BritBike Forum logo
BritBike Sponsor BritBike Sponsor BritBike Sponsor
BritBike Sponsor

BritBike Sponsor

BritBike Sponsor
BritBike Sponsor BritBike Sponsor BritBike Sponsor
Home | Sponsors, Newsletter | Regalia | Calendar | Bike Project | BritBike Museum | Spiders Cartoons, "OLD" BritBike Forum | DVD- Manuals & Parts books | BritBike Stickers & Decals
Upgrade to: Premium Membership | Premium Life Membership | Vendor Membership | Site Sponsor Membership
Photo posting tutorial

Member Spotlight
waspfarmer
waspfarmer
Vancouver Island
Posts: 255
Joined: April 2006
Show All Member Profiles 
Shout Box
Search eBay for motorcycle parts in following countries
Australia, Canada, France, Holland, Italy, United Kingdom, USA
Random Gallery photo
Who's Online Now
211 registered members (99cyclone), 1,973 guests, and 735 spiders.
Key: Admin, Global Mod, Mod
Newest Members
GrBsa, g3nd03t, mach1mustang351, Msh5337, Barry Boxall
9709 Registered Users
Top Posters(30 Days)
Lannis 118
Stuart 70
Peter R 54
desco 54
Popular Topics(Views)
345,586 mail-order LSR
Forum Statistics
Forums33
Topics63,818
Posts616,484
Members9,709
Most Online3,995
Feb 13th, 2017
Like BritBike.com on Facebook

Follow BritBike here!
Previous Thread
Next Thread
Print Thread
Rate This Thread
#692610 - 04/21/17 12:04 pm The inverted cranksahft seal....  
Joined: Oct 2012
Posts: 2,852
Hillbilly bike Online content
BritBike Forum member
Hillbilly bike  Online Content
BritBike Forum member

Joined: Oct 2012
Posts: 2,852
Running from demons in WNY
I hear stories of it from guys here who know what they are talking about. How do you know it inverted other than loss of pressure. Was the seal still inverted when you pulled the side cover? Anyone have a photo? John Healy mentioned doing bench tests on seals to see the pressure it too to invert them....
My dual engine Triumph had the front engine lose all oil pressure after a piston partially seized...I wrote off the pressure loss to piston debris in the oil pump...I totally disassembled the engine and very carefully searched for clues but found debris in rod bearings and the screen sump filter.... the oil pump appeared clean. These pre unit engine side covers are converted to seals and they appeared like new... ......I repaired the engine and it been run for about 1/2 an hour with no problems....As I mentioned elsewhere the oil pressure was 95-100 psi when the engines are reved up with moderately warm oil...(LSR is short duration and the oil never fully warms up). I now have the oil pressure reduced to 75-80 PSI after trying a lot of pressure relief springs and use of shims as required...
Kommando identified the seal I used in one of the engine as an SDA Taiwan made part.. John Healy tested these seals 10 or more years ago and said they invert at about 160 psi, and less PSI when hot.....PW seals invert at around 200 psi or more.....
At any rate I have two genuine PW seals coming ............So, any proof you have of an actual seal inversion ? Perhaps the engines having seal inversion had 100 psi oil pressure...I do know from reading that most guys do not have oil pressure gauges installed...


Naked frame LSR bikes, dressed in animal hides clinging to vibrating oily machines propelled by fire
Support Your #1 BritBike Forum!
Membership Type! Free
Member
Premium
Member
Premium Life
Member
Vendor
Member
Site
Sponsor
Recognition No Premium Member Premium Life member (5 years) Vendor Member Site Sponsor Membership
Post commercial threads No No No Yes Yes
Custom title No Yes Yes Yes Yes
Upload avatar & photos No Yes Yes Yes Yes
Link avatar & photos Yes Yes Yes Yes Yes
Private Message Storage: 10 100 100 100 100
Length of signatures 255 600 600 600 600
Removes this very advert island between post 1&2 No Yes Yes Yes Yes
Price Free $12.90/year $105.00 No End
$55.00/5 years
$210.00/year
($17.50/month)
Email
Click on button >>
  Premium Member Premium Life member Vendor Member Site Sponsor Membership
#692616 - 04/21/17 6:15 pm Re: The inverted cranksahft seal.... [Re: Hillbilly bike]  
Joined: Aug 2001
Posts: 6,604
triton thrasher Online content
BritBike Forum member
triton thrasher  Online Content
BritBike Forum member

Joined: Aug 2001
Posts: 6,604
scotland
I think the garter spring will be off the seal, after inversion.


Amateur Loctite enthusiast.
#692618 - 04/21/17 6:30 pm Re: The inverted cranksahft seal.... [Re: Hillbilly bike]  
Joined: May 2007
Posts: 1,703
R Moulding Online content
BritBike Forum member
R Moulding  Online Content
BritBike Forum member

Joined: May 2007
Posts: 1,703
South Island

When mine did this you could clearly see that the lip part of the seal was distorted.

Rod



#692620 - 04/21/17 6:34 pm Re: The inverted cranksahft seal.... [Re: R Moulding]  
Joined: Oct 2012
Posts: 2,852
Hillbilly bike Online content
BritBike Forum member
Hillbilly bike  Online Content
BritBike Forum member

Joined: Oct 2012
Posts: 2,852
Running from demons in WNY
Thanks guys....I'll pull the side cover an have a look.....


Naked frame LSR bikes, dressed in animal hides clinging to vibrating oily machines propelled by fire
#692632 - 04/21/17 7:41 pm Re: The inverted cranksahft seal.... [Re: Hillbilly bike]  
Joined: Jun 2007
Posts: 5,100
HawaiianTiger Online content
BritBike Forum member
HawaiianTiger  Online Content
BritBike Forum member

Joined: Jun 2007
Posts: 5,100
Maui Hawaii
This seal was responsible for the motor burning up.

[Linked Image]

Kinda fuzzy, but I think you can see where the seal lip is deformed.

Cheers,
Bill


Bikes
1974 Commando
1985 Honda Nighthawk 650
1957 Thunderbird/T110 "Flying Tiger"
Antique Fans: Loads of Emersons (Two six wingers) plus gyros and orbiters.
#692643 - 04/21/17 9:10 pm Re: The inverted cranksahft seal.... [Re: Hillbilly bike]  
Joined: Oct 2003
Posts: 10,909
RF Whatley Online content
BritBike Forum member
RF Whatley  Online Content
BritBike Forum member

Joined: Oct 2003
Posts: 10,909
North Georgia, USA
Originally Posted by Hillbilly bike
I hear stories of it from guys here who know what they are talking about. How do you know it inverted other than loss of pressure. Was the seal still inverted when you pulled the side cover? Anyone have a photo? John Healy mentioned doing bench tests on seals to see the pressure it too to invert them....


Your post is long, but I believe your main question was about crank seal inversion.

The only way to measure is by using an oil pressure gauge. Otherwise it's remove the timing cover to inspect.

In general, oil seal inversion (in my experience) is a rare and a non-fatal occurrence. On my 1966 6T, I found the seal and circlip popped entirely out of the cover and simply floating on the end of the crank. This engine (showing 12K miles) had never been opened and there is no telling how long it had run like that. Still, when the crank was removed, the crankshaft journals showed absolutely no signs of distress or damage. This for the simple reason that oil is being sucked into the crank, and so any oil presented to the oil input nipple is readily taken in. This is the common result on regular road bikes.

Further, IMHO in your specific application, the conversion to oil seal over the original brass bush, may not be an asset. This for the simple reason that when your engines are cranked, the run times are extremely short which allows no time for oil warming. So, whereas "bushing by-pass" once the oil is hot, as might be a concern on a typical road bike, is totally out of the picture in your application.

bigt

Last edited by RF Whatley; 04/21/17 9:12 pm.

Don't hide 'em, Ride 'em !!

RF Whatley
Cornelia, GA

"Shop Boy" at Rodi British Bikes
#692647 - 04/21/17 9:56 pm Re: The inverted cranksahft seal.... [Re: Hillbilly bike]  
Joined: Jan 2014
Posts: 3,040
NickL Offline
BritBike Forum member
NickL  Offline
BritBike Forum member

Joined: Jan 2014
Posts: 3,040
Aus
One way to help matters in your application Tony, would be to warm the oil before putting it in the bike, like the old BMW Rennsports did.



#692648 - 04/21/17 10:15 pm Re: The inverted cranksahft seal.... [Re: Hillbilly bike]  
Joined: Jan 2017
Posts: 116
TR7RVMan Offline
BritBike Forum member
TR7RVMan  Offline
BritBike Forum member

Joined: Jan 2017
Posts: 116
Pleasant Hill, California USA
Hi Hawaiian Tiger, What brand seal is that?

Looking at the '69 bonnie cover on my work bench that has original seal from 70s that has the tin shield. Comparing snap ring edge were pliers go to the edge of your seal & to the edge of old version seal, the tin of the old seal might have prevented that from happening?? The old tin version appears to cover more of the lip.

By the way, the old tin version has black rubber around the outside edge, so rubber seals outside. The rubber ends just around corner so it slightly is on tin face.

The tin covers much of the seal lip such it supports lip from rolling out. Measuring an old seal on the crank snout the gap between snout & tin is .032" meaning seal lip would have to squeeze through .032" to invert.

Certainly rubber could do that with enough pressure. I wonder how the old original version would compare to modern Pioneer Weston?

Don

#692649 - 04/21/17 10:30 pm Re: The inverted cranksahft seal.... [Re: Hillbilly bike]  
Joined: Jul 2013
Posts: 456
Tribsauk Offline
BritBike Forum member
Tribsauk  Offline
BritBike Forum member

Joined: Jul 2013
Posts: 456
Death row next in line norfolk
I have a oil seal conversion on my pre unit 750 Tribsa but only machined the timing cover just enough so the seal sits flush and left the old part remaining bush in situ so I have the best of both .. if the seal gives out I still have the bush to feed crank.With this conversion there is no place for a circlip to hold seal in situ I used superglue with no problems after approx 6000 miles.Dave


1941 BSA WM20
1958 TRI-BSA 750 PRE UNIT
1957 THUNDERBIRD
1932 R E MODEL GS SPECIAL
1947 BSA YM21
#692656 - 04/22/17 12:21 am Re: The inverted cranksahft seal.... [Re: Hillbilly bike]  
Joined: Oct 2012
Posts: 2,852
Hillbilly bike Online content
BritBike Forum member
Hillbilly bike  Online Content
BritBike Forum member

Joined: Oct 2012
Posts: 2,852
Running from demons in WNY
Bill, the photo is helpful, thanks....Nick, I spend time trying to get heat into the engine before each race...it's not easy because the machine is stationary and with no air flow the head gets too hot before the oil gets slightly warm...So the engine has to run, then shut down to allow the head to cool and started again.as it advances slowly towards the starting line.. About the bushing being an advantage over the seal, most of the Triumphs in LSR including my other bike are unit engines...
..Both engines cases are 1956, one a TR6 generator , the other a 6T alternator engine..,
The bike goes on the dyno May 4th to be thrashed unmercifully and don't need an oil pressure failure at full power causing the smoking crankshafts to bounce off the floor..


Naked frame LSR bikes, dressed in animal hides clinging to vibrating oily machines propelled by fire
#692667 - 04/22/17 1:54 am Re: The inverted cranksahft seal.... [Re: Hillbilly bike]  
Joined: Jan 2014
Posts: 1,323
reverb Offline
BritBike Forum member
reverb  Offline
BritBike Forum member

Joined: Jan 2014
Posts: 1,323
South cone
...hi Tony, I cannot add more info to help on this but I am very interested in that dyno test. May be you can shot a few clips to see what s going on..

Thanks

#692705 - 04/22/17 11:37 am Re: The inverted cranksahft seal.... [Re: reverb]  
Joined: Oct 2012
Posts: 2,852
Hillbilly bike Online content
BritBike Forum member
Hillbilly bike  Online Content
BritBike Forum member

Joined: Oct 2012
Posts: 2,852
Running from demons in WNY
Originally Posted by reverb
...hi Tony, I cannot add more info to help on this but I am very interested in that dyno test. May be you can shot a few clips to see what s going on..

Thanks

I will take a video of the bike on the dyno..... An airplane pilot once said
Quote
two engines doubles the risk of an engine failure
........


Naked frame LSR bikes, dressed in animal hides clinging to vibrating oily machines propelled by fire
#692709 - 04/22/17 12:00 pm Re: The inverted cranksahft seal.... [Re: Hillbilly bike]  
Joined: Aug 2001
Posts: 1,387
Al Eckstadt Online content
BritBike Forum member
Al Eckstadt  Online Content
BritBike Forum member

Joined: Aug 2001
Posts: 1,387
Jordan, NY
Tony, what about a magnetic block heater to warm the oil? The heater would go on the oil tank, right?. If you have an alloy oil tank you could strap it in place somehow. Of course it would require access to 110 volts (maybe a small hand carry generator).


Al Eckstadt
#692715 - 04/22/17 1:08 pm Re: The inverted cranksahft seal.... [Re: Al Eckstadt]  
Joined: Oct 2012
Posts: 2,852
Hillbilly bike Online content
BritBike Forum member
Hillbilly bike  Online Content
BritBike Forum member

Joined: Oct 2012
Posts: 2,852
Running from demons in WNY
Originally Posted by Al Eckstadt
Tony, what about a magnetic block heater to warm the oil? The heater would go on the oil tank, right?. If you have an alloy oil tank you could strap it in place somehow. Of course it would require access to 110 volts (maybe a small hand carry generator).

That's a thought, auto drag racers use oil pan heating pads, the location of the oil tank lends itself to a small heating device....This bike is tightly packaged despite the 68 inch wheel base..I do use 20/50 synthetic racing oil in both bikes that supposedly lubes better when only slightly warmed up....In the long run these engines are stressed beyond design limits like all mass produced street engines that are modified for racing...So it's a short hard life no matter what...


Naked frame LSR bikes, dressed in animal hides clinging to vibrating oily machines propelled by fire
#692743 - 04/22/17 8:39 pm Re: The inverted cranksahft seal.... [Re: Hillbilly bike]  
Joined: Sep 2011
Posts: 905
Excalibur Offline
BritBike Forum member
Excalibur  Offline
BritBike Forum member

Joined: Sep 2011
Posts: 905
New Zealand
Running less oil in a smaller oil tank would also allow faster warming and put you closer to where you want for temperature. Insulation might also help, perhaps make it removable. On Excalibur dragbike I (originally) ran a length of polycarbonate tube for the oil tank. It held about 300ml (1/2 pint) with sufficient headspace. Basically I reasoned that returning oil could be fed back almost immediately with only enough time to remove aeration was required. The idea worked a treat, saved a lot of weight. Eventually I discovered the methanol blow-by past the piston rings was crazy cracking the polycarbonate. One thing I really liked was I could see oil level at a glance. I'm sure you'd cringe at running so little oil...! It did 4+ seasons like that.
Just a few thoughts that might help you come up with solutions.

#692748 - 04/22/17 9:17 pm Re: The inverted cranksahft seal.... [Re: Hillbilly bike]  
Joined: Nov 2012
Posts: 49
koan58 Offline
BritBike Forum member
koan58  Offline
BritBike Forum member

Joined: Nov 2012
Posts: 49
Isle of Wight, UK
Hello, I have always had a pressure gauge, old mini type smiths ones.

I had the timing cover machined for an oil seal on my pre-unit T120 engine about 1980. It involved welding around the bushing boss and was only milled for the seal to recess flush (no circlip).

It improved the hot pressure enormously, from zero at tickover to ~20 psi, and 40-60 at speed.(cold oil ~85+psi).

The seal popped out quite soon, so I made a thin retaining plate with 2 screws, required slimming the crank pinion retaining nut slightly.

No further issues until 30 or so years later I noticed a drop in oil pressure from the usual ~50 to ~15 running, gentle ride home - open and find one side of the seal lip pushed the wrong way. Unfortunately I did not notice the maker of the seal, but it would have been supplied by TMS, who I have confidence in.
So it has happened once to me in 30 years, I do not think that is worrying, except for the fact that if it happens, you may not know unless you have a gauge.

Dave

#692751 - 04/22/17 9:59 pm Re: The inverted cranksahft seal.... [Re: koan58]  
Joined: Jun 2007
Posts: 5,100
HawaiianTiger Online content
BritBike Forum member
HawaiianTiger  Online Content
BritBike Forum member

Joined: Jun 2007
Posts: 5,100
Maui Hawaii
The oil seal inversion shown in the above photo did not happen to a Pioneer seal, but some unknown brand without reinforcing metal. The crank and rod failure didn't happen immediately but over about 100 miles.
It significantly lowers oil pressure when this happens but leaves just enough to impart a false sense of safety. This is why having an oil pressure test or onboard pressure gauge or indicator(pre unit) can save your motor.
I suspect that when the motor got hot, the oil pressure was basically zero, but the owner/rider didn't notice since he had open pipes on the bike. Rod journals burned to the point where they started to knock instead of just spinning a bearing and then throwing a rod like what usually happens to these motors when oil pressure is lost.

Cheers,
Bill


Bikes
1974 Commando
1985 Honda Nighthawk 650
1957 Thunderbird/T110 "Flying Tiger"
Antique Fans: Loads of Emersons (Two six wingers) plus gyros and orbiters.
#692755 - 04/22/17 10:43 pm Re: The inverted cranksahft seal.... [Re: Excalibur]  
Joined: Oct 2012
Posts: 2,852
Hillbilly bike Online content
BritBike Forum member
Hillbilly bike  Online Content
BritBike Forum member

Joined: Oct 2012
Posts: 2,852
Running from demons in WNY
Originally Posted by Excalibur
Running less oil in a smaller oil tank would also allow faster warming and put you closer to where you want for temperature. Insulation might also help, perhaps make it removable. On Excalibur dragbike I (originally) ran a length of polycarbonate tube for the oil tank. It held about 300ml (1/2 pint) with sufficient headspace. Basically I reasoned that returning oil could be fed back almost immediately with only enough time to remove aeration was required. The idea worked a treat, saved a lot of weight. Eventually I discovered the methanol blow-by past the piston rings was crazy cracking the polycarbonate. One thing I really liked was I could see oil level at a glance. I'm sure you'd cringe at running so little oil...! It did 4+ seasons like that.
Just a few thoughts that might help you come up with solutions.


The bike has a common tank , the total oil system,tank, filter, hoses is about 3-1/2 quarts....I might cringe a bit running and engine wide open for 30-45 seconds on 16 oz's of oil...

I pulled the side cover on the front engine that I had to rebuld because of lost oil pressure....It has been run 1/2 hour or so since....I turned the quill about .020 because scoring that happened before I got the crank...So it's the 70-6387 .020 seal...It's an SDA,, looks fine up close in real life.This seal did not invert causing the pressure loss.....I have two new standard seals, a 2072 PW and a SDA branded seal. I find them to be identical in appearance ,...That's not to say they are identical in quality...

[Linked Image]


Naked frame LSR bikes, dressed in animal hides clinging to vibrating oily machines propelled by fire

Moderated by  John Healy 


Home | Sponsors | Newsletter | Regalia | Calendar | Bike Project | BritBike Museum | Spiders Cartoons | "OLD" BritBike Forum | DVD- Manuals & Parts books | BritBike Stickers & Decals
Upgrade to: Premium Membership | Premium Life Membership | Vendor Membership | Site Sponsor Membership
Powered by UBB.threads™ PHP Forum Software 7.6.0
Page Time: 0.531s Queries: 15 (0.023s) Memory: 0.9326 MB (Peak: 1.2119 MB) Zlib disabled. Server Time: 2017-06-28 13:57:25 UTC