FWD Seal on Left Cam for MFI Drive on 3.0 Liter

Jeff Higgins · 01-01-2008, 07:55 PM

I just finished up my new 3.0 liter MFI project. To seal the forward end of the left cam, I simply used the "Injection Pump Drive Seal on Camshaft Carrier, 911E/S with MFI (1969-73)" listed right here on Pelican, part number 999-113-068-50-M30. It fits the camshaft end just fine, but it is way too loose in the cam tower and leaks like a sieve. This is a four bearing tower, from an '83 SC motor. This very same seal is quite tight in a couple of old three bearing towers I have laying around. The bore in the towers that it fits into is the same diameter as the cam bearing surfaces that are bored all the way through the towers. It looks like three bearing towers use a very slightly smaller diameter bearing surface than four bearing towers, unless I'm just the unlucky victim of excessive tolerance or something.

So, the question of the day is this: Is there a different seal I can use? I understand turbos use that same forward end of the left cam to drive something; do they use a different seal? I have scoured Pelican and cannot find a listing for one. Any suggestions?

914/6 · 08:15 PM

Turbo seal is the one you need
999-113-246-40

http://www.pelicanparts.com/cgi-bin/PartsLookup/search.cgi?command=show_page&Catalog_Name=911_USA_78_83_KATALOG&Illustration=107-40&Line_Item=33

Henry Schmidt · Henry Schmidt's Garage

There is no seal that just fits your application . After 15 years of one off seal holders, Supertec now makes a seal kit.
You can make your own but what a hassle.

914/6 · 09:43 PM

Henry what is this seal 999-113-246-40 ?

is it the on that seals the scavenge pump shaft , behind the drive cross pin.

That means I need one too.

Henry Schmidt · Henry Schmidt's Garage

The seal is a special order Viton seal from Wrightwood Racing. It may be a 944 balance shaft seal? but I am not certain. We ordered the seal by size not part #. The magic is the specially designed and manufactured 60-61 hard anodizes seal holder not the seal.
I am hoping PP will have these listed on their site soon.

Jeff Higgins · 01-02-2008, 06:04 AM

You just gotta love this Pelican community. I got up this morning to check this thread for answers, saw Henry's nifty seal kit, and noticed he was up early too. So I gave him a holler, and we have one on the way. Problem solved; just like that. Thanks again, Henry, for your help on this. Pictures and full story to follow on my motor once I get her sealed up and running long enough to tune.

356RS · 356RS's Garage

Henry sells a good seal kit, and you can also get a seal kit from SmartRacing Products.

911pcars · 01-02-2008, 11:17 AM

On a somewhat related note, I have MFI cams in my Weber carbed engine. The engine developed a leak at the cam seal and instead of dropping the engine for the repair (I didn't want to), I had an aluminum cover made. It's recessed to house the nose of the cam and it installs fairly easily with the engine installed using the 3 factory bolts and gasket sealer. No mas oil leaks, at least from that location.

I'm sure the original seal still leaks, but the oil isn't going anywhere.

Sherwood

Jeff Higgins · 01-02-2008, 03:55 PM

Following your somewhat related lead, I have heard before that it's an engine drop to replace that seal. I wonder why that is. I've gotten pretty damn good at it with the motor in the car, as I was trying several home made fixes over the last few days. I just pull the left rear wheel, the throttle rod from the bellcrank to the pump, and the left front engine tin. There is plenty of room in there, even to dig a seal out. Of course mine came out pretty darn easy. Too darn easy...

911pcars · 01-02-2008, 04:39 PM

Quote:

Originally Posted by Jeff Higgins

Following your somewhat related lead, I have heard before that it's an engine drop to replace that seal. I wonder why that is. I've gotten pretty damn good at it with the motor in the car, as I was trying several home made fixes over the last few days. I just pull the left rear wheel, the throttle rod from the bellcrank to the pump, and the left front engine tin. There is plenty of room in there, even to dig a seal out. Of course mine came out pretty darn easy. Too darn easy...

Thanks Jeff,
Good to know. Where were you when I needed you? :-)

Sherwood

SP2 · 01-04-2008, 06:55 PM

Looking forward to hearing about your MFI on 3.0! I hope you post alot of photos.

Henry Schmidt · Henry Schmidt's Garage

Quote:

Originally Posted by SP2

Looking forward to hearing about your MFI on 3.0! I hope you post alot of photos.

Here are a few big bore MFI engines built by Supertec.

Jeff Higgins · 01-04-2008, 09:24 PM

Here are a few photos of the motor. Sorry, but they are kind of dark. Anyway, I ran it down to the local dyno shop to get the air/fuel ratios under a variety of rpm and load conditions. It looks like I will need to change space cams, or do something with the pump. With the high rpm, full throttle mixture running about 13:1, it runs very rich - 10:1 between 3,000 and 4,000 rpm. Even the part throttle, 3,000 rpm (simulating highway cruising) mix runs just over 10:1. It idles at about 13:1, so the only really "fat" spot is in that mid-range where the space cam does its work. Changing that space cam looks like the only way to correct this. That looks like it will be the next phase of this project.

SP2 · 01-04-2008, 10:13 PM

Damn, that looks awesome! Nice new SSI's. I see you were able to get the paper tubes to bend enough on both sides for your backdated heat. I ended up having to use the red aviation tubes. Nice job Jeff.

Jeff Higgins · 07-19-2024, 04:45 PM

Reviving an old thread just so we have a record of the correct part number for the seal that fits Henry's kit. I'm just finishing up a rebuild on the motor that started this discussion and, for the life of me, couldn't come up with a part number for the seal. Henry was nice enough to look it up for me, so here goes, for posterity:

999-113-464-41

There is one more dash number, either -M204 for the Kaco brand, -M17 for Victor-Reinz, or -OEM for the genuine Porsche.

This can also be ordered by size from any manufacturer of these kinds of seals. The size code is 35-45-7, or 35mm ID, 45mm OD, 7mm thickness.

It is officially listed on Pelican as an Air Pump Drive Flange Seal on a 911 Turbo. I selected 1987 just to have a year.

I hope this helps someone else. Or, if no one else, maybe just me, when I go to rebuild this thing again in another 16 years...

Henry Schmidt · Henry Schmidt's Garage

Hi Jeff
One of my guys was telling me that someone called for the part number. Sorry if we didn't get back to you as soon as we could have.
The seal is in deed from the air pump pulley housing on the 930 turbo.

Jeff Higgins · 07-20-2024, 09:25 AM

Yup, that was me. I know you're busy, so no big deal. I got the part number and got it ordered in plenty of time. Then our illustrious USPS sent it on some scenic tour of the American Southwest, where it is still in limbo. I ordered it from our host, it shipped from Carson, CA to San Antonio of all places. I'm north of Seattle. Then it went to Dallas, now it's somewhere in-between. It's going on ten days for them to get it to me.

Which leads to another neat feature of your kit - I went ahead and hung the motor back in the car while my new seal is racking up frequent flier miles. I would hesitate to do that with the factory seal installation (although I've replaced a few in the car, it's kind of a PIA). With your kit, however, it's a piece of cake to install with the motor in the car.

r lane · 07-20-2024, 10:53 AM

You can google the size, 49x35x7 and come up with a number of options. 90311-35040 I think is a Honda camshaft seal. I run those in a couple of track motors and have had good results.

john walker's workshop · 07-20-2024, 12:04 PM

Remember I turned down a 930 housing for you years ago, but you had already found a source. Probably still have that, somewhere.

Jeff Higgins · 07-20-2024, 05:15 PM

I didn't think you got that far before I found out Henry had them. I feel bad that you actually made it and I never bought it from you. Sorry about that. If you can find it, bring it to the swap meet and I'll buy it from you there. I can't see anyone else ever needing one, and it might be nice for me to have a spare. Yeah, darn, I know we talked about it a lot, but I somehow heard about Henry's kit and snagged one of those instead.