1978 Rebuilt corvette will not start

I bought a 1978 corvette with small block cehvy 350 - I changed the cam, heads, manifold, timing chain and gears, carburator, new headers and exhaust, alternator, battery and starter - now I am trying to get
it started - I tried all the TDC with the spark plug and still nothing - I get spark, I can see fuel, and sometimes it backfires so I get combustion -
Any ideas
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Recheck the distributor and make sure you didn't re-install it 180 degrees out.

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I left the distributor in and clicked over the engine until it pointed toward cylinder #1, then I tried the same thing the other way - Can you explain in laymans term what 180 degress out is for us geeks
Tony wrote:

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If you don't understand that .... put the wrench down and step away from the car
kickstart
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if this is not a bait post ? wouldn't think ya done all ya said ya did, if ya don't understand "what 180 degress out is" ... get ya some help, timmy...
my2
--
"Key"
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> Tony wrote:
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On Tue, 19 Sep 2006 18:06:18 UTC, "database-consultant"
wrote:

I'd have to agree with Kickstart. You could have made any number of mistakes at this point. You changed the cam so it could be out of phase with the rest of the system. Are you sure that before putting on the timing chain that everything was lined up properly?
David
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database-consultant wrote:

Your problem sounds as though the ignition timing is incorrect... although the cam timing could be off, I suspect that would cause more problems than just not starting (for example, pistons hitting valves, which means it wouldn't crank for long!).
" I tried all the TDC with the spark plug"
I don't understand what you mean by this... ignition TDC is when the #1 piston (front cylinder on the driver's side) is at top dead center (top of the stoke) AND both valves in that cylinder are closed. When the engine is in that position, the distributor rotor should point at the distributor cap post holding the spark plug wire from that #1 cylinder. Determining that correct #1 piston position first requires that the engine was correctly assembled (crank and cam are correctly aligned). You can determine the firing stroke TDC by removing the driver side valve cover and making sure both valves in the #1 cyl are all the way up (closed) as the zero-degree crank timing mark line aligns with the timing pointer. OR, you can remove the spark plug from the #1 cylinder and place a finger firmly over the hole while someone bumps the engine with the starter until the timing mark aligns with or passes the pointer... when the piston is on an exhaust stroke as it reaches TDC, you will feel air pressure pushing against your finger, but when the piston is on the compression stroke the air pressure will FORCIBLY push your finger OFF the hole. You want the latter situation: TDC on a compression stroke... when you find it, leave the engine in that position while you shift your attention to the spark plug wires and the distributor.
The spark plug wires must be positioned in the correct order in the distributor cap: 1-8-4-3-6-5-7-2 clockwise when looking down on the distributor... ( http://modeltech.tripod.com/wiring101.htm ) If the distributor is 180 degrees out, the rotor will be pointing at the cap post for #1 wire, but the #1 piston is at TDC on the exhaust stroke, not the compression stroke, so the plug fires on the wrong stroke.
To get the distributor in the correct position, one must ensure that the timing pointer is pointing at the 0 degree timing mark on the flywheel and that the #1 piston chamber has both valves closed... the position I told you to leave it. Then adjust (remove and re-seat) the distributor so that it is seated properly on the block... a cross-pin at the bottom of the distributor shaft will only allow it to seat properly (insert all the way so that the "land" on the distributor case is down flush with the block) when the matching notch on the oil pump shaft top meshes with that cross-pin as the distributor is lowered into the block. The distributor shaft will turn, clockwise, I think, slightly as the driven gear on it slides/meshes with the corresponding drive gear on the camshaft, so you need to allow for that by pre-positioning the oil pump shaft notch so the shaft cross-pin drops/slides into it during that slight rotation as you lower the distributor. You will need to use a long screwdriver to reach down and turn the oil pump shaft a bit to pre-set it so that the distributor will drop & settle into the correct position as it's lowered... this takes some trial-and-error repeated attempts to get it right. You want the wires positioned on the distributor cap as shown in the diagram in the link above, such that when you have it correct, and the distributor drops/settles into position, the distributor rotor will be pointing at the front of the passenger side head, corresponding to the correct position of the #1 cylinder wire on the cap (as in the diagram shown at the link above).
This all assumes, of course (as someone already mentioned), that you correctly aligned the crank and camshaft when you put the engine together.
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yea, that's right ! exactly what I meant to say :-)
no real pun intended...
g'day all
--
"Key"
=====



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You've had lots of help. If you are real, let us know how you did.
Simple method.
Remove the driver's side valve cover.
Roll the engine to where the harmonic balancer mark comes to TDC, watching the two front rockers.
If you are at TDC for #1, both should be up and not moving. If the exhaust is closing (end one going up), you are TDC on #6. In many small blocks, the two end ones will even be slightly loose, such that you can wiggle them easily at TDC for #1.
Install the distributor so the rotor points to the #1 plug wire position, moving the distributor shaft as needed like Wayne said.
Snug the distributor hold-down bolt enough it won't move on its own but you can move it.
Attach your timing light.
Wedge a 10 inch wide piece of cardboard along the lower edge of the rockers to keep oil off the exhaust and let you see the valves work.
Pour a tablespoon of gas down the carb throat or pump the accelerator linkage a couple of times while watching to see that gas actually pumps.
Get someone to crank the engine.
Make sure the front two valves are closed (rockers up) each time the light flashes and when the engine fires, immediately check the timing and adjust as needed. I believe 4 degrees BTDC is what you need, but check a book. 4 BTDC should make it run regardless.
After you time it, shut it off and install the valve cover.
!!! Don't look down the carb while trying to start it. !!!

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Keep a fire extinguisher close by..a backfire can really wreck your day...
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Most fire extinguishers will wreck your day, too, and the next week and month and ...
If you worry about a backfire and a carb fire, keep an old blanket, like an old moving quilt, and simply throw it on and smother the fire.

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Hi Tom, can you elaborate a bit on why an extinguisher will wreck a day for so long?
Here's waving to ya - \||||
Owen ___
'67BB & '72BB
-- not affiliated with JLA forum in any way -- alt.autos.corvette is original posting -- ___
"To know the world intimately is the beginning of caring." -- Ann Hayman Zwinger
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Depending on the extinguisher, the chemicals in it are highly corrosive to carburetors and wiring. You need to get it washed off ASAP. If not, you can be in for a bunch of electrical problems and your carb can be really screwed up. And some of them become like plaster when mixed with water, so cleanup can be a hassle.
This is why Halon was used in most electronics facilities and in road racing for years, until it became hard to get.
wrote:

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Thanks for explaining it, Tom.
Here's waving to ya - \||||
Owen ___
'67BB & '72BB
-- not affiliated with JLA forum in any way -- alt.autos.corvette is original posting -- ___
"To know the world intimately is the beginning of caring." -- Ann Hayman Zwinger
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This is a multi-part message in MIME format. --------------080006010506030407020304 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit
Only use a extinguisher if it's Halon type. The sulfer/powder types will reek havoc with your engine components. A Blanket is the way to go for carb backfires. (disclaimer: Not Michael Jackson's kid!) LOL
Barking Rats wrote:

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