Well I didn't think I'd be making one of these threads so soon after finishing my build but here it goes LOL! I'm running a '69 400" Pontiac with with an Isky cam in. Can't recall the specs but it's got a good lope to it. Still streetable with a 2500 stall converter. Anyway... When I first adjusted the lash (with poly-locks) #3 exhaust valve rocker nut didn't want to tighten down as much as the others. (Going by the method of feeling the pushrods while the engine was cranking.) I just left it that way figuring maybe that one lifter was already pumped up or something. Stupid haha. So I've put about 250 miles on the car and everything seemed ok til the other night I noticed a noticable tick coming from the top of the engine. I pulled the rocker cover off and and noticed that #3 exhaust rocker SUPER loose! So ok I tightened it down to where it seemed snug again fire it up. Instantly hear crazy rapping under there. O boy! Pull the rocker cover off and there is the rocker, poly lock and the top half of the rocker stud laying in the top of the head. AWESOME! I figure it had been running so loose it damaged the rocker stud and then when I tightened it down it just finished her off. LOL so I get a new rocker stud, put it in and rotate til I know I'm off the lobe. UH OH. It tightens down noticeably lower than the other rockers... So here is where I'm looking for some advice. I started the engine once I had it snug and it seemed ok. No backfiring or anything. But seriously that one poly lock is down on there an extra 1/4" compared to the other ones and no oil is coming through pushrod while it's running. So what is it boys? Wiped lobe? Collapsed lifter? Both? No choice but to pull the intake off and inspect? I love it! Let me have it!
Check for a bent or broken push rod. Make sure the push rods aren't hitting the guide slots in the heads. Are you running 1.65 rockers? Check all the push rod guides for binding.
I smell an opportunity for more lift!! Haha! I'm really thinking it's a collapsed/damaged lifter. All the pushrods are good. Stock ratio rockers. No weird wear on anything. The pushrods all rotate nicely, the engine runs fine as it is right now. Just that one poly lock is adjusted so far down. It's almost like I've got 15 hydraulic lifters and one solid! Maybe I'll just drive and pray that the one lifter doesn't magically decide to pump up.
Could it be that the new stud is a little longer making it look like its adjusted down lower. Are these screw in studs? If they are pressed in could it be the others are starting to pull out? Just a thought....
Great read! I love your at***ude...'Oh well, it broke. Better find out why and fix it.'. Awesome. Keep us updated. More lift is better lift.
Wow a Pontiac and it actually runs, I'd just be happy with that. naw ya might try a compression test if the cam or valve are screwed up it should show up, goo luck.
Go after it, why wipe the block out over it? its a pain but maybe cheap to fix now, nobody likes blowin up their stuff.
get rid of the poly locks and the pontiac studs. use chevy bb studs and nuts and adjust the valves like a chevy. i have done it that way on all the ones i have worked on and never had a problem.
Dude. Ok you're definitely right. After I admit to all my stupidity in the following few sentences you guys are all gonna laugh, then you'll be like 'O jeez what else could he have done worng??' So... First of all the big culprit was this... 15 Pontiac rocker arms and ONE mystery rocker arm. In my defense, my dad and I were building our cars simultaneously using the same garage and shed. Somewhere along the line we must have mixed up parts and I ended up with ONE rocker arm from an Oldsmobile or SBC or something. Ayway, they all looked similar enough that when I did my initial engine ***embly, I missed that one somehow. The main difference was that the oddball rocker arm was slightly shorter and the pushrod oil hole was in a different location. (thus no oil coming through) That was the problem. That rocker arm was close enough to work but different enough to eventually break the rocker stud. And trust me I ran these rockers on the edge of loose to be safe. All the others are fine but that one was excessively loose and it took its toll on the stud. THEN when I went to order a new stud, I bought the studs for a SBC instead of a BBC. The thread sizes are the same but the Pontiac has a larger shank size for the rocker to sit on. Also the SBC stud is almost exactly .25" longer than the Pontiac stud, thus making it appear that the poly lock was down further like shizzle said. So I made some goofy mistakes. I don't believe my engine was damaged in anway. I measured the movement of the pushrods and they are all even so I don't believe I have a collapsed lifter or wiped lobe. I need to get the right stud, a new rocker arm, and I'll be back on the street. Probably with 5 more horsepower. LOL!! I LOVE HOT RODS!!!!
your optimism makes me think my engine problems might not be so bad after all! Thanks for the lift man. good luck with it.
The way I look at it is - If something doesn't break once in a while it means you aren't driving it. Haha. I gues I forgot to mention, my engine started make noise after I did a 4000rpm 150ft peg leg burnout leaving the local hang hot rod spot. I just stayed in it til shifted gears WOOOOOT All KINDS of fun!!!
Nice find. I've been down that wiped cam route and it ****s to start spending more money when you thought you were there finaly. Good luck.
Well that was my first thought, but my grand father lived by the words 'Check the simple stuff first.' I was like, 'Lets poke around under this rocker cover for a while first.' LOL If I was all negative nancy about it, I would've seen that one sloppy rocker arm in there, thrown up my hands and started pulling intake manifold bolts out... Eh I'll probably still wipe a lobe off one day. Just throw another one in there and change the oil. What does it take? 200$, 6 beers and an afternoon? Haha we don't build these cars to save money and heartache. Gotta love the whole shebang!! (I was a little surprised at only getting 9mpg though LOL) Maybe I just need to wear silk ballet slippers instead of these lead lined boots
It did sound like a collapsed lifter from what you first reported. Running that good, I'd highly doubt a wiped lobe, the guts fall right out of the thing at that point, no performance. Good detective work. Bob
I'll keep you apprised of any juicy developments. You want me to drop your name? BTW, here's the bike mostly put together...sans the rear fender and taillights. Those crazy comic book guys make up their mechanics...I just copy it (about 20" from right to left) P.S. I now think that clicking noise is from the trans....I'm thinking maybe a loose torque converter bolt or flexplate issue. Also think the lash is too tight on the p***enger side..the engine rocks on that side when it gets mega juice. Anyway....I'll get the pipes on it when I get back, get it tagged, and we'll go out and tear our sh*t up together ;P
Sick man. that looks insane. No doubt it's gonna go over well. Is that all gonna be painted before the show too? I'm so pumped because I'm getting my first two pieces printed by PCS tomorrow. Small pieces but a big deal to me! haha. Just tell whoever you talk to, to look out for me in NY. Thanks for all your help bro. I look forward to turning more wrenches with you.
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