Can't adjust valves, or just how badly did I screw up?

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mentalQtip
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Re: Can't adjust valves, or just how badly did I screw up?

Post by mentalQtip » Wed Jan 22, 2014 9:23 pm

Ok then. I guess I'll be looking to borrow a atv lift and starting to psych myself for pulling the engine. I admit that really intimidates me. Thanks for all the advice. I'll get back with results and feedback.

Thanks again

Joseph

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Marc
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Re: Can't adjust valves, or just how badly did I screw up?

Post by Marc » Wed Jan 22, 2014 9:27 pm

However, it's not at all unusual for there to be some discrepancy in valve installed heights if a valve job was done without scrupulous attention to it. Is #1 intake the one protruding more, or is it the exhaust that measure .012" "longer"?

If this is really a `77 engine it should've left the factory with solid lifters (engine codeletter "GD"). The US market didn't get the "GE" hydraulic-lifter engine until `78. Be sure to check the ID on the case itself and not the fan housing, which could've been changed.

Besides the lifters, the pushrods and rockerarm assemblies were changed. Certainly, a solid-lifter motor could've been converted to hydraulics during prior maintenance (it can even be done in the car on the Type IV) ...you should check and see if all components were updated or if it was done half-assedly. There's identification guidance here:
http://www.ratwell.com/technical/HydraulicLifters.html

If there are mismatched parts, it could account for the apparent "zero" lash - particularly if the valve is protruding slightly more.

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Re: Can't adjust valves, or just how badly did I screw up?

Post by mentalQtip » Thu Jan 23, 2014 12:03 am

Engine case says GD. the #1 exhaust is .012 in. longer.
Steel pushrods
Didn't find triple headed bolt between right pushrod tubes
Looks like hydraulic lifter pictures
rockerarm assemblies have springs beween the arms, not wavy washer
A mixture of parts

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Re: Can't adjust valves, or just how badly did I screw up?

Post by mentalQtip » Thu Jan 23, 2014 12:37 am

clarification. When I put a straight edge across all 4 valve ends, I measure .012 in space at #1 intake, so #1 exhaust is longer.

Hope thats clear

Joseph

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Re: Can't adjust valves, or just how badly did I screw up?

Post by Piledriver » Thu Jan 23, 2014 1:01 am

OK, is it hitting the valve tips or the spring retainers?

If I'm visualizing the way you are measuring it ...is probably reading ~25% lower than actual.
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Re: Can't adjust valves, or just how badly did I screw up?

Post by Marc » Thu Jan 23, 2014 1:34 am

Odds are that you'll end up doing major surgery if you want to be sure that it's right, but if you feel lucky you might want to finish the valve adjustment (I'm assuming that the rockerarm is not striking the retainer and that since you say you can drag a feeler gauge through, you'll be able to guesstimate where ½ to 1½ turns in from zero would be) and run a compression test...in the unlikely event that #1 has healthy compression you might choose to proceed with getting it running before condemning it over what cold be nothing more than a sloppy valve job.

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Re: Can't adjust valves, or just how badly did I screw up?

Post by mentalQtip » Thu Jan 23, 2014 11:12 pm

Piledriver wrote:OK, is it hitting the valve tips or the spring retainers?

If I'm visualizing the way you are measuring it ...is probably reading ~25% lower than actual.
Going back and checking again the straightedge is hitting the spring retainer of #1 exhaust.

Joseph

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Re: Can't adjust valves, or just how badly did I screw up?

Post by Marc » Thu Jan 23, 2014 11:55 pm

If that's the case, unless the tip of the stem was shortened dramatically during the last valve job, it would appear that the keeper grooves are chewed up and allowing the retainer/keepers to climb up the stem - one of the possibilities that PileDriver was concerned about a while back. It might be safe to go so far as to get it running to see if there are any more serious problems (like a rod bearing knock) without any repairs but there's a risk of the end popping off the valve and letting it drop into the cylinder so if you take this chance don't run it for long.
Piledriver wrote:...the seat may be sinking into the head or eroding, or the keepers are eating the grooves they are supposed to stay in.--- for anything but a chewed up valve stem it's going to need replaced, strongly suggest doing both heads.

If you do buy new AMC heads, make sure they have been fully reworked with new seats valves etc as the AMC parts other than the castings are like made from recycled bean cans and unlikely to go 50K miles.

Several places only sell them reworked like this, and for not much more than some other places sell the as-shipped from Spain units.

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Re: Can't adjust valves, or just how badly did I screw up?

Post by Piledriver » Fri Jan 24, 2014 1:28 am

OK, cool, that's almost a best-case scenario, assuming the tip vs retainer is not the same as the rest.
.
..if the whole thing is sticking out far enough it could still be the seat/valve, if the valve tip is still in the right place and the retainer ONLY is out of place, you may be in luck...

As Marc noted, a sunk valve tip vs. retainer is probably due to keepers that did not clamp on the valve stem properly, and are merrily chewing away at the grooves that "keep" them in place.

Most likely, that valve is toast, but valves are cheap.

I'd still pull both heads and install a new set of ex valves at a minimum, and grind the keepers so they do not touch each other.

There is probably a long argumentative thread somewhere about this subject, but AFAICT the valve/springs etc all rotate regardless of whether the keepers are properly locked down.

You have hopefully found the "pro" argument for grinding keepers.
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Re: Can't adjust valves, or just how badly did I screw up?

Post by helowrench » Fri Jan 24, 2014 8:14 am

Piledriver wrote: You have hopefully found the "pro" argument for grinding keepers.
I do not believe I have ever heard anyone (of any consequence) recommending not to fit the keepers, ensuring a gap of .010-.020 exists.

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Re: Can't adjust valves, or just how badly did I screw up?

Post by Piledriver » Fri Jan 24, 2014 12:44 pm

helowrench wrote:
Piledriver wrote: You have hopefully found the "pro" argument for grinding keepers.
I do not believe I have ever heard anyone (of any consequence) recommending not to fit the keepers, ensuring a gap of .010-.020 exists.
There have been heated discussions, some folks insist the valves won't rotate.
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Re: Can't adjust valves, or just how badly did I screw up?

Post by mentalQtip » Sat Jan 25, 2014 1:55 pm

If the lifters are clearly worn(flat) would there be any point in replacing them in an engine that probably has other issues? Would there be any benefit or maybe new ones might add stress to already suspect valves?

Joseph

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Re: Can't adjust valves, or just how badly did I screw up?

Post by Piledriver » Sat Jan 25, 2014 6:08 pm

Why do you say the lifters are obviously worn out?

There is a fellow selling a new Web 73 right now in the for sale section for dirt cheap.
(no association, just a potential customer, nice stock+ cam)

Webcam nitrides their cams... Google as to why and how much of a good thing that is.
(It also explains why Webs cams cost more)

You also need a set of lifters with a proper radius ground on them, oddly CB has the best reputation for lifters, although they still may need ground (ask Rocky or tencentlife if they are radiused properly or flat like the cheapie stock ones.

If you are considering staying hydraulic, note that it will cost more and is NOT the huge maintenance reducing feature everyone thinks unless you like rebuilding motors every 50K.

You do NOT need to go with hydraulic lifters but you will obviously need to score a set of stock aluminum pushrods, the steel ones you have are too short for (most) solid lifters.

The cheapie "stock" replacement lifters are ground flat, which is wrong in non-obvous ways...
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Re: Can't adjust valves, or just how badly did I screw up?

Post by Piledriver » Fri Feb 14, 2014 1:48 am

Did you ever have any resolution?
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Re: Can't adjust valves, or just how badly did I screw up?

Post by mentalQtip » Wed Apr 09, 2014 3:51 pm

No resolution yet. I have just pulled the engine and showed the 1/2 head ti a friend who said it looked fine. I looked all four lifters and pushrods and rockers and nothing looks any different to me.
I'm now trying to get the 3/4 head off and find that the oil cooler tin blocks the head from sliding off. Do I need to pull the
fan shroud to get the tin and head off?

Thanks for getting back to me.

Joseph

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