Chevy 305 1980 to 1985 Edelbrock carb Normally this is what I do Unplug my vacuumed advance, plug the hose end and set my initial timing to is need. Usually for stock Chevy around 4-6 degrees btdc at idle. Total timing 28 to 34 degrees. Plug back in dist vacc. I bought a used distributer and for some reason I can’t get the base timing below 20 Deg. If I advance it to 40 Degrees it runs smooth. I re checked number one spark plug and it looks correct. Could it just be the springs and weights in the distributor> Thanks for any input.
Geesch! hate used distributors. Last one I had years ago apparently was modified by a racer and was all messed up. Replaced it with one we pulled from a yard and the engine ran fine. I usually set static at 8-10 with 34-36 total all in by 2500. Many most likely do it a different way. I would suspect the springs and weights for certain. Good place to look first. Was this a fresh rebuild or a running engine that you are fooling with? Might change the thinking!!
Clean up the centrifugal advance weights,make sure its not sticking and that the pins are not damaged and the springs are OK. If the distributor has been sitting this is a very common problem. Only takes a few minutes and costs nothing.Good luck with your project.
Not sure what you are saying here. After you set the base and then rev it up, it won't return to base setting...or? Have you checked TDC and verified?
yes checked top dead center. 600 rpm can't get it below 20 deg. I can't get the base timing correct. Placed thumb over number one rotated engine till compression stroke then turned engine over to zero time mark. I will check the springs and weights againe. thanks Just more fun to look foreward too messing around.
make sure the timing marks are correctly matched to TDC, i.e. slipped outer harmonic balance ring, mis-matched balancer and timing pointer, etc, etc.
Still lost here. You can't retard it until it stalls?..Do you have a dial back timing light that might have moved on you? Can't check TDC that way. All that proves is you're not 180 out of phase for install. We'll assume you have all stock parts for now. I believe 1980 timing tab was on top behind w/p, with mag pick up feature, correct?
You might have the wrong timing tab/timing chain cover, or a damper tab mismatch. Not all things are equal. The parts swap, but they do not all match. As shown below. As you can see, for instance, if you put a 1986 timing cover on, behind 1969-1985 damper, your mark will be 20º off, and so on...: Post a picture of what you have, as well as the code on the block pad, in front of the passenger-side head. Mix doesn't always match:
Good point I will check the timing marker , I have one of those top dead center finder you place in the spark plug hole as well. I'm going to start over and check each step twice. No Mag pic up. Snap on timing light yes to Dial back, block head code 14010201 ( 1980 to 1985 ) will post a better pic of timing mark thanks
The tool you have , piston stop is the thing to use. A timing light will tell you stories, that's all it does. Making The assumption that the marks are correctly lined up and then listening to the timing light's story brings about confusion. You need to verify first that the marks do indeed line up when the piston is at TDC before you can begin to work from those marks. If the marks are wrong then all of your work is wrong as well. Study the pics and post from gimpy and that will explain the mystery of parts matching. The other thing is that the balancer ring can slip on the rubber and that throws the marks off as well as any subsequent work.
If you're serious about stuff here- what happens under your foot and under the hood, total timing is so much more important than base timing. Control the total timing so you're not leaving power on the table or blowing things up, and let the base be where it lands. If the base timing is off enough to cause trouble then the distributor needs curve adjustments.
Lucky enough to have a local speed shop that has an old distributor machine with a very knowledgeable operator/technician . With correct information provided to them they can take the guess work and time out of an issue like this. I always have my distributors set up before I install, never a problem. I realize that not everyone has local access to one of these machines, so it's trial and error until you get it right
Did you mark the Balancer so you could clearly see the marks? This is my biggest pet peeve, a customer brings their car to Dyno and has no mark on the Balancer or no timing pointer and goes...uuum can you check timing. Well sure let me just go get all my shit from the engine assembly room and check where TDC is and make you a timing mark and add a pointer so I can do that first. Then they bitch when their $500.00 dyno session turns into a $1000.00 Session. I would just go buy a new HEI for $50.00 from the parts store and drop it in and save yourself the trouble.
You base or static timing is going to be whatever you set it at. Get set upon TDC then roll your engine back ward to where ever you think you should set it at. Now turn your distributer until the rotor is pointing at the number one plug. Where you have it set that is where it is. now once that is done set your dial timing light on the table and pick up the good old non adjustable timing light. Fire it up and see where you are, if you are no where close take a look at your advance weights and see what is wrong with the distributer.
What I'm seeing here is a 305 that you want to use stock basic settings, yet it doesn't have a stock timing cover or pointer, correct?
Stock 305 Edelbrock intake. This engine was a friends that passed away a couple years ago. It has been in and out of a couple cars. I believe the distributor is the issue. Thanks Sent from my iPhone using The H.A.M.B. mobile app
My friend, the point I was making is that SBC's don't come with chrome timing covers and bolt-on pointers. Also, that if it won't idle with a stock cam and 4-6 degrees advance, you've got other issues besides the distributor.
Double-true. Even if it has all OEM parts, that does not mean that they match. It could have been previously tuned via butt-dyno (by feel), and not by looking at that pointer, at all. I cannot even begin to count the number of vehicles that I have owned and tuned over the years, where I could not even begin to tell you what the timing was set to. I followed my Grandfather's rule: advance it until it pings climbing a hill, back off until it stops, and then back off that same amount more (because pre-ignition starts before you can hear it).
If you don't verify the marks with a piston stop test first , then don't even bother with a timing light . The numbers have no significance at all and butt dyno and ear is better than a book with numbers and a light with numbers and no verifiable basis to begin from
Thanks on a plus I did get her to run. Idles fine by feel. Lots of ideas and comments to get me more than pointed in the right direction. Thanks for the input and helping . Sent from my iPhone using The H.A.M.B. mobile app
Well just an update, The timing mark on the balancer is about 30 degrees to the left of the top dead center ( piston stop) from the metal marker. So as mentioned I think maybe the harmonic balancer rubber has moved. A timing light wouldn't work this far around . Does this require me to replace it or is it acceptable to drive with the new timing mark I placed on it? At least the distrubtar is in the correct spot. Thanks
You went both ways with the stop , made two marks and then split the difference, right? Some of us have been saying this right along .You probably have a stock dampener with an aftermarket cover (obviously). You could change one or the other, but if you're using the current timing tab to indicate TDC, just use your new mark and a dial back light to set your initial and total timing. Pretty sure your dampener ring didn't move. It can happen but usually stick shift, race car stuff.
This could still be a parts mismatch. An early timing tab on a late engine makes for 30°. Please post the engine code. It's on the pad in front of the passenger side head.
No, that's the one from the back of the driver's side head. We need the one stamped into the pad in front of the passenger-side head. About all that indicates is 1980-1985.
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