Advice needed

[breskit]

I'm running a Rover V8 3.5 with Weber carb and my problem is that the exhaust and plugs keep coking up, indicating that the engine is running too rich.

I have the car tuned (mobile tuner) and have fitted new plugs/ht leads, timing is now sort, CO levels are good yet the problem persists.

I'm inclined to think that the air/fuel mixture is still not correct, but don't know if this is at idle or when running. I have a 2" air filter fitted to the top of the carb (perhaps a larger one would help).

There were a couple of things that the tuner did notice. Vaccum advance on the carb was poor, and he thought the valve stem seals needed replacing due to some smoke at startup. I have a new vac. advance and will be fitting this soon. Would the valve seals have some impact (but what about the plugs)?


The carb wsa supplied by RPi and should be correctly jetted for the 3.5. Perhaps it's just mixture, but I would have thought this is what gets adjusted when the engine is tuned (not just timing).

Any help is much appreciated.

Thanks,
Tony B
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http://homepage.ntlworld.com/tony.breski

[kdavies3]

Tony it sounds like your engine would benefit from a session on a rolling road with a good engine tuner.
Unfortunately a mobile tuner will only be able to set your idle mixture correctly which is obviously not where your problem lies.
on a rolling road they can check the jetting at other driving conditions and change it to suit.
If the black deposits are wet and oily it would suggest that your engine is showing it's age.
If it's black and dryish its probably just mixture related.

Do you have a local rolling road?
Tinka had his done recently and it made a real big improvement.

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Kev Davies
Dax, 383ci Chevy Stroker, Tremec TKO
South Wales

:tu :tu :tu

[breskit]

Thanks Kev. The deposits are black and sooty (dry), there is no oil deposits or similar. Every time my trousers/jeans touch the end of the side pipes, they end up looking a mess.

There is a rolling road in the town I live, so I may give them a try.

Cheers,
Tony B
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http://homepage.ntlworld.com/tony.breski

[Andy302]

Tony,

For future reference wheres the rolling road?

Cheers

Andy R
Proper Planning Prevents Piss Poor Performance!

[SimonP]

Tony,
How old is the carb?
It may be worth you obtaining a service kit from a Weber agent.
These carbs are very sensitive to float level, it may be that the carb has suffered a jolt in transit and bent something slightly.
This will affect the primary and secondary main jet fuelling, but not affect the idle circuit so much.

Also the accelerator pump diaphragms can split too.

If it's always been like this, ask someone else what the jetting should be, then check the jet types against what you have fitted.

Rover V8s nearly all smoke a little, just at startup, because the valve stem seals aren't exactly efficient. As long as you don't have a blue cloud behind you when driving, and your HC emissions are OK, there's no problem.

Also, you have a manual choke carb. Looks like Edelbrock 1404, I can just make out the number on the photo! Sometimes if you don't use a choke cable, the choke flap will move freely. Wire it fully open if necessary.

Did you ever run it with the SUs?

Simon.

[maxGD059]

>Sometimes if you
>don't use a choke cable, the choke flap will move freely. Wire
>it fully open if necessary.

Other option is to take the choke out completely as a lot of people do. The Edelbrock 500 tends to over fuel anyway so starting usually isn't a problem

Cheers

Richard
(Hillclimb convert)

[breskit]

Thanks guys.

Andy, the rolling road is on Cheyney Manor Ind. Est. Can't remember the name of the garage, but a drive by will remind me. I'll try and check it out later this week if I get a chance.

Simon, the carb is less than 2 years old and has only be used on the road for 6 months (only completed my build earlier this year). The engine did run, once upon a time, on SU's, but I replaced this with the Weber as it looksmuch nicer. I guess this year I'm trying to sort out as much of the running in problems that I can so that next year is much better 8^).
The carb was well packed when it was sent to me and so I don't suspect that it could have been damaged (not with that amount of bubble wrap!!).

The choke is manual and it is fitted with a solid inner cable. Works fine. Why would you want to permanently wire the choke open? Surely this would give an even richer mixture, no? (or is flap open, choke closed??)

Cheers,
Tony B
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http://homepage.ntlworld.com/tony.breski

[kdavies3]

Flap open is choke off, flap closed choke on.

Remove it all together, you don't need it.

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Kev Davies
Dax, 383ci Chevy Stroker, Tremec TKO
South Wales