The Stovebolt Site Forums The Shop Area Engine Shop Valve job questions on a 235

Hi all,
I delivered my spare engine to my mechanic brother so we can start an overhaul. I have some questions about the head work. He will check it for straightness and cracks, but I want to change the valve seats to the hardened unleaded type and need to know if the old ones need to be machined out, or if they can be removed by hand tools. Same for the valve seats. I am sure my brother knows the score, but I want to know all I can so I can contribute to the process. I am a novice to the engine internals, so any advise and comments will be appreciated. Thanks.
Ralph

I don't think you have to worry about replacing the valve seats as long as they can be reground. I'm sure this motor has run on unleaded for a long time. If the seat are not shot now, they will be fine

Yeah, Big-T is right. I drove my 235s since more than 5 years as daily drivers on unleaded gas and I drive a lot. No problems so far.

Here in Germany the leaded gas was introduced in 1956 so we say everything bevore 1960 was build to use unleaded.

Frank

Thanks guys,
When we pull the valves out, my brother can tell me if there is enough there to regrind them. If not, then I will worry about replacing them.
Ralph

About unleaded gas and the valves. I was concerned and asked this wise old man who had been building cars for eons including cutting his own gears for rare Italian racing cars. He said to put a cup of ATF in the gas tank with each fill. I took his advice and thought if one cup will work, why not the whole quart! Wrong!!! The truck ran, it coughed, it spat, it backfired and it smoked like a house on fire. I laid my own smokescreen on the highway! Never again even though it might help, I don't know. I never had a problem with it and still don't. nyone ever hear of using ATF?

I wonder why ATF? They make a lead additive for old tractors and equipment that I would rather use,
Scott

I had my head redone professionally at a local shop and there was very little cost increase to go to hardened valve seats, new valves. the works. My mott has always been when in deep do it right so you do not have to go deep again.

I agree with Bruce. Hardened exhaust valve seats don't cost much at all. I had the head re-done at an engine shop and it was well worth it.
Rick

Prices vary, but generally the 6 exhaust seats redone should cost about 90 bucks for labor and maybe $20 for the seats.A good shop then charges about 100-120 bucks for a proper valve job,the canted exhaust valves cost a touch more..The exhaust valves on a 235/261 are the same as Smallblock V-8,dime a dozen so to speak.And don'r let no one BS about stainless exhaust valves, the original ones on your engine were stainless.
Seat replacement helps performance by restoring the valve seat location instead of just regrinding the seat deeper into the head.

Thanks for all the replies guys. My biggest problem is that the nearest machine shop is 2 hours away and they seem to be always booked up or take so long that they go out of business before they finish your job. My brother has all the tools to do a valve job on the existing seats, but we have never changed the seats and do not know if this can be done with the tools he has or if they have to be machined out or take specialty equipment. Can this be done by the home mechanic? I have a milling machine at my disposal if that is required. Keep the ideas comming. I am really interested in doing this right, one time.
Ralph

It can be done by a home mechanic who is a reasonably skilled machinist using decent equipment.The old valve seat is just an area of the cast iron head, so you need to machine this out using the valve guide as a center. Then press in the new seats with a hydraulic press.Depending on the siuation,you may want to put the seats in the freezer beforehand.Then accurately cut new seats for the valves.If you boot the job, and a valve seat falls out, it's goodbye engine,so be sure of what you're doing.

Thanks Tony,
I am a fair machinist on a lathe, but not that skilled on a mill. I will take a look at it and decide. I have two spare heads, but I hate to mess even one of them up.
Ralph