This cap looks the same as the new ones I have. The numbers marking the wires (1-4) are missing as they are on the new caps, and they are present on the old ones. The pic shows 3 new screws, our new ones did not have new screws. Other than that I can't tell much from the pic. The new caps are marked 115518R. As I stated before, I cannot get the jaws of my calipers inside to measure the terminals accuately, but as close as I can tell the caps are the same. I don't need the calipers to see the difference in the rotors. There is a clearly evident difference in the rotors, which is why I keep coming back to them. Just to verify again... 115518R and 119396 are the correct part numbers for an '80 GTBi 2 valve injected cap and rotor, right? No ambiguity there? Bill
A while back, actually in the 80's Ford had a problem that was issued in a service bulliten. They had rotors and caps made of different material. They were identified with a color blue and black. They stated that you could not mix the cap and rotor of different colors. The material had a different expansion rate. They would cause rotor failure and or cap failure. Any way, I have another item you may want to check. My feeling is that is probably the rotor. Check the brass retaining tab in center mounting hole. Measure and compare to the old rotor. If it is not retained correctly on the distributor shaft. The rotor could possibly be off center. This could also give you the problem you are having. The weekend is here Good luck
The original rotor is green, and the original cap is black. All the new parts are black. There is no brass retaining tab in the mounting hole on these rotors. The rotors are a snug (not tight) slip fit over the end of the cam. When the screws are in place all 4 of the rotors had almost no play. All seems OK there, but it was a good thought. An interesting point here is that (on the Ford parts at least) the tolerances are tight enough that difference in rates of thermal expansion is enough to cause problems. Those are pretty small numbers. Bill
I got a bit more data today. I set the engine up at TDC then took some clay and pressed it onto the #1 terminal in the cap. I installed the cap then removed it to check clearances in the cap. Here's what I found: Old cap, old rotor - 0.035" gap between the rotor and the terminal old cap, new rotor - 0 or less (it scrapes) new cap, old rotor - 0.045" gap new cap, new rotor - 0 or less (it scrapes) I'll check the new parts when they arrive, then probably file down the new rotors until they no longer hit as Dave suggested. Doesn't seem like I should have to do this, but it looks like the only way I am going to get parts that fit. Bill
Where did this rotor come from? Do you plan to install it any time soon? If so I'd recommend getting some clay and checking the gap before you turn the motor over so you don't break anything. It would be real interesting to see what your rotors do in your cap, since my new rotors hit in both old and new caps.
Played with it again yesterday. Set it up on #4 and checked both front and rear distributors. Results were consistant with above. The old rotors clear the terminals by 15 to 45 thousandths on both front and rear distribs. The new rotors contact all the terminals on both front and rear distribs.
Bill - When we last spoke, you had ordered some new rotors through a different supplier (if I remember correctly). Did they arrive? Do they fit better? Best, Daniel
No, still waiting for parts. I don't expect them to fit out of the box, I'll probably have to trim them down. Bill
New rotors came in a few days ago. They worked with no problems out of the box. http://b.shaw.home.comcast.net/ferrari/2rotors.jpg Both parts in the above pic are the same part number, but as you can see the one on the left (the new one) is quite a bit shorter. Bill
This whole episode is quite bizarre..... Something to be aware of in future I suppose..... Can you terll us where the rotors came from?
Those rotors were not available for several years and I suspect whoever is making them now (despite the fact they say MM I think they are being made by someone else) is not holding good tolerences.
They was from me, and came over in the inventory from Sodacoms. Unfortunately, I had no capacity to notice "oh these particular rotors are 1mm off". Most of the rotors I have are still in Marelli blister packs; these were in a big unmarked box. I have about 30; I'll just toss them all in the garbage I suppose.
I just put some brand new Marelli OEM rotors on a customer's 80 308. The car leaves Monday to go home, but if it's not too hectic....I'll measure them up. They are damn expensive.....I saw yours after we purchased these and was kicking myself in the butt. I really like to offer my customer less expensive alternatives that do no sacrifice quality. d
I don't think I'd toss them. There was a plan about 2 years ago to have them remanufactured as they have not been available for a few years. It sounds like yours are older than that so they are prob NOS. I don't know if the plan to make them ever came to fruition so you might have some very rare parts on your hands. MM has been known to have the occasional QA problem, if I was you I would just get out my calipers and give them a little QA myself now that you know what to look for and see that they get put to use. Even the one that was too long, a belt sander or a little careful file work will make that one just fine.
Shoot me an email with your mailing address and I'll gladly send you some for free. I'd like to really know whether this is an isolated incident, or if they all blow goats.
In the pic I posted previosly the one on the left, the 'good' one, came from trutlands. I'm with Rifledriver, I wouldn't toss them. A little grinding and they should work fine. That was my plan, but the trutland parts didn't need to be trimmed. I checked the plastic as close as I could and they look like they came out of the same mold, down to the fine print. The difference is in the way the metal tip is mounted in the plastic. I measure under the lip, dead center (actually, slightly off dead center to miss the square hole there) of the tip to the plastic and get 0.100" on the trutland part vs 0.146" on the ricambi. The important thing here is they have to be checked before installation to be sure you're not going to break something.
