• Hi Guest!
    You can help ensure that British Car Forum (BCF) continues to provide a great place to engage in the British car hobby! If you find BCF a beneficial community, please consider supporting our efforts with a subscription.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

1500 mg midget, weber dgv carb & affect on timing

Share this page

R

recordsj

Jedi Warrior
Offline
What do people know about a 1500 mg midget that has a weber dgv carb on it on how it affects where you set the ignition timing. I was told by one person that with a weber carb, it likes to have the distributer rotated to advance the timing by 10 deg or so for the engine to work well. So in other words if the stock ignition timing is supposed to be 10deg BTDC, then set the ignition timing to around 20deg BTDC.

Can anybody confirm this and/or provide any insight here?
 
Fail to understand how the carb setup can have any effect on the timeing.
 
I vote no direct relationship.
 
Hers what the problem is Im sure. The Weber DGV is a very complex carb. (In comparison to an SU) It has pin holes inside the throat that are mostly completely covered when the throttle plates are at an idle. These holes control your vacum advance. Mainy weber carbs that are not jetted correctly will have owners overcompensating for an idle by means of teh adjustment screw. By uncovering more of the pin hole you increase the vacum.. I have seen alot of these conversions where they adjust the timing so the vacum advance seems to work correctly all because they were improperly jetted or had worn throttle plates. To understand that carb go to pierce website and dowload all the tuning instructions. Then when you get it reight, be prepared to start all over next year.
 
If you start at 20BTC you are going to be way ahead by the time your mechanical advance finishes up. It really depends on what type of distributor you have but that could be way too much advance. Like some have said...the weber will have ported vacuum for the vacuum advance. Some distributors are set up for manifold vacuum for the advance and some are set up for ported vacuum. I think it makes the advance curve a bit different. I would start by researching the distributor model number to give some idea what it will be doing to your advance. I have a spreadsheet with tons of distributor model numbers and the stock advance curves if you want.
JC
 
What I have is a PDF file. I can't attach it here. I think I got it from Telgerizer but if you need me to I can email it to you. Just let me know the email address.
JC
 
Back
Top