pulled cylinder studs on new harley cases after 3000 miles
Hello to all.. Just need some input on a situation that I have going on with my bike. I have a 1990 HD evolution FLHTC with 104,000 miles on it. I had 101,000 miles on the bike when I decided to take the top end apart and redo it. When I dismantled the bike I found that one of the cylinder studs had stripped from the cases. I checked around about time serts and heli coils and everybody told me there was not a sure fix other than buying new cases. So I went down to my local HD dealership and bought new cases and had my mechanic rebuild the motor. After about 3000 miles I notice that both base gaskets were seeping a little bit and I noticed tiny bubbles coming from the base gaskets and I was getting a ticking sound which ended up being a head gasket in the rear cylinder going out. Called mechanic and he told me to bring down bike. He dismantled the top end and was shocked to see that 3 out of the 8 cylinder bolts were pulled? My bike has been in the shop for a month.. Waiting to see if Harley was going to warranty the cases. I could bore you with the details with it either being defective cases or a bad torque job, but I just wanted some input on what some other possibilities could have caused this or similar experiences that people have had. I should also mention that this is a complete stock rebuild.
I have a 91 softtail, removed my heads to find the last shop that rebuilt it years ago put the studs in up side down. not sure why. did not catch this, when getting to 35 ft pounds pulled out one stud.now will have to heli coil and turn the others around. guess you have to double checkeveryones work these days.
In 19871/2 harley recommended that the studs to be installed with the shoulder stop facing up the shop that rebuit your bike my not have realized that harley quickly found out that it was not a good idea. 1 The studs could get driven to far into the cases cracking them 2 if they were not driven in far enough then the head nut would bottom out before proper gasket squish could be achived. leading to head and base gaskets to leak and cracked cases manly on the right side near the lifter blocks theres not to much meat in the case there .
well i say shoulder stops but its like a washer at the end of the treads so you know where to( stop) screwing them in you know what i mean . Yes some companies still have the stops and the stock replacements do .Some high performance studs do not but they are for custom cases mostly . I myself have ultima cases on my evo and have done others evos with them and there cases have the studs with the stops but of course they are installed properly with the stops down.
It's the bullshit casting alloy Harley has been using since about 1987 and it's an inherent Evo problem . Don't think I've ever seen or heard of a pan or shovel pulling a cylinder stud even with big bore kits and outrageous compression , I've had them where I had to smack the wrench with a deadblow hammer a few times to break them loose guys had herked them down so tight .
Well you know...if they weren't torqued down at all, like the wrench screwed them in and lost the plot, they would pull the threads to bits very quickly.....the newer cases can cope with the proper torque easily enough....somebody in a workshop somewhere needs a "talking to" in this particular instance ;-)