| Author | Message | ||
     Randy Roberson Frequent User Username: wascator Post Number: 896 Registered: 05-2009 |
Gents, I am back on the ‘77, trying to figure out why it runs as if one carb is lean. I removed the carb assembly, looking for any cause I might identify. Rather than a gasket on the downstream side of each carb, I find a hard plastic item approximately 0.225 inches thick, slick on either side. It looks like it might be intended to reduce heat soak to the carbs. Should this be gasketed with thin paper gaskets on either side? There is no sign of a gasket nor sealer in this joint. The parts lists and views in the Technical Library do not show my arrangement: my car’s carb outlet tee to manifold has two separate egr inlets and it is not clear as to the gasket arrangement. R | ||
| Jeff Martin Frequent User Username: jeff_r_1 Post Number: 693 Registered: 07-2018 |
I don't have a Shadow, but I installed the heat sinks on my MK VI, and they need a gasket on both sides. I believe they're bake-lite, not plastic. I've seen some of them with permanent asbestos/pink gasket on one side. (you supplied the other gasket) From experience with RR manuals and revisions/improvements, not all things make it into text. I think RR assumed that the people working on their cars would have a certain amount of knowledge to realize there should be some gaskets on either side of the heat-sinks. My Jaguar is no different, there are no diagrams of the heat-sink either. | ||
| Randy Roberson Frequent User Username: wascator Post Number: 897 Registered: 05-2009 |
Albers supplied a replacement which is two pieces which together equal the thickness of the Bakelite piece in my car. One side is green like some gasket material and the rest is white. No paper gaskets were supplied; in fact I thought I was getting two thin paper gaskets for the spacers I already have. If what you say is correct, I will need three paper gaskets per carb. Sheesh. | ||
| Jeff Martin Frequent User Username: jeff_r_1 Post Number: 694 Registered: 07-2018 |
A photo of what you have from Albers would help. The spacers that I used in my Jag and Bentley were hard on both sides, and if used that way, they would not seal _ gaskets were needed on both sides. The ones from Albers may not need any gaskets. | ||
| Randy Roberson Frequent User Username: wascator Post Number: 900 Registered: 05-2009 |
Got the carbs back together, and could not test because the fuel pump would not run. Went out this morning, turned the key on, and the pump started very quietly to pump fuel. No fuel leaks noted, so I started her right up. The engine is not smooth as it should be, even with a cold start. When the choke started opening she leaned out and got rougher, and finally died. She will restart on the choke and exhibit the same behavior; and will keep running if the choke is mostly on manually. I don’t know what else to try except professional assistance. | ||
| Jeff Martin Frequent User Username: jeff_r_1 Post Number: 696 Registered: 07-2018 |
Disconnect the weakener system from each carb and try again. If still no success, make sure that the pistons move freely in the dash pots. (is there oil in the damper tubes, there should be, most use ATF here) If they do, remove both dash pots and pistons (do not get them mixed up and be careful of the jet needle). Look down into each carb and make sure that both jets are the same distance from the top of the jet bridge. If one is level with the jet bridge, or near the edge, then that's the problem. What is the history of the carbs, did this start doing this on its own one day, or were they rebuilt and now it's doing this ? | ||
| Brian Vogel Grand Master Username: guyslp Post Number: 3385 Registered: 06-2009 |
Also, for good measure, disconnect the anti-run-on solenoid (or, I guess I should say the vacuum line from it) as well. Brian | ||
| Randy Roberson Frequent User Username: wascator Post Number: 901 Registered: 05-2009 |
Hi, gents: I have disconnected the weakener system; in fact I disconnected all vacuum and plugged the source tube; no change. This began spontaneously and not in conjunction with any repair, tuning, or tinkering. | ||
| Jeff Martin Frequent User Username: jeff_r_1 Post Number: 697 Registered: 07-2018 |
You didn't say if you checked where the jets are in relation to the jet bridge ? Given that, does the car have points, or the Opus Lucas electronic ignition ? I'm running out of ideas. | ||
| Robert J. Sprauer Frequent User Username: wraithman Post Number: 858 Registered: 11-2017 |
A 77 would have the Opus which are known to get wonky before they final go. | ||
| Randy Roberson Frequent User Username: wascator Post Number: 902 Registered: 05-2009 |
Opus is gone, replaced by a Pertronix setup. Although looked at, the specific check of the position of the jets in relation to the jet bridge has not been thoroughly done; I need more knowledge before I am comfortable knowing what to do. | ||
| Jeff Martin Frequent User Username: jeff_r_1 Post Number: 698 Registered: 07-2018 |
The SU carbs are not complicated, although at this point, it's unlikely the problem. All the fuel out of each carb flows out of each main jet in each carb _ you can clearly see them when you remove the dash pots along with the pistons and the jet needle along with the pistons. If you want to make the car run rich, the jets are lowered below the jet bridge, and to lean things out, they are raised. They should not be level with the jet bridge, not enough fuel would be pulled into the engine. Both jets should be relatively in the same position. So you're running a Pertronix ignition, was the coil changed/wires/rotor ? Sometimes new coils can become faulty depending on the quality. There are many new rotors that are junk, I get mine from here. Did your check the spark too on the suspect side of the engine that appears tp be running lean ? Spark should be bright blue to white, not orange. https://www.distributordoctor.com/red-rotor-arms.html | ||
| Randy Roberson Frequent User Username: wascator Post Number: 903 Registered: 05-2009 |
Thanks for all advice; once home from Disney Orlando, I will begin pursuit of these items. |
