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#21
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427 Chevy aluminum head head bolt washers work perfect.
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#22
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Jeff |
#23
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'...I simply tightened the rocker nuts (I upgraded to BBC studs) to 20 foot pounds and buttoned it up..."
Sorry, but I don't understand this , at all. You used BBC studs, which are 7/16, all the way up. Then tightened the nuts to 20 foot pounds ??? Since there is no bottle neck to stop the nuts, does that mean that you simply tightened the nuts 'til they ran out of threads on the studs, and at 20 ft lbs the adjustment was just right ??? If this is the case, were these factory BBC studs, or some aftermarket brand, and what was their length above the head, & what was the length of the the threads ??? Please help me understand this. I suppose that if the lower end of the threads are only very slightly too low for the correct adjustment @ 20 ft lbs, you could put washers under the studs. ??? And, for those who wanna use the factory bottleneck screw-in studs & nuts, but have had some cut off the deck & heads, the washer under the stud method might work ??? Last edited by ponyakr; 04-14-2019 at 03:09 PM. |
#24
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Unless you installed longer pushrods or installed the springs at a different (taller) installed height, there would be no geometry issues. Valve recession does not typically exceed the hydraulic lifter's ability to take up the "slack" in the clearance.
I think you just missed the boat on doing the adjustment on the base circle of the cam. With the valley cover off, it is pretty easy. The intake closing/exhaust opening method gets a little complicated.
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Triple Black 1971 GTO |
#25
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Quote:
Clay
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All the federales say,they could've had him any day They only let him slip away, out of kindness...I suppose Poncho & Lefty |
#26
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Quote:
If done by the method you suggest, you tighten the nuts to 20 ft-lbs with the lifter on the base circle. If you aren't on the base circle, you will never know what you have torqued the locking nuts to since it takes about 55 ft.-lbs to get the nut to bottom out as you compress the valve spring. It doesn't work.
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Triple Black 1971 GTO |
#27
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Thanks for all the info guys. It's a stock head that has never been off the engine with stock pushrods and rocker arms. It's not a valve to piston clearance issue regarding sticking nor is it bottom end related as it'll rotate just fine with the rocker arms backed off. I know that the lifters and pushrods should be tight once torqued down, but they should also spin slightly too when the lifter is at the most relaxed (base of the lobe). I checked 3 other stock-ish engines I have here and they both spin the pushrod and lifter (not easily when the lobe is fully up and valve open obviously).
I've done a few engines over the years and I have a decent idea of what it should feel like, which is why I stopped once I noticed that the two cylinders did not want to cooperate. I got #6 adjusted correctly and it "feels" like it should, slightly springy with very little movement when you push down on the rocker arm and the pushrod will rotate with the lifter. Clay's suggestions got me thinking and I think he's on to something. This morning I got a quick minute before church to check things out and noticed that several of the lifters were a little reluctant to compress but started to when I leaned on them a little. They also soaked in oil overnight so maybe they were a little sticky due to sitting on my shelf for the last decade? I also bopped the top of the valves in question with a rubber mallet and they opened and closed slightly, so perhaps the 2 valves are just sticky from sitting? They just turned 47 years old last month after all... I'll resume work on it tomorrow and see if the combination of soaking the lifters in oil longer and manually opening the valves freed something that was just a little "off" and I was being overly cautious to avoid damaging hardware. (I have a '73 455 on the stand next to it and it has 2 bent pushrods in it even though it ran fine, so it's definitely possible to screw something up) |
#28
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No reason why you can't double check the preload the same as you do for polylocks or crimp nuts with the standard Pontiac torque-to-spec nuts. With the lifter on the base circle of the cam (choose your favorite method), bring the nut down while feeling for zero preload. Once you achieve that, the nut should only go another half to full turn before bottoming out. If you have to turn the nut over a full turn before bottoming then you can't use the stock method - and it's time to go with crimp nuts or polylocks.
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Mick Batson 1967 original owner Tyro Blue/black top 4-speed HO GTO with all the original parts stored safely away -- 1965 2+2 survivor AC auto -- 1965 Catalina Safari Wagon in progress. |
#29
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Ah, that makes sense, sticky valves. Old school was to use transmission fluid to loosen them up. They probably have some fancy stuff for that now.
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#30
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Possible!
Quote:
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“Nothing in the world can take the place of persistence. Talent will not; nothing is more common than unsuccessful men with talent. Genius will not; unrewarded genius is almost a proverb. Education will not; the world is full of educated derelicts. Persistence and determination alone are omnipotent. The slogan Press On! has solved and always will solve the problems of the human race.” ― Calvin Coolidge |
#31
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SB Chevy head bolt washers. Buy a set of 34 and you will have 2 sets and some extras.
My first thought was that the cam is in wrong. Still think that
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GOOD IDEAS ARE OFTEN FOUND ABANDONED IN THE DUST OF PROCRASTINATION |
#32
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Why?
What is wrong about it?
__________________
“Nothing in the world can take the place of persistence. Talent will not; nothing is more common than unsuccessful men with talent. Genius will not; unrewarded genius is almost a proverb. Education will not; the world is full of educated derelicts. Persistence and determination alone are omnipotent. The slogan Press On! has solved and always will solve the problems of the human race.” ― Calvin Coolidge |
#33
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Larger base circle?
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68 Firebird, trying a q-jet now. 434/10.5:1/997's/240-242 HFT/4L80E/2800 Yank/3.42's/ Vintage Air/ 13.0 @105 mph 70 Lemans, 350/350, A/C, mostly stock 14 Ram CC, 5.7 Hemi, 8-speed, 3.92 lsd 97 Trans Am, HPP Aug 2012 http://www.highperformancepontiac.co...tiac_trans_am/ ***Sold*** |
#34
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Just a follow up: let the lifters sit a few days and 3 that were sticking freed up just fine and the rockers tightened to 20 ft-lbs and all valves now open and close correctly. Verified compression on all 8 cylinders too. Engine is fully assembled and ready to drop on car once it stops raining...
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#35
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Nice.
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1964 Tempest Coupe LS3/4L70E/3.42 1964 Le Mans Convertible 421 HO/TH350/2.56 2002 WS6 Convertible LS1/4L60E/3.23 |
#36
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Think I'd squirt some oil on the valve stems and let it seep down the guides before I fired it up. Just might help prevent some galling if rusty guides had the valves stuck.
Clay
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All the federales say,they could've had him any day They only let him slip away, out of kindness...I suppose Poncho & Lefty |
#37
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I use a tiny dab of moly paste on the rocker balls and ends of push rods (@ rockers), also dribble some oil over the tops of rockers before starting.
My engine builder was a player in the alky dragster world before he retired from driving (his own car, which he did ALL the work on...). Between rounds when servicing the valve springs, he had a foaming lubricant he would shoot through the valve springs, after checking each spring...
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1977 Black Trans Am 180 HP Auto, essentially base model T/A. I'm the original owner, purchased May 7, 1977. Shut it off Shut it off Buddy, I just shut your Prius down... Last edited by 77 TRASHCAN; 04-20-2019 at 03:17 PM. |
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