Thread: timing a 350 chev blazermotor

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Originally Posted by Itoldyouso

Trying to diagnose these things via keyboard is sort of like trying to do heart surgery over the phone..............there are so many variables and possibilities to consider. One thing that confuses me is you say you recently rebuilt the motor but that little is known about the internal components. If you rebuilt the motor you should be have intimate knowledge of each of the parts you mentioned. How do you "rebuild" a motor and not know those things?

You could have your crank/cam misaligned to start with, or it could be as simple as dropping the distributor in with the rotor pointing where it shouldn't be pointing. You could also have the plug wires crossed up, as mentioned.

I think you are being wise to take it to a mechanic, but even he is going to have fun because the assumption will be that the internal components are installed properly, when that might not be the case at all. I hope though that you just find out it is something simple.

Don

little is known about the internals cause i got a block crank cam and lifters from a Chevy 3/4 ton the same year as mine from a friends junk yard, but the truck is running now with good power but at high rpm when you let off the gas the engine dies, is this a carb problem? or something else? thank you for all the help so far everyone

85% of all thought to be carb problems are actually ignition problems.
Make sure the timing light mark is 8 to 12 degrees at idle with the vacuum advance hose disconnected. Raise the rpm while watching the timing mark and you will see the mechanical advance run up to about 22 degrees.
Now hook up the vacuum advance hose to the carb. You should use the ported connection. Ported will have no vacuum on it at idle. As you raise the rpm more vacuum will appear. The other connection is intake vacuum. This is less desirable connection. Either way you should get about 32 to 36 degrees of total timing at around 2500 rpm.
If this is all correct and you have no other vacuum leaks, you may have a carb problem. What carb are you running?

the carb is a edlebrock and it looks like a 500 to 600 cfm 4brl manual choke, it highly resembles my 650 performer i got for my mustang