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 Technical BBS > 1- Porsche Technical Forums > 911 Engine Rebuilding Forum

Reply
 
LinkBack Thread Tools Rate Thread
Author
Thread Post New Thread    Reply
Moderator
 
304065's Avatar
 
Join Date: Dec 2001
Posts: 9,435
Assembling 1966 901/05 Engine: Phase II-Sealing up the Short Block

Well, many of you may have seen my prior thread in which I button up the bottom end of the engine for my 1966 911. It's been a while but time for an update from today's progress.

I needed to set the intermediate shaft backlash. This was an area of concern for me because when I put the crank and the intermediate shaft in the case, I didn't measure very much backlash, or play, between the helical gears on the intermediate shaft and the crank. So I wanted to make sure it was present, and that the end shims were correctly set so that the relationship of the gears was correct.

There's a reason nobody talks about this procedure, it's because it's either not regarded as important or not really understood. But it's actually simple, although I'm certainly open to further enlightenment from the real experts.

Because the gears are helical (i.e. diagonally cut) the play between gear teeth is set by moving one shaft relative to the other in the direction of the axis of the shafts (not the radius of the gears). To set this axial play, and thus the backlash, there's a cover that bolts to the case at the end of the intermediate shaft. This cover presses on the end of the shaft and keeps it tight against the crank, maintaining the correct relationship between the gears.

So to alter the backlash spec, you use thinner or thicker shims between the case and the intermediate shaft plate. These have the effect of allowing the shaft to move out of the case or holding it in-- the splines on the other end allow the shaft to move, and the thrust axis of the gears tries to move it out, so you just put the right thickness shim in between the case and the plate and that holds the shaft where you want it. Simple.

Here's where it gets complicated. On the early engines, the factory made a nice hole next to the shaft into which you can insert a pin to push the shaft toward the oil pump. I guess this was eliminated in the later case. Anyway, the shims are no longer available, so people rely on stacking paper gaskets and compressing them in order to get the backlash in spec. I happen to have the following:

1) an original metal shim from the engine, this was .25mm thick, steel. It was sandwiched between;

2) two paper gaskets .05mm thick- one was unusable and torn, the other was in good shape-- these were made from orange paper, similar to original chain box gasket material.

3) the thicker paper gasket from my engine rebuild gasket kit. This was much thicker than the others, but compressible as you'll see.

To make these measurements correctly you need the P220 special tool- this consists of a machined steel plate with three holes in it spaced to fit the studs in the case that hold the cover on, and then a hole in the center for a dial indicator that contacts the intermediate shaft.



The way you use this is, bolt it to the case using M6 nuts (10mm ATF)-- with the SAME torque you would use in normal assembly, which is 11NM (8 foot-pounds, not a whole lot but you have to go easy on these little studs or they will shear). You then use a lever to push the shaft as far toward the oil pump as it will go, then zero out the indicator. This is easy with the chain boxes off, you just use a piece of wood (no splinters please!) to wedge it forward.

To measure the backlash you then move the shaft in the OTHER direction, toward the plate. In order to do this, I actually put a drift on the shaft where it met the oil pump by reaching through the sump plate-- and a couple light taps on the drift moved the shaft out to contact the plate.

A note about dimensions. You aren't looking for a lot of movement, the factory spec is 0.08-0.12mm. That is eight to twelve hundredths of a millimeter, "three to four thou" for those of you diehards in decimal-inch.



So first I tried the uncompressed thick gasket. Whoof! .030mm!



OK, this time I tried one of the thin gaskets and the shim. Too little! .06mm!

__________________
'66 911 #304065 Irischgruen
Ex-'71 911 PCA C-Stock Club Racer #806 (Sold 5/15/13)
Ex-'88 Carrera (Sold 3/29/02)
Ex-'91 Carrera 2 Cabriolet (Sold 8/20/04)
Old 07-26-2008, 04:36 PM
  Pelican Parts Technical Article Directory    Reply With Quote #1 (permalink)
Moderator
 
304065's Avatar
 
Join Date: Dec 2001
Posts: 9,435
Finally, once the paper gasket had been compresed by multiple on/off cycles, I got it to compress under the normal torque to 0.12mm, the high end of the spec, no problem.



Cover on. With the same shim, the backlash should be the same.



Next, a few other items. I buttoned up the breather, oil thermostat, oil pressure adapter and new sender. I have an ancient sender for concours purposes, this one is brand spanking new, intended to tell me the oil pressure!



Next, I wanted to verify the correct deck height, which I specified to be 1.0mm with .25mm base gaskets. Unfortunately my pistons are of the high-dome type, so there is no convenient flat surface on which to measure. However, there is a flat surface where the top of the dome was milled flat, and I know the dome height is .570 inch from JE (JE pistons ARE a bunch of decimal-inch holdouts, it won the War!). So by measuring the height of the dome above the top of the cylinder and then subtracting that measurement from the known dome height, I would have the distance the "theoretical" top of the piston without the dome was below the cylinder top.

So I used the old Bruce Anderson "Jo Block" (nobody calls them Jo, or Johansen blocks, anymore, just plain old Gage blocks) method- I wrung a 20 and a 10 together to match the solid 30 on the other side, then used a Chebby "deck height bridge" that was too wide for our cylinders to bridge over the top of the gage blocks. Basically this is just a piece of aluminum with a hole in it for a dial indicator.

Wait a minute, all my metric dial indicators are 1mm travel. Out of the box came the cheap Chinese-made decimal-inch indicator from my Summit rod bolt stretch gage. This has a 1" (25.4mm) travel, perfect for measuring the half-inch or so of dome height.

So I zeroed the indicator on the gage blocks on my surface plate and set up with the blocks on the cylidnder top. Not easy to balance them, but once the indicator was in place everything held nicely. The verdict. . . .0.530 inches.



Subtract that measurement from the .570 dome height and you get 0.040 inch, or 1.01mm. . .

. . . WHEW! I love it when a plan comes together. Before it's all done I'll also measure piston-to-head clearance with solder. Cofidence in the deck height means my compression ratio calculation will be accurate also.

On we go. One invisible mod is the 130mm pulley instead of the small '66 one, this turns the fan faster for better cooling (yes, I know we debate this). The question: will it fit inside the '66 engine mount? Answer?

130mm pulley: no way to change the belt without a partial drop. Problematic.



'66 pulley: no problem! This one gets installed until I can source and have blasted and powdercoated a later engine mount-- I hope the studs are in the right place.



Last item was putting the repro sump cover on and sealing it up. The yellow stuff is Aeroshell Fluid 2F, an aviation corrosion preventive oil, to preserve this engine pre-start. I had to use the "new" hexagonal plugs for the oil pressure and overpressure pistons, because the old style with the screwdriver slot have a different depth, they would hold the springs at a different height and throw the readings off. Oh well, you can't win the Manhattan trophy with them in.





Enjoy the photos, look for more updates in the (hopefully) near future! Pistons and cylinders are next.
__________________
'66 911 #304065 Irischgruen
Ex-'71 911 PCA C-Stock Club Racer #806 (Sold 5/15/13)
Ex-'88 Carrera (Sold 3/29/02)
Ex-'91 Carrera 2 Cabriolet (Sold 8/20/04)

Last edited by 304065; 07-26-2008 at 04:56 PM..
Old 07-26-2008, 04:54 PM
  Pelican Parts Technical Article Directory    Reply With Quote #2 (permalink)
Registered User
 
911 tweaks's Avatar
 
Join Date: Apr 2006
Location: northeast
Posts: 3,639
looks great John !!
Just a tid bit you probably already know or if not it is worth telling the masses that read your posts, myself included... when using powdercoated parts ANYWHERE on a car, engine... the 2 mating surface points i.e. the coated part and where it makes contact to what ever it mates up to, MUST NOT HAVE POWDERCOAT !!! I was told this by a friend that missed this on a couple of areas of his car resto and the parts will, not maybe, but will loosen up and then bam goes the what ever that WAS attached. Very important... that round area, usually washer in size area must not have powdercoat. Mask this odd with hi temp teflon tape before giving your parts to your powdercoater. If you miss an area, you can remove the coating but you will mess up what ever plating you may of done to the parts to prevent rust and or for coloring if you used clear powdercoating.

Please keep you awesome posts and info coming... your info very well presented and understandable !!

I as many can't wait till your build is complete and you fire her up !!

Bob
__________________
I live for 911 tweaks...
Old 07-27-2008, 03:43 AM
  Pelican Parts Technical Article Directory    Reply With Quote #3 (permalink)
Try not, Do or Do not
 
Henry Schmidt's Avatar
 
Join Date: Apr 2004
Location: Fallbrook, Ca. 92028
Posts: 5,909
Garage
Adjusting the end play is simple (just use a feeler guage) when you have the proper shims and gaskets.



There are actually 3 different pressure /spring plugs. On early engines with late style springs and valves we use the mid 70s plug. It is virtually the same height as the late plug but maintains the original aesthetics as the original plugs. It can be identified by the groove cut around the perimeter.




__________________
Henry Schmidt
SUPERTEC PERFORMANCE
Ph: 760-728-3062
Email: supertec1@earthlink.net
Old 07-27-2008, 10:48 AM
  Pelican Parts Technical Article Directory    Reply With Quote #4 (permalink)
Try not, Do or Do not
 
Henry Schmidt's Avatar
 
Join Date: Apr 2004
Location: Fallbrook, Ca. 92028
Posts: 5,909
Garage
The use of threaded pipe plugs in place of freeze plugs offers a more secure repair that also offers an easy way to clean oil galleys for future service.
In the alternative, hand machine/fitted aluminum plugs seem far superior to brass freeze plugs. This freeze plug alternative looks like something Ollies might do.

On most engines the factory aluminum plugs are still available.




__________________
Henry Schmidt
SUPERTEC PERFORMANCE
Ph: 760-728-3062
Email: supertec1@earthlink.net
Old 07-27-2008, 11:20 AM
  Pelican Parts Technical Article Directory    Reply With Quote #5 (permalink)
Moderator
 
304065's Avatar
 
Join Date: Dec 2001
Posts: 9,435
Henry, how do you use a feeler gauge to set the end play?

Great that you have all those shims in stock, definitely makes it easier.

I'm going to look around for a pair of those mid-70's style plugs-- the groove reminds me of the cam oil restrictors-- I guess when Porsche wants to differentiate a circular part the best way to warn the mechanics is to cut a groove in it!

Of course that plug was done by Ollies when they cleaned my case. I see what you mean about a threaded plug being easier to R&R.

Thanks for the reply, always good to have an expert check your work.
__________________
'66 911 #304065 Irischgruen
Ex-'71 911 PCA C-Stock Club Racer #806 (Sold 5/15/13)
Ex-'88 Carrera (Sold 3/29/02)
Ex-'91 Carrera 2 Cabriolet (Sold 8/20/04)
Old 07-28-2008, 05:10 AM
  Pelican Parts Technical Article Directory    Reply With Quote #6 (permalink)
 
Now Available for Ordering:   101 Projects For Your BMW 3 Series 1982-2000  [more info]
Registered User
 
sithot's Avatar
 
Join Date: Sep 1999
Posts: 706
Beautiful job, John!

Unfortunately there has been no Manhattan Trophy since 1995 and the car that won was a 1955 Porsche 550 which subsequently burned to the ground in a garage fire a few years ago. That wasn't the only irreplaceable loss. A Bruce Jennings Carrera was lost too.

So, fear not and go for the best parts for the job at hand!

Best of luck with the engine!

Tom
__________________
R Gruppe #111
Early S Registry #235
res ipsa loquitur

Last edited by 304065; 09-19-2014 at 05:56 AM..
Old 07-28-2008, 06:16 AM
  Pelican Parts Technical Article Directory    Reply With Quote #7 (permalink)
Try not, Do or Do not
 
Henry Schmidt's Avatar
 
Join Date: Apr 2004
Location: Fallbrook, Ca. 92028
Posts: 5,909
Garage
Quote:
Originally Posted by john_cramer View Post
Henry, how do you use a feeler gauge to set the end play? edit.......................................
Simple enough:
It is important to consider/inspect the surface of the cover plate before you start the process.
It is not uncommon to find the cover plate to be grooved or scored for previous installations. Check the contact end of the shaft for the same type of damage.
Install the plate finger tight sans shim and gaskets.
Measure the gap between to case and the plate with a feeler gauge. We use SAE but if you have metric feeler gauges, use them.
When you have the gap measurement add your desired end play to the gap measurement and that will tell you how thick your shim and gasket combination should be. With the thin paper gaskets we allow .0015" or 20% for crush. It is important not to over tighten the three mounting nuts. Install 574 on the gaskets as a sealing precaution.
The book states .003"-.005" shaft end play. This tolerance is large enough to tell us that Porsche does not feel that the end play is especially crucial.
We set the end play @ .004" as a general rule.

If the radial play is out of spec, we have the case machined for a trust bearing and install a late style intermediate shaft.

With the later style intermediate shaft you can insert a feeler gauge between the thrust bearing and the thrust surface on the intermediate shaft prior to assembly. If the end play on the later style shaft is excessive all you can do is replace the shaft. At this time the thrust bearing only come in one thickness.
__________________
Henry Schmidt
SUPERTEC PERFORMANCE
Ph: 760-728-3062
Email: supertec1@earthlink.net
Old 07-28-2008, 11:55 AM
  Pelican Parts Technical Article Directory    Reply With Quote #8 (permalink)
Moderator
 
304065's Avatar
 
Join Date: Dec 2001
Posts: 9,435
Fan debate. . .
__________________
'66 911 #304065 Irischgruen
Ex-'71 911 PCA C-Stock Club Racer #806 (Sold 5/15/13)
Ex-'88 Carrera (Sold 3/29/02)
Ex-'91 Carrera 2 Cabriolet (Sold 8/20/04)
Old 07-29-2008, 10:37 AM
  Pelican Parts Technical Article Directory    Reply With Quote #9 (permalink)
Try not, Do or Do not
 
Henry Schmidt's Avatar
 
Join Date: Apr 2004
Location: Fallbrook, Ca. 92028
Posts: 5,909
Garage
John
I find it wholly inappropriate to move a post without the posters consent. I violated no rule, the post was in keeping with the thread and by moving my post or anyone else's post, you change the context in which the content was intended to exist.
This may be a simple case of a little power run amuck.
__________________
Henry Schmidt
SUPERTEC PERFORMANCE
Ph: 760-728-3062
Email: supertec1@earthlink.net
Old 07-29-2008, 01:05 PM
  Pelican Parts Technical Article Directory    Reply With Quote #10 (permalink)
Try not, Do or Do not
 
Henry Schmidt's Avatar
 
Join Date: Apr 2004
Location: Fallbrook, Ca. 92028
Posts: 5,909
Garage
Quote:
Originally Posted by Henry Schmidt View Post
John
I find it wholly inappropriate to move a post without the posters consent. I violated no rule, the post was in keeping with the thread and by moving my post or anyone else's post, you change the context in which the content was intended to exist.
This may be a simple case of a little power run amuck.
What? no response to my comment.
__________________
Henry Schmidt
SUPERTEC PERFORMANCE
Ph: 760-728-3062
Email: supertec1@earthlink.net
Old 08-07-2008, 08:30 PM
  Pelican Parts Technical Article Directory    Reply With Quote #11 (permalink)
Author of "101 Projects"
 
Wayne 962's Avatar
Quote:
Originally Posted by john_cramer View Post

There's a reason nobody talks about this procedure, it's because it's either not regarded as important or not really understood. But it's actually simple, although I'm certainly open to further enlightenment from the real experts.
Good writeup! But the reason why this isn't really talked about too much is because it only applies to the early cases (1965-1968 1/2)...



-Wayne
__________________
Wayne R. Dempsey, Founder, Pelican Parts Inc., and Author of:
101 Projects for Your BMW 3-Series 101 Projects for Your Porsche 911 How to Rebuild & Modify Porsche 911 Engines 101 Projects for Your Porsche Boxster & Cayman 101 Projects for Your Porsche 996 / 997
Coming in 2014:
101 Projects for Your MINI Cooper
Old 08-08-2008, 01:23 AM
  Pelican Parts Technical Article Directory    Reply With Quote #12 (permalink)
Moderator
 
304065's Avatar
 
Join Date: Dec 2001
Posts: 9,435
Quote:
Originally Posted by Wayne at Pelican Parts View Post
Good writeup! But the reason why this isn't really talked about too much is because it only applies to the early cases (1965-1968 1/2)...



-Wayne
Thanks Wayne! You mean the world didn't end in 1969!

Of course the later intermediate shaft bearings are a thrust-type bearing so this procedure is not used.
__________________
'66 911 #304065 Irischgruen
Ex-'71 911 PCA C-Stock Club Racer #806 (Sold 5/15/13)
Ex-'88 Carrera (Sold 3/29/02)
Ex-'91 Carrera 2 Cabriolet (Sold 8/20/04)
Old 08-08-2008, 05:45 AM
  Pelican Parts Technical Article Directory    Reply With Quote #13 (permalink)
JCF JCF is offline
Registered User
 
Join Date: May 2004
Location: The state of ME.
Posts: 1,717
Quote:
Originally Posted by sithot View Post
Beautiful job, John!

Unfortunately there has been no Manhattan Trophy since 1995 and the car that won was a 1955 Porsche 550 which subsequently burned to the ground in a garage fire a few years ago. That wasn't the only irreplaceable loss.
Not a total loss - I believe I have seen that (55 Spyder's) frame and engine and it is slowly being brought back to life by an artist/magician/engineer.
__________________
Du must schwein haben

'67 901/05 rebuilt 2.2
Bultaco Metralla 62 "XDina"
'68 BMW R69S
Old 11-18-2008, 04:49 PM
  Pelican Parts Technical Article Directory    Reply With Quote #14 (permalink)
Registered User
 
Join Date: Feb 2005
Location: Melbourne, Australia
Posts: 643
I measure the depth of the seat on the early plugs to be 12.6mm and the late ones 9.2mm. I'd like to retain the early ones for appearance. Is there any reason I can't shim the early ones 3.4mm to achieve the same spring pressure?

andy

Quote:
Originally Posted by Henry Schmidt View Post
There are actually 3 different pressure /spring plugs. On early engines with late style springs and valves we use the mid 70s plug. It is virtually the same height as the late plug but maintains the original aesthetics as the original plugs. It can be identified by the groove cut around the perimeter.




Old 06-25-2013, 03:43 AM
  Pelican Parts Technical Article Directory    Reply With Quote #15 (permalink)
Moderator
 
304065's Avatar
 
Join Date: Dec 2001
Posts: 9,435
Andy, I don't see why not, as long as the shim stays put.

See here for more details

Ultimate Oil Pressure Relief Valve Thread
__________________
'66 911 #304065 Irischgruen
Ex-'71 911 PCA C-Stock Club Racer #806 (Sold 5/15/13)
Ex-'88 Carrera (Sold 3/29/02)
Ex-'91 Carrera 2 Cabriolet (Sold 8/20/04)
Old 06-25-2013, 06:05 AM
  Pelican Parts Technical Article Directory    Reply With Quote #16 (permalink)
Reply

Thread Tools
Rate This Thread
Rate This Thread:

 

Tags
901/05 , john cramer rebuild


All times are GMT -8. The time now is 03:23 AM.


 
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2016 Pelican Parts - 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.