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Knucle vs. Pan cylinder head bolt pattern question?

Moderators: Curt!, Pa


Posts: 8
Knucle vs. Pan cylinder head bolt pattern question? If a Knuckle cylinder head has been mounted on a Pan cylinder, would the holes in the head need to be modified to fit the pan cylinder bolt hole pattern? Can the head later be remounted on a Knuckle cylinder without a problem? Thanks, Kevin.


Posts: 607
Location: Menomonie, Wisconsin, USA
Only one bolt hole needed to be moved and usually it can be put back but sometimes it takes a bit of work because the holes overlapp.

Jerry

panic

Be careful when purchasing or assembling a modified head.
On occasion, the "builder" saves the price of the correct 7/16-16 NS knucklehead tap by using a common 7-16-20 NF tap and a panhead bolt.
If you put the bolts in the wrong holes, guess what happens...


Posts: 33
Just curious, but what is the purpose of modifyng Knuck heads to fit on Pan Jugs? The heads are expensive and the jugs are inexpensive by comparison, so why would someone do that to perfectly good Knuck heads? Is there any advantage to Pan jugs over Knuck jugs that I am missing?


Posts: 729
Location: nekoosa,wisconsin,usa

Boots99,
Sometime after your day Knucklehead cylinders became scarce. This was before B.A. ( before Anders) ! Back then Pan cylinders were all that was available .
JKE
Call on God, but row away from the rocks.


Posts: 159
I didn't think the knuck heads needed modding only the pan jugs to suit knuck heads. Am i wrong? Bolt pattern that is.


Posts: 33
I don't mean to sound like a smart ass, but some of you guys are real restorers. I just build stuff I like for myself. I'm asking to learn from you. But knuck jugs have been available from V-Twin for a long time. Low quality, but available. Also, has anyone come up with a method for putting a quality steel sleeve in a beat up old knuck cylinder or a low quality V-Twin cylinder? I would think those options would have been better then butchering up nice knuck heads.

panic

only the pan jugs

Let me know when it's done.


Posts: 767
Location: CA USA
We put the pan jugs into the knuck motor most times at the request of a customer. Conventional wisdom was that pan jugs were stronger, probably were. At least they were available and cheap. Tedd didn't exist. Aftermarket jugs didn't exist. A few folks made expensive stuff. I think axtell and some others did. Sleeving was not as reliable as it is today. Very few folks were concerned with correctness, just gettin down the rode with as strong and reliable a motor as we were capable of building back in the dark ages. Now were trying to undo all the fixes of old. Jerry referred to the overlap of the bolt holes. Here's a good pic in this ebay auction of the head bolt hole overlap that occurs when you change to pan barrels on a knuck.
http://cgi.ebay.com/ebaymotors/ws/eBayI ... K:MEWAX:IT


Posts: 607
Location: Menomonie, Wisconsin, USA
Here is what could happen to Knucklehead barrels. They do not have the reserve of strength that panhead cylinders had. The 2 blown cylinders that I have seen - 1. had 1 dark piston and one light so may have had air leak and 2. Point gap was off so maybe one cylinder was out of time.

To put pan barrels on a knuck you have to trim ot remove the firering on the cylinder and move the bolt on the head.

Image

Image

Sorry Jon for using you as an example. This happened late last fall.

Jerry


Posts: 607
Location: Menomonie, Wisconsin, USA
When Killer's knuckle blew a cylinder years ago Kyle (Amklyde) said that there was nothing apparent that could have caused it and I believe it was only +.040 and I have a FL barrel at standard with stress cracks.

Jerry

panic

Pan barrels seem to have considerably more strength at the flange.


Posts: 19
Location: Valentine, NE 69201
How about modifying pan cylinders to knuckle head bolt pattern. I have n.o.s. S&S cylinders for 3 5/8 " bore and don't want to modify heads. Can it be done?
Thanx
Steve
It's a hard life if you don"t weaken.

panic

Locate the missing bolt area on the barrel.
Where does the bolt go?


Posts: 607
Location: Menomonie, Wisconsin, USA
I suppose anything is possible but I wonder if maybe you will run out of casting? Or do a trade with a guy that already has modified pan barrels. I just happen to know of such an individual and no it is not me.

Jerry


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