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
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
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
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.
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.
"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.
Thanks, Carl.
Carl, any luck?
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.
Thanks
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.
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