Uh oh this is bad. Reference sensor mount broken

rojeho · rojeho's Garage

Trying to replace both speed and reference sensors. Unbolted, was prepared for it to be tight so imagine my joy when it popped right out. Until I realized why.

What's my next step???

How did this happen?

John_AZ · 03-19-2016, 09:49 AM

Curse the PO.

Probably was cracked earlier and finally failed.

Post a WTB on the Pelican parts board. Should be reasonable-under $50. Ebay has a few as well.

Reference sensor mounting bracket.

COVER THE BELL HOUSING TIMING TDC HOLE WITH TAPE!! or you will drop a part in the hole.

To remove the bracket there are 2 bolts with a trial and error test of tools. Very small hands help or prepare for many bloody cuts.

GL
J_AZ

mytrplseven · mytrplseven's Garage

Hard for me to tell from the pic, is this the speed sensor? It would be the one nearest the firewall. If so, make sure whether or not a shim (shaped like and "8") should be included when the sensor is re-installed. The turbo and some N/A models use one and should be installed if germane to your model for proper clearance from flywheel. See my pic to understand what happened to my car when the PO left it out:

rojeho · rojeho's Garage

No, it's the reference sensor. I had not tried to remove the speed sensor yet so I still don't know if there is a shim in there or not.

JAXTURBO · JAXTURBO's Garage

... been there. I had to basically split mine to get it out. Rear most sensor cemented itself in place. It was the original sensor. The sensor closest to the block did use a sleeve on my '86. Don't forget to maintain the air gap upon reinstallation. The sensor blocks are reasonable pricewise...

DannoXYZ · 03-20-2016, 05:07 PM

That crack was probably caused by someone trying to pry the bell-housing off without removing the sensor bracket. From the bottom of the bell-housing up to there, that's a large moment arm to apply a lot of torque to that bracket.

911tracker85 · 03-21-2016, 05:45 AM

dang .... I read some of these posts and consider how lucky I have been so far on my project cars. refreshing/restoring these old cars is hard enough without the extra frustration of this kind of stuff.

Quote:

COVER THE BELL HOUSING TIMING TDC HOLE WITH TAPE!! or you will drop a part in the hole.

roger that. and if it is a 951 and you remove the HCV you can dump coolant down that hole and damage your clutch. I had a piece of rag stuffed in it but the coolant can soak right through it. ask me how I know....

my solution, alum HVAC duct tape. can handle the heat.

JonA · 03-21-2016, 06:30 AM

That other sensor has to come out and the cracked bracket removed and replaced. If the remaining sensor will not come out you will need to do some challenging cutting/wrenching/prying to get the bracket off. I removed the intake manifold and oil separator and repositioned a bunch of the wiring to get at mine and did some fancy cutting with a plumber's mini hacksaw.
There are a ton of posts here, do a search. We have all been there.

Luck,
Jon

mikekirby · mikekirby's Garage

I was able to purchase a new Reference Sensor housing from Pelican. They are out there. I did have to modify mine as it had a bit more of a tail. So we ground it off and it fit right into place.

rojeho · rojeho's Garage

Two questions - am I better off to remove the intake manifold before I start this? Will it clear more space for me to remove the bracket?

What's the best way to set the spacing? Is there a source for the 8mm shim?

Off to start searching.

fiily · 03-22-2016, 05:17 PM

Yes, remove the intake for more room, but before removing the intake mani. buy 4 new intake gaskets ($2/ea from pelican parts)so your not waiting around for days to put the intake back onto the car.

John_AZ · 03-22-2016, 08:37 PM

Quote:

Originally Posted by rojeho

Two questions - am I better off to remove the intake manifold before I start this? Will it clear more space for me to remove the bracket?

What's the best way to set the spacing? Is there a source for the 8mm shim?

Off to start searching.

The spacing is not 8mm----------------------it is .8mm or the thickness of a credit card.
Cut up a phony card you get in the mail and slip it under the sensor to gap.

Factory spec is .8mm +/-.3mm

Some members will glue a thin washer on the reference sensor bottom and then remove it when gap is set.

J_AZ

Arizona_928 · 03-22-2016, 08:49 PM

Quote:

Originally Posted by John_AZ

The spacing is not 8mm----------------------it is .8mm or the thickness of a credit card.
Cut up a phony card you get in the mail and slip it under the sensor to gap.

Factory spec is .8mm +/-.3mm

Some members will glue a thin washer on the reference sensor bottom and then remove it when gap is set.

J_AZ

+1

I have gapped flywheels that were not completely symmetrical, and have to watch out so that they don't chew up a sensor. (they had high & low spots)

rojeho · rojeho's Garage

Thank all, appreciate the guidance.

944 Ecology · 03-24-2016, 06:47 AM

Quote:

Originally Posted by John_AZ

The spacing is not 8mm----------------------it is .8mm or the thickness of a credit card.
Cut up a phony card you get in the mail and slip it under the sensor to gap.

Factory spec is .8mm +/-.3mm

Some members will glue a thin washer on the reference sensor bottom and then remove it when gap is set.

J_AZ

Better to use cardboard which is 0.8 mm (.0032 inch) thick. Glue it to the end of the rearward sensor. You will not have to remove the sensor once the gap is set, since the cardboard will wear down / disintegrate over time.

Dr DIY · Dr DIY's Garage

Just a decimal point correction - .8mm = .032 and not .0032 . (Actually .031496)

944 Ecology · 03-29-2016, 04:51 AM

Quote:

Originally Posted by Dr DIY

Just a decimal point correction - .8mm = .032 and not .0032 . (Actually .031496)

Thanks, the finger that hit the 0 key gets a bit twitchy at times...

rojeho · rojeho's Garage

Had time to get back to this. I don't think this is what the factory intended.

The "B" opening is a larger diameter. Is there a sleeve on the sensor that is supposed to slide off? I didn't try too hard but that too didn't seem to want to come off.

JoshB · 04-01-2016, 06:56 PM

Yes - should be a sleeve in it.... I've got a couple of these - would sell one for $50 shipped.

DannoXYZ · 11:01 AM

Quote:

Originally Posted by rojeho

Had time to get back to this. I don't think this is what the factory intended.

The "B" opening is a larger diameter. Is there a sleeve on the sensor that is supposed to slide off? I didn't try too hard but that too didn't seem to want to come off.

Yes, on the larger broken "B"hole, there's a sleeve. From the deeper gouge, the figure-8 spacer/washer is missing. And the adjustment bolt wasn't tight enough and vibration allowed the bracket to drop onto the flywheel teeth over time.

Don't use little L-shaped allen-keys. Not going to get enough torque. Use a 1/4" flex-cable extension.