Fuel injection rebuild

[Simmy]

That's good to hear, but I will hold off on my enthusiasm until I get Bruce to take a look. Thanks Fourier!

In the interim, I shifted focus onto the new Unitech rods and their bearings. No funnies here, everything measures out clearly. Bearing clearances of 0.04-0.06mm (though most are at the low end), and zero slop in the wrist pin bushing. Had to clean up the back of the bearings at the parting lines though. This was after noting that light was still shining through a gap behind the bearing after being torqued up.





Also figured I should lap the cylinders into the case and heads (should have done it before I cleaned them the first time). Also confirmed that they are all the same height when installed (not torqued yet). Here's hoping that means I am not going to struggle with the deck height.

[Simmy]

So, I finally got some feedback on the crankshaft. It does have 0.045mm run out, so it's another regrind.
Having thought about it, I don't think I bent it... It's forged, and the damage to that bearing was pretty minor. I am thinking something may have happened when it was balanced, and I didn't pick it up when I measured it the first time.

Oh well... Lesson learned. New bearings next week and a trip to Volkspares to get some odds and ends.

[fourier]

Pity it can't be straightened, but now you know, and progress can be made.

If a crank has to be re-ground, I normally buy new bearings and put them in the engine case. Once the case is torqued to spec, I measure (dial bore gauge) the bearings ID's. Then I have the crank custom ground to have the correct oil clearance on each journal.

If you don't have a dial bore gauge, an automotive machine shop can measure the bearings, and machine the crank accordingly.

[Simmy]

Thanks for the suggestion. I was sort of wondering about that, but you distilled it quite clearly! So thanks!
Bruce still has the case and crank, so I will give him a shout in the morning.

[Simmy]

Hi and happy new year to anyone still following this lot. Things slowed down over December, January got shot to hell with work, and now it's Feb... But here's another chance to restart.

Since I last posted, I had a couple of things sorted out:

• the crank was reground straight according to bearing measurements. So now all of the clearances are where I want them to be.

• The flywheel was refaced, and I just opted to get a new clutch kit as I wasn't happy with the pressure plate. Nothing fancy... Just a LUK generic which will serve well enough for now

• Soda blasted, cleaned and rebuilt the carb for the run in period

• Cleaned up the inlet manifolds for later

• Cleaned up my dad's old hobby lathe which has sat around for 30odd years. It's running now, but needs a little more work to true up the chuck and get some cheap cutting tools to learn with

So, on to my next steps. I want to trial fit pretty much everything, and this is what I have so far... INPUT IS WELCOME AND ENCOURAGED!

The distributor and drive gear
Basically it looks like I need a spacer to take up the excessive end play. It must be closer to 3mm on both the old and new case using the stock dizzy. To make matters worse, I just found out that Volkspares sold me a dizzy which with a hopelessly long drive shaft. They machine it for the clamp, but it doesn't seat right and is impossible to set the end play properly
Plan is to machine a spacer on the lathe ( a good starter project), but don't know what to do with the dizzy. Will probably take it back and try to swap it out for something actually fits.

Thoughts on the spacer and a new distributor?







The cam gear
It looks like the cam gear I have is just slightly oversize. There is no backlash and although rotating the crank doesnt cause the cam to jump out completely, but I can hear and feel it hopping up just enough to make me concerned. There is no size marked on the gear (@Tony, got this from you a while back) so not sure what it should be. Should I be concerned enough to swap it? Can one fix this by running the gears together with a bit of fine lapping compound, like I read here: http://haysvwrepair.com/rebuilding-an-a ... toy-style/ (roughly half way down on the installing the cam section)



The cooling fan
Also fitted the new Scat welded and balanced fan, but I found that when you use the stock spacers it rubs against the backing plate. So It needs a massive spacer to get the clearance needed which means there isn't a lot of thread left for the nut. I also doesn't run true and there is a lot of wobble. The stock fan fits fine, and has no visible wobble. Anyone had a similar experience with the depth of the fan, rubbing and wobble? I don't feel that it's a bent alternator shaft.

(Will try upload a video)

[fourier]

Good going!

Glad you got the crank and oil clearances sorted. At least now you know it is correct. The bearings will require no "running in", (the way some "mechanics" try to get around lack of attention to detail).

I would return the distributor. It is a makeshift electronic conversion, with who knows what advance curve. The incorrect advance curve could fry your brand new engine. Find a good OEM distributor. At least you know the advance curve will be correct for an aircooled Beetle engine.

Did you install the two shims below the distributor drive shaft, and the spring between the distributor and drive shaft? This should take care of end play, unless there is something wrong with the engine case.

As far as the cam gear issue goes... Place the crank and cam in one case half. Turn the crank, while keeping slight finger pressure on the cam close to the gear end. If you feel the cam wanting to lift out of the bearing, the gear is too tight. If it stays put with very slight finger pressure, I would run it. I have never attempted the lapping compound fix, but be sure to remove all carborundum paste from both gear surfaces when done, otherwise they will continue grind away at each other. Use a brass wire brush on a Dremel to remove the paste, when grinding is done.

I would not use the Scat fan, if it has the issues described. Have a stock fan TIG welded, if you are concerned that it will explode due to high revs. I also have one of those Scat welded fans for a future project, but would Not use it, if it has the same issues.

Good luck, and keep up the good work!

[Tony Z]

I am guessing that the dizzy is a modified Golf item. If this hasnt been modified internally to have the same advance curve as the beetle, then take it back. The bug needs less centrifugal advance but at a much faster rate than the golf.

The aftermarket cam gears only come in one size. If you want things perfect your only real option is to get a bunch of used cams and remove their gears until you find one that fits your setup properly.
I've run the same combo of engle cam with that cam gear on a number of engines and havent yet had an issue. They all seem to have very little backlash and do lift out of the bearings a little.
You need to check all the teeth for any machining burrs that need cleaning off. Once you are happy that its good, bolt the cam and crank into the case with their bearings and torque the case together. Then spin the crank by hand with very little pressure to ensure all is free. If it wants to bind up due to the cam gear, you will feel it here.
Also, the cam gear is a softer material than the crank gear. The cam gear isnt a perfectly polished finish on the teeth like it would be if it was a hardened steel. So you will find that these little machining "peaks" will polish away when in use.
If you arent happy with the gear, email me and I'm sure we can work out a plan.

I've had a fan that needed some spacers swapped around to clear the fan housing. But I havent had one that didnt fit.
check here --> http://cbperformance.net/pdf/2168sheet.pdf
I dont think I've ever seen a fan that didnt have run-out. The question would be how much is too much?
Are you sure you have started out with the doghouse shroud and the same size fan as the welded one you've got? From memory, the earlier fans are 30mm wide while the later fans are 36mm wide.

[Simmy]

I am sure you are 100% correct on the golf guess. I will take it through and ask. Since the dizzy is only going to be used once the fuel injection is running, I wont stress about it for now.

Thanks for the advice on the cam. I did check and clean burrs, but I will bolt it all up and see how I feel about it - no need to send it for another trip to CPT for the sake of it Are cam gears surface hardened in any way? The surface of the teeth do have a "mottled" appearance - not sure if its machining-related or a case hardening thing.
Whilst thinking about it - is there anything special about cam bolts and washers, since none came with either the gear or the cam? I am assuming that they must just seat in the counter-bore, but can otherwise be pretty much standard hardware?

I can get the fan to fit - it just needs a very large spacer which prevents the wavey washer from seating on the hub properly and limiting the amount of threads that are engaged. I would eyeball the runout at 0.5-1mm, which feels too much for my liking. I think my issue is that runout + limited threading + up to 9000 RPM on the fan just makes me nervous.
Can fans be straightened? I still need to take the entire rotating assembly to be balanced as a unit, to maybe this can be attended to at that point...
I am going to use Dynamic Balancing in Edenvale to do it, and they also seem to offer services for industrial fans, so I will probably get another opinion there too.

[retrovan]

Not sure what others think, but I would have a bush turned to off set the van cover to the outside and weld to cover so normal mounting takes place of the fan.

You can have the fan balanced before fitting.

Herman

[Tony Z]

the crank gear is hardened steel. The cam gear is an alloy of sorts, maybe cast aluminium? This makes it softer than the crank gear. This is done to reduce noise generated by the gears.
The cam bolts are a SAE thread (American standard - UNC or UNF if I remember correctly). Try to get a button head bolt if you can as it sits "more flush" than a hex, giving more oil pump clearance.

0.5mm to 1mm of fan runout isnt perfect, but I wouldnt fuss about it. I'm pretty sure the fan on Angrrr has more runout that that.
Remember, the fan pulley system begins to slip at some point which limits the actual fan speed to less than the calculated theoretical max.

[Wentzel]

Glad to see you're still at it.

I had a similar cam gear issue but couldn't find a std gear that was loose enough. I ended up using a straight cut that was a bit loose to my liking but hoping it will work ok.

My welded fan has a similar issue and I had to add some shimms. Its been running like that for years without any problem, I do run the fan belt on the loose side to allow slipping at higher rpm and try to save my alternator bearings.

[Simmy]

Thanks for all of the feedback. I slept on it a bit and fiddled a little, and found it was tight only about a quarter of the cam-gear circumference (you can see where the leading tooth of the gear is wearing) and that there was a tone change in the meshing. I realised this must be due to some radial runout, pulled out the dial guage, and found that it's been machined off centre by 0.05mm.

I can't find any spec for this, but I suspect it's one of those "just live it" things? Maybe just settle it in using the lapping compound method? This is not like the Babbitt on bearings which could embed some of the abrasive particles?

[retrovan]

I would just polish it with a wire brush till it runs smooth

HJerman

[Tony Z]

try taking the gear off the cam again and see if you havent picked up a little burr when fitting it.
Maybe polish off a little paint/coating on the cam to get the gear to run closer to true

[Simmy]

Thanks for the suggestions.

Its tight around about 90° of rotation, not just a small arc where a burr on one tooth might be the cause. So I will try the wire brush method to start, and leave polishing of the cam's hub as plan B. It fits pretty snug in the gear, and I would think that's something you want to maintain.