Posted by alloy_625 on August 31, 1998 at 22:39:50:
Your other answers imply that you don't know the thermal gradients, implying conjecture like the rest of us.
You are correct. Our thermal imager only goes up to 600C and it couldn't image a piston, let alone a whole head, not that I care enough to go through with the experiment.
What is your bias (I suspect I already know)? Maybe now you'd like to stop hiding behind an alias - you have my email if you don't care to do it here.
Please don't suppose yourself qualified enough to understand my motives.
If I wanted to trash DPR, why would I bother with stage VI? As I see it,
stage VI is one way to increase compression without resorting to a bottom
end buildup. I personally don't like it for reasons that have been examined
in excruciating detail. If I'm wrong, my loss right? God knows how much
hate mail I'd get if I gave out my e-mail address. As for accountability,
I am following up the threads... although it has gotten tiresome. I just
wish T.O.O. and NITRO would come back soon so I could go back to lurking
and learning. I suspect everyone else has already fallen asleep
following this thread.
Posted by T.O.O. on September 01, 1998 at 07:28:51:
In Reply to: DPR, Stage VI, Welding, My Bias posted by body on August 31, 1998 at 22:39:50:
I haven't read enough of this "discussion" to fully understand the dispute,
but I will say this: Welding cylinder heads is a most traumatic process
for the parent aluminum alloy used in the head. The amount of heat necessary
to properly weld in additional quench areas, will destroy the heat treat
of the casting. As the casting is now "softer" after welding, it allows
the valve seats to "walk", and many other parts of the casting will also
"change" dimensionally, even if they are remachined after the welding process.
The only way to weld a head and not end up with "junk" is to first strip the casting of the seats, guides, studs, and anything else that is not part of the parent aluminum casting. The area where the material is to be added should be milled open to allow water the same access to the new welded area as it has around the remaining combustion chamber, ie. all the chamber and surrounding areas would be of the same relative thickness.
After the welding is complete, the casting must be normalized (a process that heats the entire casting and destroys any stress and former heat treat), and then re-heat treated to the same specs. as the factory casting.
During normalization and re-heat treatment, the entire head will "warp" to some degree, and now it's time to remachine all necessary surfaces, including valve guide and seat registers, deck surface, intake surface, exhaust surface, and camshaft bores...to mention a few. The head will now be as structurally sound as a new casting, and it will also have proper cooling characteristics.
If the "easy does it" welded head is for drag strip only, and you're willing to have several valve jobs done before the head "work hardens", do it the simple way, but remember that each new valve job costs compression and also flow, as the seats are lower with each re-do.
Welding aluminum correctly is an expensive and lengthy procedure...that's why ProStock heads cost so much.
Posted by andre on September 01, 1998 at 10:22:30:
In Reply to: Re: DPR, Stage VI, Welding, My Bias posted by body on September 01, 1998 at 07:28:51:
Sorry for the ignorance, I know only guys like you can know the real poop on pro-stock internals, so I'm hoping to get it straight from the proverbial horse's mouth ;).
The thing is that I've had other people that I also respect tell me that the heads in pro-stock competition are billet (and then hand-ported to smooth the "ridgies")...I trust your "insider knowledge" much more than this other guy (smalltime relative to you but knows waaaay more than me), but I'm just confused as to why/where you would be welding AL in one of these heads?
Thanks for the other info! Missed having you around (and hope the racing season is going well for you),
p.s. Do you happen to know what alloy of aluminum most head castings
are made of? Thanks again -- you/Endyn are a fount of wisdom...
Posted by T.O.O. on September 01, 1998 at 19:24:25:
In Reply to: pro-stock heads? posted by body on September 01, 1998 at 10:22:30:
ProStock heads can not be machined from billet stock. They, by NHRA
rules, must be castings with an approved "factory" part number. In ProStock
the competition is so tough that you'll often see the 16 car field in a
qualifying time spread from 6.90 to 7.00 seconds, and about 20 cars that
don't qualify running from 7.0 to 7.08 ets. When the competition is this
tight, and repeatability from run to run is necessary, you can not have
cylinder heads that are going to have the seats walking and cylinders leaking
more than about 3% max. Any cylinder head that isn't re-heat treated to
356 T-6 specs is pure junk. The welding is the result of a continuous development
program by all teams and Pro engine builders. We have three dedicated individuals
who do not do anything except design, build and test Pro heads and manifolds
for the customers we have. It's the single most competive form of racing
in the world...and that's including F-1, NASCAR, CART, and any other form
of racing you can think of. You must remember that the Pro cars don't have
more laps to catch up if there's a driver problem, so it's mandatory to
create an advantage. If your competition cuts your nuts at the tree, you'd
better have the mid range and top end to drive around them, or the only
driving you'll do the rest of the day is home.
The Indy Nationals will be on TV over the weekend and Monday's finals as well. As it's the biggest drag race of the season (double points and money), the competitors will spend anything to qualify, let alone win. If you win Indy, people will remember you even if you never race again.
So with so much pressure and the fact that everyone's heads are almost identical castings, when some "shape" change improves performance, it's welded in. In many cases the entire intake and exhaust ports are "moved" to promote greater swirl, or better manifolding. When ever we relocate things, we mill out the areas where we're going to create new walls or chamber shapes, and weld new material in place. Back in the old days, we used to weld the hell out of the heads and make more power on the dyno, then go to the track and the car wouldn't run. Heat!! You wouldn't think that localized hot spots could cost power in a quarter mile, but I'm here to tell you that it's so important that we have one associate who does nothing except design water jackets in the heads, and the steam manifolding, which is worth 50 hp easy. It's become a real art form.
So we spend a week welding and re-heat treating once we have a design that's looking good on the computer and the SLA models we make to validate shapes before we spend a lot of time and money on the real things. We have over a hundred sets of heads we've finished and never shipped, because as they were being packed we found a little more in a slight change, and we'd made our best obsolete before it could get out the door.
We do use machining centers to do the basic material removal, but then we EDM the texture we want in the ports and chamber, and then all heads are hand rubbed....and most by me. When you see ENDYN on a casting, it might as well be my name.
Posted by 2forme (firstname.lastname@example.org)
on September 01, 1998 at 10:22:15:
In Reply to: Re: DPR, Stage VI, Welding, My Bias posted by body on September 01, 1998 at 07:28:51:
Thanks for the information injection TOO. I appreciate commentary from someone who has actually been involved in the process. A few questions.
I have not pretended to be an expert on welding or metallurgy in this thread. However, limited empircal evidence (my engine) suggests that methods used to weld my head (quick and dirty, so to speak) worked. Allow me to explain.
1. Examination of cam journal wear 15,000 miles after the modifications showed no abnormal wear. Clearances were not checked before and after, but one could make the assumption (please correct me if I'm wrong) that problems caused by welding (be they a warping of the head or softening of wear surfaces) would show up in abnormal, uneven wear or even breakage (getting the cam caps mixed up can cause those problems too), particularly since the effects of the welding would likely be variable over the head. Additionally, the number of Stage VI heads out there without complaint suggests that no issues have surfaced yet. I'm not a believer in luck, so how can I explain this?
2. Power production of the car has stayed relatively constant, with variances of less than 1% in power to the wheels on the dyno. I would expect that issues like seat walking would again cause issues with valve sealing and thereby power production and longevity, particularly with the reprofiled valves being used to improve power production (IOW, reduced margin area). Again, I don't believe in luck.
As further data, the car now has 20,000 miles on the head and has taken a number of extended length journeys (1000+ miles round trip) as well as day to day, bumper to bumper commutes and of course, the requisite drag racing (about 60 passes in that time frame). Thus, the engine has been subjected to all forms of stresses since the modifications.
Any insight you can provide is appreciated. Oh, and Alloy_625, why don't you drop me an email.
Posted by T.O.O. on September 02, 1998 at 21:06:35:
In Reply to: Re: DPR, Stage VI, Welding, My Bias posted by body on September 01, 1998 at 10:22:15:
As with our up-coming blower system, ENDYN has offered a money back
gaurantee since 1970, and we have had 2 returns.
The peoplle and teams we work for do not demand the steps we take in producing our equipment. The demands are self imposed, because if something we built craps out on the last lap of the U.S. 500, the INDY 500, the Daytona 500, or any professional event our components are run in, it doesn't do our customer relationship any good, nor does it do anything positive for morale at the business.
We've gained a reputation over the years of producing components and systems which are "the Rolex of the industry".....a quote from Roger Penske. We have earned that type of complement because we have studied the competition's work, and we have also conducted a continuous metalurgy research program to insure the quality of our product. Our knowledge is what has brought the Livermore and Sandia Labs to our door for developing non detonating "spaces", as well as the lightspeed manufacturing technology program. We also have multi-alloy pistons which we make....the crown is "soft" and it progresses into a low expansion alloy from the oil ring down, allowing piston to wall clearanses of as little as .0015".
I'm not questioning your knowledge or the techniques that others may use in cylinder head preparation, Obviously, if it works, it works. We just don't do it that way because we've seen what can happen, and we'd like to think that if something we build breaks, God Caused It. You might also consider the fact that many of our programs are based on contracts that pay as much as $13 million / year, and with stakes that large we're not about to perform any "quick and dirty" work for our customers....as I've said, it's simply not the way we do business. You may surmise that the average racer doesn't purchase our components, and you are correct. You'll also find that we turn down over 60% of the potential programs available each year. While all our personel are the best I've been able to assemble, we feel that, regardless of size, as quantity increases, quality decreases.
I'm glad your components work well, and it's a shame that we spend so much time and effort the way we do the welded mods, but it's hard to teach an old dog new tricks.
Posted by T.O.O. on September 01, 1998 at 11:09:43:
After reading and posting my earlier comment relative to welded heads,
a situation that ENDYN became involved in has come to mind.
In 1984 when our stuff was allowing Glidden to make a joke of ProStock, we were approached by Roy Hill. The same Roy Hill who later spent some time for stealing equipment from transport trucks, and now is running the Roy Hill Drag Racing School.
Roy had been running all season with engines prepared by Dick Landy, and he'd failed to qualify at every national event. With the World Finals at Pomona the last race of the season, Roy was desperate to run well so his sponsor wouldn't leave him. He asked me to do a set of BOSS heads and a manifold for his 500" Ford engine. I requested one of his Landy heads as a point of reference, and when it arrived I was shocked at the amount of welding and relocation that DLI had done. When I flowed them, the #'s were terrible until you reached .800" valve lift, and then they zoomed. The cams we ran then had a peak lift of about .800", so anywhere below that lift and the poor engine was not able to breathe without really "working hard".
The heads I did for Roy were based on some select castings that had no unfavorable core shift, and they flowed a directional 500 cfm at .800", but they reacched 400 cfm by .400" lift....lots of area under that curve. The amount of my labor was "minimal" and the total cost of labor was only $3000.00..............Landy charged $14,000.00 for reworking heads for Roy.
I red labeled the heads and manifold we'd built to DLI near LA to be put on one of Roys engines at Landy's, and dyno testing, and they produced over 130hp more than any engine combination Landy had built all season. On the first run, the engine had so much torque that it destroyed the rear trailing link suspension and almost flipped the car leaving the starting line. Willie Rells was at the track and the car was repaired and ready to "qualify" the following day. It qualified 3rd in the field of 16, which was the first time he'd qualified all year!!
Dick Landy ran into me in the pits, and was really pissed at me. "Do you understand what you're doing to the market selling stuff that runs that well for so little money??!!" My answer was that I only priced my work at rates that I felt were fair for the amount of work performed. Well, Dick was still pissed, and kept looking at me funny and finally asked if we'd run into each other before. My answer was "yes, at the SuperStock Nationals (the most important race of the season) in 1969". He really got upset then, becuase in the final round of experimental superstock competition (32 cars in the field), I strapped a hole shot on his Mopar sponsored Dodge, and although he passed me like a freight train as we crossed the finish line, I won by inches. I made sure he remembered well, as he'd argued with the track officials about the fact that I had not red lighted.
Well, Roy fired Landy at the track, and then proceded to cuss me out. Why??? He was pissed because when he had the valve vovers of between rounds, it was embarassing to not have heads with a lot of welding to re-shape the ports!!! It wasn't enough that we'd made 130 more hp, or that he'd finally qualified, or that the price was cheap...there weren't any weld beads for people to see!!
I learned a lot from that experience. From that point on we had one of our welders weld everywhere imaginable. We did the same porting and the manifold was the same, but the price went to $25,000.00 per set, and Roy gladly paid it.
Strange world we live in, the car ran the same with the original non welded heads, but they were put in boxes and never run again. Welding is everything to some people, especially if you can see it.
Posted by 2forme (email@example.com)
on September 01, 1998 at 11:36:45:
In Reply to: Spinning Heads, The Truth......................... posted by body on September 01, 1998 at 11:09:43:
Truly interesting post. You might be interested (but not surprised) to find out that shifting ports around (mainly up) doesn't seem to do much good on B18C's either. I guess the Honda engineers knew something when they put the design together.
A question - what is core shift? Are we talking about casting flaws created by movement or misalignment of the mold/die/whatever?
Posted by T.O.O. on September 01, 1998 at 21:11:05:
In Reply to: Re: Spinning Heads, The Truth......................... posted by body on September 01, 1998 at 11:36:45:
Honda's heads have very well designed ports, that's the primary reason
that they can produce small engines with reasonable torque at low rpm (due
to the severely under-square, long stroke, short rod geometry), and still
make good power at high revs (the flow). So for most applications, Honda's
engines are very well conceived, designed, and manufactured from excellent
materials. If they weren't you'd never see the performance that is the
"norm" at the drag strips and road races.
There are numerous ways of casting components. Sand casting is the dominant form in the automotive industry...some using pressure as well. In order to cast a hollow and complex component you must have a core box that you insert the compressed sand and resin "female" ports and water jackets in. There is frequently some misalignment, howecer most takes place during the process of pouring the aluminum into the completed core box = mold. After cooling the box is opened and the process of vibrating the sand from the water jackets and ports begins. When there is a slight shift, you'll see a casting (mold mark) in a port, even after the head is ported. Any material removal in an area where the shift went the wrong way might make the port pretty, but it'll cost in flow. There are many heads that people feel cheated on because the porter didn't remove any material here or there, but fact is the head probably needed material added in those areas.............=$$$$.
The Asian heads are certainly better than domestic pieces, as far as being "out of the box" good, but with the exception of some Toyoda pieses we were involved with back in 1987 (they were investment cast), I've yet to see a "perfect" head casting that had al the shift in a favorable direction.
You'll be seeing some new and innovative casting technologies in the OE soon, and the heads will be so uniform that I really don't thing anything other than a valve job which will allow one to taylor low lift flow vs. mid and high will be necessary. We've been investment casting heads for years here, and while expensive (but not for long), the pay off is that you can maintain tollerances of .002" per linear foot, which means that a lot of the machine work necessary will be no longer be needed. We can cast with the seats and guides in place as well as all threaded inserts. For some of the "special" programs we've done in the past, we've made the chambers and seats from H-11, and cast the steel chambers in place so the chamber areas would retain more heat than the aluminum body of the head casting. This is really "old tech" when you see what's coming, programs like the LMTAS/ SANDIA/ ENDYN "lightspeed" will allow us to produce "finished" components with any materials and any shapes with tolerances of a millionth of an inch...needless to say, no machining will be necessary. The entire industrialised world is fixin' to change.