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Cap To Block Seals For Rear Main Seal On 225 Dauntless V6

Discussion in 'Early CJ5 and CJ6 Tech' started by Ugly67, Nov 20, 2017.

  1. Nov 20, 2017
    Ugly67

    Ugly67 Displaced son of Texas

    Longmont, CO
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    I've looked all over the other postings for an answer to this with no luck. If it's already been discussed my apologies. I replaced the rear main seal and cap to block seals, with the associated pins, about 18-years ago on my '67 CJ-5 with the engine out of the Jeep on an engine stand. I don't remember having problems and the seal started leaking after about 15-years, so I decided to put in a new neoprene seal with the engine in place. I figured I'd done it once so I'm now an expert.

    I was able to replace the crankshaft seal with the new neoprene seal, but just had a devil of a time getting the cap to block seals and pins to go in. I managed to mangle the rubber cap to block seals and couldn't get the pins to go in all the way. I put the seals in according to the instructions and kind of massaged them in while I slowly tapped in the cap; trying to keep them an equal length through the whole process. Everything was greased to the hilt. Had to cut the second pin off since it kept bending as I was tapping it carefully in once the cap was set, but not torqued. Once everything was buttoned up, I was leaking oil, and I've not taken it back down yet, but I'm certain it's the cap to block seals.

    I've read in other Buick forums that you can eliminate the cap to block rubber seals and pins with some judiciously placed RTV sealant that is allowed to dry before you put the pan back on. That sounds A LOT easier. Any ideas?
     
  2. Nov 20, 2017
    tarry99

    tarry99 Member

    Northern California
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    Did you offset the parting line on the seal when installed? I would get a seal from TA Performance , I think the pins on those are optional.

    [​IMG]
     
  3. Nov 20, 2017
    NCRenII

    NCRenII yellow fever

    Far Nor Cal
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    manual says that the oem neoprene seals are expandable type that need to be soaked in kerosene for 1 1/2 minutes then installed, once installed the ends (don't cut off) need to be peened over to create a "mating surface" that will seal with the mating surface and again coated with kerosene. Once installed and run-in, oil and heat continue the expansion.
    This I found may be helpful:
    Click this <-, or this <-
    Also, do clean everything very well (I use acetone for final clean) and use a sealer on the entire face of the bearing cap where it contacts the corresponding block surface.
     
    Last edited: Nov 21, 2017
  4. Nov 21, 2017
    Ugly67

    Ugly67 Displaced son of Texas

    Longmont, CO
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    I didn't offset the parting line on the crank seal, and I've seen posts on both sides of that issue. Not sure that would address the cap to block seal problem, but I think I'll do it this next time, just because it makes sense. I like the idea of seals without pins, and I'll likely use TA seals this next time. Thanks for your help.
     
  5. Nov 21, 2017
    Ugly67

    Ugly67 Displaced son of Texas

    Longmont, CO
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    I don't have access to a shop manual, and this is the first I've heard of the kerosene treatment. I'm guessing that shrinks down the neoprene seals and makes them more malleable. Sounds like the ends are pretty pliable when soaked in kerosene, and to honest I've never peened anything that I can remember so this will be a first.
     
  6. Nov 21, 2017
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
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  7. Nov 21, 2017
    Mcruff

    Mcruff Earlycj5 Machinist

    Albertville, AL
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    The factory seals were not neoprene on the 225, they were a braided rope style, thats why you soak them in Kerosene. My replacement engine kit had both neoprene and the rope style, I went with the neoprene, no kerosene needed.
     
    mike starck likes this.
  8. Nov 21, 2017
    mike starck

    mike starck Member

    salem,oregon
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    unfortunately the OEM rope seals contained asbestos fiber therefore are no longer available. The new style rope seal didn't seem user friendly and I have searched the swap meets for the old style with no luck.I will say I never had a rope seal that I installed leak.Can't say that for neoprene. But life goes on and we will do the best we can with what they give us. The serrations on the seal surface on the crankshaft don't help the cause either.
     
  9. Nov 22, 2017
    Ugly67

    Ugly67 Displaced son of Texas

    Longmont, CO
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    Thanks a TON for the link to the factory manual pdf. What an amazing thanksgiving gift! Really appreciate.
     
  10. Nov 22, 2017
    NCRenII

    NCRenII yellow fever

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    McRuff, the rope seals the crankshaft journal. The neoprene (square rubber) seal the sides of the cap to the block.
    Ugly67 think of the rear main cap: every surface needs to be sealed. The crank journal is sealed by the rope (olden material) and now rubber/neoprene. The three surfaces of the block where the cap meets needs to be sealed. The horizontal surface (top of cap either side of the bearing) needs a sealant applied (red rtv for one).
    [image]ECJ5[/image]
    Then there is the sides of the cap, this is where the square blocks go. Some people do not use them and rather squeeze as much rtv in there as they can get in there, insert a wire to push it into corners, add more sealant. In any case wherever seal or sealants are used to keep oil in it's imperative to have the metal be sparkling clean. I use a cleaner (permatex gaser remover) to remove all traces of old sealant, scrub with a bronze brush and final clean with acetone. Main oil leaks are to be avoided. Some people now use anerobic sealants since they "cure" in the absence of air/moisture.
    Lastly the oil pan seals the final edge of the cap (and block). Do use a quality oil pan gasket and rtv there.
     
    Last edited: Nov 23, 2017
    Keys5a likes this.
  11. Nov 22, 2017
    Ugly67

    Ugly67 Displaced son of Texas

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    I appreciate all of the expert advice and guidance. Here's the plan: I've ordered crankshaft and cap to block seals from TA Performance. They're all neoprene and don't require pins. I'll be clocking the neoprene crank seal about 5-degrees off the block surface.

    Thanks to those who either forwarded or cited the service manual which is clear that the neoprene cap to block seals need to be soaked in kerosene prior to sticking them into the side slots after the cap is torqued into place. There's no way that would have worked the first time around. My cap to block seals were just too big. Don't know why, but they were. I'll be cleaning everything out of every conceivable crevice (except crank/bearing surfaces) with a brass brush and acetone prior to reassembly. I'm anxious to practice my peening skills; I have ball peen hammers. If I'm unable to get the neoprene cap to block seals to work, I'll yank them out and go the RTV sealant route as a secondary option. I like options.

    RTV the appropriate spots with pan and reinstall with a new pan gasket from TA Performance. I'm confident with the brain trust on this site that I'll have success. Thanks again to all.
     
    tarry99 likes this.
  12. Nov 23, 2017
    NCRenII

    NCRenII yellow fever

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    Knowing you are getting ta perf parts, do follow their directions. makers have changed materials. the pin style you mentioned the rubber slides in and the pins tapped in to expand to seal. some people put a dab of rtv at the bottom of the channel prior to installing the cap and strip so when the side seals are installed and pins driven in it squeezes out and fills cavities. I do not know what type seal ta performance supplies. check with them.
     
  13. Nov 23, 2017
    fhoehle

    fhoehle Sponsor

    Harford Township, PA
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    I had a Green Diamond International engine that had a similar setup to the Dauntless. Instead of neoprene seals for the cap to block area they gave you a bunch of string and a dowel. You put the string in the hole and tamped it down. I used RTV in the hole prior to string and, bizarre as the setup was, it worked.
     
  14. Nov 27, 2017
    Ugly67

    Ugly67 Displaced son of Texas

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    I received my seals from TA Performance, and the side seals are the same as the one's that I had before with the pins. We'll see what happens. This time I will be soaking in kerosene and hopefully that's the fix. If not, I'll discard the neoprene seals and use well-pressurized RTV to seal the sides.
     
  15. Nov 27, 2017
    tarry99

    tarry99 Member

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    RTV is your friend...........make sure all sealing surfaces are clean and free of any debris..........then prior to installing the seal or RTV wipe the areas down with brake-clean.........I also like to make sure the cap is aligned as there is plenty of room for mis-alignment.............here is a link: Blueprint 225
     
  16. Nov 27, 2017
    NCRenII

    NCRenII yellow fever

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    Back to what you have written here. op said neoprene, above you said same ones. Both times you've mentioned pins.
    To be successful lets be sure.
    1) Neoprene needs to be soaked to expand.
    2) Rubber seals need rtv (ultra black is one) squirted, just a little, into the side channel and the seals slid in and after in place the pins driven into the channels to expand the seals. DO NOT SOAK RUBBER as they need to bond to the rtv.
    Needless to say off-setting the seal ends is imperative as is a small amount of rtv on the top of cap mating face, and of course the side seals.
    I just searched the net and found this article that goes through both procedures. while you may chamfer the cap (you'll see this described) do not chamfer the block with crank in place for fear of getting metal filings in there. any chafering needs additional rtv to seal and it's not required.
    Install procedure <- click
    idk why ta performance does not have an install link.
     
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