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Posted: Thu Mar 04, 2010 7:13 am
by 911hillclimber
The bangs are certainly through the exhaust Gary, about 9'' of flame spat out!
Nothing spits back out of the carbs.
If it were a valve then it would be rough everywhere I feel, and the tick over straight after starting was so smoooooth it was very impressive.
As things heat-up you might look to ignition ober mixture?
The spark from the dizzy top was absolutly huge, 20mm of fat blue lightening!
The spark on one plug checked was big and fat too and the engine does not miss when running.
It has always been hard to start, much harder than my old 2.2T on webers.
From warm/hot it used to start very well.
The idle mix adjustment are the neeedles with the lock nuts on I think towards the top of the carb outer body?
I might open a few turns more on each carb (after noting where Bob left them) and see if a bit richer might help.
Can have a play fri pm when the neibours are out and about.
We woke the village up last night.....

Posted: Thu Mar 04, 2010 8:02 am
by davidppp
Hello Jon.
I really do suggest you go from square one: compression, (and leakdown ideally too), ignition (did it actually go onto a Crypton/ Sun etc..an old fashioned type with a CRT?, do you have a strobe?, what do the plugs look like and do check each exhaust stub.), then and only then mixture( did it have lamba readings each bank?).
One of the problems I know is the sheer noise!
FWIW my money is on sparks still.
Its just too tempting to duck hunt I know..unless you have a full set of known good bits its very costly..and is still possible never to klnow the diagnosis..
Kind regards
David
Posted: Thu Mar 04, 2010 8:07 am
by MikeB
If it is not spitting back through the carbs, then the idle is not too weak. A flame from the exhaust indicates that either unburnt fuel is getting into the exhaust or a valve is not closing when the sparkN fires
Posted: Thu Mar 04, 2010 6:23 pm
by 911hillclimber
If a valve is cracked open wouldn't the engine always run 'rough'?
Once started and cold it ticked over just great.
Also Mike, when the engine was last racing it ran great on near new 46mm webers which sadly did not come with the engine when I got it.
The one big thing changed is the carbs and the racing headers!
Posted: Thu Mar 04, 2010 7:13 pm
by MikeB
OK
The fact that the engine runs well when cold and seems to perform OK at top end would rule out a bent valve. Certainly, if it ran on 46s before, then the 40s are going to choke it a the top end (hence the lack of overall power.
It has all been said before by others, so all you can do is the basic tests David has mentioned to check the mechanical side and then see what the RR exhaust gases analyser says re the mixture.
As to the PMOs, all I can say is that Mr Parr knows his stuff, and the set up he provided for mine hasn't needed to be adjusted. EFI with a crank fired ignition is going to need a whole RR session to set it up, so you need to factor that into the cost. But here's hoping you get the current set up sorted next week

Posted: Thu Mar 04, 2010 10:18 pm
by 911hillclimber
The game behind the 40's was to give a torquey engine at the expense of outright power.
Several knowledgable people said this was a good move and would work well.
The Bruce anderson book puts this right on the edge of the 3.2 and close to 46's.
The 40's have 36mm chokes (as recommended by Rich Parr).
The whole set-up is ok by me if only it ticked-over without the explosions.
Just ordered the NGK P5ES's to see if they might work better. Only £11 the set delivered off ebay.
Obviously i do need to check everything before calling rich and spending a cool $3K on the basic carbs (£2400 landed in my garage)
The PMO's are the simplest swop, just unbolt the old, bolt on the new.
Imagine if it still popped after that expense....

Posted: Sat Mar 06, 2010 7:38 am
by 911hillclimber
Got the plugs out (again...) on the flame side and all 3 are exactly the same colour and surface 'texture'
ie clean!
I've also been distracted by the steering wheel position on the car!
It has always been uncomfortable in as much that the wheel sat too low into my lap. I'm not a fat guy or a skinny one either so I sat in the car and positioned the wheel in space where I thought it the most comfortable.
It was 3.5'' higher and 1.24'' to the right!
This makes me feel far more inside the car, more room to the gear lever and more elbow space for those hero opposite-lock slides..
So the hacksaw came out and the entire steering column mounting cut out and a new one fabricated.
This clears even more space from under the front roll hoop and looks a whole lot better.
Bit of welding, bit of painting and the car will be ready for Hi-Tech on wed for the truth on the carbs.
I'll either be smiling or sulking, but not given in!
Posted: Thu Mar 25, 2010 9:01 pm
by jwhillracer
Must be a lot of work going on, Graham, this had nearly slipped off the bottom of the second page.......................
Did you get your drive in the Rally car at Loton? Any more news? I know one car came back to Cornwall in kit form
Cheers!
JW
Posted: Thu Mar 25, 2010 10:20 pm
by 911hillclimber
The 'Weber Saga' overtook everything!
I've 'refined' the gear change yey again this week and even added a bias spring to hold the lever in the 1st-2nd plane to try to add a little 'car' feel to things.
Will be starting the thing tomorrow to see how it is now, and to try all gears with engine running.
Re-fit the body and clean/polish and all is ready about 3 weeks early!
Roger had a Caterham at Loton all weekend, but will be bringing the orange 911 to the Party in the Park event to celebrate the 50 years of Loton and 75 of the Club.
I'm on a promise for a run that day....
I think you refer to the fab Pilbeam from Cream County. If so, that was a strange failure of the rear -end. Watched it unfold.
Starting to get ready in the mind now for 2010.
sports car class could be very light this year......

Posted: Fri Mar 26, 2010 4:59 pm
by 911hillclimber
While the kids were at school, the housewives sitting with their feet up etc I decided to start the Lola from cold to see how it fares...
I would appreciate some tips on starting a big 911 on webers from cold.
I used to use 2 prods of the pedal and churn over, just catching the first glimmers of a fire. Any advances on this?
Anyway it eventually fired after a few pops and after a little tickle of the carbs it settled to a steady tick-over of about 1000 rpm.
After a few mins...no bangs.
After 5 more ...silence, just the steady purrrr
After 15 as

above!
A few healthy blips and still all is good. Not a pop in the ears at all.
Spurred-on by this landmark, I polished the body for some bling and sorted a few bits.
Down to small items to improve on.
Spurred-on some more, and sat in the thing, pressed the re-engineered clutch system comfortably down and the gear snicked into all 4 without a bulk or a crunch. Test drove each gear all of 12'' along the garage, but this IS progress!
Time will tell if this all hangs together at Prescott in a few weeks time.

Posted: Fri Mar 26, 2010 5:04 pm
by jwhillracer
Great news Graham! Yes, 2 - 3 pumps on the throttle first, and then catch it as it fires up. The early 911's (like yours and mine) and the 914/6 have a hand throttle for warm-up, but you'll just have to sit in there looking cool and blipping the throttle.....................
Cheers!
Jonathan
Posted: Fri Mar 26, 2010 6:01 pm
by hot66
911hillclimber wrote:
Anyway it eventually fired after a few pops and after a little tickle of the carbs it settled to a steady tick-over of about 1000 rpm.
After a few mins...no bangs.
After 5 more ...silence, just the steady purrrr
After 15 as

above!
A few healthy blips and still all is good. Not a pop in the ears at all.
superb news

How many different 'experts' did it go through until you found someone who could actually setup/ tune the carbs properly ?
Posted: Fri Mar 26, 2010 6:30 pm
by 911hillclimber
I went through at least a dozen on here!
I am very grateful to all those on this excellent forum for the help in my Weber Thread, but it was only in the last month that things fell into place starting with a chat to Andy at Webcon at the Retro Show.
His thoughts were to give a lot of guidence.
Then to Matt for pushing me to contact Mick at Hi-Tech and the loan of his webers; was that good advice!
To Mick himself; Old Skool, no non sense and knows what he is up to.
Last year I had hoped I would have got this far after two full Rolling Road sessions, but there we are. Going back I hoped I had a good set of carbs!
A lot of hope here and little to show until Hi-Tech except about £1000 of messing
Put it down to experience.
On tick-over, you can feel all is not well with the one side, the pulses from the silencers are uneven side to side and the one is much cooler, but it runs, it is quiet and that is enough for 2010.
I know all is ok on full circuit, and 224 bhp in 510 Kg = 440 bhp/ton
It will be a serious challenge to get the best out of it.
Thanks for the starting proceedure Jonathan, will test it tomorrow.
We go racin' in 3 weeks time!

Posted: Fri Mar 26, 2010 11:07 pm
by Matt black70
Glad to here all is still well Graham.
When I start mine after standing for a while it tends to like a more heavy footed approach. Rather than 2 or 3 prods try 4 or 5, I then lightly pump while cranking which works well. I find a light tickle is needed once firing until it clears it's throat, probably until the float bowls have fresh fuel. As your car is under carbed you may fine a heavier foot helps.
When and where is your next run?
Cheers
Matt
Posted: Sat Mar 27, 2010 6:50 am
by 911hillclimber
Prescott Matt in late April- 24/25th, then Shelsley on 1/2 May, then Loton on 15/16 May all assuming I get an entry.
Prescott will be a test of the gear shift for sure!
Shall I hang onto the webers for a while or return them asap?
