Luck is not with me at all. Put the new heads on and car was running great for a while. Then started popping through carb. Take off valve cover and rocker arm bolt broke flush with the pedestal. I had loctited it into the head and did all I could to try to get it out. Now the hole is messed up! Talked to machine shop and said probably all that can be done is find somebody good with cast iron welding and completely close the hole and then drill and tap a new one. I am getting really tired of tearing this engine down and putting it back together .....
I know the feeling too well. If at first you don't succeed, try again. [ repeat as necessary ] Hang in there. You'll getter THIS time.
Would you be able to drill the hole out a little larger and put what is called a healicoil (I think that is how it is spelled) in it to get it back down to the right size? This would be a pretty simple fix if that would work. These are also sometimes refered to as a Threadsert. Jon
I'm gonna leave it to the machine shop to figure out the best fix .. I did try to drill it out to insert a helicoil but the bolt that was still stuck in there screwed up the hole when I tried to drill. The bolt is alot harder than the head to the bit wandered .. I tried to avert disassembly by doing it on the car ... no go ..just made it worse. The head is a fresh rebuild so I hope it isn't trashed .. And the factory bolts are going in the the trash and replaced with ARP Chome Moly Bolts ...
Dan- I would be wondering about how much tolerance you have on those pushrods if you broke a bolt. The geometry could be different from your last heads depending on pedestal height. I know that you are running a stout cam in lift. Did you go to a later model head? There could be some differences. Are these roller rockers? Factory rockers? 1.6 vs. 1.65 vs. 1.7 makes a big difference sometimes. Just some thoughts. Seth
Yeah ... I checked it closely ... I did not see any indication that there was either coil bind or the rocker pedestal hitting the edge of the rocker arm slot. They are factory 1.6 rockers (1.55 if I am lucky) so I was concerned they would be hitting the edge of the slot. I had to use .030 shims for proper preload on the lifters. I checked the other rockers and they also look fine. I bought a brand new rocker kit which included the bolts. I figure either a bad bolt ... or more than likely ... I over-torqued the bolt. I drove the car about 5 miles before the problem and it ran fine until the bolt broke. My depression is slowly wearing off .. I already ordered a new head gasket and intake gasket set as well as a set of the correct ARP 170,000 PSI bolts to replace the OEM bolts ... I bought the heads via the internet so I emailed him asking if he could help me out with a driver side replacement head. Hopefully he can either fix this head or atleast re-use the components and save me some money ... As far as the cam ... It was an exhaust bolt that broke ... .512 lift on that one ... .509 on the intakes ...
For some reason, I remember your cam being higher in lift. Mine is 470/474 with 1.6 roller rockers. Maybe it was a bad bolt. Seth
That is going to be a rather expensive bolt though! I figure with the flex and inaccuracy of the factory rockers I may be getting 1.55 lift tops ... which equates to less than .500 lift at the valve .. The cam lobe lift is .319/.320 ....
hang in there! it will be worth it and so much better when you do get it done. its been almost 4 years of hit and miss for me. mike
DMHINES..............feel your pain. Not bragging but I can get any bolt out. I just need a welder. I never drill unless repairing a caliper bolt with helicoil. Sorry to hear about your bad luck. If yo do not have adjustable rockers you really need to pay attention to rocker geometry and good studs(ARP etc..) If need be get a set of custom push rods to solve your problem as well. Good Luck and do not ever ,ever give up on that sweet azz Mav. Unless you wanna give it to me
Thanks ... I was just letting off steam ... It just sucks that the car has been all show and very little go with all the engine issues .. Looking at it in the garage cut it for a while but now I want to drive it Plus I am missing a ton of car shows and pulling intakes and heads and replacing gaskets gets tiresome and expensive. The ARP bolts are on their way and hopefully I have a plan of attack on repairing the head on Monday when Machine Shop guys are working ... I am using stock length hardened push rods and some Crane shims to get the geometry correct .... Dan
Check closely for spring bind, then check the rocker arms have all the travel they require, most of the performance rockers will allough a longer travel. Without that travel its kind of like pulling the top off a bottle of beer the cap being your rocker arm stud.
