STROMBERG HELP

[gearbox]

Hi All;

Rebuilt my Stromberg CD175's on my 1970 Plus 2 (early 69 build) 50/1171, and see that the "Jet Adjusting Screw" is not the type that I am familiar with as all the ones I had worked with in the past had a screw adjustment slot with lock nut or just a float chamber plug. It seems that the one I have is like the jet adjusting screw internally, but without the screw, rather just a nut protruding out the bottom. I screwed the unit home and now it seems that I am not getting fuel to the engine. Does anyone know if these have to be screwed out and if so, by how many turns for initial set up? Thanks, any help would be appreciated, as of now, I have not found any information about the jet adjusting screws I have, Allan

[gearbox]

Here is a better view of the Jet Adjusting Screw I am asking about. Is this supposed to be seated "home" or does it serve as an adjustment and is screwed in and out? And if so, what would be the initial set up? 1 turn, 2 turns, 3 turns out? Thanks Allan

[nmauduit]

I have not messed with strombergs for a while, plus there exist a number of variations, so am not likely to be of much help I'm afraid...

I'm assuming that during rebuild you made sure that the needles were centered with the jets, and that the carbs operate smoothly all the way. You may want to double check piston travel, then with piston all the way up if the jet holder can be screwed further up (are the 2 carbs identical regarding the position of that nut? could the round brass part be seated further up? can you check proper needle location with respect to the jet from the carbs opening?).

that said, the photo triggered a question to me :
could it be a modified/replacement cover of an emission model (protecting a non openly adjustable jet) ?
http://www.howacarworks.com/fuel-system ... arburettor
http://www.howacarworks.com/fuel-system ... arburettor

last, since the car does not run (I suppose you've already tried to get it to run on the last known working position), maybe you could take the brass nut out and look exactly what is behind...

[Craven]

Hi,
I would guess you have carbs that have been modified by the manufacturer to meet the emission control requirement for a non-consumer adjustable unit. Adjustment of mixture of this type pre-set by
1, the jet is set at a predetermined height in the body.
2, Variable position of the needle in the piston.
I suggest the nut should be fully home.
I?m sure there must be plenty of info out there giving details of the adjusting tool needed and how to use it.
The workshop manual does give info on a jet height setting rod.
FWIW
Ron.

[gearbox]

Thank you all for the input. I also believed that the adjusting jet screw should be tightened home. The brass nut is attached to what looks exactly like the adjustable version of the jet and not just a plug, but there is no signs of any adjustment that can be made, unless there is something under the spherical cap on the bottom of the nut . All I did was soak it in carb cleaner, blow it out with air, and replace the rubber O rings on the part. Both carbs are getting fuel, but the plugs are dry as a bone. I am getting 165 PSI across all 4 cylinders and all the vacuum ports have been plugged except for the headlight vacuum tank which I will try today. Could a leak here be that great as to not allow the engine to have sufficient vacuum to suck the fuel in? I could only hope and will let you know my findings. For a system this simple, I can't believe it is not working. I'm thinking I must have overlooked something completely obvious. But thanks again and any further suggestions would be appreciated, Allan

[Craven]

Hi,
If you think your problem is no fuel passing the main jet, you could try using a finger to lift the piston from the bridge. This should at least wet the plugs if nothing else when the engine is cranked. May need an assistant!
Ron.

[gearbox]

New issue. Took the carbs off and double checked everything. Floats are still set at 16mm with the carb upside down from the surface of the gasket to to the highest point of the floats. Found a clump of dirt in both the bowls which was strange as everything was cleaned and blown out before hand, fuel pump rebuilt, new hoses and inline filter. So cleaned out everything again and blew compressed air through everything. Now it seems that I am getting fuel spitting out one of the vent holes on only the front carb. See picture. From what I see, this is a vent for the bowl, and the fuel is squirting out in unison with the the fuel pump pumps. Squirt squirt squirt. But in examining the float valve again, it does shut off. The fuel pump is the standard glass bowl pump and was rebuilt with an AC rebuild kit. But I am thinking that either the new float valve is bad or the pump is putting out more the 2-3 PSI required. But again, it is only happening with the front carb. I have a fuel pressure regulator with gauge and thinking of that putting on, but leaning towards a bad valve. But it test out as well as the back carb which is not leaking. Any thoughts? Thanks Allan

[gearbox]

Success! The engine started on the first crank. Combination of issues. Seems like the brand new float valves that I installed was the problem. After the 3rd time going through the carbs, I decided to swap out the valves with the old ones and it fired right up. The other issue was of my own causing as I noticed the dab of anti seize I put on the spark plug threads had made its way to the electrodes which allowed it to spark, but I guess it was not hot enough. Now to pack it away until I get back in November so I can pull the engine and replace the ring gear. Yeah the gear reduction starter I got with the car chewed up the second one so I have the old Lucas being rebuilt. The fun just never stops lol.

[nmauduit]

glad to read that you're going forward.

regarding the ring gear issue, there could be a compatibility issue (number of teeth on pinion and ring) that you may want to look into, see for example : lotus-twincam-f39/starer-ring-gear-teeth-t32121.html

[gearbox]

glad to read that you're going forward.

regarding the ring gear issue, there could be a compatibility issue (number of teeth on pinion and ring) that you may want to look into, see for example : lotus-twincam-f39/starer-ring-gear-teeth-t32121.html

LOL, yet another unresolved mystery which there are so many opinions on. Is it 10 tooth or 9 tooth pinion? 110 tooth or 135 for the ring gear? All of my Lotus I ever owned had the 9/110 combination and the same with this Plus 2. The issue was the PO was diagnosing some unknown issue with the car which caused him to pull out every wire, electrical component, including the starter, alternator, regulator, solenoid, etc., and a carb, 5 years ago before falling ill, leaving the car in a disassembled state. Prior to that, I was told the car was recently restored and running fine. I was unable to determine from the family what he was chasing, so all I could do was to systematically go step by step, and replace all the parts he removed and test along the way. The ring gear was shot when I received it and the gear reduction starter was in the trunk. When it was re-installed in the car, it did crank the car for a short time before just grinding and spinning in place. Replaced the ring gear with the same starter, and it worked well, but the sound wasn't right. But thought to first address the Strombergs. Given the issues I had with the Strombergs, there was goodly amount of just cranking and no start. Not a crazy amount, nor did I ride the starter more than 6 or 7 rotations and allowed more than ample time between attempts, but soon thereafter, it started to first grind, and then spin. It had once again removed teeth. I found the original old Lucas starter in the pile of parts and cleaned it up and it bench tested good. So installed that and the sound was so much more pleasing and worked great and was able to start the engine. But then the pinion started to "Stick" in the ring gear on the compression stroke and lock the motor if it did not start right away. I am assuming that the gear reduction starter wore out all the teeth facing front of the motor and the old Lucas engages from the rear, so there was some material left on the ring gear for it to work until it didn't, and now the pinion gear is getting trapped on what is left on the peaks of the ring gear. Pulling the engine is pretty much a one day affair on these Plus 2's so ordered a new ring gear and a rebuilt Lucas starter. But for now, I have run out of time and have to go back to work. So when I get back in November, I hope to have a few nice days to pull the engine again and then sort out the wiring nightmare. BTW, from what I have determined, the wiring harness in the car is from a later model using an alternator so none of the wires are the correct colors or laid out in the correct locations. The fun just never stops lol. Thanks Allan

[rgh0]

Some pre-engage starters sold for twin cams do not actually throw far enough to fully engage the flywheel teeth so after working for a while they start to chew out the teeth and finally not engage.

cheers
Rohan

[gearbox]

Rohan, I believe you are correct. I had three of these gear reduction starters, one that came with the car and the other two brand new in the box, and they all measure identically. From what I had seen of the 2nd ring gear, the damage appears to be on 80% of the teeth facing forward. When I installed the Lucas starter which engages from the rear, the ring gear had just enough meat to engage until it too finally wore out and started to jamb the teeth of the starter. But when I first engaged the Lucas, it sounded so much better so will be rebuilding all my Lucas starters and staying with them until I figure out how much to remove from the flange of the gear reduction starters. You would figure they would have figured this out by now lol. But luckily it's in a Plus 2, so pulling the motor is easy.