Small block chevy 350, one of the rocker nuts comes loose on a regular basis and I have even bought brand new rocker nuts to try and fix the problem but it still comes loose.
Can I "double nut" the rocker nut? (put 2 nuts on it which I believe would hold better)
Or, should I install a new stud? I have never installed a stud but it looks like you double nut it and back it out of the head and thread a new one in.
Any help much appreciated. Thanks, rick2950 at hotmail
Two things to consider;
1) The stud is a press fit and it's pulling out.2) The cam lobe is wearing down.
The heads are the 60's Double Hump or Camel Hump heads,, any idea if those are press in or screw in studs? casting number 3890462
If the cam lobe is wearing down, I will be very dissapointed, it is a comp cams unit (268h) with probably only 200 or 300 miles on it over the last 2 years. But when I broke it in, I did not use any sort of 'additive' to the oil other than the lube applied directly to the cam when installed. The local shop that just did a big block for us, sold me a bottle of Crane Cams Super Lube Break-In Concentrate to add to the oil for the big block and mentioned that the oils now days are missing some stuff that the older oils had and this is causing cams to go flat prematurely..... this has me concerned that if my cam is going flat then maybe it's because of the newer oils.... argh..
Two things to consider;
"Rick2950" wrote
If the nut is unscrewing, there would be less threads showing than the other studs, and back to "normal" when you retighten.
If the stud is pulling out, more and more threads will show each time.
If the cam is going flat, it should be easy to see the the readjusted rocker "rocking" less than the others.
200-300 miles over 2 years? Maybe enough time for a lobe or two to rust while sitting, then grind the crap out of the contact face on startup?
In the case of 1) would it be possible to install a screw in stud on the vehicle, or is there not a machined "pad" for it to seat on? I agree with your thoughts though, those nuts don't *seem* like they should work, but in service nobody generally has issues like this. There *are* special locking nuts made for high performance applications if you can rule out a stud pulling out (my best guess as to what is happening)
just thinking out loud...
nate
Actually it's ZDDP that is missing in the latest API gasoline engine rating. They've actually reduced the allowable amount of zinc in the oil for emissions reasons. I just changed the oil in my truck today, the Rotella 30W was still the old formulation but the 15W40 had a newer gasoline API rating so I bought the 30W.
nate
Mike Walsh wrote:
makers began recommending 5W30 oil for use in hot weather.
Actually, it was (is) ZDDP. Viscosity has nothing to do with it.
Certain 0W20 and 5W20 motor oils will easily out perform most
10W30 motor oils.
You tell me... How did you spec the machine work? Stiffer than stock valve springs? If they have press in studs and/or you don't know, someone didn't carry the ball like they should have, especially considering the age of the heads.
The high shear/high wear additives have been gone from motor oil since the institution of OBD2, which make it 12 years now. Big problems reported with cam and lifter failures in the aftermarket with non roller camshafts, especially if no additive was used, lighter break in valve springs weren't used and proper camshaft break-in procedures weren't followed. The answer was as close as your local GM dealer, $9.00 would get you a bottle of their "EOS" engine oil supplement.
He's exactly correct, along with the fact that there are scant few domestic flat tappet lifter manufacturers around anymore. (read; cheap offshore crap)
Not because of the oils, because of lack of proper information.
I think you hit the nail on the head with your "was" comment. I've been told that this has now been discontinued. Have I been told right?
There are still aftermarket suppliers of ZDDP.
I just bought a dozen bottles not more than 2 months ago. (my secret stash)
Yup.
I remember some of the Pontiac engines that had problems with studs backing out, and it was common, in those prehistoric days, to drill the stud tower and stud, and "pin" the stud with a roll pin. I guess a set screw would work as well.
Things like this can really be a PITA, and I hope the OP posts his solution.
aarcuda69062 wrote in news:nonelson- snipped-for-privacy@newsclstr02.news.prodigy.com:
In case anybody's interested, there's an ad for the oil with ZDDP in the restoration magazine "Skinned Knuckles".
There's no Web site, just an email address and phone number: snipped-for-privacy@motorheadoil.com
800-343-8649
If the studs are press in you can buy a kit that includes a spot facing piloted drill, tap and thread locker. You remove the existing stud and use the drill to ream the hole and face it, then tap in new threads and install screw in studs. NUT it is best to do this with the heads off the engine. If your doing it with the engine installed than your going to make VERY sure you keep any of the filings from getting into the engine.
OR the other option is to pin the existing studs. You make sure the stud is fully seated and then drill at an angle through the head boss and the stud and then insert a roll pin with some loc-tite on it.
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