more overlap means more fuel, less compression well less fuel but nto neccisarily.

 

Leaning your map out in the vacuum area is normal for a rebuild. Your motor now is trying to idle at 1000rpm's at a higher map area causing the rich condition. Did you have to adjust your idle screw to get it to idle? The bigger the port the less vacuum the motor with have. The idle will come when the seals "break in".

How much did you port the motor?

chuck

 

I ported it a fair bit.. only a street port, but went a bit silly with the exhaust port hight, I think anyway, don't have much to compare it too...

And i'm just about to go and try to adjust the idle screw now to get the basterd to idle...



but yeah anything lower than 1,000rpm and it doens't sound too happy...

 

even with everythign good with exhaust ported up some it wont wan to idle at less then 1k, thats pretty normal for a streetport, its not gonna idle all that smooth with aport

 

https://www.nopistons.com/forums/ind...howtopic=35643

How big is your exhaust ports compared to this?

going to rebuild another motor with bigger exhaust ports and bridge the secondary ports.

chuck

 

is that upper black line the lower part of it stock?

 

sleeper7, mine are roughly the same timing as those i'd say..

maybe open a bit earlier..... and different shape, more square.



and yeha I didn't think it would idle totally smooth, which is fine, i like lumpy idles



I've just got it to idle at about 1,500.. I got it down to 1,000 but it wasn't too happy, will need to do some more fiddling with the microtech map tomorrow, got a maths lecture in an hour so I can't do much more today...



I actually had to richen it up some and also open the idle screw alot!!

 

i am pretty sure u have vacuum leak/s, spray that carb cleaner!

 

Umm you sure? because I had to open the idle screw to allow more air in?



I would've thought that if I had a vacume leak just simply richening it up would work?



But when I close off the idle screw thingy it just dies?

 

it shoudl idle at 1k MAYBE 1200 because of your port, but i doubt it

so just check for vacuum leaks, with higher rpm teh engien makes enouf vacuum to be happy thats why it idles better at higer rpm, and with lower rpm u have a leak thats why it cant make enouf vacuum. unless of course the map is way off but doesnt soudn like it is.