To you guys with a 6 cylinder... I'm helping a friend trying to get his rebuilt 1970 911T going. He has 40 webers and MSD ignition. The carbs are rebuilt and squirt gas. We're getting a strong spark. We've set the Z1 mark at the housing and #1 lead on the distributor to the notch. At first he was off 180. We fixed that. With starting fluid we might get a little action but hardly any. We've turned the distributor some both ways but nothing. Any ideas? Thanks

I wish I could help you, having had numerous 911s over the years, but you're at the wrong place. Try RMG in Sunnyvale CA. I think it's Sunnyvale. How are things down there in Texas? I've never been there myself. Can you still legally drink & drive?

Check the cam timing. Maybe it was set up wrong in the rebuild.

Typically cam timing are the issues when they don't start. 1 cam off does it.

Thanks for the quick replies. That's what we're afraid of: the cam timing though he (we) spent a lot of time believing we got it right... it did try and start but would not keep going. I suppose it would do that on 3 cylinders (given that only one cam is off).
Usually if you have spark, starting fluid will get the show going.

Keep in mind that #4 is 180 out when # 1 is at TDC and # 1 is at overlap when #4
is at TDC
Cam position is measured at overlap.

I've set my timing on initial rebuilds 5 degrees btdc. Sometimes seem to need a hare more and then reset once cams are broken in to full advance at 6000rpm at 30 degrees. These are mechanical injection engines with bosch distributors. You may have a marelli and I think they are set to 35 degrees full advance. I agree cam timing may be your issue but think you would have already bent valves if it was off, may want to check compression.

All good points made above.

One thing you did not describe - fuel delivery. What's the set up and do you have a regulator and gauge close to the carbs? too low a fuel pressure might cause what your seeing. I don't recall the pressure needs for the Webers offhand, but might be worth verifying you're seeing 4-6PSI at the carbs.....

Also: double check the firing order + plug wire connection. Be frustrating to drop the engine to check cam timing only to find you had two plug wires swapped ;-)

- Tony

something I can tell you from recent experience. you need to set the distributor very carefully. I did a bunch of dizzy swaps not so long ago and in the process on one installation I ended up one tooth off. I've put in a LOT of distributors in these motors and I was having a distributor problem and had a few to choose from. I just rushed it once. I twisted it around a lot. still didn't start. pulled it out. started over. problem solved.

If that doesn't do it and you have both fuel and spark, then sorry to say sounds like one cam is likely 180 out.

Kelly

He did have the dizzy off 180 and was getting a few spits and pops. As for the cam timing I helped him with, when we were done there was no interference. Everything rotated smoothly. Could we be a pin hole off (on the cam gear) and have no interference? I do wonder if one of the cams is off a hole.

I don't know if he has a fuel pressure regulator. I'll have to check. We checked all six carbs. They all squirt gas.

As far as the distributor being a tooth off... does that make a difference? Isn't the main thing that the rotor lines up with the mark on distributor? One thing we're not sure of what part of the blade of rotor do we line up with the notch. On my 914, I put it at the middle.

Cam timing can be checked easily with engine installed.
Simply remove the intake valve covers and install the dial indicator.
Even easier...check the compression or do a leakdown test.

rgalla9146... that's a good point, we could check the intakes. Not as easy as when it was on the engine stand but pretty doable.