B7100 leaking oil from odd location at head

[N3BP]

Hello,

I purchased a 79 B7100 this summer and have been slowly replacing parts as needed on it. I put it back together and all seems to work well except for two oil leaks.

The first leak is a bad rear main seal, unfortunately.

The second is from two odd locations on the cylinder head. Picture attached. They appear to be plugged holes. I have no clue what they are for, but they both are leaking oil.

Anyone have a clue to what the hang they are? Can I just RTV around them, or are there pressurized oil galleys behind them?

My end goal is to stop the leak without having to pull the head. Any help is much appreciated.

Thanks,
Brandon

 

[North Idaho Wolfman]

Those are plugs in oil galley holes, they were drilled when the head was made, looks like the plugs have worked out, and no RTV will not seal them.

You need to either remove the plugs and put new ones in or drive them in and see if they reseal.

 

[Tooljunkie]

How about cleaning and a drop of loctite? Perhaps not, as bore would need to be clean also.
Thread and tap for a pipe plug?
First would be drive in and see if they seal.as wolfman said.

 

[N3BP]

Thanks for the reply gentlemen. I did try to pull the one out with a set of vicegrips and could not get it out. I did mar the aluminum sleeve in the process. Hopefully I didn't screw it up because I don't believe I am going to get it out. I'll try to drive them back in. I'll try the loctite and see if that works to help seal. If not, I'm half tempted to weld them shut. Don't know why they have this two piece setup. It appears I can still get the parts.

Thanks,
Brandon

 

[North Idaho Wolfman]

It will be hard to weld them as the head is cast steel and the plugs are aluminum.
You would be better off getting new plugs and pull out the existing plugs and replace them.

 

[Tooljunkie]

Drill plug,tap it and thread small bolt into plug. Then you have something to pull on.

 

[North Idaho Wolfman]

Drill plug,tap it and thread small bolt into plug. Then you have something to pull on.

Easy out might be even faster!

 

[Tooljunkie]

Easy out might be even faster!

Actually,once threaded-a piece of pipe and a couple washers-as bolt tightens against pipe with washers it will pull the plug. I have a tool for pulling pins in tilt steering colums, and it works great.

 

[N3BP]

So my temporary fix was to punch the pins back in and place a thick glob of red RTV over them. The pins pushed back in easy, but they don't appear to come out easy.

I doubt this will hold and I already ordered replacements, but it sure would be nice to last through the snowblowing season.

So I'm letting the RTV setup for a day and I'll run it tomorrow night to see if it holds. Thanks for all the input fellows.

Brandon

 

[North Idaho Wolfman]

So my temporary fix was to punch the pins back in and place a thick glob of red RTV over them.

You would have been better off using epoxy putty to do it, as that will hold!

But it can always be redone if they leak.

 

[N3BP]

Well it seems I lucked out. The "temporary" fix was holding after an hour of operation. Thanks Again

 

[Tooljunkie]

Hope fix holds,perhaps it was some odd event that caused them to work out, like engine got really hot and oil pressure relief stuck. Or maybe this is just what happens from time to time.
I was going to suggest jb weld. But wolfman came up with epoxy putty, i fixed a briggs crankcase with it once,held for 15 years.

 

[N3BP]

Yes, I'm hoping it holds until warmer weather. I though about various scenarios that would cause them to push out. Overheating being one of them. I also wonder if the vibration that occurs on a diesel engine helped nudge them loose. Cummins had issues with case alignment dowel pins working loos due the constant vibration. Either way it does seem to be a rare occurrence.

 

[Tooljunkie]

They are soft,hammering them back in may have swelled them a fraction and in turn tightening them up.