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Haven't checked the compression, the shortblock is stock. The heads shouldn't have upped the ratio any so i'm guessing around 8:1.
@.050 218int/228exh lift .500/.500 lsa 114 so fairly mild cam for a big block. |
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I will do the piston stop again. This weekend. That makes sense but it seems strange that it lined right up with the factory balancer mark. I'm out of ideas so it's worth a try. I'll post back when I do and let you know what i find.
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weird timing issue
You know it sounds like to me that you do not have the crankshaft gear set straight up. It's probably one of those crankshaft gears that have 3 keyway settings. One keyway has a dot, the next has a square, and the other has a triangle.
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Read this, and then if you have any more questions just ask.
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I have the small block cam retarded 4 degrees, the big block is straight up. I haven't messed with the small block for a while. I am adjusting initial timing. I don't know when the mechanical advance starts but i would assume after 750rpm. I have the vacuum advance unhooked and when i slow the timing much below 60 it starts idling rough and will die.
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As long as you've confirmed TDC, firing order, etc. like you have, unless the carb is way out of tune/faulty/"modified", there's no way it should need anywhere near that kind of timing. So I'd start w/the carb: As long as the carb is working right and not too far from factory specs, I'd start by baselining the transfer slots of whatever carb you're using. Then use initial advance and idle bypass air to get it to idle w/o the primary throttle blades being open too far. This can be done in several ways depending on the carb; a Holley can use the secondary throttle shaft adjustment screw to tip them open a little. If bad enough (although this is rare) holes can be drilled in the primary blades, but that's only as a last resort. |
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Could the spark plug really be firing when the crank is 60 degrees btdc at idle? I wouldn't think it could run let alone start. I'm just wondering if it's actually firing at 12 or 14 and somehow i'm coming up with 60. |
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I know you said you used a piston stop to verify TDC, but if this is a sbc engine you're working with, there are several different combos of timing tabs/damper lines, so you might want to double check what you have. |
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Like i said, I have used 3 timing lights. With the piston stop, the mark on the balancer lines up with the 0 on the timing pointer. I do not have a MSD box.
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Hold your head up
Have you tried restabbing your distributor? somthings off cause I dont believe your actually running those numbers. You said you got it running by ear right? So it must have been sounding normal, then you checked and it was off right? well I dont think it would ever sound normal at 60.
So, here is what we can assume. Either your distributor, balancer, TDC, timing light,... thats about it. One of those isnt right. I know its a bummer to continue to do things over and over but since its not right you have no choice. Just try going at it on a fresh day, and re-stab your distributor. This has to be perfect and there is a ton of videos on you tube showing tricks and common issues. double check everything make sure the clamp that is attached to the number one wire from the timing light is facing the right direction. make sure the vacuum advance is plugged at both ends. make sure you are using the correct timing tabs, I know this has been stated already but you would get a 60 reading at the 2 oclock spot if you were really needing to be at 12 oclock. (maybe). Most likely its not running at 60 and the numbers your getting are incorrect. which is a bummer but better than having an engine running at 60 advanced. Ive seen guys put heavier springs in the distributor when checking initial just so they know they are not getting a false reading cause by mechanical advance showing face while its idling. Then put lighter springs back in so you know its opening all in by 3000. I actually use one med. and one light in the final product. just seems to work good for my set up. I also have vacuum advance and after reading all kinds of stuff online about how its a must in street driven vehicles, I took some advice and plugged it for driving and it accelerates much better and now never exceeds 34 degrees. Even sounds better when accelerating. Hopefully, this msg will get your spirits up a lil, I know how frustrating it can be. Hell, I bet we all have been there one time or another so we want nothing more than to help. Im no pro either, just this last year I have been through this many times, and I continually resort back to these forums or you tube for help. |
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- First Chevy uses number one on the drivers side as the number one cylinder that timing is checked from, I'm assuming your light is hooked to this, if not this would be the thing to do. - Second would be you've got a high resistance ignition wires which cut off part of the ignition signal (a thing they're supposed to do) which delays the inductive coupling of the timing light from forming enough voltage to trigger the light when it's needed in a timely fashion for accurate measurement. things happening fast a small delay within the inductive coupling can be a lot of crank degrees. - Third, the cam is a tooth or two out of time and needs a lot of advance from the ignition to operate the engine. Bogie |
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