I have a numbers matching 70 GS455 with a factory 4 speed transmission that I bought from the original owner about 42 years ago. I just got the engine back in the car after a complete rebuild from a highly respected and reputable Buick engine specialist. Upon the first startup I broke in the camshaft and as it ran I noticed some valve train noise. When it idled down it died and then over heated. I wasn't too concerned as it was 90 plus degrees out and we were in a garage with little to no air flow. So since that first run the valve train is quite noisy. It has 1.6 ratio TA roller rockers and a mild performance cam. I have consulted my builder and upon his advice I tried readjusting the rockers, adding a can of oil treatment, because, well you never know. I tried the original rockers, the cast aluminum ones and nothing changed. I have since installed new lifters from TA and measured the pushrod length on six different lifters, and then averaged the lengths I measured and added .050 for the required preload.That number was 9.343 pushrod length and the ones in the engine measure 9.347, so they're very close. They are the 3/8 pushrods from Kenne-Bell that I purchased many years ago. They're showing wear at the point where they pass through the hole in the head. I'm planning to order the 5/16 ones from TA on Monday in the stock length to eliminate the pushrods rubbing on the head. So, after all that what am I overlooking? I know it's something simple but what? I drove the car 30 miles from where I was working on it to my home. It ran well, but at traffic lights I could hear the clattering. And my hearing isn't what it used to be. Anyone have thoughts on this?
If you can hear it from behind the wheel at traffic lights, that’s a problem. Some cams are noisier than others, but lifter quality has sucked for awhile. If the lifters leak down too fast because of sloppy tolerances, they will be noisy when hot. Is it all of them or a few?
3/8 pushrods are too big for the heads. They rub on the head and make all sorts of noise. Change those for 5/16 and you'll be ok. I had the same issue years ago.
Thanks for the advice guys. My new 5/16 pushrods arrived yesterday and I haven't had an opportunity to install them yet. We had a thunderstorm Friday with a lot of downed tree limbs that took the power lines out. We have electricity back this afternoon so tomorrow I'll be out in the garage working on the Buick.
