically thin layer of RTV sealant. and when the housing is tightened to the block most of that is squeezed out and over time what little that is still there will deteriorate Either the bolts will become loosened slightly from the constant pounding form the torque of the engine or heat and cooling what ever, eventually it is going to leak. because the main sealing is not between the mated surfaces but the tiny little bead of sealant that forms along the edges
The solution that I have done to every housing I have installed for the past 45 or 50 years I learned from my dad long before that. Back when the housings were made of cast iron before RTV was ever invented
You cut a very small grove all the way around the housing on the mating surface.
Note the evidence of oil leaking to the outside of the housing

First I cut a small grove using a ball file with a baby hobby tool
then I made the grooving tool to deepen the cut

This is a poor quality video since my friend nor I am are video graphics engineers
but is explains the process

[olderdan]

I totally agree with your observations and comments on this issue, I do the same thing on my motorcycle engines on all mating faces and junk the gaskets.

http://www.homemadetools.net/forum/g...2000#post75558

[Frank S]

I totally agree with your observations and comments on this issue, I do the same thing on my motorcycle engines on all mating faces and junk the gaskets.

http://www.homemadetools.net/forum/g...2000#post75558

Yep, my dad told me that there has never been an automotive engineer who knew everything. I acquired a war surplus HD 45 sometime around 1968 he and I stripped it to the last bolt then rebuilt it our way. every mating surface had a tiny little grove cut in them either to hold the gaskets or to aid in sealing He had dozens of little tricks he showed me while we put it back together. Probably the only 45 in the country at the time that you could ride hard all day then park it on a white towel and not get shot by my mom for ruining her towel.
It doesn't take much of a grove on most things like motorcycle cases just a few thou wide and deep is enough. A lot of the Japanese cycles have groves made for "O" rings Imagine that!

[jfwahl48]

Old-school people are just great

[madokie]

if cutting grooves in precison machined mating surface is not your thing ,, Its not mine.. just use permatex aviation form a gasket ,gasket sealer , or what ever its called these days, the dark brown black thick gooey stuff.to both sides of your gasket, nothing i have leaks oil !!!!!! and no i am NOT a fan of silicon sealer for engines and such , its made for weather stripping, and caulking use..

[11thhourfabrication]

if cutting grooves in precison machined mating surface is not your thing ,, Its not mine.. just use permatex aviation form a gasket ,gasket sealer , or what ever its called these days, the dark brown black thick gooey stuff.to both sides of your gasket, nothing i have leaks oil !!!!!! and no i am NOT a fan of silicon sealer for engines and such , its made for weather stripping, and caulking use..

Hi
The Aviation sealer works but it is a PITA to take the unit apart afterwards and to clean before assembly. Try using Permatex Hylomar it seals just as well but is easy to disassemble and clean up for reassembly. Originally made by Rolls Royce to seal their engines. Use it on all my motors and no oil leak issues to deal with.

[NortonDommi]

Hylomar sealant
I think the best thing about Hylomar is that it is non-hardening, defiantly my favourite. I'm not a fan of RTV because I have seen it gooped on and beads and strings of squeeze out, internally drop down and clog the oil pickup. That said I have used the right stuff sparingly on a lot on Japanese bikes and all sorts of cars because that is what is specified and never had a problem but I'm a nut on clean parts that are straight. I can certainly see the merit in the groove though.

[Frank S]

One f the reasons why I grove the flywheel housings on heavy duty diesels boils down to this. Here you have an engine capable of close to or more than 2000 ft lb torque output or around 2800 Nm take your choice, and a transmission weighing over 800 lbs literally hanging on the back of this with a low reduction of 14 or 19 to 1 multiplying the torque from the engine to the driveline all of this is held together by 8 tiny little 15 mm bolts and 2 16 mm dowels.
When all you have is 2 flat machined surfaces mated together with a thin almost non existent thickness of sealant to keep oil from leaking all these forces are working against a long term proper seal even when no actual oil pressure is involved there is the fact that 2 dissimilar metals cast iron engine block and the aluminum flywheel housing react differently to stresses and most of all heat factor in a million miles or more of hard work that microscopic film of sealant is going to be eradicated so in a sense the only real seal you ever had was the squeezed out bead adhering to both parts. By adding a small grove to 1 of these parts I have created a cavity for the bead to be held between the parts instead of on the edges. I have effectively made an "O"ring out of the sealant. Will it ever leak? of course given the right conditions but so can "O" rings once they get old and brittle if there is ever any movement. But this engine has 925,000 miles on it and judging from the past 4 years of oil sampling I figure it to only have another 8 to 900,000 miles of life left in it or about 5 years I'm trying to talk my friend into buying an engine for me to rebuild and have sitting on the shelf so to speak just in case his engine dies. or I might wind up and install it in 1 of his other trucks.

[NortonDommi]

Hello Frank,
I understand fully the reasoning and wholly agree with you. Basically you are mitigating a design fault. For the record I like like gaskets, real ones not goop but they are still subject to the same problem if the basic design is flawed.
Spare engine is a good idea. When I was working in the rubbish industry I and a couple of other guys convinced management to let us build a spare engine during occasional slack time. TWO DAYS after it was finished it was used and saved the company a lot of money in penalties,(we got a good stock of spares out if that). A rebuilt engine can also be sold if your mate decides to retire.

[DIYer]

Thanks Frank S! We've added your Groove Cutting Tool to our Transmission category,
as well as to your builder page: Frank S's Homemade Tools. Your receipt:

Groove Cutting Tool by Frank S

tags: seal, hand tools, grooving