Oil Line Screwup

S

Stephen Hill

Joined
Oct 28, 2009
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A friend, new to Nortons, just told me that he accidentally swapped the "in" and "out" hoses on the oil filter bracket. After he started the bike, and idled it for a short period of time (not sure how long), one hose and the oil filter burst.

Assuming the engine is not damaged from oil starvation, what other damage should he be looking for? Example, will the oil seal on the primary side of the crankshaft be dislodged? Any other areas to check??
 
Is the oil filter on return side as intended? If just swapping the in/out at the filter housing, that will still allow for oil feed to the engine - the return oil was just trying to go backward through the filter, which may have a one-way flapper valve. Was the hose that blew the one connected to the return at the engine?
 
Stephen Hill said:
A friend, new to Nortons, just told me that he accidentally swapped the "in" and "out" hoses on the oil filter bracket. After he started the bike, and idled it for a short period of time (not sure how long), one hose and the oil filter burst.

Assuming the engine is not damaged from oil starvation, what other damage should he be looking for? Example, will the oil seal on the primary side of the crankshaft be dislodged? Any other areas to check??
Click to expand...
The crank seal will not be damaged.

The scavenge side of the pump (which blew the oil filter) is unrelated to the crank seal.



Edited for accuracy.
💡
 
Last edited:
concours said:
The crank seal will not be damaged.
The pump was sucking air, no appreciable pressure was produced.
The scavenge side of the pump (which blew the oil filter) is unrelated to the crank seal.
The connection rod bearings would be suspect, having been starved for "a short period of time", which is subjective, and means different things to different people.

Fit an oil pressure gage on the bike. Before proceeding.
Click to expand...
If he only swapped hoses on a filter in the scavenge line, why would the rod bearings be starved?
 
Maybe your pal would like to keep this in the file.


Oil Line Screwup
 
Interesting that the filter blew up. These should be able to handle a pressurized oil system as they are on the pump output side in many applications.Is the purpose of the filter check valve to help keep oil in the filter between rides, as an anti drain back valve? Or is it a bypass vlave if filter clogs up?
 
Hi all. It was my bike in question (1973 850 Commando)
All this mistake came about due to a leaky oil tank. repaired and replaced - minus the bottom mounting bolt. chose to have it welded up with a patch over it. the tank rests quite comfortably on the battery box with some adhesive foam affixed. the right side cover keeps it all in place.
I had my young son do the replacement with new hoses and clamps, but alas he (gets thrown under the bus in the story here) wasn't that fastidious and swapped the lines. I believe this didn't affect the small local jaunts done since the repair, as noted by YukoNorton, oil flows in and out of filters not caring which hole it uses. But starting on the fated day - using the attached (bloody brilliant!) Alton Starter, must have been too much, and right then at cold startup caused the Filter to expand and warp, as well as the Oil feed - attached incorrectly to the OUT at the filter mount, to be forced off violently!

My guess is that the check-valve in the filter did its thing and stopped any oil entering and leaving without the proper RSVP. POP!
I won't be doing a post-mortem on the filter, but I will take photos.

Thanks for all the interest, and quick replies.
 
Fast Eddie said:
Blowing is enough to be able to tell.

New ones have ‘in’ / ‘out’ cast into them:

andover-norton.co.uk

Motorcycle parts and spares for Norton motorbikes - Genuine Andover Norton Spare Parts - Andover Norton Motorcycles Parts - Original Andover Norton Parts

Motorcycle parts and spares for Andover Norton motorbikes: Andover Norton manufactures and supplies all Genuine Factory Spare Parts for Norton motorcycles built before 2002.
andover-norton.co.uk
Click to expand...
Oodles Oil pressure! with the dislodged feed hose pointing at the ground spewing.
Mine does have the IN/OUT. Just impossible to read while mounted... lying on your back... upside-down... :)
 
Morgan Onda said:
Hi all. It was my bike in question (1973 850 Commando)
All this mistake came about due to a leaky oil tank. repaired and replaced - minus the bottom mounting bolt. chose to have it welded up with a patch over it. the tank rests quite comfortably on the battery box with some adhesive foam affixed. the right side cover keeps it all in place.
I had my young son do the replacement with new hoses and clamps, but alas he (gets thrown under the bus in the story here) wasn't that fastidious and swapped the lines. I believe this didn't affect the small local jaunts done since the repair, as noted by YukoNorton, oil flows in and out of filters not caring which hole it uses. But starting on the fated day - using the attached (bloody brilliant!) Alton Starter, must have been too much, and right then at cold startup caused the Filter to expand and warp, as well as the Oil feed - attached incorrectly to the OUT at the filter mount, to be forced off violently!

My guess is that the check-valve in the filter did its thing and stopped any oil entering and leaving without the proper RSVP. POP!
I won't be doing a post-mortem on the filter, but I will take photos.

Thanks for all the interest, and quick replies.
Click to expand...
Expect no engine damage. However, it sounds like you were not using lines acceptable for hot oil. Unlikely for a Norton to make enough pressure to burst a proper oil hose! Most likely using the first black fuel or vacuum line found at the local auto parts.

My stepson also blew a hose on his 850, connected correctly, but it was not meant for the purpose.

I use this:

Amazon product ASIN B000CRBQAE
It is also available in3' lengths. Withstands 300F and 250PSI.
 
Morgan Onda said:
Hi all. It was my bike in question (1973 850 Commando)
All this mistake came about due to a leaky oil tank. repaired and replaced - minus the bottom mounting bolt. chose to have it welded up with a patch over it. the tank rests quite comfortably on the battery box with some adhesive foam affixed. the right side cover keeps it all in place.
I had my young son do the replacement with new hoses and clamps, but alas he (gets thrown under the bus in the story here) wasn't that fastidious and swapped the lines. I believe this didn't affect the small local jaunts done since the repair, as noted by YukoNorton, oil flows in and out of filters not caring which hole it uses. But starting on the fated day - using the attached (bloody brilliant!) Alton Starter, must have been too much, and right then at cold startup caused the Filter to expand and warp, as well as the Oil feed - attached incorrectly to the OUT at the filter mount, to be forced off violently!

My guess is that the check-valve in the filter did its thing and stopped any oil entering and leaving without the proper RSVP. POP!
I won't be doing a post-mortem on the filter, but I will take photos.

Thanks for all the interest, and quick replies.
Click to expand...
Your young son learned a detail about the Commando and kudos to you for giving him the responsibility and a rare oppurtunity (amongst the young lads these days) to spark an interest in these great machines
 
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