Cylinder head work

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turbostang

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I picked up a set of heads off a Venture, with the intention of porting/polishing them over the winter.
Anyone here ever port a set, and if so what should I look for.
How thick are the castings, any thin spots I should be careful.

Do they like big ports, or is the shape more important. I have done lots of car heads, but this is my first set off a bike.
 
My heads were just ported by Rod a Pro Chassie Racing.I painted them tonight.I'll let you know in a few weeks how it turned out.
 
Other than the cams are these heads identical?

Do they have the same size valves and passageways as the Vmax?
 
wfcall said:
Other than the cams are these heads identical?

Do they have the same size valves and passageways as the Vmax?

Everthing I have seen says yes, unless someone can prove me wrong.
They only cost me $10, and came off an 85 Venture with only 23k miles.
 
Wow, that's good to know.

The guy at PCW told me that the Vmax has valves made out of "stellite" which he said is a really good thing and something you don't want a machiine shop to change out for an aftermarket valve unless absolutely needed.

I wonder if the venture valves are the same? Probably I would imagine just to save Yamaha from running two different production lines for heads?
 
wfcall said:
Wow, that's good to know.

The guy at PCW told me that the Vmax has valves made out of "stellite" which he said is a really good thing and something you don't want a machiine shop to change out for an aftermarket valve unless absolutely needed.

I wonder if the venture valves are the same? Probably I would imagine just to save Yamaha from running two different production lines for heads?
I think most exhaust valves anymore are made out of stellite because of their hardness and ability to handle heat. If the stock exhaust valves don't have a bad burn mark or the stem shows no real wear, a face grind (touch-up) will make them like new again if ground on a valve grinder. Most places install new because they make money on the valves too and is not a "must have", most of the time. Chances are your old valves are better quality anyway.
 
I have not explored the heads that much in detail but I do believe there is enough difference that starting with Vmax heads would have been better. I will have to sit down and check both sets side by side.

The stellite he was referring to was the valve seats. Many years ago when we had leaded gasoline the seats were not needed since the lead in the fuel actually acted as a lucbricant and let the valve job last longer. Since the transition to unleaded fuels the older cars really suffer and a lead substitue should be used. The vehicles designed after that change over already has the harder seats in place.

Valves can be purchased in many configurations and almost all have hardened tips to lenghten their life. Some of the lightes valves are actually hollow and sodium filled. the lighter weight allows for more rpm before float becomes a problem. They can run a lighter spring and make the valve ramp angle on the cam a little steeper so more effective lift is gained from increased duration.

I do believe the cams are different too though either set will work for aftermarket stuff since they are hard welded up and reground anyway.

One thing overlooked by many (except good head builders) is the guides. Over time they wear and allow the valve to slop around in there and this is where you can get some oil burning.

Aftermarket valves are very expensive (though I sell them too) and would usually only be ordered if going to a larger size to get more power and flow. Of course the head has to be enlarged and blended to accept the bigger valve.

Sean Morley
 
wfcall said:
Wow, that's good to know.

The guy at PCW told me that the Vmax has valves made out of "stellite" which he said is a really good thing and something you don't want a machiine shop to change out for an aftermarket valve unless absolutely needed.

I wonder if the venture valves are the same? Probably I would imagine just to save Yamaha from running two different production lines for heads?
Sure reads like he was talking valves here and not seats. I've always had a choice of regular exhaust valves or the stellite kind, which cost more but wear much better. They even have valves made out of a titanium alloy mixture. Metals are getting stronger and lighter all the time.
 
Sorry to burst any body's bubble but :
Stellite is a hard surfacing alloy used on the tips, valve faces of exhaust valves, and on valve seats. The alloy contains cobalt and tungsten. To my knowledge it's not used in billet form to make valves. I've used it in SMAW rod to hard surface mining equipement and tractor blades.
It is far to brittle to be used as a valve stem. Becareful about cutting valve faces on exhaust valves as the stellite coating is thin. The lightest cut possible and then lap in the valves with a paste lapping compound.

As far a porting goes:
I wouldn't open the bowl, smooth the short radius and blend the seats. The intake port should taper in size and not be polished. Air flows better aginst the boundry layer of air rather than the mirror finish of a polished surface. Though I have polished exhaust ports to keep carbon bulidup to a minimum.
But it's just my $ 0.02 here and I sure there are other opnions.
Lew
 
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Lew L said:
As far a porting goes:
I wouldn't open the bowl, smooth the short radius and blend the seats. The intake port should taper in size and not be polished. Air flows better aginst the boundry layer of air rather than the mirror finish of a polished surface. Though I have polished exhaust ports to keep carbon bulidup to a minimum.
But it's just my $ 0.02 here and I sure there are other opnions.
Lew

That is what I thought too, rather than hog the heads out just open and blend all edges.

Anyone else?
 
one2dmax said:
I have not explored the heads that much in detail but I do believe there is enough difference that starting with Vmax heads would have been better. I will have to sit down and check both sets side by side.

The stellite he was referring to was the valve seats. Many years ago when we had leaded gasoline the seats were not needed since the lead in the fuel actually acted as a lucbricant and let the valve job last longer. Since the transition to unleaded fuels the older cars really suffer and a lead substitue should be used. The vehicles designed after that change over already has the harder seats in place.

Valves can be purchased in many configurations and almost all have hardened tips to lenghten their life. Some of the lightes valves are actually hollow and sodium filled. the lighter weight allows for more rpm before float becomes a problem. They can run a lighter spring and make the valve ramp angle on the cam a little steeper so more effective lift is gained from increased duration.

I do believe the cams are different too though either set will work for aftermarket stuff since they are hard welded up and reground anyway.

One thing overlooked by many (except good head builders) is the guides. Over time they wear and allow the valve to slop around in there and this is where you can get some oil burning.

Aftermarket valves are very expensive (though I sell them too) and would usually only be ordered if going to a larger size to get more power and flow. Of course the head has to be enlarged and blended to accept the bigger valve.

Sean Morley

Thanks Sean, that's some really good info.

Here is what I found when I asked "Mr. Internet"

http://en.wikipedia.org/wiki/Stellite

and

http://www.stellite.com/products_services_components_machinery.asp

Now I'm more confused than ever.
 
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I'd just like to add a comment here. One of the reasons the VMOA crowd left me with a bad taste in my mouth was some needed to be right and found great joy in countering what others have stated. Telling someone he is wrong can be done by any idiot. Showing where and what is wrong brings enlightenment to others without the need to put anybody down. It would be highly appreciated if the information given by others would be understood clearly before nixing it. We all have special knowledge in various things and using a bit of humility in adding your knowledge to the pot makes for a friendlier atmosphere. Just my .02 worth.
 
mikemax04 said:
Sure reads like he was talking valves here and not seats. I've always had a choice of regular exhaust valves or the stellite kind, which cost more but wear much better. They even have valves made out of a titanium alloy mixture. Metals are getting stronger and lighter all the time.


I was talking about valves but the guy at PCW might have been talking about the seats. I may have misunderstood him.
In any case I have taken no offense to anything anyone has said and actually found it to be some good information. The comments by Sean and Lewl were both informative to me as both these guys have thier area of expertise.

I think that correcting possible misinformation tactfully is an OK thing because there are some people that don't need to say "in my opinion only" when they have the experience in the subject matter to flatly state what they know.

As usual I take things I hear and then proceed to research it myself to learn more.

The context of my conversation with PCW was the discussion of building a 1500 tourmaster and my question to him was
"With the stage 1 head package is the stock valve size retained and if they are retained is a better aftermarket valve of the same size installed?"
He proceeded to tell me that the valves are made of stellite and very few aftermarket valves are of that quality, and for that reason they keep them in service.
 
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Rusty, PCW was talking about stellite VALVES. No brag, but I'd bet that I have installed and worked with more stellite valves than anybody on here. I got them cleaned up by a machine shop that does valves professionally. Notice I posted previously that it should be a clean-up grind only, never stating the whole valve is solid stellite or even the shank. Personally I don't know if the head is solid or just has a covering and I don't really care. If it does have a covering of stellite, then it is possible to have a variable thickness, like in case hardening, where you could have a case of 1/32" or more that is grind-able and still have the hard protection. Some valves can't be reground because part of the valve is burned away. Others are grooved deeply from the seat and are also beyond re-use. Some have deep pits that won't clean up, some show several thousands wear on the stem from the guides and the possibilities go on and on. As far as I know, only the exhaust valves are stellite because the intakes get cooled by the incoming mixture. If others find any disagreement in what I have stated, they should be specific in what they disagree with because I'm always willing to learn.
 
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Listen Mike,
If I insulted you with my tone concerning the statement about stellite valves, it was not ment as a personal attack or to disrespect you or anyone else. Just going with experiences with stellite and it's uses. I do know how to be more diplomatic and will do so in the future.
Lew
 
Not a problem Lew. Stellite can be coated on an average of 1mm which equals out to roughly .040 of an inch. Plenty stock to clean up. It's happened so many times before where individuals simply state someone is wrong without any reference or proof at all. At my age I have more trouble keeping things clear in my mind rather than not having experience. I don't mind being told I'm wrong when I am because others on here depend on the information we all supply. Besides, I'm not too old to learn. Like you, I've spent my life in the machining industry.
 

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