2.0 stock(ish) rebuild, Initial carb jetting Options

[AE354803]

Since this is my first major project on the 912, I figured I would make a project thread since I'll have lots of questions.


The back story:

Car is a 67 912 with a 2.0 914 type IV, Weber 40 IDFs, bosch .050 dist installed. Transmission is original 912 with 914 gears 3,4,5 installed, newly rebuilt (synchros, selector forks, etc.) 73 911 front end suspension/brakes/steering, dual zone master cylinder, ER polybronze all around.

I've been investigating a loud, clanking noise for the past few months. The noise happens regardless of engine/oil temperature or pressure. It is present below ~3000 rpm and then disappears entirely above 3000 rpm. When the noise is gone the engine sounds great. While this noise was present I have driven the car from San Diego to San Francisco and back, as well as San Bernardino and a few other trips, so I think I've put on approx. 2500 miles (it's been present and slowly getting worse (as best I remember) since I purchased the car (June 2012)).

The noise has bugged me but I always figured since everything ran fine that maybe this is just characteristic of this engine. However I stopped driving the car a few months ago because the more I ruled out what it wasn't the more I worried about what it was and it's eventual catastrophic failure stranding me and destroying the engine.

Seems to be coming from the center of the case. I've gone through the valve train and replaced a stripped stud, installed new adjusters and made sure everything was wearing and fitting properly (which it was).

After this did not fix the issue I decided that before something destroys itself and everything around it I would remove and rebuild the 2.0 so that I wouldn't have to worry in the future. I wasn't using the car just because of the noise and the gut feeling that it was a time bomb. I suspect an issue with a main or rod bearing (possibly multiple) or excess piston slop, maybe a deteriorated piston skirt.



The Project:

1. Remove and rebuild to mostly stock the 2.0 type 4.
I have Weber 40 IDF's, GA 2.0 heads, WebCam Hydraulic+Carb grind w/ WebCam hydraulic lifters (turns out to be some ), Bosch .050 distributor (will most likely install Petronix or other electronic points)
Turns out that I had low compression bus pistons, some unknown cam, the cam to cam gear mounting bolts were too long and machined the base and also half of the cam thrust bearing was missing. The crankshaft timing gear was no longer a press fit and could be removed by hand, the crankshaft itself had material missing due to the slop.


2. Rebuild specifics:

New (used) stock oil pump
Rebuild heads [new SS exhaust valves, guides and retainers, heads cut to accept new cylinders without gaskets]
new gaskets/bearings/rings throughout,
EMW 96 mm cylinders and KB 96 mm pistons
new reground crankshaft and gearstack,
494 webcam and mechanical lifters w/ double thrust bearings and new cam gear
Petronix electronic points and rebuild dist.
Static balanced rods (0.1 grams) pistons (1 gram)
New Sachs pressure plate
New motor mounts and heavier mount bar to frame mounts (1/4" steel plate)
Install engine to exhaust header flange supports (engine did not have them)
CB Performance rotary fuel pump
Cut to length pushrods and solid rocker arm spacers


3. Have a set of EMW bus headers that I will add heating tins to and install with a new header and muffler. Not until after the engine is back in and running.

4. Fix small issues found along the way (so far fix bumper mounting alignment and rear engine bar mounts need to have a steel tube installed w/ bolt through to remove play and prevent further wear.)


This is my list for now, I am expecting it to grow, thanks in advance for any help.

Andy

[Bleyseng]

looks that way and with the hydro cam you are leaving a lot of hp on the table.
New 96mm flat top pistons
Web cam carb cam
This will wake up this sleepy motor.

[AE354803]

looks that way and with the hydro cam you are leaving a lot of hp on the table.
New 96mm flat top pistons
Web cam carb cam
This will wake up this sleepy motor.

Questions on 96mm:
Ultimately I want this engine to be very reliable and I'm willing to leave a little power on the table in order to do it. At the minimum I will put in better pistons, but for an additional $200 I can just go to 96 mm if it seems like a good fit for me.
My concerns are with cooling, adding ~4% surface area to the piston and removing 2 mm diameter from the cylinders will result in more heat going into less metal (unless the 96 mm cylinders are same OD->ID thickness).


Would going to 96 mm piston/cylinders reduce my reliability much?

Will I be able to use my stock rods with a 96 mm kit?

Can I continue using the stock oil pump? If I would need a bigger oil pump I would like to use one that doesn't require modification if possible. (engine already runs/ran very cold, took a while to hit 180F, highest was 210F)



WebCam 86 grind?
I was planning to swap to solid lifters, can anyone give me some thoughts on the webcam 86 grind? Looks like I should have a pretty decent power gain based on the added duration and opening the cam gives over stock and more duration over the current webcam hydraulic carb.

With the Anaheim swap meet coming up I am going to keep my eyes out for some piston sets up there. Any advice on what to check for? What brands/types to go for and stay away from?

[AE354803]

I think I might be missing a case bolt, not sure but I found an open hole in the upper case. I didn't bother counting all 20 case bolts due to laziness.

[Cupomeat]

I think I might be missing a case bolt, not sure but I found an open hole in the upper case. I didn't bother counting all 20 case bolts due to laziness.

My engine and all the others I can remember did not have a bolt in that hole. I've used it for a strap to lift the engine on to the stand and other reasons. I could be wrong but I think you are good there.

[AE354803]

Thanks Eric for the info.

Had no luck at the swap meet this weekend so I'm starting to look for other peoples unused parts (save a little money).

I found what appears to be a good set of 96mm slipper skirt design (whatever that is?), looks like they are from AA?

Can someone identify what pistons/cylinders these might be?

http://www.thesamba.com/vw/classifieds/detail.php?id=1208843





(IMG:http://www.914world.com/bbs2/uploads_offsite/images.thesamba.com-14801-1362451987.1.jpg)