No Vaccum after breaking rocker shaft bolt

sdteb

trying to get it like you
Joined
Feb 10, 2003
So after blowing a HG and putting 'new heads' on it that were ported and valve job with big valves, started the car up every thing was great. driving her around and literally a rocker shaft bolt on the front driver side... replaced it with grade 8 bolts started back up, hard to start and sounded like i didnt tighten them down correctly, very luggish response, so I order ARP rockers bolts and put it back together, very hard to start and as literally 3-4 in vaccum....wTF???? before the rocker shaft bolt broke it was so smooth, i cannot find a vacuum leak ANYWHERE

help
 

salvageV6

Daily Driver
Joined
May 25, 2001
Did you do a compression or leak-down test yet?

Another test would be to pull the valve cover off the side with the broken bolt and have a look while it's idling.
 

sdteb

trying to get it like you
Joined
Feb 10, 2003
pulling the heads back off , sucks,,,,,no compression on the cylinder where the rocker shaft blot broke. bent valve? hole in piston? ill have it off asap worked on it today
 

sdteb

trying to get it like you
Joined
Feb 10, 2003
ok so i pulled the head off when i could not get any compression on number 1 cylinder.... 3 had some compression and i gave up aftr that,.... when putting 'new' different set of iron heads and new big valves in it with new valve springs should i have had to measure for new pushrods? this is a roller cam engine... remember after about 10 miles it broke a rocker shaft bolt and then ran like this...
ill post before p vids of it running fine at start up and pics of the head and piston today.. i poured alky in the valves and not leaking ..

the original pushrods are 8.250 in length....080, could this be the culprit?
 
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Chuck Leeper

Toxic old bastard
Staff member
Joined
May 28, 2001
when putting 'new' different set of iron heads and new big valves in it with new valve springs should i have had to measure for new pushrods?
Most certainly.
My guess is, you coil bound some springs, and subsequently, found the weak link in the shaft.
Lay a strait edge across the tips of the valves. Big differences in installed height?
 

sdteb

trying to get it like you
Joined
Feb 10, 2003
no bent pushrods... it would be awesome if someone have a good youtube video on verifying pushrod length on buick v6... to double check my work, yes, its my first time measuring these.... even though i have couple of these.
 
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