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BBC valve train troubles

5K views 34 replies 13 participants last post by  novass 
#1 ·
I'm in the process of putting on a new manifold and Holley Sniper on my 468 when I found some of my rockers are offset and wearing bad. I don't know what's causing them to sit off to one side. It almost looks like the valves are sitting wrong or the retainers aren't correct. They are 346286 heads and appears to be stock rockers. What can I do to correct this before it gets worse. I attached some pics, hopefully someone can see what's causing this.

Thanks!


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#2 ·
Gee-ma-neez.. at first I was going to say the guide plates need repostioned to line up the pushrods better, but the more I examine the pictures the more I see that looks un sat. Don't like the way the retainers look or are positioned either. Of course , the rockers are junk.

Have a valve spring compressor? I can send you a Lisle on engine one to borrow if not. You may need it.
 
#3 ·
Agree with 427, guide plates are "probably" correct but I've seen crazier things before. Those valve springs hanging off the retainers don't look good at all. I have a feeling those heads will be coming off.
By the way what fuel pump are you going to run with the Sniper? The in tank one?

Don
 
#7 ·
So if your guideplate is wrong its pulling the pushrod to the left. If the the guideplate is removed can the pushrod go any further to the right before it hits the head? Still have to address the valve spring and retainer problem though. Like to see what happens when you pull that valve spring off.

Did you have it running with the Sniper yet?
 
#8 ·
Did you have it running with the Sniper yet?
I just started pulling everything apart, I'm installing a Performer, Sniper, and Hyper spark ignition, that's when I pulled the valve cover and noticed my rockers. Kind of threw a wrench in my plans for a quick install! At least it's still cold and wet here so I can't drive in anyway.

I think I'll pull the guide plate and see how it all aligns up, then pull a valve spring and see what's up with them. I bought the car this last summer and it ran great, sure am glad I found this before it got worse!
 
#10 ·
Properly setup valve springs will go a long way in how well an engine runs.

Tell us a little more about this engine, miles, what cam, any modifications?

I'd highly recommend new valve springs, retainers and locks and while they're apart, new valve seals. Get a nice matched set of springs for your cam. Roller tipped roller rockers will do nicely too, get steel ones, not aluminum.

Most people put air pressure in the cylinders to keep the valves from dropping in when you take the springs off. A better idea I used was pull the plugs and, with the piston around BDC, poke into the plug hole about four feet of 3/8" nylon rope then rotate the crank until it stops. The piston will be pressing the rope against the valves.
 
#11 ·
Tell us a little more about this engine, miles, what cam, any modifications?
Unfortunately I don't know very much about this engine as I bought the car this past summer, I was told it is 79' 454 bored to a 468 and rebuilt about 5 years ago with less than 10k miles on it, I think it has a mild cam as there is a little lump in the idle, other than that it is stock from what I can tell. Again, not sure what springs were used on the valves.

Thanks for the tips!
 
#13 ·
I know you dont want to hear this but you might as well stop wasting time and just pull the heads right now. That one valve tip is beat to death and I am sure the rest of them are the same way. It is probably worn through the tip hardening. I have seen springs worse than that but it still doesn't make it right. The guide plates are probably a lot of the problem but it has gone too far to just move them.

Pull the heads and get them fixed properly. And I am not saying that because I own a machine shop :)
 
#18 ·
Agree 100%. And make sure you replace those guide plates after freshening the heads. I had a friend with the same problem on a freshly built 454 some years back. His problem was poorly stamped and formed (aftermarket) guide plates. Good Luck.
 
#14 ·
I've never seen a valve retainer sit so far off center with a spring and the position of the push rod coming up out of the guide plate is whats offsetting the rocker to the side. Maybe the guide plates have a big enough mounting hole that they can be adjusted to put the pushrod more on center. How does the rocker look on the other valve that the same guide plate positions that pushrod.
 
#15 ·
You know... I was ALMOST going to say the same thing, but not having enough experience, I hesitated only say " alot I dont like to see".

The pro is spot on. Pull 'em both. to me, a non pro, I don't like not knowing. You pull them off, and freshen them up, then you know its 100%. PS have you done a compression test yet? Not required, just asking.

Yeah, the Lisle is on "on head" compressor. I use it with a mag tipped machinists scribe to catch the locks. IT's MUCH easier to disassemble when they're up on their sides; and you can use a big C clamp compressor. And let the lock fall on the bench!

Not a bad thing. A bad thing would have been to plug all your EFI stuff on, and then have a poor running engine due to the valves. Which may have caused an undue amount of "failed tuning" on the EFi. Now THAT would suck bad. This dont.

PS, I found postioning the guide plates one of the least precise " sort of move it around until it fits" steps in head assembly. I did have to use Comp adjustable plates, with sort of bend in the middle allowing a better fit. Not on all the valve sets, but on a few. Once we had them set, I didn't use their set screw; I had junior weld them in that position. Log story short; I set them in loosely and wiggled them about and "eyeballed" the alignments until the pushrods centered on the valve stems.

Now that I've admitted what an amatuer I am, a pro may correct that procedure.

and do read up on rocker arm geometry. There is a thread going on now. VERY important on our BBCs.
 
#22 ·
I was offering to ship mine to lend you, but for a few more pennies than shipping to and fro, you could own one. Lisle 16750 Valve Spring Compressor.

But man... that dont look copasetic in too many ways to the naked eye. Pull 'em.
 
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#23 ·
I was offering to ship mine to lend you, but for a few more pennies than shipping to and fro, you could own one. Lisle 16750 Valve Spring Compressor.



But man... that dont look copasetic in too many ways to the naked eye. Pull 'em.
I really appreciate your offer, I was thinking of the same thing, I found used ones on Ebay for under $30 then I would have one. And yes, it's not looking like it's a simple fix, need to do it right the first tine!

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#24 ·
I found out a little more. All the intake rockers are off a little on the left side, the right side looks fine. I took off a guide plate from each side and exchanged them and the same problem exists. The heads have matching cast numbers so there aren't two different ones. It's like I need a different set of guide plates for each side.. the heads will need to come off just not sure why one lines up differently than the other. Need to do more digging.

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#26 ·
As I said Scott, I needed some adj ones to make a few lineup. One, BTW had a helicoil in the stud thread causing it to cant off a bit. ( "never been touched" the man said. Yeah. )

I'll say it again, these "porcupine" heads work well , and are durable, IF they are set up correctly. and "IF" is in the details. Be patient. You'll get good support here going along; lets get it done right!
 
#27 ·
Are the guide plates holding the push rods over to one side? maybe take one off and see how the PR aligns with the stud & valve stem?, does the PR show wear from rubbing the guide plate? edit: think someone did a bad valve job making the valves canted/angled differently? guess the guide angle would have to been all screwed up too, just trying to think out loud
 
#28 ·
I'm dealing with Peanut port heads, so, with what I'm finding I might start looking at a new set of heads, that way I won't be throwing money at sub-par parts and can invest in better heads.

I really appreciate everyone's input, I'm still at a lost on how these were put together wrong in the first place, it's SO obvious that they aren't aligned. At least I caught it before it dropped a valve or something worse!
 
#30 ·
Don't be to hard on peanut port heads. My last set I used were in the high 11's with just a little porting at home, new stock size valves and a valve job. Here is the best part, the 461 had like no compression 7.9 they are not sub-par heads by no means.
 
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#29 ·
PP heads have been proven here on TC with dyno and drag slip results that they can make good power but it sounds to me like someone really screwed your heads up some how and like you said it's really good you caught it, if you try to have your heads fixed I'd watch not to go to deep $ and any after market head needs checked unless you get them from a known reputable shop IMHO, I ended up (after 2 machine shops) at $1100 on a set of '69 "063" for my 454, X2 + a little that for my brand new pro built brodix heads with extra mods from Lewis Racing aka Wolfplace for my 489 I'm in no way trying to sell you on anything at all but be careful with auto machine shops telling you they can do things that just doesn't get done and you end up paying for it, sorry about the ramble but I'm still a little ticked about a local machine shop, also Vortecpro here has heads that are very reasonable that put out great power :thumbsup:
 
#32 ·
Heck I have a complete set of 1986 "140" ? RV heads w/studs, stamped rockers, balls &nuts I might have the stock guides with 22,4xx miles you can have, you pay the ride, and they worked fine on my 454 but I pulled them off in favor of "063's" but they're about 75 lbs. each and shipping would be $$$, and I'd toss in a new set of Mr. Gasket shim head gaskets PS I sprayed copper gasket seal on 1 gasket but never tried them
 
#34 ·
If you've got this kind of wear on several other rockers, check pushrods too. You would be wise to drain the oil and cut/inspect the oil filter for the metal in it. Material may have migrated throughout your bbc. If you find that is the case it may be best to pull and rebuild.
 
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