lotustwincam
|
| posted on 25/6/06 at 08:52 PM |
|
|
Ford Bosch/Valencia Distributor
Has anyone tried modifying the advance curve on the Valencia distributor.
I'm looking for info on dismatling the dizzie, plus what springs to use and how much to limit the total advance by? Want to try to get it as
near as possible right the first time as the carbs have to come off each time to remove the dizzie.
Engine is 1660cc Crossflow, with approx 11.25CR, big valve ported head, Kent 244 cam, lightened, balanced, twin 40 DHLA carbs, etc.
Thanks in advance for any help offered
|
|
|
|
|
paulf
|
| posted on 25/6/06 at 09:26 PM |
|
|
I used one on my crossflow before fitting megajolt, it may be ok on a standard engine but as you imply the total advance needs to be reduced for
correct operation
I found it an easier option to fit the megajolt as it gave me 3d mapped ignition , shift lights and soft rev limiter.
The cost works out at about £120 for the megajolt and ford parts then you need to fit a trigger wheel available off ebay for about £20.You can then
adjust the timing at will without any dismantling etc or even whilst driving.
Paul.
quote:
Originally posted by lotustwincam
Has anyone tried modifying the advance curve on the Valencia distributor.
I'm looking for info on dismatling the dizzie, plus what springs to use and how much to limit the total advance by? Want to try to get it as
near as possible right the first time as the carbs have to come off each time to remove the dizzie.
Engine is 1660cc Crossflow, with approx 11.25CR, big valve ported head, Kent 244 cam, lightened, balanced, twin 40 DHLA carbs, etc.
Thanks in advance for any help offered
|
|
|
lotustwincam
|
| posted on 25/6/06 at 09:44 PM |
|
|
Thanks for your prompt reply.
Megajolt is most likely the way I'll go at sometime in the future (like next year), but having blown my budget on the engine I'll have to
make do with the valencia distributor (which I already have) for now.
The dizzy mod sounds simple enough, but I can't find any info about dismantling the unit or by how much I need to limit the travel.
Like I say, the carbs and manifold need to come off (even to just remove the distributor cap), so I want to try my best to get it right first time.
Drew
|
|
|
02GF74
|
| posted on 26/6/06 at 08:47 AM |
|
|
there is somewhere on the web a tming curve to be used without a vacuum type disstributor, whcih ideally ius what you want when running twin
weber/delos.
I know I have a print out of it at home, just need to find it....
|
|
|
Syd Bridge
|
| posted on 26/6/06 at 09:00 AM |
|
|
If you take the vacuum off,(and you probably would with webers), then you should find two springs on the advance weights underneath the plate. The
lighter spring is the initial advance. Leave it alone. The heavier spring needs to be annealed, or heated to orange hot, then allowed to cool in air
slowly. This will soften it and allow the advance to increase. You can buy fancy spring kits with loads of different springs to fit, but what I put
above can work and does.
Cheers,
Syd.
|
|
|
paulf
|
| posted on 26/6/06 at 09:33 PM |
|
|
I found a basic map that suggested 12 degrees at idle increasing from1000rpm to max 36 degrees at 3500 rpm .Syds idea sounds feasible as the initial
advance will still be gradual and then final amount would come in sooner but you would still need to limit the maximum advance by building up the tip
of the rotating advance lever by the correct amount . Maybe you could check advance at 4000 rpm with existing set up then weld a bit on and check at
same revs then work out the final amount to add on to get the correct amount of final advance
Paul..
|
|
|
lotustwincam
|
| posted on 26/6/06 at 10:10 PM |
|
|
Thanks for all the suggestions.
I know its a reasonably straightforward mod. I was just hoping that someone might say that i need to reduce the movement by X.X mm to limit the total
advance, and replace the heavy spring with the light one out of "such and such" a dizzy.
In the absense of that info, your idea seems sound Paul about measuring the current total advance before making any mods. At least that should reduce
the number of times the distributor needs to be removed from the engine.
Drew
|
|
|
.jpg)
