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69 307 head change runs like crap

950 views 8 replies 6 participants last post by  docvette 
#1 ·
i have a 69 c-10 with a original 307.It had the original heads on it and it sucked 2 valves due to soft seats.I put new heads on it and new cam,timing chain,intake,carb,headers,and a hei distributor.It was real hard to get to start and it cranks like it has no compression but it does start and i am trying to figure out if i put the timing chain in wrong i have the cam gear in the 6 o clock position and the crank gear in the 12 0 clock position and i have set the distributor and i am just racking my brain with this.I had the crank at top dead center and cet the chain like that i am now thinking this was wrong help please someone
 
#5 ·
Do a compression test. If it's really low, make sure you don't have the valves adjusted too tight. If you have the valve adjustment spot-on (go to www.compcams and do it like they instruct you).

If you have the valves set right, and you have low compression (less than 100 lbs), you've got the timing chain off.

Of course, I am assuming the valve job is up to snuff, and they are sealing. They did get a quality valve job, right?


If your compression is up to snuff, then there's only one thing from getting it to run right and that's to time the distributor properly.

Be scientific in your variable eliminations. Test, don't guess!!!


Brian
 
#6 ·
the plugs ere covered in gas everytime i start it it runs ok at first then is hard to keep running and it deffinately not idleing on its own.it seems like i might have a couple valves on the passenger side too tight it is blowing smoke out that side and popping out that side
 
#7 ·
69chevc-10 said:
the plugs ere covered in gas everytime i start it it runs ok at first then is hard to keep running and it deffinately not idleing on its own.it seems like i might have a couple valves on the passenger side too tight it is blowing smoke out that side and popping out that side

You might have washed the cylinders down with raw fuel. Very bad situation and can wipe out a set of rings. Make sure your carb isn't dumping raw fuel down in the engine, clean the plugs, and put some oil in each cylinder. Change the oil, make sure it's not full of gasoline.

brian
 
#9 ·
Doc here, :pimp:

Check to be sure 5 and 7 plug wires aren't reversed..HAND OVER HAND them to be sure..they are the only two wires next to each other at BOTH ends,,and will cause the exact problem you have..

A lot of guys Pro and Novice both, will blow it off and say" Yea, Yea it good I sure" and find a month later and a ton of UN~needed parts later that 5 and 7 were reversed..

Check your static timing also..

Number 1 cylinder TDC compression, Timing marks aligned, Both intake & Exhaust valves closed , no pressure on the lifters (not too much slack either..)

*--->If you can't co~ordinate these, you have timing chain/gear issues..<---*

Drop the dizzy in, and watch the rotor, It will advance clockwise a bit, this is because the gear teeth are diagonal cut, It will go about a tower in a half in some cases..Note the amount of change and then withdraw the dizzy.

Line the oil pump shaft up to that location with a large screw driver, and reset the dizzy, for number one plug tower, allowing for advancing as the gears seat..

The easy way to do this is make magic marker lines on the base of the dizzy, for exact #1 plug tower, and the difference of rotor movement as it seats..due to the cut of the gears..(I.E...#1 and the amount of distance BACK required to make it sit on #1 plug tower when bottomed out..)

#1 plug tower in the stock location for SBC's is 5 to 7 O'clock, (depends on year, and obstructions) 7 is usually good.

Direction of rotation is clockwise.

The F.O. is 1 8 4 3 6 5 7 2..

This will clear or include the cam Timing and dizzy timing as suspect..If it all checks good move on to the valve train..

Doc :pimp:
 
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