Plugging Timing Case Holes

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swooshdave

swooshdave

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I noticed that although the cases I'm going to use have the mods done to the windage and oil pickup, the holes in the timing case haven't been plugged up.

Does it matter how you plug the holes?

Should the holes be tapped and a short set screw with locktite be used?

http://www.tacomascrew.com/s.nl/it.A/id.19566/.f

I also saw mention of the plugs. Which I assume you don't thread and just drive into the holes?

http://www.tacomascrew.com/Products/Socket-Pipe-Plugs/025-905-1_4

I haven't found brass ones yet, I assume brass has similar expansion characteristics as the aluminum?

And what size?
 
swooshdave said:
I noticed that although the cases I'm going to use have the mods done to the windage and oil pickup, the holes in the timing case haven't been plugged up.

Does it matter how you plug the holes?

Should the holes be tapped and a short set screw with locktite be used?

http://www.tacomascrew.com/s.nl/it.A/id.19566/.f

I also saw mention of the plugs. Which I assume you don't thread and just drive into the holes?

http://www.tacomascrew.com/Products/Socket-Pipe-Plugs/025-905-1_4

I haven't found brass ones yet, I assume brass has similar expansion characteristics as the aluminum?

And what size?
Click to expand...

I believe I read on this forum a little while back by one person that the holes were threaded and TWO short set screws installed with locktite. FWIW.
 
Thank you. Still doesn’t say how to plug and specifically with what.

These holes are currently not threaded.
 
Ever the optimist :D

I think you would need a tap but the holes are odd sizes (around 12.5 and 9.5 mm)
The smaller not having a lot of space around it, someone must have posted something beyond a finished picture ?
 
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Time Warp said:
Ever the optimist :D

I think you would need a tap but the holes are odd sizes (around 12.5 and 9.5 mm)
The smaller not having a lot of space around it, someone must have posted something beyond a finished picture ?
Click to expand...

One would think but I searched high and low.
 
Jeandr said:
Here is my blatant copy of CNW's breather system. The reed valve is off e-bay ($10 + shipping) and it is used in pocket bikes with two stroke engines. Unfortunately, my tools are not big enough and I had to have the crankcase machined by a real machinist ($110) I cut my own gaskets from material I had stuffed in the rafters in the basement. Cost comparaisons are about $150 Canadian $ for mine and $265 US +$140 US (shipping there and back) for CNW but I have to admit that CNW logo speaks quality and trickiness. Did I ever mention I am a cheapskate :lol:

Plugging Timing Case Holes


Here is what must be done to plug up the holes in the RH case and the added hole to drain the timing chest.

Plugging Timing Case Holes


The multiple arrows point to holes that have been blocked and the single one on the left points to the new drain hole (sorry for the french text). I plugged up the hole to the points wires because I am using an old timing cover with a tach drive gearbox on the end of the cam. The plugs can be found at engine rebuild shops, I used two 1/4" NPT (National Pipe Threads) plugs and three 1/8" NPT plugs. The old breather was plugged with an aluminum plug I turned, I think it's 9/16" or 5/8" x 20. A plate could be used or get a 3/8" NPT plug. Plugs are 25¢ for the small ones and 50¢ for the big ones.

Jean
Click to expand...

https://www.accessnorton.com/NortonCommando/crankcase-breather.3698/#post-34796
 
swooshdave said:
The irony that I replied to that post all those many years ago is not lost on me. Thanks!
Click to expand...


Dave, until you ASK a question about how to do something and then discover that you (correctly) ANSWERED the same question that someone else asked 10 years ago, I wouldn't worry about it!

Yes, I recently did exactly that on another forum (not moto related). It was pretty darned embarrassing to post a question and then get an answer within an hour saying, "Mike, take a look at YOUR post from July 12, 2009 that answers YOUR question of today! :) "
 
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You can get the right size brass hex pipe plugs from Mcmaster Carr with quick delivery.

1/4" brass hex pipe plugs #1491N187

1/8" brass hex pipe plugs #50785K112

Or make aluminum plugs and hammer them in. Use a drift with a larger diameter than the hole so you won't drive them in too far.

Plugging Timing Case Holes
 
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Ok, I dropped my cases off with a friend in the club. He's a retired machinist and is also working on a 72 Combat engine. In fact he had his case already set up in his mill ready to cut away the windage flange when I got there today. We looked at the one engine case I have that is already cut away and discussed how much to cut and where. He has an ample selection of hardware (as any good machinist will) and has some set screws to use to plug up the timing case holes.

Three things I need to figure out:

  1. Are steel set screws ok? Is there some reason to use brass aside from availability?
  2. Where exactly to drill the drain back hole. I know somewhere around where the oil pump is so I need to revisit all the pictures to determine an exact location.
  3. And lastly, how to make a couple reed valve bodies. I'm thinking of using the Triumph ones like @grandpaul does but make custom bodies for the back to the 72 cases. They are readily available. I think @jseng1 uses the BMW ones, which are round.
 
Dave

Yes I use the BMW reed valve parts. Adaptable cheap reed valves are available from Mikes XS. See return oil hole below.

Plugging Timing Case Holes
 
jseng1 said:
Dave

Yes I use the BMW reed valve parts. Adaptable cheap reed valves are available from Mikes XS. See return oil hole below.

Plugging Timing Case Holes
Click to expand...

I always thought the BMW ones were interesting. Any chance they are small enough to fit into the breather assembly on the back of the 72s?
 
DO NOT DO NOT DO NOT cut away the windage flange just relocate the oil pickup to the rear and leave the rest as is.
 
We have used metric stainless grubscrews (setscrews) to good effect on three bikes now.

Plugging Timing Case Holes

We drive them in with JB Weld, then centre punch the thread to prevent any possibility of them even moving again.

Sorry they’re metric - everything else on the bikes is imperial, honest guv!
 
bill said:
DO NOT DO NOT DO NOT cut away the windage flange just relocate the oil pickup to the rear and leave the rest as is.
Click to expand...

Well, too late now. But not to worry, less than 1/2 inch was removed to expose the oil pickup hole. Shouldn't be too detrimental.
 
jseng1 said:
You can get the right size brass hex pipe plugs from Mcmaster Carr with quick delivery.

1/4" brass hex pipe plugs #1491N187

1/8" brass hex pipe plugs #50785K112

Or make aluminum plugs and hammer them in. Use a drift with a larger diameter than the hole so you won't drive them in too far.

Plugging Timing Case Holes
Click to expand...

Tap the holes for the brass plugs or just drive them in? @jseng1
 
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