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Mk II vs Mk III detail differences?

General engine tech -- Drag Racing to Circle Track

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numboltz
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Mk II vs Mk III detail differences?

Post by numboltz » Thu Jan 18, 2018 12:00 am

http://www.hotrod.com/articles/mickey-t ... -stingray/

Always interested in reading about the first canted valve engines, and have often seen that
Chevy made many changes' all apparently in the cheaper direction, between 1963 and 1965.
Anyone know, in detail, what the changes were?

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Re: Mk II vs Mk III detail differences?

Post by GLHS60 » Thu Jan 18, 2018 2:36 am

MK II vs MK IV:

There was no MK III.

There's a great article in a 1963 Hot Rod magazine where they do a tear down on a Mystery Engine.

An interesting thing, as Chevy had 2 427's at the time, H-D 427 was suggested as it's name!!

I don't think anything was really downgraded, pushrod guides were cast rather than stamped.

Mystery Engines were all 2 bolt main and the lifter bores were in line.

I have the magazine somewhere, I'll try and find the date.

May, 1963.

Thanks
Randy

Link to story!!

Post your input.

https://macsmotorcitygarage.com/inside- ... ry-engine/
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Re: Mk II vs Mk III detail differences?

Post by Ratu » Thu Jan 18, 2018 3:16 am

Mk III was a place holder, a lable reserved for a potential engine. Packard had a V-8 line and when that company failed there was a proposal for GM to purchase the production line and designs etc from the Packard liquidator. GM were seeking a new V-8 big block at the time and Packard's V-8 was set on 5" centres which meant plenty of room to grow in future. Further, it appears there was a V-12 variant of the V-8 which could be manufactured on many of the same tools. In the end the Mk III project never progressed much further than investigations and analysis work (possibly some testing). It was not taken much further and instead it was decided to modify the MII, developing it into the Mk IV.

Smokey Yunick commented favourably on the Mk II design and expressed his admiration for its lead designer on several occasions. He mentioned to me that the Mk IV was "productionised" in an unsympathetic manner and that some of the good aspects of the original design were discarded. He was dismissive of the early versions of the Mk IV. It does appear he had a point, as it took a while to sort out the Mk IV BBC and make it work reliably for high performance application. I recall him saying that during the transition the valve centres were altered some and that the port shapes were changed. There were other amendments but I can't recall all of them. I regret not asking a few more questions and writing it all down, but he sure was a prickly personality, sometimes impatient and fast to annoy. He could close a conversation down quite quickly and make a person feel unwelcome real fast!

It would be interesting to revisit the two engines, put them side by side and go through the details and analyse the differences.

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Re: Mk II vs Mk III detail differences?

Post by GLHS60 » Thu Jan 18, 2018 3:32 am

One of my links seem to have disappeared, I'll try again

It is the article with pictures.

Thanks
Randy

http://wildaboutcarsonline.com/members/ ... ne_1-9.pdf
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Re: Mk II vs Mk III detail differences?

Post by Newold1 » Thu Jan 18, 2018 7:52 am

Thanks for the magazine article and its pics. I long ago tossed mine but I remember those pictures very well. I always loved two early developments in those Mark IV's. One was the interesting little bump in the upper left corner of the exhaust port and the oval shape of the exhaust port. Somehow those two developments got lost in the original production Mark IV's and only appeared as improvements in later years through testing and performance version aluminum heads. The other early great part in the pictures for me were those great cast iron header manifolds. The Corvettes received a later variant exhaust manifold but it was not as good as these early racing offerings.

I always understood that the two iterations of the Mark versions were really not both Mark engines. One was the modified 409 (427) W engine named the Z11 and the HD-427 Mark III engine described in that article that appeared at the 63 Daytona race. There have been some releases of info and pics on some prototype developments but I have always heard that none of those made in into GM Racing programs or production. IE: the overhead cam 427, etc.
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Re: Mk II vs Mk III detail differences?

Post by ProPower engines » Thu Jan 18, 2018 1:46 pm

having never seen the original block and valve train lay out that was some fancy push rod guide plate engineering.
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Re: Mk II vs Mk III detail differences?

Post by numboltz » Fri Jan 19, 2018 11:52 pm

Interesting that in spite of multiple statements in the articles of the day stating it was entirely a racing
engine, the cylinder heads have heat crossovers in their castings and it appears that the intakes
have those provisions, too.

Other trivia I have seen includes the fact that they used the same basic rod forging as the 409, with
the pin hole moved a small amount. I would assume that the block went down the same line as the
409s did, even though the decks were at a different angle. With the cranks being interchangeable,
the rods similar and the bore spacing the same I wonder just how much detail difference there was
in the basic block castings? Be fascinating to compare the two blocks.

Finally, I have read that Chevy was forced to sell 2 engines to Ford to prove the engines were
available in the market place and thus NASCAR legal. Apparently late in the season Junior
Johnson was plumb out of engines and by some form of shenanigans was able to acquire one
of the two from Holman & Moody. I suspect the other one is the grandfather of the 385 series not
too mention the Cleveland family.

There must be at least one patent for the canted valve idea, but so far I haven't found it.

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Re: Mk II vs Mk III detail differences?

Post by GLHS60 » Fri Jul 05, 2019 2:09 pm

Reviving an old thread!

Checking to see if this post makes it through.

Awhile back, just before my stroke, I re-read Smokeys 3 book series and took some notes.

He didn't actually directly compare both Engines but made several comments throughout.

If the thread continues I'll post the notes I made back then for discussion.

If not, I'll start a new thread.

Thanks
Randy
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Re: Mk II vs Mk III detail differences?

Post by PackardV8 » Fri Jul 05, 2019 4:20 pm

The late, great Francis L Preve for 33 years was the historian at GM Power Train Tonawanda Plant and was an avid drag racer at Lancaster Speedway. He told me he always felt it was a mistake when they chose to abandon the MKII block and go with the new MKIV design.

FWIW, the MKIII option had some adherents. Being able to buy the complete and brand new Packard V8 design and production line had many cost-saving advantages and the bean counters were all for taking it on. However, engineers don't get many chances at a new clean-sheet design, so they played the "Not up to GM standards and will have the reputation of being from a failed car company to boot." By selling wolf tickets, the Engineering Department won out over the Accounting Department.
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Re: Mk II vs Mk III detail differences?

Post by F-BIRD'88 » Fri Jul 05, 2019 5:14 pm

Racing at Lancaster is an adventure.

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Re: Mk II vs Mk III detail differences?

Post by Schurkey » Fri Jul 05, 2019 5:26 pm

GLHS60 wrote:
Fri Jul 05, 2019 2:09 pm
Reviving an old thread!

Checking to see if this post makes it through.

Awhile back, just before my stroke, I re-read Smokeys 3 book series and took some notes.

He didn't actually directly compare both Engines but made several comments throughout.

If the thread continues I'll post the notes I made back then for discussion.

If not, I'll start a new thread.

Thanks
Randy
I, for one, am happy to have this thread revived. Please continue.

I've also got the 3-book set, but I never went so far as to take notes. I do remember that Smokey acted as though the designer of the Mystery Engine and the Mk IV more-or-less "gave up" and transferred to Germany. I'm not sure that's fair or kind--but of course I wasn't there to watch any of it.

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Re: Mk II vs Mk III detail differences?

Post by Kevin Johnson » Fri Jul 05, 2019 6:10 pm

numboltz wrote:
Fri Jan 19, 2018 11:52 pm
...
There must be at least one patent for the canted valve idea, but so far I haven't found it.
https://patents.google.com/patent/US3276438A

Dick Keinath cited: https://patents.google.com/patent/US2769434A

Witzky did not claim the canted valve arrangement as unique rather the rocker arm mounting.

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Re: Mk II vs Mk III detail differences?

Post by GLHS60 » Fri Jul 05, 2019 8:06 pm

Schurkey wrote:
Fri Jul 05, 2019 5:26 pm
I, for one, am happy to have this thread revived. Please continue.

I've also got the 3-book set, but I never went so far as to take notes. I do remember that Smokey acted as though the designer of the Mystery Engine and the Mk IV more-or-less "gave up" and transferred to Germany. I'm not sure that's fair or kind--but of course I wasn't there to watch any of it.
Excellent!!

I was mostly taking notes re MK II and MKIV Engines to try and figure what smokey really meant.

He jumps around from topic to topic but there are many tidbits through out.

(1) First mention of the Mystery Engine and Dick Keineth (page 127):

I really liked my new job at Chevy...to work on the development of the Chevy "Mystery Engine".

A brainchild of, as I saw it, Dick Keineth. A young Engineer who reported to Duntov.

Now the Boss (Knudson) and I are close, and I'm exposed to all the in-fighting and god stuff

His views on big Corporate politics are very enlightening, who gets the say and why.

His story on why Ford Oil pans are on backwards is a great example!! (Page 131)

Concerning Detroit Engineers operating with their hands tied behind their backs.

Few had the balls to stand up and tell the world what the problem is.

(2) Or like Dick Keineth (sic) who ended up at Opel in Germany. Maybe best Engine man GM had.

What did he do to get banished? He fought to save a good Engine design (page 145)

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Randy
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Re: Mk II vs Mk III detail differences?

Post by GLHS60 » Fri Jul 05, 2019 8:34 pm

(3) In 1963 I built a chevy with a so called" Mystery Engine", or porcupine Engine, right at 600 HP--

- these things would flat haul ass. Should never have run 'em. Never was but 42 sets of parts.

Actually those were 427 cubic inch, and very close to the big block as finally produced and sold in mass.

He goes on to say he offers Johnny Rutherford to run the Mystery Engine Chevy in the 1963 Daytona 500 We had a hell of a time keeping the Engine running. Oiling is a little weak and the rods are shaky.

Johnny gets a half day practice and sets fast time for all qualifiers. Johnny wins 125 mile qualifier.

Smokey thought Johnny had eye problems, called him Mr Magoo.

Smokey wanted to skip a few races and get oiling better. and let Johnny drive a Bud Moore Mercury.

(page 214-215)

Page 254 he mentioned the Mystery Engine powered 1963 Corvettes built for Mickey Thompson.

Thanks
Randy
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Re: Mk II vs Mk III detail differences?

Post by ProPower engines » Sun Jul 07, 2019 12:17 am

After seeing the valve train layout and how the push rod guides were made inline is it possible they used a 409 block
with the canted valve head.
Never had thought about it till now or had two side by side but some guys did run a 409 block and used the at the time new 454 crank in them. While the Z11 is said to have used a 6.135 long rod the 396-454 did also but the 409 block with the canted valve head would explain how the 396 and 427 heads came to be.

Is it possible that GM had the later 396 BBC on the drawing board and had some stuff made at that time and they adapted
the canted valve 396 heads to the larger bore 409 block?

Back then the back doors of the car manufactures had cool parts leaving to be run in nascar this may have been one
of those times when someone said hey why not try this and kick ass in february.
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