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getagripgreg
Greg Stasko

(33 posts)

Registered:
10/23/2008 12:08AM

Main British Car:
BOP Cylinder head bolt sealant, POB #4?
Posted by: getagripgreg
Date: November 23, 2008 02:37PM

Hi,
I'm getting ready to put the heads back on my Olds 215, and the manual calls for POB #4 sealant (or equivalent) on the threads of the head bolts.

What type of sealant is it and what do folks use? Searching online only turned up Lycoming aircraft engine info.

Do the bolts seal into a water cavity?

Thanks,
Greg


Citron
Stephen DeGroat
Lugoff, SC
(367 posts)

Registered:
10/23/2007 09:43PM

Main British Car:
1970 MGBGT V6, 7004R, AC, matching trailer 3.1 liter

Re: BOP Cylinder head bolt sealant, POB #4?
Posted by: Citron
Date: November 24, 2008 01:38PM

I build mostly chevy 350's, but I use CarQuest Sensor safe silicone sealer, red or black or clear.
I never have any leaks and never blow head gaskets due to the sealant affecting the toque settings.

Steve


getagripgreg
Greg Stasko

(33 posts)

Registered:
10/23/2008 12:08AM

Main British Car:
Re: BOP Cylinder head bolt sealant, POB #4?
Posted by: getagripgreg
Date: November 24, 2008 02:28PM

Thanks Steve,

I prepped the block to put the heads on yesterday and figured it out. About half the bolt holes go into the water jacket, and half are blind. The Felpro instructions called for pipe sealant. I think I'm going to use Permatex aviation.

Anybody else have a favorite?

Also, the head gaskets are not marked top, but are metal on one side and composite on the other. Damn instructions say to just line up the holes if there is no top mark, but these are symmetrical! Does the steel side face the deck or the head?

On another note, there are six helicoils in the block, two of them very badly done, and there were 30 year old metal chips in the bottom of the holes! Hacks. :p

Cheers,
Greg
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ex-tyke
Graham Creswick
Chatham, Ontario, Canada
(1165 posts)

Registered:
10/25/2007 11:17AM

Main British Car:
1976 MGB Ford 302

authors avatar
Re: BOP Cylinder head bolt sealant, POB #4?
Posted by: ex-tyke
Date: November 24, 2008 08:36PM

Greg,
I used Permatex red sealant (good for 650 deg F) on my Olds some years ago and never had a problem.
A word of caution....don't forget to use the same sealant on the exhaust header/manifold bolts - they also extend into coolant galleries.


Dave
David Gable
Jax
(112 posts)

Registered:
10/23/2007 05:40AM

Main British Car:
Re: BOP Cylinder head bolt sealant, POB #4?
Posted by: Dave
Date: November 25, 2008 09:11AM

So, the 215's DO have head bolts going into water jackets? I've been told by someone who should know that they don't. Curious.

Mark at D&D told me that the 300's do not have any wet head bolts, just some front cover bolts. I asked before I built my motor and just called and asked Mark again to be sure. No water leaks, just nervous after reading this.


MGBV8
Carl Floyd
Kingsport, TN
(4513 posts)

Registered:
10/23/2007 11:32PM

Main British Car:
1979 MGB Buick 215

authors avatar
Re: BOP Cylinder head bolt sealant, POB #4?
Posted by: MGBV8
Date: November 25, 2008 09:48AM

"So, the 215's DO have head bolts going into water jackets?"

He's asking about the Olds 215 that has six head bolts per cylinder. The Buick/Rover blocks are different. I have to go out in the garage to double check, but I'm fairly certain that the Buick/Rover holes are all blind.


Dave
David Gable
Jax
(112 posts)

Registered:
10/23/2007 05:40AM

Main British Car:
Re: BOP Cylinder head bolt sealant, POB #4?
Posted by: Dave
Date: November 25, 2008 10:23AM

Thanks, Carl.



Dave
David Gable
Jax
(112 posts)

Registered:
10/23/2007 05:40AM

Main British Car:
Re: BOP Cylinder head bolt sealant, POB #4?
Posted by: Dave
Date: November 29, 2008 01:00PM

Carl, any luck?


MGBV8
Carl Floyd
Kingsport, TN
(4513 posts)

Registered:
10/23/2007 11:32PM

Main British Car:
1979 MGB Buick 215

authors avatar
Re: BOP Cylinder head bolt sealant, POB #4?
Posted by: MGBV8
Date: November 29, 2008 02:30PM

All the head bolt holes in the 1989 Rover 3.9L block in my garage are blind, no water passages involved. Should be the same for the Buick 215.


Dave
David Gable
Jax
(112 posts)

Registered:
10/23/2007 05:40AM

Main British Car:
Re: BOP Cylinder head bolt sealant, POB #4?
Posted by: Dave
Date: November 30, 2008 09:24AM

Thanks


ex-tyke
Graham Creswick
Chatham, Ontario, Canada
(1165 posts)

Registered:
10/25/2007 11:17AM

Main British Car:
1976 MGB Ford 302

authors avatar
Re: BOP Cylinder head bolt sealant, POB #4?
Posted by: ex-tyke
Date: November 30, 2008 01:16PM

A quote from the 1961 Oldsmobile F85 Service manual:

"All cylinder head bolt threads must be coated with POB No.4 Sealer or equivalent, Torque head bolts 45-55 ft.lbs
and torque exhaust manifold to head bolts 18-24 ft.lbs."

I know for sure that the exhaust manifold holes are not blind as I wrestled with a couple of leaky ones over the time that the Olds was installed and it seems logical that the main headbolts have open holes based on the manual intructions above.
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getagripgreg
Greg Stasko

(33 posts)

Registered:
10/23/2008 12:08AM

Main British Car:
Re: BOP Cylinder head bolt sealant, POB #4?
Posted by: getagripgreg
Date: December 14, 2008 11:47PM

Thanks for all the information.

I had to helicoil several holes before getting the heads on and looked closely to try and figure out which ones went into the water jacket, and honestly could not see any. I suspected that the lower row of holes might intersect the jacket the way the exhaust holes do, but didn't see any evidence of it.

I ended up using Permatex Aviation sealer on all the bolts in case I missed something but also as lubricant for the torquing.

I also mounted the gaskets steel side up and coated on the head side with Copper-coat. (which was useful, because I had to pull the heads off more than once to repair stripped holes, and the gasket stayed with the head.)
Before and After
before.jpg
after.jpg


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