308 GT4 Distributor work and Crane XR3000 conversion

As some of you know I had some problems with my ignition, and after some good advices I decided to convert the ignition system to the Crane Cams XR3000. I prepared by reading a lot of good threads in the forum and other places. Since this has helped me a lot I thought it might be useful for others if I shared the process. I am not an experienced Ferrari mechanic, so I do not feel that I can give an "how to guide". But some other guy like me might find some of the information useful, and I would appreciate feedback from the more experienced Ferrari owners if I have done something wrong or can improve something.

I ordered the following parts:
Crane Cams XR3000 system. A used system that my fellow Scandinavian Pero sold me for a nice price.
Crane Cams PS 60 Coils. Bougth from Summitracing.
Magnecor spark plug cables. The 308 cables have partnumber 87293. Bought from Magnecor USA. You can not use solid core original cables as this might disturb the XR3000 system.
Distributor gasket, distributor grease and bearings from Dinoparts.eu.

My car is a Ferrari Dino 308 Gt4 1975 (might be late 1974 production). Assembly number 648. Serial 09472. It has twin distributors, Marelli 159B. Its a Euro version, and first sold in Switzerland. My timing marks are 6deg, AF 18deg and A5 35deg, all before TDC (PM). My distributor does not have a spined connection, but rather an adapter plate.

Here is what I did:

Disconnected the battery and locked/clogged front wheels.
Jacked up rear drivers wheel. Placed in 5th gear.
Removed the front distributor cap and spark plug wires (mark the wires 5-8 if they are not marked).
Rotated rear drivers wheel counter clockwise (same direction as when the car is driven, do not rotate the other direction) engine until the A 6degrees 5-8 timing mark lined up (this is just before the PM 5-8 mark on my engine).
Checked that the distributor rotor was pointing against the mark on the distributor.
Marked the position of the distributor. Marked all wires (R1 and R2 if you have that). Removed distributor.


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Sorry, I wanted to include the pictures (without uploading them). But IMG and HTML code is off, so untill I find out how to fix it you will have to click the links to see the pictures.

Removed rotor and the 3 screws that hold the top bracket on the distributor. Pulled the bracket of.

http://tjommi.com/59.jpg

Marked the placement for the points with a sharp marker, and removed them all.
Placed all old points parts in plastic bags and marked them .
Removed mini seeger ring that secures the top bearing.
Flipped the distributor and removed all the 6 screws that secures the center unit to the body. I would suggest that you take your time to clean the groove in the screws and find a screwdriver that fits perfect. Apply some force down when you try to unscrew them, as they could be stuck. Apply a little heat if necessary.

http://tjommi.com/60.jpg
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http://tjommi.com/72.jpg Old parts put in bags.

I was supposed to make a centerpunch mark in the rivets that holds the filterholder, to be able to drill them out. But when I punched them, the rivet popped out.
Removed the E-clip under the top bearing to get some more room for my bearing puller.
Pulled the bearing of with a 3 arm puller (by doing this you might damage bearing, so you should replace it).
Removed gasket from the distributor body.

http://tjommi.com/61.jpg Pulling top bearing.

Used a paint marker to mark the one side of the advance mechanism.
Took two small shims of the top of the centerpiece of the advance mechanism (this are situated just below the E-clip).
Pulled of the centerpiece and the small shim below.
Took of the weight arms of the advance mechanism.

http://tjommi.com/62.jpg Advance mechanism.

Flipped the center unit.
Marked the placement of the adapterplate (the one that connects the distributor axle to the crankshaft,) in case I had to unscrew it.

http://tjommi.com/65.jpg Marking posistion

Removed cotter pin.
Removed securenut and washer.

http://tjommi.com/66.jpg Removing securenut.

Removed the adapterplate from the axle with a 2 arm puller. I did not want to use to much force, so I just tightened up the puller, and applied some heat, tightened it up a little bit more and finally it popped off. Note that too much heat can damage the bearing seals and other parts.

http://tjommi.com/69.jpg Pulling adapterplate
http://tjommi.com/70.jpg Adapterplate

Removed seeger-ring that secures the bottom bearing.
Used a 3 arm puller to remove the bearing holder and bearing from the axle. While pulling the bearing of I wiggled out the Woodruff key.

http://tjommi.com/71.jpg Pulling bearingholder

Punched centermark in the 3 rivets that holds the bearing holderplate.
Drilled the rivet heads off. Then drilled out the center of the rivets and punched them out.

http://tjommi.com/73.jpg Punch marking rivets
http://tjommi.com/74.jpg Rivet heads drilled

Made countersink holes in the thin gold colored plate, so that I can assemble them with M4 countersink screws.

http://tjommi.com/76.jpg After countersunk bore

Knocked the bearing out with a socket.
Pushed a in new bearing (SKF 62202-2RS1). Used a little bit of heat on the holder, and a little freezing spray on the bearing, and I was able to gently push it in.
Secured the plate with 3 M4 16mm screws, and applied blue Loctite 243 (medium).

http://tjommi.com/77.jpg Old bearing with seal removed.

Exept from old grease, the bearing looked fine, so I am not sure if I needed to replace it.

http://tjommi.com/78.jpg Bearing mounted with new screws.
http://tjommi.com/79.jpg Bearing mounted with new screws.

Cleaned distributor body. Took out o-ring from the distributor topbearing holder. Cleaned it and replaced the o-ring with a 22mm x 2mm o-ring. This was the closest I could find, and worked well. Used a little bit of Molykote 55M on the o-ring.

http://tjommi.com/80.jpg Spider with new o-ring.
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Cleaned all the advance mechanism parts and the axleunit. Cleaned the spring assemblies one at the time to make sure I did not mix them up. Note that some of them have small shims, while others don’t. If you take away the paint markings, make sure to mark them again, so you do not mix them.


Put the bottom bearing assembly in front of my fan heater to heat it up a little, and applied some freezing spray to the axle. Pressed the bearing on by hand (if you need to use force, only apply it to the inner bearing race). Mounted the seeger ring. Mounted the woodruff key. Had to use a plastic hammer. Heated the adapter plate in front of the fan heater, and cooled the axle. Tightened the nut to 50Nm. I do not know the exact recommended torque, but the nut/axle is very similar to the flywheel on my Vespa where 50Nm is normal torque, and 50Nm is not too much for a normal M10 bolt. The hole for the cotter pin line up perfectly. Put on a new cotter pin.

Assembled the advance mechanism and greased it up with distributor grease, all parts except the top E-clip. Sprayed on some Loctite 3020 gasket “glue” on the new gasket.

I then pressed on the rotating plastic discs from Crane cams. Be sure to press evenly on whole top area of the disc. I used an 30mm oil seal tool (for mtb suspension forks).
Pushed on the E-clip.
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Fitted the optical trigger. This required some trial and error. I was not able to get the disc 100% in the middle (axial direction), because the top bearing holder touched the trigger. Had to fit it a little below middle, but there should be enough clearance anyway. Mounted the top bearing (608WII-2RS bought from Dinoparts.eu, measures: OD22mm ID7.95mm and 11mm width), again using some heat and cooling. Tapped it in place with a bearingmountingspacer and a hammer. Be sure that the axle is resting on the table, not the distributor body when you apply force. If not you may damage the bottom bearing.
Mounted the small seeger ring that secures the bearing and put on the top bearing holder.

I used a rubber grommet where the cable exit through the distributor, in the other hole I put a 8mm rubber plug. Used one of the threaded holes for the condenser, to mount a cabletie mount.

Since my Crane Cams unit were used, I had to make a new set of contacts. Went for some that are waterproof.

Before I put the distributor back onto the engine, I tuned the optical trigger to activate exactly when the rotor aligns with the mark. I had already hooked the Crane Cam up in the car, so I just connected the distributor to the ignition module, connected the battery and put the start key into position 2 (DO NOT START THE CAR). By looking at the LED on the ignition module I timed it so that the trigger activates exactly when the rotor lines up with the mark.
After that I installed the distributor on the engine, and made sure that the rotor aligned with the mark. Since I was sure that the trigger was aligned with the rotor, I used the LED to get it in the exact spot.

Note that I did not cover up the holes in the distributor, between the advance mechanism and where the points or now optical trigger is located. This was a mistake, that I will fix, because you do not want the grease from the advance mechanism to enter the distributor cap or mess up the trigger. The grease is probably sticky enough now, but who know what will happen after years of use.

I am going to continue about the Crance Cams unit placing and timing.
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I made made an aluminum baseplate for the Crane Cams XR3000 modules. Tapped threads for all the bolts and 3D printed some clamps to hold them.
I used a 2-3mm thick neofoam between the modules and the plate, and also put o-rings on the bolts. I only had titanium bolts in that size, but its a Ferrari so why not. Used blue loctite 243 (medium) on all the bolts, and also secured some of them with nuts on the bottom (just in case). After this I have read some places that the modules get hot. If that proves to be the case I will remove the neofoam between the modules and the plate, so it the plate can help cooling them down.

I placed them on the square frame tube that the coils are connected to.

They wiring is easy. You just follow the Crane Cam manuals. Remember that the tachometer cable ( i think mine was brown) goes on the negative side of one of the coils. Red wires from the Crane Cam modules to the plus on the coil, yellow to the negative side. Made a new ground mount in the frame for the ground cable (black). Then it only needs power from the car, this wire was yellow on mine. The rest (blue wires to the R1) and the R2 wires can be taped up and hidden.
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Regarding timing. This setup should basically be the same as running without the R2 points. Since most of the information regarding conversion to only R1 points, say that one should start with the 6deg (or 7deg) static timing, I did the same.

It was cold (around 5deg Celsius) and I had to use a some choke to get it started. First it started, and then suddenly died again, even though I pushed down the accelerator. After a while it started and after a warmup it was running ok. When my friend accelerated up the engine hit a "dead point" which needed excessive throttle to get past. It was not even close to the A5 mark (35degrees) at 5000rpm.

The workshop manual says that static timing should be 16 degrees BTDC, and the owners manual says 18deg BTDC. I only have an 18deg mark. The owners manual advance curve also says that the advance is 9deg (on the distributor) at 2500 rpm (on the distributor). As the distributor is only turning at half the rotation of the flywheel, this would be 18deg advance at 5000rpm. 18 deg advance from 18degree static is a total of 36 degrees, and the owners manual says that the advance at 5000rpm should be 35-36deg. So my conclusion is that the 6deg mark is for the R2 points, the 18deg mark is for static timing (or idle) and the A5 35deg mark is for timing at 5000rpm.

The reason that mine timing marks are so different from the other guides I have read is probably because I have an Euro version and the guides are mostly for US cars. As far I know they have the R2 timing mark AFTER top dead center, and the 7deg mark is for the static R1 timing. I will guess that the camshafts also are different, but I am not sure. From reading the US advance curve they also advance more.

So I adjusted the static timing to 18deg, and tried again. Still needed some choke to start up, but after that it was running fine. It was running very fine when we increased the rpm, especially after 2500-3000rpm. At 5000rpm the front distributor timing marked perfectly with the A5 35deg mark. The rear distributor was a couple of degrees apart. We did never go beyond 5000rpm, as the engine was running without load.

So then I consider that job complete for now.

The little bit of lack of advance on the rear distributor might be that I packed the advance mechanism with to much grease (inside the spring holders), so it might improve with time.
Anyway, I am now more convinced that I later this winter will move both the triggers into the same distributor, and also close the holes in the distributor body between the advance mechanism and the triggers.

 

Thanks guys. Your thread, carreaper, is very useful now when will put both triggers into the same dizzy. I will check out those Beru plugs.

If anyone should disagree with my conclusion regarding the timing, let me know. 18deg static seems much, but that is what I can read from the info and it worked a lot better.

 

Since the distributors did not advance identically, I have now put both the triggers into the same distributor. I covered the holes with some Kapton film and tape that will handle the temperatures fine.

I timed them static to 18deg, but at 1000rpm it was a little bit hard to get them perfect. The timing mark was jumping a little bit front and back (still within one or two degrees), so I focused on the 5000rpm timing (35deg). They should now both be on the 35deg mark at 5000rpm.

I have only tested the car in the garage, but the results are really promising. After a little warm up the engine runs great. It revs up perfectly, and the sound is amazing
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Today we had dry roads, and it has been raining a lot since they salted the roads last time, so I took the car out for a test drive. I recently bought the car, and the ignition had problems from the first time I drove it.
WOW! It is now a totally different car. It has a nice and steady idle, around 1000rpm as far as i remember and revs up perfectly. The sound is amazing. I can not believe this is my car If you do not want to convert to a system like the Crane Cams or Pertronix, I would recommend all 308 owners to make sure that the ignition system and timing is perfect, because the difference between before and after this fix is huge.

 

Thanks. I have already collected a couple of miles of smiles. I must correct that the distributors on my car are Marelli 159A, not Marelli 159B as I wrote in the beginning.