Jump to content

Timing sensor Leak


Colorobo

Recommended Posts

I recently replaced the cam chain cover gasket because it was leaking and I noticed the timing sensor was leaking (again/still).  So, I bought a replacement sensor & oring from our popular MG aftermarket parts retailer.  I applied Permatex 300 gasket sealer to the new sensor & oring  then installed them.  Now at about 500 miles later, I 've got a leak from the sensor lower fastening screw...it seems.  My next course of action is to get another new oring, remove the sensor, clean up everything, install new oring, goop up the whole mess with Permatex 300 (including screws if screw holes are open ended into timing chest) & reinstall.  This is getting to be an annoying pita.

Hey Docc....if you're reading this...Is the #112 oring the same size as the oem oring for this sensor?

Thanks,

Art

Link to comment
Share on other sites

Yessir, that #112 works. I am not sure what the actual metric size is. Use Nitrile (Buna-N), or Viton instead of plumbing parts.

Be careful not to use so much sealant that it changes the spacing of the sensor from the timing wheel.

These sensor have been reported to leak through the wiring. My ugly JB Weld repair has remained effective for many years/miles:

IMG_0302.JPG

  • Like 2
Link to comment
Share on other sites

Thanks Docc!  I've got a McMaster-Carr baggie of #112 (60 durometer) Viton orings from back in 2020 when I was messing with the original sensor.  The original leaked from the top of the sensor molded housing and after I sealed it, it began to leak from where the molded housing meets the cable casing.  Yeah, the old thing would seep, the new set-up leaks.  I plan on getting to this on the next rainy day.

Thanks,

Art

  • Like 1
Link to comment
Share on other sites

  • 1 month later...

Update:  Timing sensor still leaks.  New sensor, new oem style oring & Permatex Motoseal gasket maker (looks like hondabond/yamabond stuff) and leaking at lower screw.  Before with the old sensor my leaks were coming from the top of the old sensor moulded housing & cable casing......now with new parts, it leaks at the lower screw. Frustrating.

Any sealing ideas or other things to look at in that area?  Cyl. base gasket, presure sensor, oil feed lines & timing cover are all dry.

Art

  • Sad 1
Link to comment
Share on other sites

  • 4 weeks later...

last year I found an oil leak from this sensor on my Scura and found that the sensor was touching the timing wheel and causing the sensor flange to lift slightly and leak oil and stall the engine. after mounting the limiting washer and the ring, everything is fine.
translated by google translator.

 

  • Like 1
  • Thanks 1
Link to comment
Share on other sites

1 hour ago, Vladimír64 said:

last year I found an oil leak from this sensor on my Scura and found that the sensor was touching the timing wheel and causing the sensor flange to lift slightly and leak oil and stall the engine. after mounting the limiting washer and the ring, everything is fine.
translated by google translator.

 

Hi Vlad,

I'm suprised the bike would run with the sensor contacting the timing gear. 

The new sensor (with new oring) I installed required shimming so that there was sufficient clearance between sensor & gear.  I will probably pull it apart again sometime this Fall to figure out what I missed that results in the new sensor leaking.  This latest leak is not from the sensor itself as in the past but from the baseplate/oring area.  The original leaked from two divots at the very top of the molded portion of the sensor, I epoxyed those and the leak stopped.  At short time later, the sensor began leaking from the area where the molded sensor housing meets the cable casing so I epoxyed that area too and the leak stopped for about a year then began leaking again.  This Spring I replaced the sensor & oring because I got tired of epoxying and chasing a leak.  The new oring I used was from one of our popular Guzzi aftermarket suppliers and I wonder if the oring I received is marginal, maybe I will try an getting a "genuine" Guzzi oring.  Docc has uses a #112 oring on his bike but I had no success in seating a 112  on mine without distorting the sensor base plate & shims.  From what I recall, the sensor screw holes are not drilled all the way through into the timing housing chamber which leads me to think I have an oring sealing problem. Oh well, I hope your issues are now resolved.

Art

Link to comment
Share on other sites

1 hour ago, guzziart said:

Hi Vlad,

I'm suprised the bike would run with the sensor contacting the timing gear. 

The new sensor (with new oring) I installed required shimming so that there was sufficient clearance between sensor & gear.  I will probably pull it apart again sometime this Fall to figure out what I missed that results in the new sensor leaking.  This latest leak is not from the sensor itself as in the past but from the baseplate/oring area.  The original leaked from two divots at the very top of the molded portion of the sensor, I epoxyed those and the leak stopped.  At short time later, the sensor began leaking from the area where the molded sensor housing meets the cable casing so I epoxyed that area too and the leak stopped for about a year then began leaking again.  This Spring I replaced the sensor & oring because I got tired of epoxying and chasing a leak.  The new oring I used was from one of our popular Guzzi aftermarket suppliers and I wonder if the oring I received is marginal, maybe I will try an getting a "genuine" Guzzi oring.  Docc has uses a #112 oring on his bike but I had no success in seating a 112  on mine without distorting the sensor base plate & shims.  From what I recall, the sensor screw holes are not drilled all the way through into the timing housing chamber which leads me to think I have an oring sealing problem. Oh well, I hope your issues are now resolved.

Art

I am certain the #112 O-ring is an approximation for those of us in the SAE world and the actual sensor O-ring is metric and of a particular durometer. I have no way of divining either of those things. It is not beyond Moto Guzzi's manufacturing standards that any particular casting could have enough flaw to fault sealing. Worth a careful inspection of the seating areas of the surface and the bore where the sensor resides . .  .

  • Like 4
Link to comment
Share on other sites

On 8/3/2023 at 10:04 AM, docc said:

I am certain the #112 O-ring is an approximation for those of us in the SAE world and the actual sensor O-ring is metric and of a particular durometer. I have no way of divining either of those things. It is not beyond Moto Guzzi's manufacturing standards that any particular casting could have enough flaw to fault sealing. Worth a careful inspection of the seating areas of the surface and the bore where the sensor resides . .  .

Yeah, this thing is really kicking my butt!!  I don't know what I'm missing.  I regret tossing out the oem sensor without measuring the thickness of the baseplate maybe it was more substantial (thicker) than the aftermarket piece I bought.  Or maybe the O.D. of the sensor is slightly larger than the original. I'll certainly give it a try again and more closely scrutinize what I'm doing.  I have a baggie of 112's from Mcmaster Carr so, no shortage of orings.  I've installed crank seals, input/output shaft seals, head & base gaskets, crankcase gaskets, valve cover gaskets, rear drive seals& gaskets, etc.....no leaks!!  This simple oring sensor seal is driving me nuts!  Well, that and the right fork leak on my Eldo but I'll whine & complain about that to the Loop Frame Group.  Thanks for listening.

Art:wacko:

  • Like 1
Link to comment
Share on other sites

Probably the easiest way to look for excessive crankcase pressure is to loosen the dipstick with engine running.....I guess.

Link to comment
Share on other sites

My old sensor leaked just enough to bother me. It appeared to be through the sensor, not around the o-ring. I washed it in IPA, & heated it over 100°C with a heat gun a few times. While it was hot I brushed epoxy resin all over the sensor and blew the excess off with the heat gun & a rag. As it cooled, some resin wicked into crevices in the sensor. It seemed to work. 

As for putting any gasket goo on an o-ring, I believe that's a bad idea. One or other is fine, but if the sealant doesn't stick to the o-ring, then you have added another leak path, and inhibited the O-ring's ability to keep sealing with thermal movement.

  • Like 3
Link to comment
Share on other sites

1 hour ago, MartyNZ said:

My old sensor leaked just enough to bother me. It appeared to be through the sensor, not around the o-ring. I washed it in IPA, & heated it over 100°C with a heat gun a few times. While it was hot I brushed epoxy resin all over the sensor and blew the excess off with the heat gun & a rag. As it cooled, some resin wicked into crevices in the sensor. It seemed to work. 

As for putting any gasket goo on an o-ring, I believe that's a bad idea. One or other is fine, but if the sealant doesn't stick to the o-ring, then you have added another leak path, and inhibited the O-ring's ability to keep sealing with thermal movement.

Lots of us wash in IPA. Some prefer Scotch Ale.

We might be talking about different things . . . ;)

  • Like 1
  • Haha 1
  • Sad 1
Link to comment
Share on other sites

1 hour ago, docc said:

Lots of us wash in IPA. Some prefer Scotch Ale.

We might be talking about different things . . . ;)

Yeh, sorry Docc. I meant isopropyl alcohol, or any mild solvent. Using your IPA would be wasted. :bier:

  • Like 1
  • Haha 3
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...