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-   -   time to rebuild (https://67-72chevytrucks.com/vboard/showthread.php?t=328533)

73chevyman 02-12-2009 10:45 PM

time to rebuild
 
well got to the truck last weekend and was trying to figure out why it was back firing. Well what i didn't want to see was true. it was backfiring due to #4 exhuast valve not opening. I was hoping that the lifter lunched on me. got to the lifters and they were fine but the #4 lifter had a 1/4 lobe in it. so i had no choice but to pull the cam shaft out. it was scary looking lol. it was completely round. it was so round it looked like it was made that way lol. got all the parts today and tomorrow i'm going to start putting everything back together. I've done my share of research on this site and found every answer i was looking for. this will be my 3rd upper end rebuild but the the first 2 didn't go too well now i did my homework and this should go as planed. what this is boiling down to is thanks for all the info people has put up it does help people like me to understand things like valve adjustment don't want to whip another cam cause i just threw it together well time to get her to perrrrr like a 350 should:smoke:

Pyrotechnic 02-13-2009 02:44 AM

Re: time to rebuild
 
Make sure you are using a high zinc oil. Also use break in additive.

73chevyman 02-20-2009 10:41 PM

Re: time to rebuild
 
I got some assembly lube put the new cam in. I put it on the whole cam and even lubed up the lifters. cleaned and installed the push rods. Made sure #1 was up put the new timing chain on and cover. and put the harmonic balancer on. Did all this yesterday and today after work. Getting up early tommorrow and hopefully finish everything. got the first valves lash out too before light became a problem. everything on #1 needs a 1/2 turn then time to set the rest on #6. Its been a slow process just got over a cold so its back at it. I'm taking my time cause I don't want to miss anything just want first start up be as smooth as possible. Hopefully it will be running tommorow. but before i close up the intake and valve covers i'm gonna waste a quart of oil to make sure all the dirt and grime is gone. Well wish me luck hopefully she'll be puring like a kitten tommorow miss the sound lol

73chevyman 02-25-2009 10:06 PM

Re: time to rebuild
 
well today as i was putting the the altinator and water pump i happened to look down noticed a 2 inch spring on the ground just below the harmonic balancer. pick up and blew my mind so i sat it on the front seat. but it played threw my mind the whole time as i was cleaning up i ran across the old crank gasket something told me to look at it. well i finaly figured out what it was it was the spring to the new gasket hope i did not mess the new gasket up. crossing my fingers going back to take the front apart tomorrow lol

85_prairieboy 02-25-2009 10:23 PM

Re: time to rebuild
 
If that is the spring from the crank seal you can take a shortcut. Pull the balancer off and use two 90 degree picks to gently feed the spring back into its groove. Be very careful because you don't want to stretch the spring. Saves having to pull off the oil pan and timing cover.

85_prairieboy 02-25-2009 10:26 PM

Re: time to rebuild
 
By the way its good insurance to use the GM break in additive. Good luck!

73chevyman 02-25-2009 10:30 PM

Re: time to rebuild
 
i'll try that but don't want it to drop in the oil pan. thanks for the info

73chevyman 02-25-2009 10:32 PM

Re: time to rebuild
 
is that a additive i add to the oil?

85_prairieboy 02-26-2009 12:50 AM

Re: time to rebuild
 
It won't fall in the oil pan because it will be looped around the crank snout. The additive I use is AC Delco Engine Oil Supplement #993104 and yes I add it to the oil. Cost me $8.99 Canadian. Cheap insurance

73chevyman 02-28-2009 06:59 PM

Re: time to rebuild
 
cool thanks

73chevyman 04-11-2009 07:59 PM

Re: time to rebuild
 
well got an update on my rebuild. well broke the cam break in went well. truck sounded awesome just had one problem had it one tooth out of time. after i did that it took me a couple of days to figure it out but when i took the cap off i had to take the wires off to turn it one tooth. well it was getting dark and when i was putting the wires back on i crossed #6 and #8. lol... after that dumb stuff I finally put the timing light on and set it 8 degrees above like the tag said. adjusted the idle screw so that it idled at 900 rpms. changed all the vacuum lines and got them hooked up like they need to be. did one last check with the vacuum gauge to fine tune everything well it move between 20 and 22 did some adjustments and got it to stay around 20. well i think i got everything were it needs to be. shes ready for the road now all i got to do is get all the paper work crap out of the way and she'll be back on the road hopefully soon..


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