Cases NOS

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jug

jug

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Anyone seen this before? My 73 cases have a second oil stop grub screw (part# 062638 I think) on the bottom of the timing side case, see pic.
Only ever thought they had one, just below the oil pump boss. Cant say I have ever seen this before.
Cases NOS
 
Just to clarify, the grub screw I took out of my old cases is fine thread (I assume BSF) while the threads on the new cases are coarse thread ( I'm assuming BSW ) can anyone confirm what thread they are?
Also the second grub screw is at the end of an internal oilway which isn't on my old cases?!?
JUG
 
I still haven't even quite figured out the orientation of that pic...

Give us a clue - what year of Commando might we be talking about here ?

Generally speaking, there isn't a lot of BSF in a Commando engine (LAB will doubtless quote the 2 or 3 that are).
Its mostly cycle thread (26 tpi), or BSW - or cycle thread or UNC in later C'dos.
And UNF in the cycle parts.

P.S. How can you guys survive without a thread gauge ?
Cases NOS
 
Very bottom of the case, the case half is resting on the cylinder mating surface. 73/74 CASES.
jug :)
 
jug said:
Anyone seen this before? My 73 cases have a second oil stop grub screw (part# 062638 I think) on the bottom of the timing side case, see pic.
Only ever thought they had one, just below the oil pump boss. Cant say I have ever seen this before.
Click to expand...

1972 and '73 750 timing side cases had a drilling for the forward scavenge pickup hole (the one that's plugged when doing the scavenge mod.) so I assume that's what the grub screw blanks off, but you're right in that it doesn't show in the parts books.

http://www.oldbritts.com/n_c_case.html
Cases NOS


According to the Stainlessbits list, 062638 is: "5/16 x 18 UNC".
http://stainlessbits.com/link12a.html
 
L.A.B
I have looked over the link to old britz case mod and am a little confused. I will be running on of Matts (CNW) reed breathers fitted to the original breather mount on the lower, rear, drive side case. Do I need to have the case machined as to allow for better scavenging? I would have thought that the breather would pump oil back to the oil tank if the mod were done.
JUG
 
I'm still not convinced that there's a scavenging problem on the street. Remember that Fred's issues were on the track.
 
jug said:
I will be running on of Matts (CNW) reed breathers fitted to the original breather mount on the lower, rear, drive side case. Do I need to have the case machined as to allow for better scavenging?
Click to expand...

That would be something for Matt to comment on.


jug said:
I would have thought that the breather would pump oil back to the oil tank if the mod were done.
Click to expand...

I'm not sure it is wise to rely on what is essentially a breather to scavenge the crankcase, however, it seems CNW also modify the timing side case when doing the breather modification.

http://coloradonortonworks.com/part-cat ... /#post-295

In order to install this kit the engine needs to be completely stripped down as we mill a mounting surface on the lower backside of the drive side case half. We also modify the timing case half.

The above mentioned results are of course directly related to how the engine is built as piston clearance, cylinder bore, piston ring quality, head work, gasket quality and much more will all play a part in how well the engine breather will operate and what kind of results you will experience.
Click to expand...
 
jug said:
Anyone seen this before? My 73 cases have a second oil stop grub screw (part# 062638 I think) on the bottom of the timing side case, see pic.
Only ever thought they had one, just below the oil pump boss. Cant say I have ever seen this before.
Cases NOS
Click to expand...

I replaced my 200xxx cases with a later 220xxx set. There is 2 more grub screws on the newer set.
I would certainly say, the more the better. Being able to clear oil tunnels and being able to shine a light and see it while looking in other holes is great thing. I am sure my newer 220xxx case had some sort of issue for there was about a bit less than teaspoon of shrapnel that I cleared out of it. These extra access points were/are invaluable.
 
jug said:
L.A.B
I have looked over the link to old britz case mod and am a little confused. I will be running on of Matts (CNW) reed breathers fitted to the original breather mount on the lower, rear, drive side case. Do I need to have the case machined as to allow for better scavenging? I would have thought that the breather would pump oil back to the oil tank if the mod were done.
JUG
Click to expand...

If your cases have the sump pickup in the forward position it will need to be plugged and opened up at the rear -with or without my reed breather.

There is definitely a problem with the pickup location at the front of the cases -even on the street. Jim
 
comnoz said:
If your cases have the sump pickup in the forward position it will need to be plugged and opened up at the rear -with or without my reed breather.

There is definitely a problem with the pickup location at the front of the cases -even on the street. Jim
Click to expand...
Thanx for that. Logic backs you up entirely.
 
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