350i distributor vacuum connector

350i distributor vacuum connector

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Discussion

KKson

Original Poster:

3,395 posts

124 months

Thursday 23rd July 2015
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Right I've been checking all I can on the engine to track down the intermittent misfire. This evening I gave the dissy a good look over and found the vacuum advance section to be loose and rattling around so I've tightened that up. One think I noticed is that there appears to be a second vacuum connection on the back of the diaphragm as pictured. The main vacuum hose fits to the front of the unit. Any idea what this second one is for? Is it merely to allow the diaphragm to move freely, i.e. open to atmosphere or am I missing some plumbing?
Thanks.


mike various

234 posts

120 months

Thursday 23rd July 2015
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On both of my cars that has been blanked off with a rubber cap.
Not sure if it does anything .

mrzigazaga

18,534 posts

164 months

Thursday 23rd July 2015
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Hi Keith mine is just open to atmosphere ...Just a thought...If you have the original dizzy on there then that could be failing..Especially if your are running a bit on the rich side at 36-38psi fuel...I had a friend who developed a mis-fire...I think it was between 2500-4000rpm...And was running fairly rich...It was so worn inside that when he pulled off the rotor arm the dizzy shaft popped out with it..He put it all back together properly and timed up the car but it was getting worst...He has just fitted a new dizzy that came with a rotor arm..Cap and coil for £100 and it has transformed the car completely...He also had what i have now...When parking the car seems to want to stall each time that full lock is applied in reverse....Mine has what looks like the original dizzy...Possibly...Just a thought mate...I guess there are a few test to be done before confirming it....Cheers...Ziga

bradderztvr

364 posts

146 months

Thursday 23rd July 2015
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Keith, my old distributor which had the old SD1 remote amp and the newer one I fitted a year ago with amp fixed to it (probably like yours), have both got an open ended steel tube like yours in the photo, so would suggest that's ok.

KKson

Original Poster:

3,395 posts

124 months

Thursday 23rd July 2015
quotequote all
Thanks for the reply gents - one less thing to worry about.

I've got some proper electrical terminal/contact spray coming tomorrow so I can give the resistor, AFM and ECU contacts a proper clean up. New coil arrived today but I'll see if cleaning the contacts does the trick before I swap anything else. I'm assuming that the very loose ignition amplifier and equally loose vacuum advance unit probably also won't have helped!

KKson

Original Poster:

3,395 posts

124 months

Saturday 25th July 2015
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Right, definitely something very wrong with the distributor! No wonder the ignition amp and vacuum advance have shaken themselves loose! I'll try a new cap and rotor arm but I'm thinking a new dissy is probably the best way forward.

http://s148.photobucket.com/user/keith_knight1/med...

mrzigazaga

18,534 posts

164 months

Saturday 25th July 2015
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Keith that vid of the dizzy...Is it bolted down properly?...If it is and its moving like that i would most certainly say you do need a new one...

Number 7

4,101 posts

261 months

Saturday 25th July 2015
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it does look like the whole body is moving, not just the cap - the clips look like they're in place. As Mark says, is it bolted up tight?

KKson

Original Poster:

3,395 posts

124 months

Saturday 25th July 2015
quotequote all
It is bolted up tight - it's just the cap and rotor arm that are moving. If I grip the central spindle it wobbles around in all directions. I think technically it is indeed censoreded

bradderztvr

364 posts

146 months

Saturday 25th July 2015
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Keith,
Changed my distributor when it caused starting and running problems.
The centre shaft had alot of play if tugged up and down.
If you've got excessive movement, it probably is fecked so sadly time to replace. Think i bought a Powerspark one from flea, user name something like "Simonbbc", based in Bromsgrove. Very helpful on the phone. Cost about £90.

gmw9666

2,734 posts

199 months

Saturday 25th July 2015
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bradderztvr said:
Keith,
Changed my distributor when it caused starting and running problems.
The centre shaft had alot of play if tugged up and down.
If you've got excessive movement, it probably is fecked so sadly time to replace. Think i bought a Powerspark one from flea, user name something like "Simonbbc", based in Bromsgrove. Very helpful on the phone. Cost about £90.
Yes these guys are very helpful and only 20 mind from me. I bought a vacuum advance unit from them. Very helpful

Top tip, they have in store a "sales bin" full of parts that have lost there box or something so deals to be had if you ask for something from the sales bin. When I was there they had a handful of V8 dizzy in

Worth asking if nothing else

KKson

Original Poster:

3,395 posts

124 months

Saturday 25th July 2015
quotequote all
bradderztvr said:
Keith,
Changed my distributor when it caused starting and running problems.
The centre shaft had alot of play if tugged up and down.
If you've got excessive movement, it probably is fecked so sadly time to replace. Think i bought a Powerspark one from flea, user name something like "Simonbbc", based in Bromsgrove. Very helpful on the phone. Cost about £90.
Hi Roger and Glen, new one ordered from the man at Bromsgrove - £103 including new high power coil. Away camping for a week from tomorrow, in the pouring rain, so will have to have a look at this when I'm back.

GOG440

9,247 posts

189 months

Monday 27th July 2015
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KKson said:
It is bolted up tight - it's just the cap and rotor arm that are moving. If I grip the central spindle it wobbles around in all directions. I think technically it is indeed censoreded
I had this too
I had a horrific misfire that wouldnt go away until my mechanic went to pull the rotor arm off and the shaft moved with it. One new dizzy later and it was perfect.

mrzigazaga

18,534 posts

164 months

Monday 27th July 2015
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Keith the same thing happened to a fellow Wedger and one of his symptoms included smelling fumes inside the car...Like really strong like an over-fuelling..He pulled his rotor arm off and the spindle came with it...He also was getting an intermittent mis-fire..I think this may of been the cause of your fuel fumes smell in the boot and the slight over-fuelling on the dyno...If the spark is not strong enough then it will not be enough to burn the fuel efficiently...Leave your fuel pressure at 38psi WOT and replace the dizzy...You won't believe the difference it will make...I think mine is on its way also...I guess most will be now due to age...

gmw9666

2,734 posts

199 months

Monday 27th July 2015
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May as well join the new dizzy club as well lol

Inspected my rotor arm, couldn't get it off, stuck solid

Spindle wise nice and tight but it would not spring back when you turn the arm like it should. You can turn the arm by hand about 30 degs so the advance will be totally screwed and all over the shop

And also a prime contender for my dyno over fueling

Moving house Friday so can't do anything until next week when I've some time

bradderztvr

364 posts

146 months

Monday 27th July 2015
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All this talk of new dizzies will I fear lead to the great timing debate seen on here before, and the possibilities or suspicions of fly wheels having markings out of Line.
All i would say is, i cranked the engine so piston 1 was at full compression and top of stroke,(used a pencil in No1 spark plug hole to measure top of stroke) with the rotor arm roughly pointing at point 1 on the dizzy cap.
Borrowed a timing light and with the use of tipex on the fly wheel and timing pointer, adjusted to 8 degrees BTDC as per TVR manual.
Runs great.


TVRleigh_BBWR

6,552 posts

212 months

Saturday 1st August 2015
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Best way to check TDC is to use a piston stop, as even with a dial gauge you get a dead spot.
You can make one from an old spark plug.

KKson

Original Poster:

3,395 posts

124 months

Saturday 1st August 2015
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Just back from a weeks camping so Wedge is very much in the dog house and unloved due to its lack of reliability. Tomorrow it's bonnet off, all plugs out, TDC found, and whipping the old knackered dissy out. New one has been delivered to my office whilst we've been away so will get that on Monday and fit Monday or Tuesday evenings.

KKson

Original Poster:

3,395 posts

124 months

Sunday 2nd August 2015
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Right, I've pulled the old dissy out today - some play in the bearings side to side but not excessive however there's a good 1/4" vertical play. If I suck on the vacuum advance it advances and then sticks and does not return to original position, if I rotate the shaft there's a nasty clicking noise and the rotor arm is noticably distorted also which is interesting. It's actually the distorted rotor arm that's causing the dissy cap to kick about.

New dissy was delivered to my office Friday so I'll fit that hopefully tomorrow night, if taxi service for the kids allows.

celcius

688 posts

254 months

Monday 3rd August 2015
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Hi keith
Good luck , let us know how you get on ..