Pelican Parts
Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help



Go Back   Pelican Parts Forums > Porsche Forums > 911 / 930 Turbo & Super Charging Forum


Reply
 
LinkBack Thread Tools Rate Thread
Author
Thread Post New Thread    Reply
Certified User
 
billjam's Avatar
 
Join Date: Aug 2007
Location: Perth, Western Australia
Posts: 1,984
Garage
Oil pump drive required on SC camshaft

Being the proud new owner of a set of SC camshafts to replace my 930 shafts recently scrapped due to cracked welded lobes (see separate thread), I am looking for the best way to add the oil pump drive to the front end of the LH camshaft.
Making up a new boss and either welding it or bolting it are the only real options that I can see.

I like the idea of a bolt-on boss but I imagine that drilling and tapping could pose a problem due to the hardness of the camshaft material. Anyone done this?
I would expect that locating dowels or a locating spigot/recess would also be required to ensure correct concentricity with oil seal.

I don't like the idea of welding on the boss due to the potential cracking problems, but I'm open to persuasion if there is evidence that it works OK.

Which way is best?
__________________
Bill
1988 Carrera - 3.6 engine (with ITBs, COPs, MS3X) and a whole set of turbo body panels waiting in the attic.
Day job ... www.sspowdercoat.com.au
Memories: '68 912, '72 911T, '80 911SC, '84 911, '85 930, '86 930, '87 911
Old 11-13-2008, 01:42 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #1 (permalink)
Registered User
 
rsrmike's Avatar
 
Join Date: Jan 2008
Location: Birmingham, AL
Posts: 538
I think a bolt on spacer is your best bet.

Perhaps find a machine shop w/ that could machine a recess in the end of the cam on a lathe. Then they could machine a spacer of near the same O.D. that would fit.

You will have to drill and tap either way as you will need the bolts to drive the oil pump

If you never intend to use an air injection pump again, you can simply drill the end of your cam, install 2 bolts, and bolt the oil pump directly to the cam carrier.

That way, you wouldn't need a spacer, and the only seals would be the paper gasket on the cam carrier, and the oil seal in the scavenge pump. Eliminating the seal on the spacer, which is really only needed to drive the air injection pump...
__________________
Professional Overcomplicator
Old 11-13-2008, 04:28 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #2 (permalink)
Registered User
 
Join Date: Dec 2006
Location: Houston, TX
Posts: 1,000
Send a message via AIM to Ag02M5
Quote:
Originally Posted by rsrmike View Post
I think a bolt on spacer is your best bet.

Perhaps find a machine shop w/ that could machine a recess in the end of the cam on a lathe. Then they could machine a spacer of near the same O.D. that would fit.

You will have to drill and tap either way as you will need the bolts to drive the oil pump

If you never intend to use an air injection pump again, you can simply drill the end of your cam, install 2 bolts, and bolt the oil pump directly to the cam carrier.

That way, you wouldn't need a spacer, and the only seals would be the paper gasket on the cam carrier, and the oil seal in the scavenge pump. Eliminating the seal on the spacer, which is really only needed to drive the air injection pump...
Sorry for my denseness here but could you expand a bit.

I am removing my smog stuff on my 964t and plan to add in some sc cams at some point. I'd like to know exactly what to keep my eye out for.

Thanks.

RT
__________________
WTB: 964/965 Turbo stuff...carbon fibre bits, Techart wheel parts, RS/lightweight flywheel, 993 EVO uprights, G50 gears or 6 sp., 964 RSR swaybars, custom droplinks and any other cool stuff, pm me! Also a nice medium build 327 Chevy engine.

Coming SOME DAY...1991 3.3 turbo, Tahoe Blue Metallic with some mods
Old 11-13-2008, 06:59 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #3 (permalink)
Registered User
 
Join Date: Sep 2006
Location: scotland
Posts: 248
Either way you will need to make sure the extension drive peice is attached bang on central on cam.
drill and tap would be the best method in my opinion however it will depend on
the rockwell(hardness) of the centre of the camshaft wether it can be done or not.
Whatever way you go many people have completed this before with cams from a 911 sc

"RT"
If you buy new "sc" cams from John Dougherty, "camgrinder" ,the cams will come with both drives to suit your 964 turbo
__________________
SP Autobahn www.spautobahn.co.uk
Porsche inspector for Peter Morgan UK
http://www.porscheinspections.com/
"92" 964 turbo,Modified and recently rebuilt using all ARP hardware..
Purpose built fuel controller set up to acheive perfect fuel curve on CIS inj.

Last edited by stup; 11-13-2008 at 07:55 AM..
Old 11-13-2008, 07:52 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #4 (permalink)
Registered User
 
rsrmike's Avatar
 
Join Date: Jan 2008
Location: Birmingham, AL
Posts: 538
Hey RT,

No worries, there is no such thing as denseness here

I confess to being terrible at explaining things.

In your case, I would contact web-cam(only people I've used) or some of the other reputable cam vendors represented here, for the sake of simplicity. They know what to do and do it well.

Bill has already been through a nightmare w/ cams on another continent and was lucky enough to get fixed up w/ some standard SC cams, so now he has to modify them for the scavenge pump drive.

He has valid concerns about adding the drive for the oil pump to "standard" SC cams which have no provision for an oil pump drive, seeing as they were from a non-turbo

In a standard turbo, w/ air injection pump, the left cam is longer, protrudes slightly from the end of the cam carrier, and supply a mounting boss for the pulley which drives the Air pump. There is another 2 piece housing that bolts to the cam carrier and acts as a housing for the pulley/smog belt, as well as a mount for the scavenge oil pump. This housing also holds a small thin seal that runs on the "extension". Which makes the concentricness? even more important.

If you never intend to use a airpump again, you can simply drill and tap two holes in the face of the cam. sometimes there are pilot holes in place that just need to be drilled and tapped to 6mmX1.0 and install two shorter 5mm allen head (6mmX1.0 thread) bolts for the oil pump drive. This would simplify the addition of an oil pump drive and reduce 1 possible oil leak (the thin seal in airpump housing) It would also move the scavenge pump approx. 1.5 inches closer to the cam carrier which might cause a fitment issue w/ a hardline from turbo drain sump to pump though FYI. However, the 3 bolt pattern for the scavenge pump is the same for the cam carrier, I believe the early 3.0 turbos w/ no air pump mounted this way...

I also know the RUF RCT mounts this way as I had one off recently, which is what inspired all this chatter. I hope this makes sense.

Hey Bill, do you see 2 "pilot holes" in the face of the 1-3 camshaft? If I recall, they aren't as hard to drill and tap as one would think. I had that same thought at one point myself...
__________________
Professional Overcomplicator

Last edited by rsrmike; 11-13-2008 at 08:00 AM..
Old 11-13-2008, 07:57 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #5 (permalink)
Forced Induction Junkie
 
WERK I's Avatar
 
Join Date: Jan 2003
Location: Wisconsin
Posts: 3,291
Garage
Quote:
Originally Posted by stup View Post
Either way you will need to make sure the extension drive peice is attached bang on central on cam.
drill and tap would be the best method in my opinion however it will depend on
the rockwell(hardness) of the centre of the camshaft wether it can be done or not.
Whatever way you go many people have completed this before with cams from a 911 sc

"RT"
If you buy new "sc" cams from John Dougherty, "camgrinder" ,the cams will come with both drives to suit your 964 turbo
This is what the Special Wishes folks did in the early 3.3l engines. Instead of casting new cams with the extension, they machined a piece. The cam they used was the SC grind.


__________________
Dave
'85 930 Factory Special Wishes Flachbau
Werk I Zuffenhausen 3.3l/330BHP Engine with Sonderwunsch Cams, FabSpeed Headers, Kokeln IC, Twin Plugged Electromotive Crankfire, Tial Wastegate(0.8 Bar), K27 Hybrid Turbo, Ruf Twin-tip Muffler, Fikse FM-5's 8&10x17, 8:41 R&P
Old 11-13-2008, 08:49 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #6 (permalink)
 
Certified User
 
billjam's Avatar
 
Join Date: Aug 2007
Location: Perth, Western Australia
Posts: 1,984
Garage
Quote:
Originally Posted by WERK-I View Post
This is what the Special Wishes folks did in the early 3.3l engines. Instead of casting new cams with the extension, they machined a piece. The cam they used was the SC grind.
This is what I had in mind as my preferred solution.

I will also look at Mike's suggestion to leave out the air pump drive as well. I scrapped the air pump some time ago but at the moment I can't quite visualise how that all fits together and where the seals run but I'll check it out when I get home in a couple of days.
I do recall seeing two holes in the end of the shaft - hopefully they are at correct dimensions to be used as pilot holes for drilling and tapping.

Thanks for the input guys.
__________________
Bill
1988 Carrera - 3.6 engine (with ITBs, COPs, MS3X) and a whole set of turbo body panels waiting in the attic.
Day job ... www.sspowdercoat.com.au
Memories: '68 912, '72 911T, '80 911SC, '84 911, '85 930, '86 930, '87 911
Old 11-14-2008, 12:14 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #7 (permalink)
Registered User
 
rsrmike's Avatar
 
Join Date: Jan 2008
Location: Birmingham, AL
Posts: 538
Hooray for pilot holes... I was thinking they had them, it's been a while though...

Bill, if you look at the plate the scavenge pump is mounted to, there are 3 hex nuts that mount the pump to the outer plate. They attach to studs that go clear through the pump and help hold it together, w/ the other two hex bolts and either side.

The three stud bolt pattern is the same as the cam carrier.

If you drill/tap the end of the cam to 6mm (possibly just tap, depending on diameter of pilot holes) All you would need are two spare 5mm allen bolts.

I think that would be much simpler than machining and mounting a spacer considering you don't need your air pump drive...

It may take a 6mm flat washer or two to space the head of the allen bolt out enough to drive the pump, I can't remember to be honest.
__________________
Professional Overcomplicator
Old 11-14-2008, 06:45 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #8 (permalink)
Forced Induction Junkie
 
WERK I's Avatar
 
Join Date: Jan 2003
Location: Wisconsin
Posts: 3,291
Garage
Here we go disagreeing again, Mike.

I'm trying to remember back as well. I was thinking of removing the air pump drive mount and after much deliberation, decided to keep it in place. Can't remember if it was the engine tin mods, or the sump lines or something else or all the above. It seemed like it was going to be that "ol' rolling snowball" effect. In any effect, billjam, it will become apparent once you have the engine out and you do a dry run with all the lines and tin.
__________________
Dave
'85 930 Factory Special Wishes Flachbau
Werk I Zuffenhausen 3.3l/330BHP Engine with Sonderwunsch Cams, FabSpeed Headers, Kokeln IC, Twin Plugged Electromotive Crankfire, Tial Wastegate(0.8 Bar), K27 Hybrid Turbo, Ruf Twin-tip Muffler, Fikse FM-5's 8&10x17, 8:41 R&P

Last edited by WERK I; 11-14-2008 at 07:03 AM.. Reason: bad grammar
Old 11-14-2008, 07:02 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #9 (permalink)
Registered User
 
rsrmike's Avatar
 
Join Date: Jan 2008
Location: Birmingham, AL
Posts: 538
LOL Dave, I agree, the sump lines may not fit so well, but depending on what he's using, could be a non-issue, or easier to fix than adding the spacer... I don't think the tin should interfere, but it might.

Dave, is there a recess in the end of your cam to help support the spacer? or does it bolt flat against the original cam face. Seems like I remember there being one, but I could be thinking of the cams I used from webcam. Been too many years since I changed cams in a turbo I must confess.

If you already have a proper spacer, I agree it's probably easier to keep the smog drive housing, I'm just specifically refering to Bill since he's already been through so much crap trying to get SC cams in his motor, I'm trying to look for the easiest approach...

For instance, I feel confident I could drill and tap the cam, and even machine a spacer to the proper O.D. if I borrowed a lathe, however, getting it bolted squarely on the cam?? nah, wouldn't be so sure. Now, if the OD of the spacer was much larger and I could drill 8mm or possible even 10mm holes so I had some room for error, maybe. But if you look at your spacer in the pic, the bolt spacing is very close to the O.D. leaving very little room for mikey-tolerance
__________________
Professional Overcomplicator
Old 11-14-2008, 07:22 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #10 (permalink)
Forced Induction Junkie
 
WERK I's Avatar
 
Join Date: Jan 2003
Location: Wisconsin
Posts: 3,291
Garage
Quote:
Originally Posted by rsrmike View Post
.........................................
Dave, is there a recess in the end of your cam to help support the spacer? or does it bolt flat against the original cam face. Seems like I remember there being one, but I could be thinking of the cams I used from webcam. Been too many years since I changed cams in a turbo I must confess........................

For instance, I feel confident I could drill and tap the cam, and even machine a spacer to the proper O.D. if I borrowed a lathe, however, getting it bolted squarely on the cam?? nah, wouldn't be so sure. Now, if the OD of the spacer was much larger and I could drill 8mm or possible even 10mm holes so I had some room for error, maybe. But if you look at your spacer in the pic, the bolt spacing is very close to the O.D. leaving very little room for mikey-tolerance
Thank god, I keep records! Here is an archive photo of the driver's side camshaft end. I agree very little room.


__________________
Dave
'85 930 Factory Special Wishes Flachbau
Werk I Zuffenhausen 3.3l/330BHP Engine with Sonderwunsch Cams, FabSpeed Headers, Kokeln IC, Twin Plugged Electromotive Crankfire, Tial Wastegate(0.8 Bar), K27 Hybrid Turbo, Ruf Twin-tip Muffler, Fikse FM-5's 8&10x17, 8:41 R&P
Old 11-14-2008, 07:36 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #11 (permalink)
Registered User
 
rsrmike's Avatar
 
Join Date: Jan 2008
Location: Birmingham, AL
Posts: 538
Rut-Roe shaggy,

I hope the pilot holes I'm thinking of aren't the unused ones on the outer edge, if so, that shoots my easy theory all to hell and back!!

Thanks for the pic dave, you win... this time... JK bro!
__________________
Professional Overcomplicator
Old 11-14-2008, 07:51 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #12 (permalink)
Forced Induction Junkie
 
WERK I's Avatar
 
Join Date: Jan 2003
Location: Wisconsin
Posts: 3,291
Garage
I don't know what those two chamfered outer rim holes are for. The sump pump drive pin actually uses the allen head bolts to drive the pump. That is the same allen bolts that mount the extension to the cam. Note: you have to use hardened allen bolts to mount the extension, otherwise they heads will snap or collapse.
__________________
Dave
'85 930 Factory Special Wishes Flachbau
Werk I Zuffenhausen 3.3l/330BHP Engine with Sonderwunsch Cams, FabSpeed Headers, Kokeln IC, Twin Plugged Electromotive Crankfire, Tial Wastegate(0.8 Bar), K27 Hybrid Turbo, Ruf Twin-tip Muffler, Fikse FM-5's 8&10x17, 8:41 R&P
Old 11-14-2008, 08:21 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #13 (permalink)
Registered User
 
rsrmike's Avatar
 
Join Date: Jan 2008
Location: Birmingham, AL
Posts: 538
There I go again w/ my suck-@ss explanations, I meant the outer holes within recessed part, I'm thinking those are the "pilot" holes I was refering to? ditto on the small chamfered holes... What up wit dat?
__________________
Professional Overcomplicator
Old 11-14-2008, 08:31 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #14 (permalink)
Forced Induction Junkie
 
WERK I's Avatar
 
Join Date: Jan 2003
Location: Wisconsin
Posts: 3,291
Garage
My memory simply is not what it used to be, but it seems the two sets of non-threaded holes are not used. The one set within the recess looks like they may have been used for pins. The outer set(chamfered), haven't a clue. Maybe oil drainage back into the other side of bearing? How's that for a wild guess?! I should have taken more pics of the cam and extension.
I'm dropping the engine this winter to fix an oil leak.........yep, back by the sump pump.
I won't have more pics until then, though.
__________________
Dave
'85 930 Factory Special Wishes Flachbau
Werk I Zuffenhausen 3.3l/330BHP Engine with Sonderwunsch Cams, FabSpeed Headers, Kokeln IC, Twin Plugged Electromotive Crankfire, Tial Wastegate(0.8 Bar), K27 Hybrid Turbo, Ruf Twin-tip Muffler, Fikse FM-5's 8&10x17, 8:41 R&P
Old 11-14-2008, 09:11 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #15 (permalink)
Registered User
 
Join Date: Jul 2006
Location: S. Florida
Posts: 7,265
Havn't read all the replies but I know Webcam will weld the oil/air pump drive on the driver side cam of SC/ Carrera cams, and or cut off the power steering drive on the passenger side of a 964 cam so you can use it in a 930.
Old 11-14-2008, 09:39 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #16 (permalink)
Certified User
 
billjam's Avatar
 
Join Date: Aug 2007
Location: Perth, Western Australia
Posts: 1,984
Garage
How to fit scavenge pump to SC camshaft

I spent some time looking at this today and have found that the solution is quite simple IF you don't want an air-pump.
As Mike suggested, bolting the scavenge pump directly to the camshaft housing is the way to go but there are a few things to watch out for. I took a bunch of photos (before and after) so anyone wanting to fit SC cams and delete the air-pump drive can follow what I have done.

Deleting the air-pump drive housing and mounting the scavenge pump to the camshaft housing will move the scavenge pump closer to the engine by 48mm.
This means that the oil suction pipe from the turbo needs to be shortened by about 48mm (cut and braze or silver solder, or use hose and clamps to rejoin pipe after cutting).
The oil pipe from scavenge pump to tank needs to be bent rearwards to new pump location (see photos).
This pipe will interfere with the sheetmetal however a simple notch is all that is required.
Deletion of the air-pump drive housing leaves a large gap in the sheetmetal above the scavenge pump. It is fairly simple to fill this gap with a small panel.

The SC camshafts that I am using (left 930.105.147.9R, right 930.105.148.9R) have 5mm dia holes at 25mm centres in the end of the front journal.
These holes are the correct size to tap M6 but the camshafts are too hard to tap with ordinary high-speed steel taps, so my preferred option of screwing in a socket-head cap screw got canned. I didn't want to risk breaking off a tap in the end of the camshaft so I have opted to use 5mm roll pins (25mm long).
The roll pins need to protrude 10mm (+/- 1mm) from the end of the camshaft to fully engage with the cross pin in the oil pump shaft.
If you wanted to use solid drive pins, I am sure that this would work just as well. Obviously, they would need to be a tight fit in the 5mm holes and they might benefit from having a drop or two of Loctite just to be sure.
It would be interesting to know what type of drive pins were used in older 930s (without air-pump).

A potential problem area to watch for is the clearance between the end of the pump shaft and the end of the camshaft. After allowing for the gasket (0.5mm), I had about 0.2mm interference here. Grinding 1mm off the end of the pump shaft fixed this and gives a reasonable operating clearance.

I hope this explanation and the following photos are useful to others planning to take the same route.
Thanks for your input Dave and Mike.











__________________
Bill
1988 Carrera - 3.6 engine (with ITBs, COPs, MS3X) and a whole set of turbo body panels waiting in the attic.
Day job ... www.sspowdercoat.com.au
Memories: '68 912, '72 911T, '80 911SC, '84 911, '85 930, '86 930, '87 911
Old 11-16-2008, 05:55 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #17 (permalink)
Registered User
 
rsrmike's Avatar
 
Join Date: Jan 2008
Location: Birmingham, AL
Posts: 538
NICE WORK! I didn't even think about using roll pins... doh! Did you use the "spiral" type pins like the ones on the clutch pedal assembly?

I'm not sure what's more impressive, your solution, or your brilliant explanation, glad to see you making progress, keep up the good work, thanks for sharing
__________________
Professional Overcomplicator
Old 11-16-2008, 07:41 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #18 (permalink)
Registered User
 
Join Date: Jul 2006
Location: S. Florida
Posts: 7,265
Thats a great solution and it gets rid of the oil seal on that end of the camshaft. At the same time that oil seal in the air pump pulley cover and the paper gasket is cheap and very easy to replace.

It's just my opinion, but for a 930 in the USA I think it may be a better idea to leave the air pump pulley and it's housing in place because you never know if the EPA or state governments will get tighter on emission controls in the future and force you to have a working air pump installed in order to register the car.
Some states are like that now.
It could be a real pain and expense to find those parts later if they have been removed and lost or sold.

Nice clean solution though, if you never need it again.

Just wondering, how similar is the air pump pulley and housing to the belt drive hardware for the injection pump on a manual fuel injected car from the early 70's?
Old 11-16-2008, 07:59 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #19 (permalink)
Forced Induction Junkie
 
WERK I's Avatar
 
Join Date: Jan 2003
Location: Wisconsin
Posts: 3,291
Garage
billjam,
You're da' man!! Nice pictoral and writeup.
__________________
Dave
'85 930 Factory Special Wishes Flachbau
Werk I Zuffenhausen 3.3l/330BHP Engine with Sonderwunsch Cams, FabSpeed Headers, Kokeln IC, Twin Plugged Electromotive Crankfire, Tial Wastegate(0.8 Bar), K27 Hybrid Turbo, Ruf Twin-tip Muffler, Fikse FM-5's 8&10x17, 8:41 R&P
Old 11-16-2008, 02:12 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #20 (permalink)
Reply

Thread Tools
Rate This Thread
Rate This Thread:

 


All times are GMT -8. The time now is 04:20 AM.


 
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page
 

DTO Garage Plus vBulletin Plugins by Drive Thru Online, Inc.