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Temporary burnt valve repair?
https://www.slantsix.org/forum/viewtopic.php?t=14394		 Page 1 of 1
Author:  Slant6Ram [ Fri Sep 16, 2005 6:58 am ]
Post subject:  Temporary burnt valve repair?
O.K. it all finally clicked for me last night. I pulled the head off a recently aquired "rebuilt" :roll: 170. It had not been rebuilt this decade, but I digress.

The #3 exhaust valve was white as a ghost. I've seen this before, but it never fully clicked that this indicated overheating. The other valves where golden brown or black (lots of oil burning in this "rebuilt" motor)

So I first pulled this white valve to have a look. It was so clearly burnt that I was immediatly enlightened as to what to look for in the future. :shock: , :idea:

I was surprised that the valve was the highly abnomal looking surface, but the seat in the head appeared to be reasonably smooth. I guess the grinding action of the valve keeps if clean like that. I suspect the angle is a little out of spec though.

The seat had not recessed badly and I am interested in 'fixing' this head to temporarily replace the BADLY worn head on my truck. New seals and reasonable valve sealing seem like it might be a big improvement.

Is there any chance of lapping in a used valve at home and getting a few thousand miles of good service from it? I have a pile of used slant six valves to choose from. I need to get through emissions at the end of this month. I only put a few thousand miles a year on the big yellow beast, so I'm hoping it could hold me over until money is a little better next spring.

Please point me to tools I might require or other information. I've now got 6 spare heads on the shelf. 2 are in various stages of porting, and all need the valves checked or refinished.
Author:  SlantSixDan [ Fri Sep 16, 2005 7:09 am ]
Post subject: 
Yep, this'd probably work as a "get-by" deal. All you should need is a valve spring compressor, lapping stick and lapping compound!
Author:  Dennis Weaver [ Fri Sep 16, 2005 8:08 am ]
Post subject: 
...an electric drill motor will work even better!

*ducks to avoid the swirl of controversy this will create* :roll: :lol:

D/W
Author:  SlantSixDan [ Fri Sep 16, 2005 8:30 am ]
Post subject: 
Controversy...?

The drill technique works fine as long as you're careful.
Author:  Slant6Ram [ Fri Sep 16, 2005 1:03 pm ]
Post subject:  Drill
The only drills I have with a chuck big enough is the bench press and a big old manual auger. I'm sure I can spin it fine with an auger, so that's the plan for now.

Any guess how long it'll last and any tips on how much lapping to do. Lucky for me, if I screw it up it's not a big deal. I figure I'll use some lead additive in this motor to slow the progression once the new head is installed. This is an old pre-hardened seat head.
Quote:
Controversy...?
I can't believe Dan and Dennis are in agreement. :shock:

Thanks for the suggestions.
Author:  SlantSixDan [ Fri Sep 16, 2005 1:33 pm ]
Post subject:  Re: Drill
Quote:
I can't believe Dan and Dennis are in agreement. :shock:
That's 'cause we both know the secret of successful valve lapping is to use TransX as lubricant. ;-)
Author:  Pierre [ Fri Sep 16, 2005 2:10 pm ]
Post subject: 
I've seen hand crank deals that have a suction cup at the end. Press the suctioncup onto the valve, turn the hand, and it acts like a manual drill spinning the cup and hence the valve. They are kidn of flimsy but they work.
Author:  oldodge [ Fri Sep 16, 2005 2:39 pm ]
Post subject: 
I've done exactly what you are planning to do with very good results in the past. Lap the valve into the seat until you have a uniform gray color (freshly ground look) all around both the valve and the seat. If you use a drill go easy on the pressure and work the valve up and down off the seat as you go. I have put a valve through the head and chucked a drill to the valve stem to grind them in on a couple four cylinder heads. Probably not good for valve guides or stems but I went slow and careful and it all worked out ok. I've seen these "repairs" last quite a long time. Good luck with yours.
Author:  argentina-slantsixer [ Fri Sep 16, 2005 3:28 pm ]
Post subject: 
I've been there with success. I used diamond lapping compound (comes in a syringe, various grits) and the suction cup with a handdrill
Author:  Dennis Weaver [ Fri Sep 16, 2005 3:35 pm ]
Post subject:  Re: Drill
Quote:
The only drills I have with a chuck big enough is the bench press and a big old manual auger. I'm sure I can spin it fine with an auger, so that's the plan for now.
Use a 5/16" or 3/8" bit with a section of fuel hose and two clamps with your small drill motor. That works better than chucking the valve in the drill anyway.

D/W
Author:  Dennis Weaver [ Fri Sep 16, 2005 3:38 pm ]
Post subject:  Re: Drill
Quote:
Quote:
I can't believe Dan and Dennis are in agreement. :shock:
That's 'cause we both know the secret of successful valve lapping is to use TransX as lubricant. ;-)
...and protecting yourself from lapping dust with a K&N respirator.

D/W
Author:  sandy in BC [ Fri Sep 16, 2005 4:13 pm ]
Post subject: 
Lapping stick, Clover lapping compound. Rub stick between hands, rotate stick a quarter turn , rub again, rotate 1/4 turn, etc, etc.

The drill method is fine on someone elses head....on your own do it right. Remember Weaver is an engineer!

Side bar your honour! I have used this method on a 3000hp marine diesel valve 6" in diameter,,,,bigger suction cup though,,,
Author:  Rust collector [ Fri Sep 16, 2005 4:14 pm ]
Post subject: 
:shock:
Author:  Dennis Weaver [ Fri Sep 16, 2005 4:20 pm ]
Post subject: 
Quote:
The drill method is fine on someone elses head....on your own do it right. Remember Weaver is an engineer!
..or I play one on TV, at least :roll: :lol:

"Do it right" would be take it down to a competent machine shop and spend the $$$ for a full valve job. Anything less is "half fast", but half fast werkz great oftentimes. :shock: :)

D/W
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