Interesting Writing by Barney Navarro

I found this by searching for Navarro Heads on Yahoo. It's kind of intersting. Does anyone have pictures of Navarro heads AND Intake?

Fordbarn Link

 

El linko es brokeno.

Try this one: Bueno Linko

 

I wish to add some information and corrections to the discussion about Pop-Up Piston Design for Flathead Ford V8 engines.  Tony Baron’s father, Frank and his Uncle Bob Tattersfield, were both friends of mine in the manufacturing era immediately after World War II.  It is correct that they were the first to make a commercial venture of pop-up cylinder heads, but I think there were others who used the principle on an individual basis.  It should be noted that I do not call my heads pop-ups; they are listed as Hi DOME HIGH FLOW CYLINDER HEADS.

 

The problem of insufficient compression potential in flathead engines has been around longer than any of the now living enthusiasts.  Sir Harry Ricardo probably came up with the first good solution that did not require a special piston configuration; the cow hoof shaped re-entrance baffle.  Ed Winfield, who became famous for his wonderful carburetors and cam grinding, used the Ricardo chamber in his first production run of high compression heads for Model A Fords.  It was with great chagrin that he found it necessary to change design because the Ricardo patent was still in effect at that time and Chrysler owned the patent.

 

When I made the drawings for my cylinder heads, I felt that the hoof shaped re-entrance baffle would provide the highest compression and highest air flow.  A subsequent test by Marlo Pichel using his dyno and air flow measuring system proved the validity of the design.  Mike Davidson, the Australian who wrote a book on flatheads, shows a higher air flow rate for those originals than all the other popular heads that don’t require special pistons.

 

Fifty years ago when many of the hot track roadster drivers were running engines with “pop-ups”, that configuration became the “in thing”.  I tried the idea also, but the amount of piston projection above the block deck was only 3/8 of an inch.  That small distance did not increase the crossectional area of the transfer region sufficiently to make a noticeable increase in performance.  As many of us did in those days, I consulted with Ed Winfield.  In our conversation, he brought up the shape of a piston in a Miller; he would never bend enough to call those engines Offys.  Now what possible relationship could a dual overhead cam’s pistons have to a flathead Ford?  Simply this:  that big lump of heat absorbing aluminum subtracts from heat of the combustion g***es that help to push the piston down.  Winfield agitated for a smaller included angle between the intake and exhaust valves of those engines until Art Sparks pushed  the idea and took the undeserved credit for the concept.  After hearing Winfield use the Miller piston as a horrible example, I didn’t need to ask any questions about Miller and flathead Ford relationships.

 

In the reasoning process that caused me to use the same radius dome as the early Chrysler hemi,  I kept in mind a number of factors that had a bearing on the final choice.  Winfield’s lump comment stood foremost in my field of vision.  This led me to think that extending the piston’s major diameter into the cylinder head was not the best idea.  Since a spherical or ball shape can enclose the most volume for a given surface area the Hemi shape won out.  The use of the same radius as the Chrysler should not infer any magical or “trick” connotation.  It just so happened that I had a doming cutter from a pair of Chrysler hemi aluminum heads that I made for Henry Kaiser in 1957.

 

C. R. Axtell, many years before the birth of the high domes using the Chrysler radius of 3.305”, often bugged me to make my heads with a pop-up configuration.  He cited some air flow work he had done on a 45 cubic inch Harley Davidson flathead motorcycle engine.  That little engine produced 60 horsepower.  How would you like to get a horsepower to cubic inch ratio like that in your flathead Ford?

 

Axtell described the Harley combustion chamber quite thoroughly, even down to the little triangular peninsular projection between the intake and exhaust valve.  Testing had demonstrated that it did not impede air flow, so it was inserted to help the compression ratio.  Another aid to compression is the island over the exhaust valve.  No matter how much you are able to whittle my high dome heads or anyone else heads, the Harley cannot be matched because of stud and water hole locations in the Ford block.

 

When Tom Gerardi first entered my shop, he asked me if I was interested in up-dating my cylinder heads.  I told him that I was very interested if someone had a car or was building one to establish some kind of record.  Tom showed a great deal of enthusiasm and ***ured me that he was my man.  I told him about the information I had received from C. R. Axtell and showed him the extra core boxes for the water jacket cores and combustion chambers.  I had some of the essential parts for a flow bench since I needed one to further refine an air flow measuring fuel injection that I developed for my Indy car.  Prior testing of that injection system was done at Garrett AiResearch, the turbocharger manufacturer.

 

When the flow bench finally reached a usable condition, I took one of my standard nostalgia heads and cut a flat dome 11/16 of an inch deep.  Of course this destroyed the head for any engine installation.  What was accomplished was to produce a cavity that could be partially filled with clay.  There were many tasks for me to address to keep my shop functioning, so I was pleased to have Tom run the flow bench at my direction.  Templates were made to s****e away unwanted clay and to produce the desired curvatures.  The 3.305” radius dome was compared with the flat dome and was found to be slightly inferior.   There wasn’t a great difference, but it was observable.  Until some dyno testing is done no one can positively say one is better than the other.  As for Tom’s ***ertion that the air flow rate had been increased to three times what is was when we started; reflect on this -  three times the air would result in three times the horsepower. Applying a claim of such magnitude to a 200 horsepower flathead would mean that you would get 600.  When casting time rolled around, four flat dome heads were made.  Tom took two for future dyno comparisons with the round dome type.  Since Tom became a trader, instead of a racer, a car never materialized.  He sold the flat toppers to someone in Oregon and the other two heads stayed on my shelf until recently.  Tom purchased four pairs of heads and sold them through adverti*****ts in Hemmings.  At $350.00 per pair, during the loss leader introductory period, his friends were expecting an impossible discount.

 

The most interesting part of this saga took place shortly after flow bench testing started.  Tom came to my shop with a couple of drawings illustrating a plan view and cross section of the Harley combustion chamber; of course we couldn’t use them because of the dimensional differences from a Ford.  What was really accomplished with the drawings was to confirm Axtell’s description.

 

My choice of the hemi-type dome for production is based on the possibility of too much heat loss from the portion of the flat top piston projecting above the block deck.  The second objection, is the dead gas space between the piston crown and extension of the block’s cylinder wall that extends into the head.  The only way that this question can be resolved is through an unbiased dyno test.

 

 As for someone taking over the production of my equipment in the very near future, I haven’t had anyone approach me with a BIG ROLL OF GREEN.  My patterns and core boxes are not wooden with wax filets, like the compe***ion, so someone attempting to duplicate casting quality without my foundry equipment would find it impossible.

 

Sorry about that I couldn't get the link to work.

 

Great read - thanks....


Mutt

 

Very interesting.Thought provoking to say the least.....

 

That's all fine and dandy... but it ain't getting your car on the road any sooner.

Get out in the garage and get that frame finished!

Sam.

 

can you still get navarro heads...anyone have a pic of the underside....also the amount of volume in the head for each cylinder

thanks
zach

 

Great topic! I've done some research into this & Harley's efforts with their flatheads - interesting stuff to say the least.

Some flow tests show that a "square" pop-up doesn't help flow because of the abrupt movement of the air at the edge of the receiving cut in the head. Yet, this is what Harley did on the K & what Baron did in the early days. It worked better than no pop-up, but not quite as good as the Navarro hemi pop-up.

All of this concern over the transfer area got me to thinking - how could I get the best of both worlds. Pop-up & keeping the transfer area open. Since I'm going to have to have custom pistons made for my 45 project anyway, what else is out there?

I figure that an angled pop-up might prove the best of both worlds. I got my inspiration from 2-stroke piston porting techniques I'd heard/read about way back when. If you had a "square" pop-up, but it didn't have a flat top & instead angled down toward the transfer area, wouldn't this have a similar effect?

This is something I'd like to try in my 45 project, but if it works, maybe in a future flathead V8 project - who knows?

It's all just stuff in my head - not been tried that I know of, not been flowed, and, of course, not been dyno-ed. So who knows, really?

I've drawn a crude picture in powerpoint & converted to .jpg, so apologies for the drawing, but hopefully you can get the general idea. None of it is to scale, it's not accurate wrt either the Navarro or the Baron/Harley design - just rough sketches to illustrate the ideas.

Anyone want to offer their opinions?

 

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Anyone want to offer their opinions?

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I think that that's a hell of a clever idea! Has nobody thought of it before??

--Matt

 

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I think that that's a hell of a clever idea! Has nobody thought of it before??

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I don't think there's much original thinking left when it comes to the flathead - I certainly don't think I'd come up with any. So I can only ***ume someone has thought of this & there's probably a good reason why it won't work.

My biggest concern would be piston rock.

In the Harley, the wrist pin would be perpendicular to the long axis of the wedge (for lack of a better term). So I wouldn't foresee any major balancing or piston rock issues.

However, in the V8, it would be parallel to the wedge, so one side of the piston would be heavier than the other - happens to be the thrust side & you're effeectively making it longer, so maybe it's a wash?

Just thinking out loud. A little knowledge can be very dangerous!

 

i agree with the angled force...i think things would wear wrong and have undue stress in certain areas...but it is good thinking...i know this would be more work then getting custom pistons...but what if you did an opposite of a releiving job...build up on the block somehow...and dome the head out above that....the gas/air flow upward from the valve so that would create a more dfirect flow around an arc rather then sideways...then use a symetrical piston that the edge does not come above the top of the block but flush..this is giving more compression also because of eliminating some of the extra space in the combustion chamber ...this is just an idea ive been thinking of...


i wish i could afford to experiment with things like this

good luck
zach

 

Actually, the custom pistons part is fairly easy, just have them leave the dome unfinished & then fly-cut it in a mill at whatever angle I end up with...

I hear what you're saying, but the air eventually has to make that turn & go down the cylinder. Having said that, a lot of the guys that are doing flow work are flycutting above the intake valve now so the air doesn't have to make as abrupt a turn to get to the transfer area...

 

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I don't think there's much original thinking left when it comes to the flathead - I certainly don't think I'd come up with any.

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I dunno. I think you may have...


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My biggest concern would be piston rock.

In the Harley, the wrist pin would be perpendicular to the long axis of the wedge (for lack of a better term). So I wouldn't foresee any major balancing or piston rock issues.

However, in the V8, it would be parallel to the wedge, so one side of the piston would be heavier than the other - happens to be the thrust side & you're effeectively making it longer, so maybe it's a wash?

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You can always balance the piston. You could add plugs of a really dense material, like tungsten, to the "lighter" side.

I think that you have a great idea.

--Matt

 

You might want to PM or e-mail Bruce Lancaster and ask his opinion. He's forgotten more about flatheads than I'll ever learn.

286 merc would be another good guy to talk to, although he's not spending any time on the computer.

I don't know whether the guys on Fordbarn.com would get fired up by this idea, but you could try.

I'd really like to encourage you to keep developing this concept into reality.

--Matt

 

here's a pic of some heads I got from Mr. Navarro,

 

here's a couple of intakes, I like the dual-carb setup,

 

Before...

 

After...

 

mr. midnite...could you take a picture of the bottom of those heads?...does he still sell them?

thanks
zach

 

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Anyone want to offer their opinions?



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Ernie; you have been spending waayy too much time designing things!

You have my curiousity going with your piston design. It looks in the side view that the dome (top) of the piston "wedge" goes all the way across, does it? Or is there a depression in the center?

Because the wedge would "push" the air/fuel mix back towards the valves at TDC (compression stroke) where do you think the best location of the sparkplug(s?) would be?

 

Not really that much time - several months back, I dove into hi-po flathead Harleys (OK, so hi-po is all relative) & did a lot of reading & research & even dug out some of my V8 books. The Navarro stuff sort of rekindled that - this is a concept I had for the Harley initially. Just about 20 min on powerpoint to make a picture because no one understands what I'm talking about when I just describe it in words. This post was just the kick in the *** to draw a ****py picture.

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looks in the side view that the dome (top) of the piston "wedge" goes all the way across, does it? Or is there a depression in the center?

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Well, right now I think it does. But this is anything but a firm idea.

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Because the wedge would "push" the air/fuel mix back towards the valves at TDC (compression stroke)

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One of the two primary reasons for the wedge. Naturally, any flathead is going to push the mix towards the valves, but I think the wedge might do it "cleaner". I'm also guessing that it might help "pull" in a fuller charge - hard to put into words my reasoning & only actual flow/dyno tests would prove it anyway. Although I think it would be minimal.

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where do you think the best location of the sparkplug(s?) would be?

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I've been thinking that if I could put it wherever I wanted, I'd put it on the edge between the transfer area & valve pocket, slightly off-center favoring the exhaust side so as not to interfere with intake flow. Although your mention of a depression might be a way to "channel" or direct it towards wherever the spark plug is. I'll think on that a bit - that's actually a very good idea - I wonder what the tradeoff would be wrt pop-up efficiency. A flame slot? Of course it would get (tm)

I've also been thinking about the valve pocket area in the head a lot. The Harleys use a stepped relief in the cylinder AND the head. Well, I guess it's not a relief in the head, but the chamber is shaped in a stepped manner. Obviously, it favors the intake.

A lot of the recent flow work that I've read about has indicated reliefs to be of questionable value in many instances. I think recent thinking is the area over the intake valve has a more dramatic effect on flow. Harley did both & spent a lot of time developing their flathead racers.

Of interest, in the motorcycle world where "new" flathead designs outlasted those in automobiles, no factory race or high-performance flathead engine was built w/o pop-up pistons after 1948. Indian & Harley alike. So there must be something to them.

It's interesting to read of the similarities between Navarro's work & the Harley stuff.

One of the challenges is the accurate placement of the heads. Indexing dowels of some sort are an absolute must.

 

Ernie, a short time ago, a fellow who purchased a 4 carb intake from me, was really "pushing" me to sell him a pair of early offy heads.

I didn't want to let them go (sell) so he borrowed them and took them back to his machine shop.

I need to insert a note about this machine shop; it has NC controled lathes and milling machines "up the hoop!"

Using the heads he borrowed, he took two "slabs" of T6 aluminum and DUPLICATED the heads! (just the head bolt holes and the combustion chamber position outline) From there he went "hog wild" with fins, TWO spark plugs per cylinder and a finish (polished) to "die for!"

ALL the dimentions are now "stored" in the NC mill. (this mill cost him about TWO mil!)

During the machining process (he is a well known drag racer and engine builder) he and I "bench raced" about the top of the pistons (remember we're talking flatheads here) he should use. He came up with an idea that maybe the tops of the pistons could be "DISHED" (like a diesel engine piston) AND that the heads would have a coresponding bump (like a womans BREAST; sorry couldn't think of a better way to describe it!! ) that had a spark plug in the center. (where the "******" would be!)

His thinking was along the same lines as your "wedge" idea; but when the piston reached TDC it would "trap" air/fuel on the top of the piston, allow for higher compression and eliminate piston rock. Keep in mind this would have to be a carefully matched combination. (heads and pistons)

While the "bench racing" continues, the heads only have valve pockets and there isn't pistons in the engine.

The TWO spark plug design puts one plug in the stock location, and the other over the piston. He thinks that if the ignition "fired" the plug by the valves FIRST it would start a flame travel into the cylinder then the SECOND plug would fire the remaining "trapped" charge. I set up a PAIR of MSD 6AL Ignition amplifiers triggered by slightly offset crankshaft magnetic pickups.

Don't know IF this design would work (if at all! ) because their aren't any pistons yet.
He does have a basic piston design "dialed in" to the NC lathe, but we are still "kicking" the head and piston combo around.

I was by the shop the other day, and his book keeper's comment was, "What the hell are you guys doing? Ford stopped making that engine FIFTY years ago!"

Larry replied, "Ahh.. yea, but maybe we can make it work!!"

 

Dave,

That's an interesting concept - a reverse pop-up. I wonder if the inertia of the air would continue to move away from the center of the piston as it approaches the, uh, ***s . I guess it wouldn't be any different than a normal dome though.

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Using the heads he borrowed, he took two "slabs" of T6 aluminum and DUPLICATED the heads! (just the head bolt holes and the combustion chamber position outline) From there he went "hog wild" with fins, TWO spark plugs per cylinder and a finish (polished) to "die for!"

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Any plans for water p***ages? Or is this to be a race-only engine?


I had thought of doing something similar, but with split two-piece heads to mill out the water p***ages. I know someone (Kong?) did this & had some trouble with leaks from the two-piece heads. But short of welding up a set of heads & starting over, I can't think of another way. Maybe Edelbrock or Offenhauser would sell me "blanks"?

 

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I had thought of doing something similar, but with split two-piece heads to mill out the water p***ages. I know someone (Kong?) did this & had some trouble with leaks from the two-piece heads.

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A 2 piece head would be more practical now,with modern machining,and sealants.

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Maybe Edelbrock or Offenhauser would sell me "blanks"?

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I'm guessing their combustion chambers are cast.
They would machine the deck surface,spark plug and bolt holes.

 

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Any plans for water p***ages? Or is this to be a race-only engine?

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Like you and Ian suggested; we did discuss a two piece (upper and lower) section head, but the engine is ONLY for racing.

BUT we did discuss "cross drilling" (top to bottom and end to end) holes that would be piped together and filled with OIL!

He raced water cooled snow mobiles where they had subs***uted OIL for the water in the radiator. He indicated that the oil would "draw" heat from the engine faster than water and when p***ed through the radiator dissapate the heat quicker. (there are a lot of snowmobile racers that swear this to be true!) Not being a snowmobile "fan", I can't vouch for this idea!

In the flat motor heads his thoughts were to use an electric motor driven pump to circulate the oil through the "cooling p***ages." We "kicked around" the idea of "manifolding" the p***ages into cylinder groups and then p*** the oil through a small cooler.

The idea got more and more complicated until we decided that just SOLID heads (given enough time between rounds) would cool down sufficently because of the big (read DEEP!) fins on the tops of the heads would be enough. (and maybe a big fan blowing on the engine while the race car was sitting in the pits)

I had done some study of early drag race flathead "tricks"; and found that some racers would just FILL the water p***ages in the heads. (don't know what with; was JB Weld around in the late '50's?)

BTW - These heads that Larry made don't have any kind of water outlets.

We (well he, I just supplied the head) setup an aluminum Canadian head and "split it in half" top to bottom and traced the water p***ages in the top and bottom halves. (nice to have the equipment to do this kind of job!) The dimentions are "stored." And if he decides to make another set they will duplicate the water p***ages and "sandwich" the two halves together.

THEN! I get to try them!

I quietly asked one day what he would have to charge to "crank out" a few sets of these heads; it was a good thing I was sitting down! He indicated that the rough tally of material and shop time would put the price around $6,000.00 a pair!!

 

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I'm guessing their combustion chambers are cast.
They would machine the deck surface,spark plug and bolt holes.

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Unkle Ian - you're right! I forgot about that.

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BUT we did discuss "cross drilling" (top to bottom and end to end) holes that would be piped together and filled with OIL!


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Can you cross drill & not hit anything? Head bolts/studs or spark plugs or whatever? I mean would you accomplish enough to make it worthwhile? What about the block? Tap the back of it for outlets & use the exisiting pumps maybe?

Oil sounds interesting & reasonable. Evans coolant is a gel-type, so I think there may be something to the oil trick.

Not many snowmobiles in the south where I'm originally from, so never even been on one. Although we did use snowmobile engines in the ultra-lights I used to fly

This is all interesting stuff...

 

He sells the heads, all you gotta do is give him a call. They're $675 I think.

 

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Can you cross drill & not hit anything? Head bolts/studs or spark plugs or whatever? I mean would you accomplish enough to make it worthwhile? What about the block? Tap the back of it for outlets & use the exisiting pumps maybe?

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The "cross drilling" idea meant that the holes would have to be very small to avoid running into head bolts etc., and the amount of "coolant flow" would be pretty small. Which was probably the main reason he "ash canned" the idea.

The block on the other hand still kept the coolant jackets and front pumps. He "rigged" a cross over from one bank to the other at the rear of the engine and hooked the pumps together (he changed the direction of the impeller on one pump) to keep water circulating and avoid any hot spots

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Oil sounds interesting & reasonable. Evans coolant is a gel-type, so I think there may be something to the oil trick.

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At first I thought he was "pulling my leg" but when he showed me the dyno specs of his snow mobile engine, (they included temps) they showed a big difference in cooling.

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Not many snowmobiles in the south where I'm originally from, so never even been on one. Although we did use snowmobile engines in the ultra-lights I used to fly.

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Most snowmobiles use air cooled engines (the ones often used for ultra-lights) but the BIG snowmobiles used in the high arctic that are used for towing a "train" of sleds and travel at fairly slow speeds, are commonly equipped with liquid cooled engines. I spent a year in the high arctic on a seismic crew, and the engines were left running ALL the time; otherwise you could never get them started again! (try - 50 degrees!! F)

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This is all interesting stuff...



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Yeah, and to think we are "playing" with a Fifty year old, inefficient, expensive, (to build) "cranky" engine!

And man, do I ever LOVE IT!

 

I think that this is interesting stuff.

Speaking of cooling the heads, do any finned heads realy help radiate heat, or are they mainly decorative?