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donbarnes Samba Member

Joined: February 28, 2011 Posts: 731 Location: Wilmington,NC
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Posted: Wed Apr 06, 2011 2:40 pm Post subject: Long-term Head/Cylinder/Case Sealing? |
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Starting to rebuild a 1600 Mexi AS41 to stock specs with new Mahle kit and wondering what is the best option for sealing between the cylinder and case, then between the cylinder and head? Not so much worried about deck height and compression/performance- Just want it to sit there as long as possible without leaking? It came apart with paper gasket between jug/case, and metal shim between jug/head. Fel-Pro still sells a head gasket set that has copper shims they claim aid in long term sealing, any thoughts on that? thanks...(and yes I have a Muir book, but wondered what everybody does nowadays)..  |
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KTPhil  Samba Member

Joined: April 06, 2006 Posts: 35847 Location: Conejo Valley, CA
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Posted: Wed Apr 06, 2011 4:20 pm Post subject: |
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No copper seals have been part of the VW engine since the clean-air models came in about '65. And typically cylinder shims go between the case and cylinders, not between the cylinders and head.
Grind the cylinders into the head with valve compound.
The paper gaskets don't work well at the case. I used them with a smear of high-temp silicone; or if I have metal shims for CR control, on the shims themselves. |
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anthracitedub Samba Member
Joined: June 20, 2007 Posts: 3241 Location: Michigan
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Posted: Wed Apr 06, 2011 4:34 pm Post subject: |
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X2 on lapping the cylinder into its respective resting place on the cylinder head. I always used gasket shellac along with the little paper gaskets on the case/cylinder fitment. |
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slalombuggy Samba Member

Joined: July 17, 2010 Posts: 9329 Location: Canada
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Posted: Wed Apr 06, 2011 6:05 pm Post subject: |
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As long as you don't over heat the motor you won't need anything to seal the cyl/head. As for the base gaskets. I used to use av gasket shelac and paper gaskets on stock motors, now I just use Right Stuff silicone and never worry about leaks on all my motors, big or stock. Use it sparingly, just a thin bead will do.
brad |
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johnnypan Samba Member

Joined: October 24, 2007 Posts: 7431 Location: sackamenna
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Posted: Wed Apr 06, 2011 9:38 pm Post subject: |
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use this cylinder to case,toss the paper gaskets...what KT says about cylinder to head... |
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babyblue69 Samba Member
Joined: May 21, 2007 Posts: 33 Location: Stockton, ca.
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Posted: Thu Apr 07, 2011 7:16 am Post subject: |
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KT
What do you exactly mean about "Grind the cylinders into the head with valve compound." Grind is what I am not sure of.
I am going to be building a 1776 motor and want to seal it up nice and tight. |
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anthracitedub Samba Member
Joined: June 20, 2007 Posts: 3241 Location: Michigan
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Posted: Thu Apr 07, 2011 7:25 am Post subject: |
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Use some light valve lapping compound, put a little on the rim the cylinder then, insert the cylinder into the head and rotate it back and fourth, the grit will seat the cylinder into the head…you don't have to go all hog nutz crazy with it, just a little…and be certain that you clean all that stuff out of there once your done.
I never used to do this procedure, but an old school dubber was doing it in a shop I worked at many moons ago…he said it was a little peace of mind type thing and I agree…may not be needed but I started doing it after that…could be an OCD type thing. |
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babyblue69 Samba Member
Joined: May 21, 2007 Posts: 33 Location: Stockton, ca.
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Posted: Thu Apr 07, 2011 9:00 am Post subject: |
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I have never used Valve Compound. After you grind the head and cylinder how much time do you have to mount them?
Or do you half mount a cylinder, grind it, finish mounting it and them move to the other cylinder repeat and apply before the compound hardens up?
Half mount a cylinder = piston on the rod, jug over piston and slid over the head studs but not enough so they do not stick through so you can rotate the head on the cylinder. |
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djkeev Samba Moderator

Joined: September 30, 2007 Posts: 32987 Location: Reading Pennsylvania
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anthracitedub Samba Member
Joined: June 20, 2007 Posts: 3241 Location: Michigan
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Posted: Thu Apr 07, 2011 9:20 am Post subject: |
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babyblue69 wrote: |
I have never used Valve Compound. After you grind the head and cylinder how much time do you have to mount them?
Or do you half mount a cylinder, grind it, finish mounting it and them move to the other cylinder repeat and apply before the compound hardens up?
Half mount a cylinder = piston on the rod, jug over piston and slid over the head studs but not enough so they do not stick through so you can rotate the head on the cylinder. |
Its not a sealant…its an abrasive used to seat valves in a cylinder head. Its like an abrasive paste. So after it is used you clean it all out of the areas, if you leave it in, you will ruin your engine. The entire procedure is not needed, its only added peace of mind...
Last edited by anthracitedub on Thu Apr 07, 2011 9:31 am; edited 1 time in total |
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KTPhil  Samba Member

Joined: April 06, 2006 Posts: 35847 Location: Conejo Valley, CA
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Posted: Thu Apr 07, 2011 9:24 am Post subject: |
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babyblue69 wrote: |
I have never used Valve Compound. After you grind the head and cylinder how much time do you have to mount them?
Or do you half mount a cylinder, grind it, finish mounting it and them move to the other cylinder repeat and apply before the compound hardens up? |
Valve grinding compound never hardens, it just dries out a little. It's just a way to ensure a really smooth mating surface for best sealing. As posted, you just use it as a gentle abrasive, then clean it off all surfaces. Then you can take as long as you like to do assembly. |
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babyblue69 Samba Member
Joined: May 21, 2007 Posts: 33 Location: Stockton, ca.
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Posted: Thu Apr 07, 2011 9:54 am Post subject: |
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Okay. thanks anthracitedub and KTPhil, my retarted mind has got it now.
Thanks for all of the help.
I will be back with more questions during my build |
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KTPhil  Samba Member

Joined: April 06, 2006 Posts: 35847 Location: Conejo Valley, CA
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Posted: Thu Apr 07, 2011 10:23 am Post subject: |
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Take it slowly, and expect to have to redo everything at least once-- that's standard practice to get it right. Ask a million questions. Read the Muir and Fisher books for two extremes on the rebuilding methods and tools needed.
Last edited by KTPhil on Thu Apr 07, 2011 10:53 am; edited 1 time in total |
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babyblue69 Samba Member
Joined: May 21, 2007 Posts: 33 Location: Stockton, ca.
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Posted: Thu Apr 07, 2011 10:37 am Post subject: |
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Re-do's I am REALLY good at.
the only thing that has me a little overwelmed is the rocker arm geometry. I have been doing alot of reading and think I know enought to start asking qualified questions not to sound like a goober. |
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KTPhil  Samba Member

Joined: April 06, 2006 Posts: 35847 Location: Conejo Valley, CA
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Posted: Thu Apr 07, 2011 10:56 am Post subject: |
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With a stock rebuild you have little to worry about with rocker geometry. At most you may need to add shim washers to make the adjusting stud contact the valve tip in the right spot.
Maybe I'mm just very lucky, but all of my rebuilds have worked out fine without adding shims. But then they have all been stock. |
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john7 Samba Member
Joined: August 06, 2003 Posts: 1549 Location: Garden grove ca
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Posted: Thu Apr 07, 2011 1:44 pm Post subject: |
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i build alot engines, all the time. im sure i am way into the hundreds but i never kept track. my sealers of choice for a leak free engine are
case haves -Yamabond or 3 bond 1104 (same stuff)
ultra black RTV on - cylinders to case
ultra black rtv- under the 6 main case half washers, the 2 washers on the case studs above and below the cam plug, under the washer on the case stud just over the oil pump.
ultra black RTV- between the oil pump and the case
Kuril K2- on oil pump cover gasket
nothing on the push rod tube seals with stock tubes, if you are using spring loaded tubes ultra black on the seals
super weatherstrip adhesive on the valve cover to the gasket (never put anything on the head side)
factory sealing nuts on the oil pump cover, use no washer and red side towards the pump cover (other wise dont even bother using them if you dont use them correctly)
oil sump plate gets german gaskets with copper crush rings & factory cap nut (i had rubber gaskets made and they work awesome, no seepage or anything)
i clean everything 3 times or until my white shop rags stay white (even the washers). this is a place most people skimp and if not totally clean it doesnt matter what sealer you use it will leak
thats about $50 in different sealers when you buy them but the tube of 1104 will last about 10 engines, the tub of kuril K2 will last years, the tube of super weatherstrip adhesive will last a long long time and the rtv will go the quickest _________________ Jesus Saves
Slot Mag King!
I accept Paypal, CASH, GOLD, SILVER, COINS, GUNS & money orders. |
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babyblue69 Samba Member
Joined: May 21, 2007 Posts: 33 Location: Stockton, ca.
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Posted: Thu Apr 07, 2011 1:59 pm Post subject: |
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I can see after all of that sealant you do not leak.
factory sealing nuts on the oil pump cover, use no washer and red side towards the pump cover (other wise dont even bother using them if you dont use them correctly)
I have been lucky on my other engines I believe I put the red on the out side and I did not leak. It has been 10+ years since I have built a VW motor, I could be wrong on the nuts but I do remember no leaks.[/quote] |
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KTPhil  Samba Member

Joined: April 06, 2006 Posts: 35847 Location: Conejo Valley, CA
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Posted: Thu Apr 07, 2011 2:37 pm Post subject: |
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There is a difference between sealing nuts (with the red plastic on the face of the nut towards the cover), and locking nuts (with the plastic on the outside, though a little countersunk into the thread area). The first is used to seal, the second to avoid coming loose. Many people confuse the two. |
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john7 Samba Member
Joined: August 06, 2003 Posts: 1549 Location: Garden grove ca
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Posted: Thu Apr 07, 2011 3:27 pm Post subject: |
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KTPhil is right they are often confused.
oh and i dont use any gasket between the case and the deep sump. only Toyota Oil Pan sealant (it is not the same as black rtv) _________________ Jesus Saves
Slot Mag King!
I accept Paypal, CASH, GOLD, SILVER, COINS, GUNS & money orders. |
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donbarnes Samba Member

Joined: February 28, 2011 Posts: 731 Location: Wilmington,NC
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Posted: Thu Apr 07, 2011 7:52 pm Post subject: |
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Whats the difference between Hylomar Aero and Hylomar Blue or Racing? And there seems to be different makers of "Hylomar", I've seen it listed under Permatex and Valco? I used to be a fan of Permatex Aviation (still have a tub of it) until I put a Mopar show car engine together with it and within a couple of years the engine was dirty and seeping in mutiple places, almost like the Aviation dissolved or broke down, had to pull it back out and reseal the whole engine  |
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