houston,we have a problem

[slosh13]

*sorry for having this thread be so long*


Well i as ive already noted , i would keep all of you informed on building my 416 . As of right now i am sharing my updated news with you guys. I got it all back together with my new cam chain, cam chain slider and guides, and the right crankcase gasket all on. I also upgraded my stock cam to a hotcam stage 2 cam. We got it all put together and fired it up and shes alive. Although shes needing a rejetting but other than that it feels strong. I went the next day to test ride it and n went into my open field and got on it and it wasnt even 15 feet before i blew a headgasket. My dad and I tore it down and we found that two of the four headbolts were not tight. But what we dont understand is that we put two nuts on the headstud and twisted and they were tight as s***.:confused: so we figure we just needed to tighten them. We put extra strength locktight on the two that were the loosest and we assembled it once again. Today i tried to run it again today. I took it in the same field and i did one pass which would be about 800 feet and i turned around coming for my second passs and half way down the field it blew yet another headgasket. so we took it apart and we found that the same two headbolts we not tight. We came to the conclusion that we will have to drill and oversize them and heatacoil(sp.) them?? If we do not get it fixed for the last race in my area, then i am starting my winter rebuild.:D So i guess its all good. I just wanted to keep you informed of how my progress has been and if anybody has been here and/or has any suggestions plz dont be shy to share. I need help on what to do. thanks.

[cals400ex]

i can't help too much with suggestions, but thats a shame what happened. what compression piston are you using? i think they recommend bigger studs when you are 11:1 or higher. i am right at 11:1 with the stock studs and i don't have any problems. also, did you use a torque wrench? i know the right exhaust one is usually the first to come loose. good luck with the rebuild.

[slosh13]

i am running a 11:1 piston and if your sitting on the quad its the left rear bolt and the front middle studs....its weird i know i just hope all goes well and i can race ASAP:devil:

[josh]

pull the top end off the motor and have a good machine shop just take a look at it, sometimes those guys can point out stuff that really needs attention that you never woulda thought of, but make sure u use a torque wrench and after you tighten all the bolts, don't be affraid to double and tripple check them, maybe something around one of the bolts isn't hooked up right causing i to come loose, i'm not sure, have a machine shop give it a quick inspection and tell em what's goin on, they are normally very helpfull

[emiliano22]

I had a time ago exact the same problem!!
I tried a lots of things and I blew up the headgasket a couple times. :confused:
The problem is not on the head or in the bolts, the problem is in the screw and the threads.
I had to change 2 at first time, a month later I had to change the others 2.
I don't know why but I had to change all the 4 threads and 1 screw.
I can't tell you more about the work because I don't know how translate it. :rolleyes:

[bandit390]

You can tighten as much as you like and add the whole bottle of locktight, but it wont solve anything. The studs are pulling out the the cylinder. I had a local guy pull the studs out and added locktight to those. No problems yet.

[slosh13]

well i am just going to take it to a local engine builder and hes going to drill/tap/oversize the holes as well as helicoiling themand he is going to put 4 new HD head studs in the cylinder. hopefully that will work:(

[josh]

should be just as reliable as stock that way, as far as them bolts holdin in there, and not blowin gaskets