ignition timing help for newbe!

[chris-stockton]

heres a quick pic of the crank pulley, looks quite grim - whats the best way to sort this out?

[sidecar]

heres a quick pic of the crank pulley, looks quite grim - whats the best way to sort this out?

....Read the article on setting up the timing that I posted!

[mgbv8]

Have you just changed to the current carb set up?

Mike the chap has changed from a 2" filter to a 3" one. This in its self may change the AFR if the old filter was causing any sort of restriction but the change also has another knock on effect...

Basically lots of people run drop base filter bases and this can place the top of the filter very close to the mouth of the carb, sticking a 3" filter on then moves the lid away from teh carb and this can make a big change to the airflow. I don't know whether the OP is using a drop base, he could be!

heres a pic of the current one - i think this would be a drop base? also the second pic on the engine hoist is of the old base - which i think is also a drop base one.

Have you tried putting a 2" filter on that base with a straight edge across the top of the plate? The pictures may be deceiving, but it looks like that base plate drop is about 2" ??

I would say that would lean the engine out if its been jetted to match the airflow of the old setup before the taller filter went on.

I've only breezed throught the thread, But does it work ok with the 2" filter but then plays up with the 3" filter fitted?

If so I would be re setting the carb before playing with timing !!

I'm sure the lads will be along shortly to slap me down for not reading the whole thread properly

[chris-stockton]

ive got a new 2" one on order - i knackered the old one LOL

the only thing that i wont be able to confirm is what drop the old base plate had on it? they were both eddelbrock - so may well be the same?

[sidecar]

ive got a new 2" one on order - i knackered the old one LOL

the only thing that i wont be able to confirm is what drop the old base plate had on it? they were both eddelbrock - so may well be the same?

Edlebrock make the bases with differing amounts of drop so without the old one its impossible to say what its drop was. I did not realize that you had changed the base as well as the actual filter element.

[chris-stockton]

ah, damm, i thought the bases were all the same? OK, but im pretty sure that the bases are very similar, as i had to adjust the fuel inlet to allow the old one to fit correctly - there seems to be the same clearance on the new one.
Interestingly when looking at the recipts, the 14x3 was purchased with the carb in 2001. so at some point it has been changed to the 14x2.

But you are all right, that moving forward it will need a proper set up and likely re-jet on the rollers with maybe the 14x3 to get the full potential out the engine.

if i can get some more time out it on the possibly safer 14 x2 then that it what ill need to do until funds allow specialist tuning

[kiwicar]

Hi
A big change here is that before you had the air into the engine via the filter comming from the engine bay with the airflow originating in the "relativly" stable under bonnet area, the new set up has the carb and filter sticking up in the airflow . . . that is quite a change in itself, combined with the shape of that drop base it must be creating very odd turbulance across the top of the venturies, also you have changed from warm ait into the engine to cold air from outside.
I think a good start would be to provide a more stable airflow into the filter and into the carb sticking it out in the breaze like that will only lead to much grief in that it will not behave the same at different road speeds, secondly get a better air filter arrangment that does something about the closeness of the top of the filter and that lifts the filter to a similar level to the carb top. If the carb is 2001 vintage I would have it apart and clean it, check the passages for rot and give it a good clean, especially the transition arrangment and the "power valve" set up (I cannot remember what arrangment these things have for handeling cruise and full power metering).
Your carb is expecting a stable stationary unrestricted airflow to draw from at the top of the venturies . . . what you are offering it is not
Best regards
Mike

[sidecar]

Mike,

Just for your info not that it matters the Eddy carb uses metering rods which poke into the primary jets. When the vacuum is high the thick part of the rod is in the jet and as the vacuum drops a piston which is attached to the rod is pushed up by a spring, this lifts the rod so that the thinner part in now in the jet.

Regards,

Pete

[kiwicar]

Hi
What ever the arrangment it is not expecting to have a 70+ mph cross draught over the venturies
Best regards
Mike

[mgbv8]

With the air filter exposed it will ice up on the motorway in cold weather. Its even worse with a bug catcher

Anything below 13C and mine used to ice up quickly on the motorway.

[chris-stockton]

Hi
A big change here is that before you had the air into the engine via the filter comming from the engine bay with the airflow originating in the "relativly" stable under bonnet area, the new set up has the carb and filter sticking up in the airflow . . . that is quite a change in itself, combined with the shape of that drop base it must be creating very odd turbulance across the top of the venturies, also you have changed from warm ait into the engine to cold air from outside.
I think a good start would be to provide a more stable airflow into the filter and into the carb sticking it out in the breaze like that will only lead to much grief in that it will not behave the same at different road speeds, secondly get a better air filter arrangment that does something about the closeness of the top of the filter and that lifts the filter to a similar level to the carb top. If the carb is 2001 vintage I would have it apart and clean it, check the passages for rot and give it a good clean, especially the transition arrangment and the "power valve" set up (I cannot remember what arrangment these things have for handeling cruise and full power metering).
Your carb is expecting a stable stationary unrestricted airflow to draw from at the top of the venturies . . . what you are offering it is not
Best regards
Mike

Logistically im not sure how I would achieve all those things in the car. Even the original set up with 2 inch filter and drop base was sticking up a bit. Add to that the phenolic space that the phenolic spacer it badly needed plus a higher base. It wud stick out even further. Are there other filter arrangements for the webber 500s?

[mgbv8]

Hi
A big change here is that before you had the air into the engine via the filter comming from the engine bay with the airflow originating in the "relativly" stable under bonnet area, the new set up has the carb and filter sticking up in the airflow . . . that is quite a change in itself, combined with the shape of that drop base it must be creating very odd turbulance across the top of the venturies, also you have changed from warm ait into the engine to cold air from outside.
I think a good start would be to provide a more stable airflow into the filter and into the carb sticking it out in the breaze like that will only lead to much grief in that it will not behave the same at different road speeds, secondly get a better air filter arrangment that does something about the closeness of the top of the filter and that lifts the filter to a similar level to the carb top. If the carb is 2001 vintage I would have it apart and clean it, check the passages for rot and give it a good clean, especially the transition arrangment and the "power valve" set up (I cannot remember what arrangment these things have for handeling cruise and full power metering).
Your carb is expecting a stable stationary unrestricted airflow to draw from at the top of the venturies . . . what you are offering it is not
Best regards
Mike

Logistically im not sure how I would achieve all those things in the car. Even the original set up with 2 inch filter and drop base was sticking up a bit. Add to that the phenolic space that the phenolic spacer it badly needed plus a higher base. It wud stick out even further. Are there other filter arrangements for the webber 500s?

Fit a rear facing scoop for the winter.

[kiwicar]

Hi
A big change here is that before you had the air into the engine via the filter comming from the engine bay with the airflow originating in the "relativly" stable under bonnet area, the new set up has the carb and filter sticking up in the airflow . . . that is quite a change in itself, combined with the shape of that drop base it must be creating very odd turbulance across the top of the venturies, also you have changed from warm ait into the engine to cold air from outside.
I think a good start would be to provide a more stable airflow into the filter and into the carb sticking it out in the breaze like that will only lead to much grief in that it will not behave the same at different road speeds, secondly get a better air filter arrangment that does something about the closeness of the top of the filter and that lifts the filter to a similar level to the carb top. If the carb is 2001 vintage I would have it apart and clean it, check the passages for rot and give it a good clean, especially the transition arrangment and the "power valve" set up (I cannot remember what arrangment these things have for handeling cruise and full power metering).
Your carb is expecting a stable stationary unrestricted airflow to draw from at the top of the venturies . . . what you are offering it is not
Best regards
Mike

Logistically im not sure how I would achieve all those things in the car. Even the original set up with 2 inch filter and drop base was sticking up a bit. Add to that the phenolic space that the phenolic spacer it badly needed plus a higher base. It wud stick out even further. Are there other filter arrangements for the webber 500s?

Fit a rear facing scoop for the winter.

I would fit it in the summer aswell as you can't have the venturies out in the breeze like that and expect them to meter correctly
There are various remote filter arrangments for 4 barrel carbs, avoid the one from RPI that looks like a bed pan made of cast ally but pretty well anything that clears the top of the venturies by at least 2" and has a 3"+ inlet should work.
Something like this would help a lot http://www.summitracing.com/parts/hfm-ledt79/overview/ point it forward or to the back of the car, either way would get you a more stable air flow it is also big enough to offer a decent size filter and not have that drop base thing and the filter wont fill with water every time it rains!
or take what you have, put a metal ring in place of the filter, plumb in a piece of 3" tube to the back and stick a remote filter down in the nose of the car to one side of the rad.
Best regards
Mike

[Darkspeed]

Hmmmmm - having seen plenty of race cars with unfiltered carb tops at 180mph + I wonder just how much influence that actually has - especially with and air velocity through the venturi being as high as it is.

I imagine that the air filter does a pretty fine job of creating enough air restistance to mean that the carb still has to pull air through it even at 150mph.

Bigger issue would be dirt and flies creating resistance rather than excessive air flow problems.

Hi
What ever the arrangment it is not expecting to have a 70+ mph cross draught over the venturies
Best regards
Mike

[sidecar]

I also reckon that whilst not ideal the filter sticking up will be OK in terms of carburation. (It may have some affect).

It won't be OK in the rain though!

I still reckon the lean bog and possible the detonation is due to the fact that the carb can now breath a lot better.

Chris do you know whether the carb was purchased from RPI? if it was and they used one of their jet and rod settings then it is likely to be miles out. In my humble they don't know their 4rse from their elbow!