Very bad news need help

[tim21391]

well my truck was running really bad.. so i took it to carb shop.. power valve was obliterated.. choke had nothing left.. bad backfire which tarnished the inside.. gasket on intake was gone.. bad vacuum leak... but good news is he rebuilt my holly for me.. did all that for around $256.. and now he said my number 4 cylinder is dead.. i havent gone and picked it up yet so i havent heard it.. but he said on the compression tester it barely moves the needle when he checks number 4 cylinder.. i talked to my friends that work at autozone.. he said either a bent pushrod. bent/broken valves.. broken valve spring. rockers not adjusted/working.. and he said hole in the piston but my oil is still lookin good so i dont think its that.. whats your opinions... and i heard also i might have a flat lobe on the cam...

[Clyde65]

have your mechanic scope that hole, it will tell you if there is a bad piston. If all clear you can open the valve cover and start the engine, see if you can notice anything wrong. Go from there. This is what I would do, oh and you will need a piece of cardboard to block the oil splatter.

[jamie72]

is it on the 402?? a rocker broke in two in mine once....

[Wrenchbender Ret]

He is using a cyl. balance tester. That doesn't give a true comp. test it just points to the offending cyl. It could be a vacuum leak in the runner to that cyl.

[tim21391]

ok my friends dad has a tester where it blows air into that cylinder.. then we will go from there this weekend hopefully its something small.. no need to take it to mechanic shop i dont think ive built engines before i just havent had to troubleshoot before

[big_al_71]

After seeing your five minute video and the way your truck was dogged I am not surprised that it was hurt specially if it was not properly tuned.

Good luck to you....

[tim21391]

it was like that before we started haha.. but oh well its just money

[tim21391]

i know you wernt doggin on me but ya you know what i mean.. you play, you break, then you fix right?

[big_al_71]

Originally Posted by tim21391

it was like that before we started haha.. but oh well its just money

Originally Posted by tim21391

i know you wernt doggin on me but ya you know what i mean.. you play, you break, then you fix right?

Thats correct and as long you understand that by all means have fun. When I was younger half of the fun was breaking it then putting it back together to mess it up all over again. My dad did not care what I did with my rides because they were mine and I fixed them when they broke I wish I could say the same about my 21 year old son

[1quik70]

I would do as posted above, pull the valve cover and be sure bother rockers are moving the same as the rest. That by itself will tell alot, if they are not, you are looking at cam, pushrod, ect. If everything looks good, I would pull the intake and check the seal on that runner, and if that checks out, the heads come off. I had the exact same problem with one of my big blocks after a 7000rpm blast, ended up kicking a lifter b/c the rocker cam loose. Bent a pushrod, broken guide plate, chewed up rocker stud, you get the idea.

As for the Build it, Play with it, break it, and do it again! I know that one all to well! My 70 Nova with 396 was running and driving fine when I put it away for winter, then got bored and started taking things apart. Now its scattered across the entire shop and I've sunk another $2k into it!

[tim21391]

ha ya big all i dont mind fixing it i just never had to do something like this so im sort of clueless haha and ya you know what i mean right

1quik70 thats how i am on my truck ive sunk about 1500 in it and a year and a half time of rebuilding the truck so i understand 100% what u mean

[tim21391]

well found the problem i think.. pulled cover off and ran it.. and rockers worked well.. shut it off and figured out bunch of them are loose and u can spin a few push rods with your fingers.. so im going to adjust all that and see from there.. hopefully thats the problem

['72customdeluxe]

The lifters do bleed down some, being able to spin pushrods is alright.

[tim21391]

well they were overtightend.. we backed them off and then tighten them to a 1/4 turn and it runs real smooth but now wont go past 70 on the highway but it town it runs basically perfect

[68 c10 ls2]

I think you over loosened them. If it wont barke 70 now but runs great sounds like the valves arent opening all the way now.

[tim21391]

so go 1/2 turn?

[kgt]

Yes, 1/2-3/4 turn past 0 lash should be fine.