912E Type IV Rebuild

[Piledriver]

Funny that said, there is something about simple.... at times I miss a capacitor, points and a single barrel carb, ha.

At times I wistfully miss a points, condenser , carbs etc, then I realize I have driven >100K miles and the only maintenance other than oil changes ~ twice a year and valve adjustment checks at same time
...I have tested several ignition trigger setups, all worked. That was voluntary so I cant count that.

Replaced: 4 spark plugs.


...I have reworked the shocks twice, installed a custom AC rig, replaced the entire rear suspension, and put an automatic in it in that period, but only changed the plugs once.

I did have to replace the air filter as the first and last time I tried to clean it the cleaner caused the uni filter to dissolve.

It is burning some oil now, the used 1.8L jugs/rings must be nearing end of life.

[Bsherrard]

999argonaut -
I am going to Delortto Carbs and I have 912E which is an L-Jet anyway. Won't be able to help you mate - sorry.

[Bsherrard]

All -
I have searched all over this forum and the web looking for a spreadsheet that lists / tracks all of the things needed to blueprint a type 4 (or any other) engine. I found reference in the ACT forum to a checklist the Jake uses but the thread has been removed. Before I put in a bunch of work creating one, thought I would ask to see if anyone has one they would like to share? Ideally I would list all of the engine components and have a checklist for the things that need to be verified / machined (ie, dimensions, clearances, weights), a place to input the final numbers for your engine, a listing of the torque values for critical engine components. a one stop document that you populate at the beginning of your build and then use during the process to make you don't miss anything and have a final build sheet when you are done.

Any help, recommendations, suggestions would be greatly appreciated.

Brook

[_thesatanicmechanic]

I would question the amazing, yet buttery soft, JE pistons. Consider the KB 96mm units? Unless you are speccing a 3K alloy JB... The KBs have really held up well. Friend has 60K miles on a set in his '79 westy 2056 with minimal oil consumption and barely any clatter on cold start up. Split duration webcam with 44s that frequently sees 5000+ rpm. Like very time he drives it.

[Bsherrard]

TSM -
the ship has already sailed on the JE pistons. Went with them as they are what Jake Raby used in his kits of old and that is the basis of the engine build. I got them from the Type4 store and they are custom for the engine. thank you for the input, though!
Brook

[raygreenwood]

Are you keeping the stock FI and computer in combination with the programmable dizzy? If so would be very interested to learn about your experiences and what improvement this would bring. 123 distributor's own website seems to guide people towards the non programmable version if you are using d/j-jet setups.

I will try to keep you guys posted late this year or early next.

I work on almost strictly D-jet (at least in air cooled cars). D-jet would GREATLY benefit from programmable. I Have no idea why they would guide you toward a non-programmable ignition set up for it....except that they probably bave no idea how to adjust fueling on D-jet....which has worlds away better adjustability than L-jet and Digifant.
I will most probably be using the CB blackbox when my engine is done.

This will be the stock D-jet distributor....with mechanical locked out....a Hall effect pickup and module slaved in for impulse and looking at a Blackbox to get a programmed curve. This will be used with a Pertronix 60Kv E-core coil (unless I can find a Jacobs or Accel Omni-coil between now and then).

It will get broken in and adjusted for fueling on the stock paired injector channels and then will get switched to the sequential D-jet trigger system I built a couple of years back.

With proper adjusting D-jet is far more capable than the state of tune the factory used it in....but aside from cam issues (which we have much better choices for now...this one has a 9550 cam going in)...and exhaust....(its getting a four-into-one)....the factory ignition control and coil weakness at higher compression was its major weakness. Ray

[Bsherrard]

I will answer my own question - looked over on TheSamba and found this thread with a very excellent blueprinting worksheet in PDF format.
https://www.thesamba.com/vw/archives/in ... ksheet.php
Will use this as a starting point and tweak in Excel.
Brook

[Bsherrard]

I am converting my 912E from the L-Jet FI system to Delorrto 40's. In the process, I want to build a new wiring harness for the engine. Can anyone advise what all connections I need to maintain?

[Piledriver]

coil power/backup lights ...i'm assuming a 911 used the same idiot setup for backup lights...
(I most strongly suggest using original wire to control a fused relay powered off the battery/starter regardless)
oil pressure idiot light
alternator power wire
alternator idiot light

[Bsherrard]

All - I have finally gotten to the point that I can mock up my 2270 (following NextGen advise to take is slow??)
the specs on the motor are in the first post. The current deck height at mock up is 0. The flat top pistons are perfectly level with the tops of the cylinders. If I lay a straight edge across the tops of the cylinders and rotate the crank, stop at TDC I cannot even get a .005 feeler gauge under the straight edge and there is no perceptible movement of the straight edge. I built 4 jigs out of 1" tube to allow tightening the cylinders to the block and when I use these there is no space at all between and if I torque it down the pistons won't transition through the cycle so there must be a very minimal negative deck height. I have Hoffman heads with a 56.4 cc chamber and 7.0 cc step. From all that I have read, It seems that I want to run a deck height of .040" which I can get with .040" cylinder shims. With that deck height, my engine calculates out to 9:1 compression ratio.
Does all of this sound reasonable? Is 9:1 high enough of a compression ratio for my cam/combo or would I be better off trying to get to 9.5:1 and if so how do I go about increasing compression? (if bore, stroke and deck height are fixed, the only thing I can changes is the cc of the heads so I guess I would need to have the 1mm step reduced?)
thanks in advance for any input / thoughts.
Brook

[H2OSB]

I think 1mm deck height and 9:1 CR is just right for a NA engine.

H2OSB

[Piledriver]

If you have the step cut in the heads that is your deck height, (minus and piston protrusion, needs measured) you would not use shims other than perhaps the stock aluminum base gaskets that are typically .008"... the stock gaskets can be left out and a smear of sealant used, in order to get the deck as desired.

9:0 is about the right compression ratio for a web 86 or equivalent... any other cam may need something entirely different.
Given a Web 163/86b 11:1 would be more in order.
(I don't know what a 9500 is spec wise, but I would personally put a bit more cam in it than an 86 to make the most of the heads and displacement etc, unless it was going in a Bus)

[Druck1]

I am just starting a similar build. I am using a build spec from a poster on the 912 forum. He used a WEB 163/86b w/ 104 lobe center, but at 8.7:1 CR. Low vs recommended above. My build will be 78 x 100, .040 deck ht. Heads most likely Brothers VW with 44 intakes/36 exh.
Is 11:1 the right CR for this?

[Bsherrard]

9:0 is about the right compression ratio for a web 86 or equivalent... any other cam may need something entirely different.
Given a Web 163/86b 11:1 would be more in order.
(I don't know what a 9500 is spec wise, but I would personally put a bit more cam in it than an 86 to make the most of the heads and displacement etc, unless it was going in a Bus)

Piledriver/ all -
The engine is going in a Porsche 912E. Here are the specs for the 9500 Cam from the Type4 Store and the specs for the 163/86b following:

9500 Camshaft
Valve Lash: 0 (w/ chromoly pushrods)
Valve Lift / Intake: .500
Valve Lift / Exhaust: .500
Duration / Intake: 284*
Duration / Exhaust: 300*
Duration @ .050" / Intake: 250*
Duration @ .050" / Exhaust: 270*
Lobe Center / Intake: 104*
Lobe Center / Exhaust: 104*

163/86b Camshaft
Valve Lash: .006
Valve Lift / Intake: .497
Valve Lift / Exhaust: .507
Duration / Intake: 288*
Duration / Exhaust: 298*
Duration @ .050" / Intake: 250*
Duration @ .050" / Exhaust: 260*
Lobe Center / Intake: 104*
Lobe Center / Exhaust: 104*

Given this information, what is the recommended range for compression. This will be street car with occasional Autocross / DE. I want to get the best balance of performance without sacrificing the reliability of the 2270 combo.

Brook

[H2OSB]

Wow, those two cams are very similar.

H2OSB