VL/WLC valve cover on UL

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VL/WLC valve cover on UL


Post by Jode » Fri May 18, 2018 5:22 pm

Hi guys,

I have seen VL valve covers installer on a UL. I have heard that to be able to fit them on a UL a thread-adaptor piece is needed - can anyone guide me to way is needed?

Best regards

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Re: VL/WLC valve cover on UL


Post by Doc37W » Fri May 18, 2018 6:36 pm

1937-'38 Us had the same screw type valve covers, lower screw adapters & tappet blocks as 1930-'36 Vs, only the upper spring covers were longer. '39-'48 went with unthreaded tappet blocks, pull down middle covers(with springs & washers), and clips to hold them against the corks in the blocks. The latter was more oil tight. Your '46 would have clip style. Doc

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Re: VL/WLC valve cover on UL


Post by Frankenstein » Sat May 19, 2018 12:49 pm

The earlier UL covers were exactly as the VL's except for length of the upper portion of the cover which is longer for UL's as UL's had longer stroke and thus taller cylinders and longer valves. The tappet blocks for VL's, UL's and WL's are the same, with the same thread for the tappet covers to screw on to. Pretty much as Doc said. I would respectfully disagree as to the relative oil tightness of the early vs late UL covers. In my opinion, the earlier covers can be made virtually leak proof, which I have not had the same success with the later covers.
My approach is to use the "O" ring made to be used on a sportster tappet block where it is pressed into the engine case as the sealing agent at all three junctions in the early screw type UL covers. At the tappet lower cover junction to lifter block, the screw connection between lower and mid cover, and the sliding juncture between upper and mid cover. In addition, I use a piece of innertube between the upper cover and the valve guide junction. Probably there is a better rubber compound for between guide and cover, as I've found the inner tube to sometimes show signs of melting on disassembly, but it maintains an effective seal none the less. Keep in mind though that I have a LOT more oil circulating in my engine vs a standard engine, and have had problems with serious leaking from the valve cover area. Whereas, with the standard oil system, very little oil gets up there and either of the standard cover setups are adequate to the job.

As a tip for using the earlier style cover, I've found the following technique to be helpful:
To inspect tappet clearance, first oil the crack between the upper cover and the mid screw cover, so oil gets down on the o ring sealing that juncture. Helps in sliding the cover up and down.
Then unscrew the mid and lower cover apart unscrewing the mid cover first, but not completely, then the lower cover, helps force the mid cover up the the upper cover. Pry as necessary to get the covers up to set tappets. on reassembly, have the lower and mid sections loosely screwed together, but not tight, just started a few threads to allow some flexiblilty at that joint, then force them down onto the threaded portion of the tappet block and start threading the lower cover onto the tappet block.
The threads on the lower cover and the threads on the tappet block have a taper machined on them that helps guide them to start threading properly, and lessens the tendency to cross thread. As you thread the lower cover on the tappet block, stop frequently and screw the mid section down onto the lower section so that those two parts never come completely unthreaded. Continue the process 'till it is all screwed down tight.
The problem avoided is the potential for cross threading the threads between the lower and mid sections, which are a fine thread and do not have the lead in taper that helps avoid cross threading.
Just one man's experience, your results may vary. :-)

Oh, by the by, the last time I bought UL screw type early covers from V twin, they actually were VL covers. That's when I went with the "O" ring at the upper juncture. They were thin enough that the shorter VL type uppers would just reach the distance, whereas the flatband sealing ring that came with the covers would actually not let the upper cover touch the valve guide and leave a small opening between guide and cover, allowing oil out.
I'm sure it's just another instance of Ted just using up what was on the shelves entirely, before ordering the right stuff.
Like the ill fitting timing main bearing cages a few years ago that wouldn't fit on the main shaft when the rollers were fitted into the cage. He just kept sending them out anyway, till they were all gone. The next batch he had made, work.
Enough rambling, hope this helps with your question.

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Re: VL/WLC valve cover on UL


Post by RCamp » Mon May 21, 2018 2:58 pm

If you're using the later style valve covers, and want a better seal than what you get with the stock seals, use O-rings as I have listed below.
I've been running them on my '46 UL for thousands of miles and have never had any leaks.

In place of the upper cork seal (18245-39) use a 35.7mm id x 42.7mm od x 3.5mm O-ring

In place of the lower cork seal (18257-39) use a 1 1/4" id x 1 1/2" od x 1/8" O-ring

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Re: VL/WLC valve cover on UL


Post by Jode » Tue May 22, 2018 9:22 am

Thanks all, great inputs, much apprechiated

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