Thread: timing a 350 chev blazermotor

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i have recently re built my chev 350 motor and i cant seem to get the timing right for the engine to start, i have set the #1 piston to TDC and the distributor to the #1 fireing spot and it shot a 3ft flame out the carb. to my knowledge this is NOT right, little is known about the internal components (crank shaft, cam, lifters, etc.) could the cam be off some? or is it another problem i have over looked? please render any help possable.

thank you, MK

Others will have more experience and guidance, but you should make sure you are at TDC on #1 on the compression stroke... common problem is distributor is 180* out of phase... you can pull the distributor and rotate 180, or rewire the cap with #1 as #6 and so on...

That's the easy solution... if the internals are wrong, though you'll need to start digging deeper. Starting with a visual of the timing set (I believe the dot on both crank and cam sprockets should be at 12 o'clock at #1 TDC) then on to degreeing the cam and checking the rest of the valve train...

I'm not the expert on this stuff but this should be a decent start... others will chime in that know more than me

Good luck...

-Chris

Did you get the cam timing marks right when installing the cam?

If so, then make sure the distributor rotor is pointing to #1 spark plug at TDC compression #1.

Make sure you have wired the rotation correctly on the dist. cap.

well i have tried you're suggestions and still my engine refuses to start, but it no longer shoots a flame, but now it shoots a blueish- white smoke just after a POP -,- it sounds like it wants to start. is there anything else i can try before tearing it apart?

Originally Posted by skids72

Starting with a visual of the timing set (I believe the dot on both crank and cam sprockets should be at 12 o'clock at #1 TDC) then on to degreeing the cam and checking the rest of the valve train...

Timing gear dots should be at 12 o'clock on the crank, 6 o'clock on the cam...With #1 @ TDC

Thats EXACTLY why we needed you to stick around!!!!!

Originally Posted by Mkadawametwa

i have recently re built my chev 350 motor and i cant seem to get the timing right for the engine to start, i have set the #1 piston to TDC and the distributor to the #1 fireing spot and it shot a 3ft flame out the carb. to my knowledge this is NOT right, little is known about the internal components (crank shaft, cam, lifters, etc.) could the cam be off some? or is it another problem i have over looked? please render any help possable.

thank you, MK

OK so far EXCEPT for the cam gear being in the 12 o'clock position,,, for VALVE timing, the small crank sprocket should be at 12 o'clock and the large cam gear at 6 o'clock. Bear in mind that this configuration places IGNITION timing 180 degrees off. Try this,,,,, pull #1 plug,,, place a finger over the plug hole and 'feel' the compression stroke (with a buddy helping) While buddy turns the engine, look at the harmonic damper timing mark, when it lines up with the marks on your timing tab and your finger can't hold the compression,,, you are in the ball park,,, now put your distributor in so the rotor points to #1,,, button everything up and you should be smiling,,, ohhh, almost forgot the rotor position is also #1 plug wire. ( firing order 1-8-4-3-6-5-7-2) clock wise, viewed from top,,, good luck,,, Peter

well i got good news and bad news, >< i got the engine to fire over and it isn't spiting fire any more, but it sounds like it is only firing on 1 cylinder, i got spark to all plugs and it is not flooded, but it doesnt start yet, this project is taking its tole frying my brain.

Take all the plugs out
do compression check
check top dead center on compression stroke # 1 cylinder
set distributor to # 1
make sure wires are in the correct order in the correct rotation on cap
make sure you are sure of the cylinder numbering for your engine
If the cam timing and valve adjustment is correctly done, the firing order correct, and fuel it should srart
It will not shoot fire out the intake if 180 out as then it would be firing on the exhaust stroke of that cylinder
If it back fires out the carb you have mistimed, intakes are too tight, or wires are crossed

Had a buddies car that was doing that same thing. Found he had put the wires on, starting with #1 in the right place, except he ran them in reverse direction on the cap... Might check that.

Originally Posted by DennyW

Have you pulled at least 4 plugs all the way out, and looked at them ?? If they are white, and dry, put another set of plugs in from another parts store. If they are wet, dry them. If they are black, burn them clean, and or replace them.

i have pulled all the plugs and there black and carbon coated i will replace thm but keep as a emergency set i have the proper wireing for the plugs and the correct firing order. (going to talk to the local repair shop for additional info)

great news!! i got my engine running but the timing is at 8 on the timing tab, to me this sounds a little high but it runs, it doesn't got the power it should and hesitates a little bit, and if i set timing to 0 it runs like crap. should the timing be a little lower?

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

Had a mechanic friend that ripped a customer's motor apart with a similar mystery problem,,, turns out the roll pln on the distributor gear sheared off and there was just enough drag to (almost) turn the shaft and rotor properly. Best of luck and keep trying,,, you'll figure it out eventually,,, besides, your support is busy scratching their heads too

DennyW has a point,,, give the engine some advance (don't be shy) and it is entirely possible that the timing tab is from another engine, making 8 or 12 degrees on tab irrelevant,,, Peter