V-Twin "Replica" Pan Heads

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awander
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V-Twin "Replica" Pan Heads

#1

Post by awander »

I recently broke down and bought a set of the V-Twin 1955-1962 "Replica" Pan Heads. These are their stock number 10-1957.

I decided that the Plumber intakes were just too much trouble(I hate all of the ways that they can leak), so I went with the 55-62 inside oiler O-ring heads, even though they aren't correct for my '52 FL.

Before I bought these, I searched for good info on them and found very little, so I wanted to post regarding my experiences with them, to hopefully help someone else in the future.

At first glance, they seem really nice. The castings seem solid, machining is well done(though not deburred, some edges are really sharp).

These came with valves installed, so I'll want to pop those out and check guide clearance, and valve-to-seat fitment, but from what I can see, they look fine.

Here are some photos I took of the front head from all angles(I'll put the Rear Head photos in a second post):
Front Head R Side
Front Head R Side
Front Head right.jpg (118.2 KiB) Viewed 2912 times
Front Head Rear Side
Front Head Rear Side
Front Head rear.jpg (96.8 KiB) Viewed 2912 times
Front Head Left Side
Front Head Left Side
Front Head left.jpg (130.87 KiB) Viewed 2912 times
Front Head Front Side
Front Head Front Side
Front Head front.jpg (88.42 KiB) Viewed 2912 times
Front Head Bottom
Front Head Bottom
Front Head bottom.jpg (115.96 KiB) Viewed 2912 times
Front Head Top
Front Head Top
Front Head top.jpg (110.11 KiB) Viewed 2912 times
awander
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Re: V-Twin "Replica" Pan Heads

#2

Post by awander »

Here are the rear head photos;
Rear Head rear.jpg
Rear Head rear.jpg (75.9 KiB) Viewed 2911 times
Rear Head right.jpg
Rear Head right.jpg (114.61 KiB) Viewed 2911 times
Rear Head left.jpg
Rear Head left.jpg (117.05 KiB) Viewed 2911 times
Rear Head front.jpg
Rear Head front.jpg (119.03 KiB) Viewed 2911 times
Rear Head top.jpg
Rear Head top.jpg (117.88 KiB) Viewed 2911 times
Rear Head bottom.jpg
Rear Head bottom.jpg (113.89 KiB) Viewed 2911 times
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Re: V-Twin "Replica" Pan Heads

#3

Post by Panacea »

They sure look good, Did you do the port finish?
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Re: V-Twin "Replica" Pan Heads

#4

Post by awander »

Panacea wrote: Fri Oct 09, 2020 1:18 am They sure look good, Did you do the port finish?
No, I haven't done anything to them in those photos.

Today I used 15psi air and a couple of large rubber stoppers to see if the valves were sealing, and I couldn't detect any leaks.

I'm still going to pull the valves out and check the seats and the guide clearances.

Once I am sure that part is good, I will get to work on some deburring of the machined edges, and maybe a little countersink/contouring on the spark plug hole inside the head.
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Re: V-Twin "Replica" Pan Heads

#5

Post by kitabel »

That deep machined relief around the seats is a puzzle: it doesn't exist in stock heads, the seat OD is almost flush with the as-cast chamber contour.
I'm sure it does not hurt breathing, it may be an improvement. What concerns me is why was it done?
Having the actual seat so low raises the valve stem, which affects rocker arm range of motion.
How many CC does the relief add (reducing the static CR)?
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Re: V-Twin "Replica" Pan Heads

#6

Post by awander »

kitabel wrote: Fri Oct 09, 2020 1:46 am That deep machined relief around the seats is a puzzle: it doesn't exist in stock heads, the seat OD is almost flush with the as-cast chamber contour.
I'm sure it does not hurt breathing, it may be an improvement. What concerns me is why was it done?
Having the actual seat so low raises the valve stem, which affects rocker arm range of motion.
How many CC does the relief add (reducing the static CR)?
kitabel, I noticed that as well. I will make some measurements before I install these heads, and compare the volume of the chamber to a stock head.

I'm also not sure that the actual valve seats are lower in the head, I think that the relief may simply be a larger radius than the dome of the combustion chamber. I'll see if I can measure that as well.
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Re: V-Twin "Replica" Pan Heads

#7

Post by RooDog »

While checking the CCs, can you also check the valve stem protrusion?
What do the ports look like?
....RooDog....
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Re: V-Twin "Replica" Pan Heads

#8

Post by Excalibur »

As a side note, there was a warning note with my new STD heads to check head bolts didn't bottom out in thread holes. One in particular can break through into the intake port IIRC. Mine were clear though I did swap to Shovelhead bolts.
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Re: V-Twin "Replica" Pan Heads

#9

Post by awander »

RooDog wrote: Fri Oct 09, 2020 4:21 am While checking the CCs, can you also check the valve stem protrusion?
What do the ports look like?
....RooDog....
Will do, Roo! I'll report back when have the numbers.

I'll take some photos of the ports tomorrow.

I pulled the Front head Exhaust valve this evening, and checked clearance in the guide-it came to right around .0015", which fits with what Kibblewhite recommends for cast iron guides with their valves. No telling what "brand" these valves are, but at least it's in the ballpark, I guess.

Valve to seat contact looked pretty good-I could make out a dull ring where it looked like they were lapped in. I put some blue sharpie on the seat and dropped the valve in and twisted it back and forth a few times, and it rubbed off the sharpie in a nice thin band all around. The valve itself had a nice blue band around it when I took it out.

Now I just need to make a long stalk with 14mm spark plug threads on the end, so I can easily hold the head(s) with the vise while removing and re-installing the other valves...no fun juggling the spring compressor, the keepers, and the head...
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Re: V-Twin "Replica" Pan Heads

#10

Post by awander »

Excalibur wrote: Fri Oct 09, 2020 4:34 am As a side note, there was a warning note with my new STD heads to check head bolts didn't bottom out in thread holes. One in particular can break through into the intake port IIRC. Mine were clear though I did swap to Shovelhead bolts.
Thanks, I'll make sure to check that.
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Re: V-Twin "Replica" Pan Heads

#11

Post by awander »

I don't have any incredibly accurate means of measuring the volume of the combustion chambers, so I used what I have: some kerosene, and a small measuring cup.

My old Stock 1952 Plumber Intake Rear Pan Head with J12YC Spark Plug installed, filled the chamber just to the point where the fluid was beginning to run over from the domed area to the recess where the cylinder spigot fits, held almost exactly 4 oz of kerosene.

The new Rear Head held very slightly less than that, maybe 3/4 oz. The transition from the domed area to the spigot recess is less well-defined on the new heads, but I got it as close as I could.

So the new chamber is very slightly smaller, though this may be made up by the extra radius on the transition from dome to recess in the new head.
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Re: V-Twin "Replica" Pan Heads

#12

Post by awander »

I took both valves out of the rear head, and took some photos of the seats and the port. The seats appear to be steel:
Rear Head Valve Seats.jpg
Rear Head Valve Seats.jpg (84.56 KiB) Viewed 2767 times
Rear Head Exhaust Valve Seal.jpg
Rear Head Exhaust Valve Seal.jpg (73.28 KiB) Viewed 2767 times
Rear Head Exhaust Port #1.jpg
Rear Head Exhaust Port #1.jpg (76.59 KiB) Viewed 2767 times
Rear Head Exhausr Port #2.jpg
Rear Head Exhausr Port #2.jpg (103.85 KiB) Viewed 2767 times
Rear head Intake Port #1.jpg
Rear head Intake Port #1.jpg (70.7 KiB) Viewed 2767 times
Rear Head Intake Port #2.jpg
Rear Head Intake Port #2.jpg (64.06 KiB) Viewed 2767 times
Rear Head Intake Port with Flash.jpg
Rear Head Intake Port with Flash.jpg (50.67 KiB) Viewed 2767 times
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Re: V-Twin "Replica" Pan Heads

#13

Post by awander »

Roo, with the seals on there, I can't measure the valve stem protrusion the way the book says, from the shelf on the valve guide.

Are there any measurements that would be meaningful without pulling off the seals?
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Re: V-Twin "Replica" Pan Heads

#14

Post by RooDog »

I suppose the thing to look at is how much clearance you have for valve travel, that is, how much lift will the valves tolerate?
I would just make sure the valves are not sunk too deep in the heads. Check for valve collar to pan clearance and be sure the rockers don't touch the inside pans also. Pretty much do a performance valve setup & clearancing for whatever cam you're gonna use.
Get your Dremel out and do a little clean up work in the pockets and you should be good to go....
You already have Shovelhead intakes, I suppose that is a good thing....
I don't know how helpful any of my ramblings was, but all in all they don't look bad, bust need a little TLC to be rockin' the blacktop....
....RooDog....
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Re: V-Twin "Replica" Pan Heads

#15

Post by awander »

OK, the valves...Here are some shots of the valves and keepers from the rear cylinder:
Keeper 1.jpg
Keeper 1.jpg (36.66 KiB) Viewed 2751 times
Keeper 2.jpg
Keeper 2.jpg (35.17 KiB) Viewed 2751 times
I'm no expert on valves and keepers, but from what research I did, it seems the important things about the keepers are that they:
-have an ID that very closely matched the OD of the valve stem
-have the correct taper to match the collar
-are the right OD so that they fit into the proper height in the collar when installed.

These seem good on all of those measurements, but, one other thing that I sort of expected, was that the width of the "land" on the keepers (the part that fits the groove on the valve stem) would be about the same as the width f the groove in the stem, but as you can see, these are nowhere near as wide as the groove.

I did also find someone who said that a good test for proper fit was to assemble the keepers and upper collar onto the valve with no spring, and if they would stay in position with nothing holding them there, it was good. As you can see below, these do pass that test:
Valves with Keepers and Collars.jpg
Valves with Keepers and Collars.jpg (63.83 KiB) Viewed 2751 times
So, how important is the width of that land on the keepers matching the width of the groove in the vlave stem? Am I worrying about nothing?

Finally, the outer valve springs are (poorly) painted and seem to be in good shape, while the inner springs are not painted, and have a good amount of rust on one side. Should I be concerned about this? See belwo:
Spring 1.jpg
Spring 1.jpg (77.75 KiB) Viewed 2751 times
Spring 2.jpg
Spring 2.jpg (74.68 KiB) Viewed 2751 times
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