Panhead Cylinder Oil Passages

[sieber60]

Looking for clarification on oil passages on 50 to 52 cylinders. I have a front and rear cylinder with date codes K 1-0 and K 20-2 if I understand correctly, one is Sept.1 1950 and the other is Sept. 20, 1952. Both cylinders have the oil passages that drain into the base area of the cases (looks like one has been welded up at some time) and both have drain holes in the bore area. If I am reading Palmer right, they shouldn't have the drain holes in the bore area. Is that correct?

Thanks
John

[exeric]

It is my understanding that drilling a drain hole in the base area of early Panhead cylinders is an improvement that minimizes plug fouling, and improves oiling. Anxious to hear other opinions.

[Rubone]

Looking for clarification on oil passages on 50 to 52 cylinders. I have a front and rear cylinder with date codes K 1-0 and K 20-2 if I understand correctly, one is Sept.1 1950 and the other is Sept. 20, 1952. Both cylinders have the oil passages that drain into the base area of the cases (looks like one has been welded up at some time) and both have drain holes in the bore area. If I am reading Palmer right, they shouldn't have the drain holes in the bore area. Is that correct?

Thanks
John

That is correct John, however, the date codes repeat so are you sure they are not a decade later? Factory holes generally look a bit different than dealer or owner drilled.

[sieber60]

That makes sense, I was overlooking the obvious. The date codes are consistent with the 60' and 62' as well they don't have the MCC logo and the holes don't look like they were drilled outside of the manufacture. Thanks Robbie!
John

[Speeding Big Twin]

John, in DCs on cast-iron pieces such as genuine H-D Panhead cylinders the letter K indicates October.

Are we talking about 74ci cylinders? If so the cylinder with K 1-0 may have been used for a 1951 model or 1961 model. A drain hole in the bore could suggest the latter especially if it appears factory-drilled. But how would we know for certain? What if that hole was drilled later on and the person responsible did an excellent job?
On this cylinder the lack of an MCC logo doesn’t help because it wasn’t used on Pan cylinders for 51 models or 61 models.
Is there a boss on the R-H side at the base? If not, is there any sign it was removed? Photo?



A 74ci cylinder with K 20-2 may have been used for a 1953 model or 1963 model and in both instances I’d expect a drain hole in the bore as original.
On this cylinder the lack of an MCC logo could suggest a 53 model, provided of course a logo was not removed for cosmetic or other reasons. Does it look like a logo was removed? Photo?
Also a 53 model would have a feed hole as original while a 63 model may not although any cylinder that didn’t originally have such a hole could be drilled later on.



Which cylinder is the front one? Whichever one it is, can you post a photo of the top of it please. And a photo of the back of it too. Thanks.
Eric

[sieber60]

Hi Eric,
Yes, these are 74ci cylinders. I'm pretty sure I know what boss you are referring to and it does not appear that it has been removed and doesn't appear the MCC logo has been removed, as you mentioned if the person responsible did an excellent job it could be hard to tell. Thanks
John

[sieber60]

Eric,
Here are five more pictures showing the base.

[Speeding Big Twin]

Thanks for the photos. As I mentioned above, on the cylinder with K 1-0 the lack of an MCC logo doesn’t help us.
Also not helping us on this cylinder is the size of the DC plate. It’s what I call small but that’s what I’d expect on a 74ci Pan rear cylinder regardless of casting in Oct 50 or Oct 60. And the size of a DC plate is something that I use only as a guide anyway because there can be exceptions.

On the R-H side at the base I see no sign that a certain boss was removed. On 74ci Pan rear cylinders I have examples of a boss from as early as June 6, 1950 and as late as Sept 13, 1950. It wouldn’t be expected on any Pan cylinder cast in 1960 but would it have been there on a 74ci Pan rear cylinder cast on Oct 1, 1950? I can’t say for certain but for comparison I checked my photos of 74ci Pan front cylinders. On them I have examples of a boss from as early as June 17, 1950 and as late as Oct 2 and Oct 3, 1950. I imagine that a boss would have been on a 74ci Pan front cylinder cast on Oct 1, 1950 and therefore my guess is that a 74ci Pan rear cylinder cast on Oct 1, 1950 may also have had a boss. But your rear cylinder has no boss and no sign it was removed so I’ll also guess your rear cylinder was cast on Oct 1, 1960.



On the cylinder with K 20-2 the DC plate is what I call big or large and it may help indicate casting in Oct 52 as opposed to Oct 62. If Oct 62 I’d probably expect the plate to be smaller. However, again the size of a DC plate is something that I use only as a guide, and not as a definite means of ID, because there can be exceptions.
Also helping indicate Oct 52 is the feed oil hole because an Oct 62 cylinder wouldn’t normally have it. But a feed hole is another feature that should only be used as a guide because such a hole could be drilled in a cylinder that didn’t originally have one.

Something else suggesting Oct 52 and not Oct 62 is the size of the relief in this fin.







No MCC logo is another indication of Oct 52 as opposed to Oct 62. Obviously a logo could be removed but I don’t think it happened in this instance, partly because I see no sign of removal but mostly because the top of the cylinder appears consistent with Oct 52 and not Oct 62. We can’t see the entire top of your front cylinder although your photo below shows part of a certain area I was looking for.







But on the next cylinder the outer edge of the surface area is closer to the bolt hole. The earliest I’ve seen this difference is on a front cylinder cast on July 23, 1962 but I’m using a cylinder cast on August 28, 1962 because the picture is better.







The change at the top of the Pan front cylinder seems to remain in place through the end of the 65 model year. But yours isn’t like that so the DC on your front cylinder indicates casting on October 20, 1952 and not on October 20, 1962.

Also notice on the August 62 cylinder the relief in the fourth fin from the top looks larger than on yours which is another difference that seems to have been introduced at some stage during the 62 calendar year.
Eric

[sieber60]

Okay...Good information, now I know what I'm working with.

Thank you!

[Speeding Big Twin]

You’re welcome. In April 2010 I emailed MCC and told them I was researching DCs etc and I asked if they could help but my first attempt came back as undeliverable (unknown address) so I tried their info email address later the same day. I assume my second email got through but I received no reply so I tried again the following month but no response then either.

Later that year on the Panhead and Flathead forum there was a certain long discussion about Panhead cylinders and a lot of info was posted. Since then a few more things have been learnt but to this day I’m still accumulating photos to help with identification.
Eric