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

[AE354803]

Progress:

Removed engine last night by partial drop. Ready to go on the stand for complete disassembly. Already found issues with the support bar mounting method that need to be fixed.

Easiest engine I have ever removed though. 3-4 hours solo start to finish which isn't bad for my first drop.


Ready for the stand


Empty Bay

[AE354803]

So I pulled the engine apart enough to remove the heads. Everything looked pretty nice, the Webers might need some work (they had leaked gas down onto the gaskets below the carbs. But I guess I can take care of that later unless someone knows what that might be indicative of.


The heads looked good, see pictures, only thing I was wondering about was a ~0.5 mm spacer about 1/4" width that was at the mating surface between the cylinder and the head. Does anyone know if these are normal?

Heads look decent, there are no cracks visible, 42mm intake, 36mm exhaust, based on the picture below there may be some leakby at the valve seat so I'll get them reground.



Probably evidence of worn valve seat, any ideas??

[AE354803]

Seems like the rings are definitely going, I think that's too much oil to be in the cylinder for only having been sitting for a few weeks.

What do you think?

[reharvey]

I think you have a set of low compression VW Bus pistons in the engine.

[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.

[Dave_Darling]

The "spacers" are the head gaskets. Several schools of thought on these; some say to use them and other say to leave them out.

--DD

[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.

[AE354803]

The Outer diameter at the bottom of the cylinder is 99 mm, the ID of the cylinder hole in the case is 99.5 mm, so if I go to a 96 mm piston then the wall thickness at the bottom will go from 2.5mm to 1.5mm if it is going to fit into the case without modification.

Do the 96 mm P/C's fit into the stock case w/out modification?

I know the decreased wall thickness is is below the compression region of the cylinder but is it safe to decrease the wall thickness by that much?

[Dave_Darling]

96mm cylinders should not require any case modifications. I had thought the spigots in the case were larger than 99mm somehow?

Anyway, the 96es should work without machining.

--DD

[AE354803]

96mm cylinders should not require any case modifications. I had thought the spigots in the case were larger than 99mm somehow?

Anyway, the 96es should work without machining.

--DD

Thanks Dave, I measured around 99.5 mm, however the batteries were out so I was using the 1mm tick marks on the shaft.

With 96mm should I have any need to increase oil flow/cooling?

[Dave_Darling]

Probably not, but it depends on about a zillion other factors.

--DD

[pnewman]

Please keep us up to date on your progress. It is a great learning tool for others.

[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)

['73-914kid]

Valve pockets in the pistons make me want to think that they are indeed 96mm pistons/cylinders from AA for the stock 2.0L stroke crankshaft.

[AE354803]

Anyone know where I can get a replacement for this ball thing? It hold the bar the attaches to the throttle cable and runs both Webers. Obviously it is slightly worn.

Also, I need a flywheel lock (the batman looking thing) and can't find one, or can't remember where I saw them. Any ideas?


Andy

['73-914kid]

Hex bar pivot

Those ball sockets tend to wear out after many miles of driving, and you might want to look into seeing what kind of condition the hex bar itself is in. They both tend to wear out in conjunction. The same place sells new hex-bars.

[euro911]

Pelican Parts has the flywheel lock