I bought theses graphite impregnated Teflon seals from Mac's. My engine builder and the shop foreman both told me to get rid of that junk when I brought it over this morning. They won't assemble the engine with this style seal. It's a Mercury 8CM block, what the best rear main to use? This is what I have that I guess I'll be throwing in the trash. Posted using the Full Custom H.A.M.B. App!
they poo-poo'd customer supplied parts, but wouldn't suggest a replacement? real helpful those guys. FYI, that seal material is used in countless other pump, engine and rotating equipment applications.
I've used this machine shop for years. They built the engine in my sedan. Unfortunately they don't do many flatheads, in fact this is the second one they ever did. The first is still on the road but I think the rear main might be leaking in that one. They had a flat motor guru for years but he retired and took his secrets with him. Posted using the Full Custom H.A.M.B. App!
tell them to use it I don't see why that one wouldn't be any good, most likely they are probably just not used to using a seal like that in other more modern engines
Maybe they haven't seen a flathead rear main seal??? They have only built one other flathead ,what seal did they use in that motor????
only one other flathead? to each their own, but i'd have gone with a shop that knows the engine better
...or show them a prewar labyrinth seal flathead..."See this Air here? You gotta get that in JUST RIGHT so oil doesn't get out!" I've never used anything but the original ropes, well soaked in advance, and I haven't had any problems. I can't tell you anything about the newer stuff. For newer type I would try them if bought through a place like Joblot, Red's, or HH... I think Mac's would happily sell you anything that reached them in a box marked "Flathead Rear Seals" whether it was the greatest development in the last 50 years or wadded up Chinese newspapers. Innovative stuff should come from someone that has tried it, if you are not sure blow an extra 29 cents and get a set of original type.
I'm not aware of anything else that is available for the rear... You can get a neoprene seal for the front, but I've not heard much good about them. Those look like graphite impregnated rope seals, the same kind that come in Fel-pro gasket sets. Nothing wrong with them at all if they're installed properly. And yea, I woulda just told them to use whatever they did on the first engine and let them figure it out...
As long as the seal is packed properly, and the crank has no damage, it will last a long time. Many shops nowadays do not know the proper procedure of installing rope seals, as they do not run across them often. ---John
I used an NOS rope seal that I soaked in oil for a week or so. No leaks there.....and you know how hard I beat on that Flatty.
The graphite impregnated Teflon seals are the best seals to use in the flathead. They are lot better than the original rope type seal. I think you need to find a better shop if they were unable or willing to use the seal you supplied.
The seals from Best Gasket Co. seem to be the brand of choice these days. Not sure if that is what you have, their rear main seals are reported to have a knife blade and guide thing to trim them properly. See http://www.bestgasket.com/
Yup, its a Best gasket. They said they have nothing but bad luck with them. This is a good shop, they do a ton of circle track cars, the Forman has a 410 sprint car and my builder has a pavement late model. Their engines were built in house. Like I said, they built my engine too and I've been hammering on it for going on six years now. But I guess just because they do a lot of race motors doesn't mean they're good with flatheads. I think I'm going to just go back tomorrow and tell them to use the graphite seals. Posted using the Full Custom H.A.M.B. App!
I was just digging through the garage and managed to find a flathead gasket set. It's a Fel Pro unit and these pieces were inside. I'm going to bring them over and see what they say at the machine shop Posted using the Full Custom H.A.M.B. App!
iv got 3 running flatheads and none of them leak at all, and Iv got that type rear seals in all of them. use them..
Tell your machine shop that if they invent a new improved flathead rear main seal they can patent it and become Thousandaires.
I have used the original rope seals in all kinds of engines for 60 years. Never had a leaking problem. Buick small block chev, 6 cylinder chev, y block fords, so on.
Well, the guys at the shop were happy I was able to find these. Everything is all balanced and machined up. Now I'm just waiting on the assembly. Posted using the Full Custom H.A.M.B. App!
It looks like the ones in my 8BA, hasn't leaked since done in 2006. I located a machine shop that all the local antique car gurus use, and those guys are picky ! Find out which machine shop they do business with, and go talk with them. 4TTRUK
Its all about installation. They make it simple by suppling a cardboard guide and a razor knife to accurately cut rope.
My friend that builds flatheads everyday has been using Best Gasket black ones since they came out I don’t think he would if they leaked every time he ran in a new motor on the stand
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