911 2.2 Tuning assistance questions

[keitho64]

I have a few questions for the knowledgeable Pelican Heads out there but first a little background.

The car in question is powered by a 2.2 with Weber’s, but I am not sure if it is a T, E or S motor. The engine has not been run in a long time (years). I have the carbs balanced as well as I can get them, but the number 6 cylinder is pulling less vacuum through the Unisyn at idle and 3000 RPM. At idle it is relatively smooth with minimal popping (exhaust). When you first accelerate, it will pop out the carbs (Intake) a significant amount and then eventually rev up. If you hold it at a steady rpm, say 3000, it will run smooth with minimal popping. The popping is slight in exhaust but not through the intake. The only intake popping occurs upon acceleration. The distributor is a Marrelli from a T motor and the car has new wires and plugs. I have neither adjusted nor checked the valves yet, but there is no valve train noise.

I drove the car this weekend some and you need to feather the throttle at first but once you get it running it will pull to 6000-7000 quickly and seems very strong. I should add that the car is running off battery power, as the alternator is not charging.

So here are the questions.

1. Is it possible the number 6 cylinder is low due to sticking valves and after being driven for a while it will clear out?
2. Is it possible the number 6 cylinder is low due to misadjusted valves?
3. If the car is running off the battery, is it possible the lack of initial acceleration is due to inadequate voltage?
4. The carbs were rebuilt before I ever ran the car. Is it possible I need to clean out the passages again due to dirt in the system? (The fuel filter looks clean) Since the car stumbles upon first application of throttle I am suspicious of the accelerator pump circuit. However, I do not know if the lack of voltage could be partially to blame.

Based upon what I experienced this weekend here was my plan of attack.

1. Check and adjust valves if necessary
2. Find source of charging problem and test drive after repaired.
3. If the problem(s) still exist remove and rebuild carbs then adjust again
4. If problem still exists return to Pelican for more advice.

So does everyone agree or disagree with my thought process? I will add that I have attempted to perform a compression test with ill fated results. After reviewing the posts here on compression tests I figured I would wait until I have driven the car some.

[A Quiet Boom]

Check for partially plugged idle jets and circuit on the number 6 cylinder. At 3000rpm free rev you're still operating primarily on the idle circuit.

[keitho64]

I noticed some weepping of gas from the accelerator pump so I just ordered two rebuild kits. I am going to go through the carbs and make sure they are all clean. I will post again after they are rebuilt.

Thanks

[jess p]

With a fully charged battery and not using any accessories,
ie radio,headlights or AC. You should be able to drive
approximately 65-80 miles on batt power alone.










66 912 350 sbc
66 912 2.7
76 911 widebody turbo

[Zendalar]

If you find out whats wrong with your cylinder number 6, please tell me also

I have recently (4 months) rebuilt engine and there is almost no vacuum at #6 on idle (the cylinder does not fire).

Heads/valves were done at this mechanic (all ok)
Cylinders honed
Rings new
Ignition system completely new
Valves adjusted
carbs cleaned (but I still suspect something is wrong..has to be)
New spark plugs (NGK)
New spark plug wires (connectors ok)
New distributor cap
Fuel system renewed (new pump, new fuel hoses, tank sandblasted, new filter)
Ground wires renewed.

I have adjusted carbs and checked air leaks and such like a million times, but still no vacuum at #6.

I had this same problem before rebuild, and I suspect the only place the problem could be, is the carb. This is because all the heads, cylinders, pistons, rockers etc have changed their place during the rebuild...still the same problem...

[CamB]

That Marelli distributor is a problem waiting to happen unfortunately. Tune up parts aren't available anymore.

It could even be related to your current issues (I don't have enough experience to tell).

[RoninLB]

Pelican sells a 2.7 RS dizzy for a great price..the dizzy works great w/carbs..I think PMO recomends it/or did........Ron

[si2t3m]

First i'd do a visual check to see what is happening on #6.

With the engine off, look inside #6.

Activate de linkage to see if the throttle plate on #6 is moving or not. (#3 and #6 are on seperate shafts and linked with the 2 other barrels on the carb with small allen bolts. 4&5 might be opening but #6 might stay closed.

Also activate the linkage to check if the accelerator pump jets is squirting fuel. Might be a good idea to measure the volume of fuel from the accelerator pump jets to make sure they are identical from side to side.

As for the the popping issues it appears to me that you might be lean on idle. i'd check the size of the idle jets. Any idea how many turn out you are with the idle mixture screws?

On my engine when I ajust the carbs (while turning in the idle mixture screws) , there is a point where i can hear it poping in the exhaust, just before loosing the cylinder and having the rpm drop.

You can check the idle circuits with the engine running. By turning in the idle mixture screws, slowly by increment of 1/4 turn and waiting about 10 seconds for the engine to react, you should loose that cylinder or at least have an rpm drop. If nothing happens and it's fully turned in, back it out completely. If nothing happends then the idle circuit is blocked somewhere.

http://www.pelicanparts.com/914/Parts/914-6/914-6_weber3_big.htm

shows a nice diagram of the idle circuit. Mine had theidle circuit blocked on 2 barrels in the 22 passage.

HTH

Marc-Andre Morin
70 914-6 conversion 3.0L Webers

[si2t3m]

Zendalar

I had 2 idle circuits completely clogged, it wasn't firing on those 2 but i still had vacuum activity on them.

I was figuring that if the valves are adjusted and opening when they should, the piston activity even with no firing should be pumping air.

Could it be sucking air from somewhere else like under the throttle plates? but you check it.

Does the throttle plate open when you play with the linkage on #6.

Could be that for some reason the intake valve is not opening or that the exhaust valve doesn't close all the way???

Just thinking out loud.

Marc-André Morin
70 914-6 conversion 3.0L Webers

[keitho64]

Marc

Thanks for the post. I should have stated that all 6 throttle plates open together. I checked them with a feeler gauge at rest and with the idle screw turned in. All three plates per carb are the same.

The car does have 55 idle jets. I upped them from 52. The mains are 125. I would also like to add that while I was working on the adjustments, I pulled the air bleed adjustment screw completely out of number 6 cylinder and nothing happened. There was no change in the idle, no vacuum leak nothing seemed to happen. I am new to webers but my gut tells me this is not right. I believe that the carb is obstructed in some way. I ordered the rebuild kits from Pelican yesterday so as soon as they show up I will rebuild the carbs. As for the accelerator pump I do think it is obstructed as well.

Since the car sat for a long time I am beginning to suspect dirt has made its' way into the carb.

Thanks again for the advice.

[Roland Kunz]

Hello

First to check would be the float level from the carbs and have the float wightet or just 4 new ones. Go trough the carbs first and have them preadjustet as good as possible. Don´t care to much on synchronization. Just turn it to run "smoth" when warm.

Then have the ignitionside checked and drive the car a bit. While you wait for cooling down to check the valves you can look at the face from the sparkplug and have messured compression or have a leak down.

Would be nice if you could checkwhat type of engine you have.
If the engine# and the type# are missing or your engine looks puzzled togehter then you can have a mixed engine with different heads or different pistons ( Everything is possible ).

After you set the valves maybe cheked the overlap timing, have a perfect ignition then you start synchronizing the carbs.

If you do that before its just waste of time

As you have low vac on cyl 6 I have to make sure you talk about the cyl 6 from the engine wich is on the passengerside far forward.

Grüsse

[keitho64]

I took both carbs off last night and here is what I found out, keep in mind the only carb that is dismantled is the driver’s side.

When I removed the passenger side carb I noticed there were some small (about 1/4") spacers on cylinder 4 and 5 but none on 6. I don't know how I missed that when I had the intake off before, but I did. Needless to say, number 6 cylinder was never sealed good. I am positive this is the cause of low vacuum on that cylinder. Nothing like a vacuum leak to make an engine run bad. The driver’s side had all three on. These look like they are to isolate heat. I was planning to leave them off.

When I tore into the driver’s side carb the front float bowl was dry and the back one was wet. Hmm, that explains why the accelerator pump was shooting air at times. Also, two cylinders had 120 main jets and the third had 125. I know all 6 cylinders have 55 idle jets because I put them in. This carb has 185 air correctors, F1 emulsion tubes and as I stated before the mains are mixed up.

Once I have the carbs rebuilt and installed I will let every one know what is going on.

Thanks for all of the feedback.

[keitho64]

OK Time for another update - I have been slow working on the 911 lately.

I have the carbs rebuilt and started with F1 emulsion tubes, 180 air correctors, 55 idle jets, 130 mains. I did find a lot of dirt in the carbs along with a host of other problems. I ran it for a while last night and it sounds better than ever. This weekend I am going through the adjustments of float, accellerator pump, balance etc. Then I can start putting some miles on it to see how my choice of jetting was.

I did check the vacuum on all cylinders at idle and 3,000 and lo and behold all 6 are pulling the same amount of air. The reason I had such low vacuum on number 6 was due to the fact that there were 1/4" spacers/insulators under cylinder 4 and 5 but not 6. Hence the vacuum leak.

Zendalar, I don't know if this would be the same on you car or not. All I can say is I had this apart two other times and NEVER noticed the missing spacer. Thankfully, I did not crack the intake bolting it down.

I did manage to install my new oil line, adjusted the valves and fixed a few other things.

Stay tuned (bad pun) for another update. It looks like I can at least dirve it some before snow flies. I can finish the interior over winter.

Thanks again for all the advice.

[Rich911E]

It better be running before the snow flies -- I'll need some excuse to get away from the relatives at Thanksgiving!

So, pictures?

Rich

[keitho64]

Well anything I can do to spare you from the relatives will be worth it. Just remember one thing...in November it gets cold here in Chicago, colder than it ever gets in San Diego. Hint, Hint.

I sure hope to have it done when you are here. Maybe you can tell if this thing has S cams or not. The least I can do is have it ready for you to drive.

[keitho64]

OK Findings to date are:

It looks like the motor is a 2.2T but I am suspecting it may have E or S cams. The car pulls so strong to 7,000 that I have to wonder. Also, the intake and exhaust ports have had some porting done. The exhaust ports are close to 35MM in diameter and the intakes are close to 33MM.

I have the Webers rebuilt with 60 idle, 130 main, F1 emuslion, 185 air correctors (but I am installing 180's tonight), 32MM venturri. All 6 barrels are pulling equal vacuum.

I was driving the car some just to warm everything up and start the break in process. The car pulls very strong through 3 gears(7,000 indicated on the tach seems effortless). I did not push it harder as the speed was building faster than I was comfortable with at this time. The first few hard runs emitted a lot of smoke but the more I drove it, and the HARDER I pushed it, the smoke cleared. I suspect the rings are starting to seat. The car begs to be driven HARD!

The only two items that are keeping me off the road are the lack of brake lights and the alternator that will not charge. The brake light switch is on order and per my Pelican order status it is on the way. I plan to take the alternator off tonight and try to find a local shop to test/rebuild it. If things go as planned I will be able to drive this weekend.

I wish there was some way to bottle the aural pleasures of the flat six singing at 7,000. It even impressed my son who commented on the sound.