blown alky sbc advise needed !
Discussion
The yob said:
hi
ive just finished build my sbc blown alky engine, im having some issues with her! is the anyone in the warwick midlands area who knows athing or to about these engines who would be willing to come over to my unit and shed some light ? im stumped !
many thanks
mat
Whats happening?ive just finished build my sbc blown alky engine, im having some issues with her! is the anyone in the warwick midlands area who knows athing or to about these engines who would be willing to come over to my unit and shed some light ? im stumped !
many thanks
mat
For a stat getting the thing to run!, Everything is spot on and ive ran out of ideas!, When we do get it to run the engine has no throttle response when you open the butterflies and just spits fuel out the injector hat nozzles at the back, Also the blue flames out of the headers tell me something isn't right!, The seems to be sooo much fuel geeing in, I'm running 55 hat jets and 150 main pill on the return. The thing that stumps me even more the engine is the exact same spec as the chap i bough all the parts off, same cam, rods, pistons, stroke, heads everything!............Help!
Assuming you've checked cam degree and ignition timing (you don't say what ignition you're running), you also need to check barrel valve adjustment. If you can't get it to fast idle then something is not quite right! Also maybe a phone call to Jeff Bull or another reputable engine builder, they are nice chaps and will probably be happy to give you a few basic pointers over the phone.
The yob said:
For a stat getting the thing to run!, Everything is spot on and ive ran out of ideas!, When we do get it to run the engine has no throttle response when you open the butterflies and just spits fuel out the injector hat nozzles at the back, Also the blue flames out of the headers tell me something isn't right!, The seems to be sooo much fuel geeing in, I'm running 55 hat jets and 150 main pill on the return. The thing that stumps me even more the engine is the exact same spec as the chap i bough all the parts off, same cam, rods, pistons, stroke, heads everything!............Help!
Blue flames mean its retarded big time. You only running hat nozzles? What barrel valve do you use? Square of K style? What size pump? Leads on right order? Blues flames from all cylinders? Edited by BennettRacing on Thursday 16th April 11:13
we use the supermag 3 for ignition, The only place i can get the eninge to run (after many times of trying!) is with the ignition backed right off and that's when the blue flames kick in! The fuel pump is a 80a Hilborne, we use the square style barrel valve not the k series, ive checked the leads etc.! .........ever think your in over your head!
.........ever think your in over your head!it's just an engine, the principals of running it are the same.
As Luke's mentioned it sounds like the timing is retarded. The fact it's firing in the exhaust and won't advance / rev, points to either the timing being way too retarded, in which case it would be hard to start and pull the battery down or theres something stopping the engine reving.
Does the Supermag have an advance curve or is it timed all in ?. Is the dizzy / rotor phased properly ?, Does the cam have a 5-7 firing order swap ? Do you run a start retard ? is this working / wired correcly to only be active when cranking ? Are all the plug leads on,have you measured their resistance ?, arranged properly and none cross firing ?
Take a timing reading while running and post it back up. Luke can probably give you a safe ballpark suggestion for timing and fueling to get you going.
As Luke's mentioned it sounds like the timing is retarded. The fact it's firing in the exhaust and won't advance / rev, points to either the timing being way too retarded, in which case it would be hard to start and pull the battery down or theres something stopping the engine reving.
Does the Supermag have an advance curve or is it timed all in ?. Is the dizzy / rotor phased properly ?, Does the cam have a 5-7 firing order swap ? Do you run a start retard ? is this working / wired correcly to only be active when cranking ? Are all the plug leads on,have you measured their resistance ?, arranged properly and none cross firing ?
Take a timing reading while running and post it back up. Luke can probably give you a safe ballpark suggestion for timing and fueling to get you going.
The yob said:
we use the supermag 3 for ignition, The only place i can get the eninge to run (after many times of trying!) is with the ignition backed right off and that's when the blue flames kick in! The fuel pump is a 80a Hilborne, we use the square style barrel valve not the k series, ive checked the leads etc.! .........ever think your in over your head!
What timing are you running? Square is fine we ran a 7.1 on a square type so there good. .........ever think your in over your head!If its hat only its easy, just need a few details of motor etc.
What size blower is it?
What overdrive?
Brief spec of motor
Did you leak the barrel valve down?
Can you take a photo of the barrel valve as it is now and email it to me?
Also email what tune you have in it now and what timing.
Have you made sure you have set the mag on no.1 and not no.6 ? Easily done.
That would also explain your grief.
Gassing Station | Drag Racing | Top of Page | What's New | My Stuff