bravenrace
Jedi Hopeful
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Hi guys,
I have a '74 TVR 2500M with the TR-6 engine, and have a couple questions the TVR guys couldn't answer. I bought it in non-running condition and have just recently got it running. The carbs were rebuilt by Apple Restorations (I think that's the name) and never run before I bought the car.
I did a complete tune up and the car runs smooth. My questions:
1. I have not been able to sync the carbs. There is a huge airflow difference between the front and rear carbs that I can't adjust out. If I check the airflow at 1500RPM, it is equal in both carbs. I tried sync'ng them with the sync tool and by ear, and wasn't successful. The engine idles and runs smoothly, has good compression and pulls a steady 18" of vacuum. I've never driven a stock 2500M before, but the car does seem a little slower than I'd expect for a car with this power to weight ratio, but that's the only thing that might point to a problem. Otherwise it runs great. Any ideas as to why the carbs won't sync?
2. The distributor has a vacuum retard, but no vac advance. The retard is disconnected.
The only change from stock is that I installed a pertronix ignitor. I'm getting 10 degrees of mechanical advance, and am running 15deg of initial advance. I don't have a lot of experience iwth these engines, but do with other types of engines. From my experience, an engine like this should be running a lot more total advance than 25 deg. I'm thinking more like 35 deg total. Looking at the advance mechanism, everything looks like it's working fine. I could change the springs and get the advance in earlier, but it seems that unless I were to modify the weights, there's no way to get more mechanical advance. So my question is, what is the appropriate timing curve for a stock 2.5L engine? I'd appreciate any insight you can provide.
Thanks,
Jim
I have a '74 TVR 2500M with the TR-6 engine, and have a couple questions the TVR guys couldn't answer. I bought it in non-running condition and have just recently got it running. The carbs were rebuilt by Apple Restorations (I think that's the name) and never run before I bought the car.
I did a complete tune up and the car runs smooth. My questions:
1. I have not been able to sync the carbs. There is a huge airflow difference between the front and rear carbs that I can't adjust out. If I check the airflow at 1500RPM, it is equal in both carbs. I tried sync'ng them with the sync tool and by ear, and wasn't successful. The engine idles and runs smoothly, has good compression and pulls a steady 18" of vacuum. I've never driven a stock 2500M before, but the car does seem a little slower than I'd expect for a car with this power to weight ratio, but that's the only thing that might point to a problem. Otherwise it runs great. Any ideas as to why the carbs won't sync?
2. The distributor has a vacuum retard, but no vac advance. The retard is disconnected.
The only change from stock is that I installed a pertronix ignitor. I'm getting 10 degrees of mechanical advance, and am running 15deg of initial advance. I don't have a lot of experience iwth these engines, but do with other types of engines. From my experience, an engine like this should be running a lot more total advance than 25 deg. I'm thinking more like 35 deg total. Looking at the advance mechanism, everything looks like it's working fine. I could change the springs and get the advance in earlier, but it seems that unless I were to modify the weights, there's no way to get more mechanical advance. So my question is, what is the appropriate timing curve for a stock 2.5L engine? I'd appreciate any insight you can provide.
Thanks,
Jim