Oil leak from camshaft seal with MFI question

brittbolen · 07-19-2004, 12:41 PM

I have a stock 70 911E with all the MFI goodies

My mechanic tells me that my only major oil leak is coming from the seal where the MFI pump gear comes off the end of the camshaft, and that it's leaking pretty good (he used the phrase "it smokes like a mosquito fogger")

I have the option of having him fix it and with that have the engine in top shape (he's already fixed a bunch of things) or leave it and contiue having the thing leak etc.

Obviously I want to fix it. My question is how hard is this seal to replace?

I'm not very expirienced, but want to learn more. So far I've rebuilt all of my brake calipers correctly, replaced pads and rotors, and changed my valve covers. Fixing this oil leak sounds like a *****, especially with the very minimal tools i have...

should i just let him do it? he claimed it's a real pain to do without a lift, and may require pulling the heat exchanger. So i'm leaning towards not fighting this battle myself, plus I want the damn car back!

thanks,

britt

jstobo · 07-19-2004, 12:59 PM

I think the easiest way to fix it is to pull the motor. You have to detach the left side sheet metal that covers the cam to get at the seal. You will have to disconnect the MFI belt also so you will have to retime your MFI. Then it is only a matter of pulling the old seal and installing the new one. Don't tap it in too far or you will have a time changing it in the future. Good Luck.

72doug2,2S · 72doug2,2S's Garage

While you're in there you might as well replace the timing belt and the forgot the name (sprocket toothy thing) the belt runs on unless it's in pristine shape. -Easy to do since you've got to take it off anyway.

I had a top end rebuild last year, but we missed replacing that cam seal and it leaks a little. It's one of those next time I'm there things.

Grady Clay · 07-19-2004, 01:49 PM

Britt,

Your mechanic is correct, you need to remove the left heat exchanger. The issue is where the exhaust flanges bolt to the heads. How long since it has been off? What condition? Repairing broken exhaust studs are much more difficult than replacing the seal.

Doug is right on; replace both Gilmer belt pulleys and the belt while you are there. You need all three, otherwise a silgle old part will damage the new. If functional, save the old parts for road spares.

jstobo is correct, it is much easier to do this out of the car. However with some patience you can do this DIY while in the car. The worst that can happen is you sheepishly tow it to your mechanic. You get credit for trying.

Be very careful to not damage the seal surface on the cam when removing the old seal.

Best,
Grady

brittbolen · 07-19-2004, 02:00 PM

The heat exchanger has not been off since I've been around the car. The puts them at 13 years. The exchangers are a little rusty looking, but solid. You can see how oily the left one is from this photo. And that photo was taken after the car had sat for at least a year...

http://eludicate.com/~bolen/911E/photos/photo.php?photo=./20030622-183305/DSCN4509.JPG&return=%2F%7Ebolen%2F911E%2Fphotos%2F

I'm leaning towards letting him tackle this, I want to work on the car, but I want to drive it too!

thanks for the info,

britt

vol96 · 07-26-2004, 09:48 PM

I replaced that seal on my car w/o pulling motor or heat exchanger. It wasnt easy but it can be done.

It was a long time ago. I pulled left rear wheel. Got my small hands in the wheel well and removed sheet metal that covers cam pulley (remove mfi drive belt first...after setting mfi timing). Fabbed a seal puller out of a can opener. Remove seal and install new one. Dont forget to lube new seal with a little grease or heavy oil.

Its not an easy job. Even pulling the old seal and getting the new one on is difficult because you are working in awkward positions.

brittbolen · 07-27-2004, 07:07 AM

I went ahead and had my mechanic do it. took him maybe 3 or 4 hours to do the whole thing, including pulling the heat exchanger, replacing the seal and the belt, and fixing the timing. I'm glad he did it, he found a rat nest under the shroud on top of #3 while he was in there, and another one in the heat exchanger. Plus he was able to drain a lot of oil from that exchanger.

Now the car runs great and doesn't smoke or leak at all!

Britt

vol96 · 07-27-2004, 08:52 AM

Sounds like you made the right choice. It took me much longer than 4 hours....more like 4 days.

Its nice when you get an oil leak fixed..isnt it?

Joe

bkdamkr · 08-28-2004, 03:54 PM

Hey everyone, where can you get the replacement seal? What's the part number? I'm resealing my 73 911S (2.4 MFI) and can't find a part number or any info to order/buy a replacement seal. It's got to be easy, but I've scoured all of my manuals and Pelican's site, to no avail. Thanks, Brian