I participate with at least NG and all are chatting or helping with something, this one seems to have gone into hibernation.
I've just spent the last two days getting a V8 to run smoothly by tinkering with all of the bits and pieces bolted to it, plus I have given it a good service as well. I've never worked with so many cylinders at once :-))
I also dug out some test kit I bought in the seventies,made by Lucas and Gunson, to check RPM etc last time I used it was on my 3.0 litre MK1 Capri. I also got the heater working well so quite chuffed with myself. Next weekend I am going to manufacture a U tube so that I can balance the carbs so food colouring in water should make it look professional don't you think.
In lieu of a manometer, try pushing a small diameter pipe into the carbs (in turn) as far as possible and listen carefully to the air being drawn in. When both sound the same, they should be pulling equally, and balanced. I presume it has twin SUs or Strombergs fitted. I remember that if a slide were to be physically lifted ever so slightly, say with a twist of a screwdriver, and the engine revs rose, then the mixture was too rich. Conversely, if the revs dropped, the mixture was too weak. Revs remain the same means the mixture is OK. This technique worked well and was quite noticeable with single carbs, twins may be a little more subtle. I bought a ColourTune plug back in the mid 70s to set SUs and Strombergs, although you may need two. It resides in a drawer in my shed and was last used when I "re-jetted" a carb after soldering them up and micro-drilling them out.
I have a Gunson Glass plug of my own which I must admit I forgot about but I do know where it is. You should be able to do it with one as setting the mixture is done before setting the idle speed of both carbs with the piece of pipe. If she is presently out balance then she will fly when correct as it aint sluggish at the moment especially as she is an Automatic. I have really enjoyed the last two days sorting out the little niggles and there is nothing nicer than doing fifty to the sounds of a V8 :-))
Martin P
In lieu of a manometer, try pushing a small diameter pipe into the carbs (in turn) as far as possible and listen carefully to the air being drawn in. When both sound the same, they should be pulling equally, and balanced. I presume it has twin SUs or Strombergs fitted. I remember that if a slide were to be physically lifted ever so slightly, say with a twist of a screwdriver, and the engine revs rose, then the mixture was too rich. Conversely, if the revs dropped, the mixture was too weak. Revs remain the same means the mixture is OK. This technique worked well and was quite noticeable with single carbs, twins may be a little more subtle. I bought a ColourTune plug back in the mid 70s to set SUs and Strombergs, although you may need two. It resides in a drawer in my shed and was last used when I "re-jetted" a carb after soldering them up and micro-drilling them out.
Having fiddled with many a Rover V8 I have also played the same game of raising the piston to see which way the revs went (though I couldn't recall which way was which). The SUs on my Rover P6 had a little spring loaded lifting button for doing just this.
The other thing is to go on plug reading - but beware. The manifolds on many V8s are split plane, and serve the two central cylinders on the opposite side, and the two furthest apart on the same side (or is it the other way around - I can check in the garage if it is an issue as I have a Rover V8 manifold with twin SUs sitting there - and a V8 engine too). If its not a Rover I suspect the same is still likely to apply.
Finally - I had one V8 that a pub Landlord had trouble with in a Rover P5B. The engine had been recently rebuilt and I spent an afternoon (plied with free beer) trying to get it to run sensibly - and failed. It turns out the timing chain was one tooth out! I now fit duplex timing chains on any V8 I rebuild, and after discovering the crankshaft timing was 6 degrees out on my Land Rover V8 I now will always use a dial gauge to get the crankshaft timing right.
But the V8 I am most interested in was advertised in Cerdigion a few weeks ago - a black Vauxhall Monaro. I might just trade in my V6 Calibra for that - it wasn't yours Martin by any chance ??
The SUs on my Rover P6 had a little spring loaded lifting button for doing just this. (clipped)
Steve
-------------------------------------------------------- For a single carb if the piston is raised by approx 1/32".This should causea slight momentary increase in engine speed without impairing the even running.If the engine stopsmixture too weak ,if revs continue to increase if piston raised more mixture too rich. The above to be carried out at a increased idle setting Mike.H
I've spent a few hours restoring a plug tester I bought at Enstone. First 8 pics.
formatting link
A very good example of pressing into service an ex WD device - ie, the late
1920's aero engine starter magneto. The rest of it is based upon a bit of box section steel pipe & a few proprietary fittings.
For a short period of time I was in office today but not long enough to visit, will see you Friday. Just tried on my second only suit owned by me a DJ with shirt and tie, got married in first. I look proper dapper I does.
How about classic electronics then ? I have been running Boyer Bransden electronic ignition on my 1969 Norton Dommie for about 25 years (I bought the bike in 1978). It cured an awful problem with the Lucas 6CA ignition system, which not only allowed you to run different timing on each cylinder, and allowed the points cam to wobble about all over the shop giving variable timing due to a nasty needle roller bearing, but it also spilled oil on the lower set of points, making it very hard to start. These days I have more engineering ability, so I could probably modify the bearing and seal arrangement but back in my student days the electronics were a quick and easy fix, and have never given trouble.
However, the programmable efi is not on a classic vehicle, its on a
1988 Land Rover - which by my standards is a new vehicle - its a bit of a rolling test bed for experiments, efi is one of them (mainly because I couldn't stand not knowing how efi worked), the tuned engine is another, programmable timing is going on at this moment, dual batteries plus inverter, LPG may be another in due course. The other efi is on a V8 Marcos - thats the way it came from new. However, I think that is a Joseph Lucas (Prince of Darkness) unit, and as a result may stop working at any moment. Don't worry, when I get this out of my system I will likely revert back to diesels (or steam) - but the Norton stays as it is for now.
Has it got an alternator Martin? IIRC Rover V8's were all so equiped or have you gone back to a good old dynamo?
Are the carbs SU's? If so, forget the gadgets and rubber tubes and do it by ear. Best way there is and, yes, I did have access to all the then modern stuff in the 70's coutessy of a relative who was a Crypton salesman with a complete demo rig. I still do the Mini (twin 1 3/4" su's) and the MGB that way.
High class cars of the day came fitted with Alternators, the carbs are SU's and as I have never had to balance carbs before I shall be using my brothers Vacuum gauge, which he told me yesterday he has. I had a bucket fitted to my MK1 3 Litre Capri so never had any of this technical stuff to do, to be honest I don't think she is far out because she idles and pulls quite nicely. Just playing really :-))
There are two aspects to balancing multiple carbs, air flow and mixture. You have to set one, then the other, then the first agian and so you alternate between the two settings hopefully changing them less each time you check. Remove the air cleaners and anything else that stops you seeing into the carb inlet. Get the engine warm and let it tick over for a few mins to settle. Start by slackening the throttle linkage between the carbs and make sure the butterflies aren't being held open by the choke, friction or anything else. Old oil is a frequent culprit. Set the tickover up to about 1000rpm roughly the same on both carbs. Lift one piston about half way up and note how much the revs drop. Let that piston down and settle then do the same with the other. the revs drop shows how much work each carb is doing. Adjust the throttle stops until each carb drops the same revs when the piston is lifted. They are now doing the same work. Now set the mixture by lifting the piston about 1mm. If the revs rise and stay up it's rich, if they fall and stay down it's weak, if they rise a little but stay about the same it's correct. Adjust the mixture by the brass nut around the jet under the carb. It should be about finger tight. Do this for each carb. Now go bak and adjust the air flow again as it will have altered slightly. Then do the mixture again. Unless things are wildly out, two trips round the system should be enough. When you're satisfied, drop the tickover by an equal amount on each carb. Tighten up the throttle linkage making sure there's no slack on one carb. Replace the air cleaners etc and you're done.
The theory about raising the piston so far is that it weakens the mixture so far that carb does nothing so the drop in revs represents the work is WAS doing. You MAY be able to lift the piston far enough on the pin underneath (for mixture setting purposes) but that depends on the car. Try it and see.
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