STD Panheads ??

[twincamzz]

Finished installing new base gaskets & Cometic MLS  head gaskets on my '61 this morning & was out for a short ride to check things out. 75 miles or so & all a sudden it sounded like I blew a head gasket. Stopped to check it out & discovered that the rear head cracked...or should I say finished cracking. Already had a couple small cracks at the spark plug & one of 'em decided to crack all the way to the top motor mount, dammit. I realize there are places that could prolly fix these old heads, but at 55 years old ( 1956 set of heads ) I figure they have seen all of the good life they are gonna see. I found a good deal on a  new set of STD panheads & they will be here in a week or so.

I've read that STD heads used with panhead cylinders requires shorter head bolts at the intake. Anyone know just how much shorter they are ?

[CraigArizona85248]

Damn!  Sorry to hear about your OEM head cracking.  I love the OEM castings.

Don't know about the headbolt length.  I've only installed STD heads on shovel cylinders.

-Craig

[twincamzz]

Yea, I really hated to see the old gal give up the ghost too, especially after just getting her back in the wind. "Life" got in the way of this small repair & my Pan had been  down for almost a month. Thank goodness I still have my RoadGlide to ride or else I'd run off n join the circus or something. lol.

Heard from the seller last night & it turns out these are Panhead "replacement" heads & I use all my original headbolts. Only if using their Pan/Shovel Panheads with Shovel barrels do you need to use the shorter bolts by the intakes.

[Snuff™]

Hey Twin!
Sorry to hear about your heads.
What day is "Trash Day"?  Might swing by the night before and do some "Dumpster Diving".

-Snuffâ,,¢

[CraigArizona85248]

Yea, I really hated to see the old gal give up the ghost too, especially after just getting her back in the wind. "Life" got in the way of this small repair & my Pan had been  down for almost a month. Thank goodness I still have my RoadGlide to ride or else I'd run off n join the circus or something. lol.

Heard from the seller last night & it turns out these are Panhead "replacement" heads & I use all my original headbolts. Only if using their Pan/Shovel Panheads with Shovel barrels do you need to use the shorter bolts by the intakes.

Nice! I wonder if they have the stock fin shape and exhaust spigots? I hate how square most STD heads look. They did make a head that looked very close to OEM.

-Craig

[twincamzz]

Hey Twin!
Sorry to hear about your heads.
What day is "Trash Day"?  Might swing by the night before and do some "Dumpster Diving".

-Snuffâ,,¢

Not really sure it would do ya any good Snuff. lol. Here's a few pics of the damaged head.

This shot shows the 2 small cracks that were around the spark plug hole the day I got the bike. Look closely & you can see where the crack "forward" of the plug hole decided to move all the way to the motor mount.



Next shot you can see one of the places that the other crack decided to go to. Look between the 3rd & 4th fin from the bottom & you can see the crack. BTW, fins were already cracked there.



Last shot shows the underside of head. Crack goes  from spark plug hole to valve, to  other side of valve, then all the way out to the end of the fins.



It's not a very pretty sight, that's for certain.

[twincamzz]

Nice! I wonder if they have the stock fin shape and exhaust spigots? I hate how square most STD heads look. They did make a head that looked very close to OEM.

-Craig

Yes, the heads that are on the way have the stock shape intake & exhaust ports. Too bad this pic only shows the intakes. Not sure how close the fins are to stock, but they look fine to me. I really think it will not be that noticable once on the bike.



Replica Panhead Heads by S.T.D., 1955 to 1962, Stage 1 Ports, Assembled

Panhead barrel bolt pattern - Internal oiling - Stock intake and exhaust ports - Single plug - Original style casting

Sold in pairs.

Fully assembled with Manley springs, valves & steel collars. Cast iron guides, blue Viton rubber seals with stock black nitride finish. Full hand blended radius valve job with Serdi cutters for ultimate flow. Full hand port for maximum horsepower and torque. Can also be ordered with Big Bore 3-5/8 complete or raw.

* Manley Valves * Manley Springs * Manley Collars

All STD heads are cast from aerospace quality 356 T6 "A" Prime alloy with a tensile strength of 45,880 psi, the highest rating of any aftermarket heads.

[Pzokes]

The STD heads shown in the pictures appear to me to have the fin design of '58 and later heads. 

[CraigArizona85248]

The '58-'62 heads only had two "partial" fins by the spark plug hole and five complete fins below the spark plug hole.  Like these:


The '55-'57 heads had three "partial" fins by the spark plug hole and four complete fins below the spark plug hole.  The heads pictured above are '55-'57.

Note: The '63-'65 heads went back to the fins like the '55-'57 heads, but they had the external oil line bosses as well.

-Craig

[Pzokes]

Craig,

You're probably right.  My Panhead stuff, my Panheads, and even my Palmer book is in a storage building.  All I've got to look at is my Twevo/Fatso, and my Flathead.  Luckily I marked all the Flathead boxes before I moved, or I'd have nothing to work on.  I'm renting a house with one stall  from my brother-in-law while I wait for the bank to decide on a "short sale" house I've been trying to buy.

[BART]

STD is still out of business, right?  That was my understanding.

BART

[twincamzz]

Yep, STD is out of business, but thankfully the folks at Spyke decided to buy up a bunch of inventory. They list these heads on ebay & seem to be open to offers as opposed to "this is the price...take it or leave it".
Other folks may have a supply of STD panheads as well, this just happens to be where I got mine.

Fins might be a little different than stock for '61, but these are as close as my old gal is gonna see unless I win the lottery. lol. Waitin' on the big brown truck to deliver 'em from California as we speak.

[greybeard_541]

Shorter bolt below the intake only applies to the dual bolt pattern heads when installing on shovel cylinders. On pan cyl's all bolts are same length.

Greybeard

[CraigArizona85248]

Fins might be a little different than stock for '61, but these are as close as my old gal is gonna see unless I win the lottery. lol. Waitin' on the big brown truck to deliver 'em from California as we speak.

Heck yeah!  I'd run em' too.  Those look great.  And honestly, they are probably a lot stronger then stock.  It's a shame STD went under.  I'm hoping someone will get their tooling and keep us supplied with new heads.

-Craig

[twincamzz]

The '58-'62 heads only had two "partial" fins by the spark plug hole and five complete fins below the spark plug hole.  Like these:


The '55-'57 heads had three "partial" fins by the spark plug hole and four complete fins below the spark plug hole.  The heads pictured above are '55-'57.

Note: The '63-'65 heads went back to the fins like the '55-'57 heads, but they had the external oil line bosses as well.

-Craig

BTW, I wanna thank Craig for pointing out the differences in the fins on the heads throughout the  Panhead years. Other than the plumbers intake versus the o-ring intake & the internal vs external oiling, I assumed the rest was all the same. You know what they say about assuming...   

[Snuff™]

Also different....'55 D-ring was fitted with only six fastener screws vs. the common twelve.

[twincamzz]

The '58-'62 heads only had two "partial" fins by the spark plug hole and five complete fins below the spark plug hole.  Like these:


The '55-'57 heads had three "partial" fins by the spark plug hole and four complete fins below the spark plug hole.  The heads pictured above are '55-'57.


-Craig

Went out to the garage last night to take another look at my old heads. Now I'm really confused as these are 16700-56 Front with a tag that reads 10-7. I assume that means cast in October of '57, which would be correct for a 58 model year Duo-Glide ? there I go assumin' again ! lol.




And 16701-56 Rear





Despite the fact that 2 of the fins have been cut off of each head for whatever reason, it's obvious there were 5 full fins on these at some point in their life. Maybe I'm just reading your message incorrectly, I dunno ? 

BTW, yer absolutely right Snuff, I forgot all about the D-ring bolt difference in '55. Keep it comin' ya'll. I love to learn about these old girls.

[Speeding Big Twin]

Tim, I’ve been following this thread and the one on H-G. And yes, 10-7 indicates October 1957 casting although that is no guarantee it was used on a 58 model. Harley didn’t always use parts straight away. Sometimes they did and sometimes they didn’t.

As you've indicated, your heads appear to have had some fins trimmed and I've posted a 10-7 front example below for comparison:

 

Apart from what we've seen so far in this thread, there are at least two other H-D Panhead head casting numbers which have a 56 suffix: 16704-56 (front); and 16706-56 (rear). Therefore it is unclear when the LATER casting numbers of 16700-56 (front) and 16701-56 (rear) made their first appearance and some heads from both sets have no date codes. And my photo collection so far shows the two earlier casting numbers were UNDERNEATH the D-ring ledge, not on the top of the head. Also, some heads in the earlier set have six vertical fins (or ribs) on the top of the head but some have nine. For the later set, so far I’ve only seen nine vertical fins on top. 

I CANNOT say for sure, but it MAY be that the two later casting numbers were first used for 1958 models because that’s when the horizontal fins were increased in size and we know about that fin size change from the September 1957 issue of The Enthusiast which was the announcement issue for 58 models. And it appears that the two later casting numbers then remained in use through 1965 even though over that period at least three sets of heads were used: 58â€"early-62; late-62; and 63â€"65.

It seems the date codes on most Panhead heads cast in 1958 and later have two characters to indicate the year of casting: 5 58, 3 60, 4 61, 10 63 etc. However, there is at least one exception, with 1959 sometimes using two characters to indicate the casting year but on other occasions using only one so you’ll find codes like 2 59 but also others such as 10 9.     Eric 

[twincamzz]

Thanks for the information Eric. I noticed in the photo you posted that the cast date tag has been partly machined away, very similar to the photo of my front head. Was this something done at the factory or a result of someone machining the D ring ledge to gain a flatter surface for the gasket to sit upon ?

Also, you mention some heads having no casting tag. That appears to be the case in my rear head, the sadly departed. I looked on the underside of the D ring ledge & found no casting tag & as can be seen in the photo I posted, no casting tag is present on the top side.

[CraigArizona85248]

Also different....'55 D-ring was fitted with only six fastener screws vs. the common twelve.

True.  I've seen those in pictures.  All the '55 heads I've held in my hands had been drilled by previous owners for twelve cover screws.  I guess they just leaked too much with only six?  Must be why Harley-Davidson went back to 12 cover screws in '56.

-Craig

[Speeding Big Twin]

Tim, those areas where the date code plates have been partly machined away look neatly done to me and that may indicate it was done by the factory. But it’s possible it was done by someone else. I’ve seen some that are fairly rough and those rough ones would have been done by someone other than Harley but when they appear neat it’s hard to say. Sometimes the date code plates are better positioned and of course that means they don’t get in the way.

I can’t explain why some parts have no date code and apart from them being absent on some heads with the 56 suffix, they are often missing from heads used on 1948 model Pans.     Eric     

[Speeding Big Twin]

The six-hole D-ring was first fitted to some late-54 models. This is mentioned in the scans below which are from the September 1954 issue of The Enthusiast and that was the announcement issue for 55 models. Although we often call them D-rings, and some H-D parts catalogs identify them as cover reinforcements, you’ll notice in The Enthusiast that they were called sealing plates:







Originally they were listed as #17509-54 but were later changed to #17509-54A and I expect the A was added because the later version had twelve holes. And I imagine the reason Harley doubled the amount of holes was because their claims about an oil-tight joint and little chance for oil seepage proved to be wrong.
 
Diagrams in some later Harley catalogs show a D-ring with only eleven holes in it and I think I know why that is. Anyway, it’s obviously an error so there’s no need for alarm.       Eric

[Deye76]

SBT,  great information and illustrations. Never heard them called "sealing plates" before. Gonna inform an old time engine builder I know the error of his ways LOL.

[fourthgear]

Yes & some believe the sealing plates are not needed & look better with out them .

I like them , myself.