prawnabie
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| posted on 20/12/08 at 04:51 PM |
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Crossflow ignition timing
Hi Guys
Im trying to set the ignition timing on my crossflow.
Specs are
234 cam
twin 40 webers
1300 pistons
rally spec electronic distributor w/o vac
1700cc
I have set it to 10 dbtdc with my timing gun but it pops through the carbs and exhaust. It is also getting very hot very quick as the paint its
bubbling on the head by the 2 centre exhaust ports.
at what rpm does the need to be set ans has anybody got any tips?
Ta
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Memphis Twin
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| posted on 20/12/08 at 05:28 PM |
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Forget about setting it at idle. Being as you have a timing gun (strobe) I would suggest that you need a fully advanced figure (4000rpm +) of 34 degs
BTDC.
Cheers Chris
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David Jenkins
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| posted on 20/12/08 at 05:36 PM |
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That's a brave approach, especially when it's overheating at idle!  
I did my 1600 x-flow at idle, vacuum connection to the dizzy removed, and (I think) set to about 10 degrees for unleaded (it's got a
modified-for-unleaded head). Looking at the Haynes book, it shows 3 different settings - 1.3 LC and LC economy engines = 12 degrees, 1.3 HC and HC
economy = 10 degrees, every other kind of 1300 = 6 degrees. Are you sure you've picked the right target?
If you've set your idle near-enough right, I'd check that the car isn't running really lean. A colortune is quite useful as a
moderately accurate indicator.
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quaybook
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| posted on 20/12/08 at 05:48 PM |
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Ignition timing
Your ignition is too far retarded. Try 14 degrees at idle. As the previous post says, you need 34 to 36 degrees at 4000+ rpm, then check carefully to
ensure that it does not pink under load.
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prawnabie
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| posted on 20/12/08 at 05:51 PM |
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Hi
Thanks for the advice. The carbs were off the original engine (1660cc crossflow) so im hoping they should be near enough for me to get it running
without overheating until I can get the car finished and to the rolling road.
anybody else got a similar spec engine?
Thanks
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prawnabie
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| posted on 20/12/08 at 06:45 PM |
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HAHAHA MUPPET!!!
I painted the tdc mark white instead of the 12 mark.
I'll get me coat!!
thanks to all who helped!
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David Jenkins
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| posted on 20/12/08 at 06:53 PM |
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britishtrident
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| posted on 20/12/08 at 08:12 PM |
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If it is over heating at idle its is too retarded. Try this set it to 5 BTDC static , then do some road tests advance the iginition a little
at a time untill you hear pinking when accelerating from about 1200 rpm in 3rd gear.
When you detected pinking you know the ignition is too adavanced so retard it 2 to 3 crankshaft degrees.
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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