Valve spring and stem seal questions

CORVETTE SPECIFIC - Applicable to all or most models

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australi
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Postby australi » Sun Jun 24, 2012 12:41 pm

I agree with you Doc. Valve seals easy to do (if you can be bothered to DIY).
Retainers come off no problem in situ. I've done it on motorbikes. I have all the tools including the air connector to sparkplug holes, just didn't get around to buying the lever type spring compressor, but only 50 bucks or so from walkers auto one.

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68ragtop
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Postby 68ragtop » Mon Jun 25, 2012 9:32 am

Thinsg are starting to fall into line. Have the tools (thanks Doc), have a compressor coming later in the week, got some umbrella seals coming from ebay later this week. Now just doing a bit of reading on the process for handy tips, like put the car in gear to lock the crank to stop the air pushing the piston down when air is applied just in case it was slightly off TDC.

Azza

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riverracer
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Postby riverracer » Mon Jun 25, 2012 5:07 pm

68ragtop wrote:handy tips, like put the car in gear to lock the crank to stop the air pushing the piston down when air is applied just in case it was slightly off TDC.

didnt do that with mine a few months ago.
took all the plugs out, covers off, removed all rockers and push rods (kept in order)
put air fitting into #1 cyl, dosent matter if engine turns as piston blows down
tap on retainer to loosen collets, bolted lever to stud, levered down on retainer, used magnet to carefully remove collets.
removed spring, washed and checked for damage
cleaned valve stem and surrounding area of all evidence of old seal, placed seal on stem
replace springs and retainer, carefully replace collets
removed lever and gave the retainer a quick tap to check collet seating
remove air fitting, then proceed to next valve along, then next cyl, then other side
then replace the push rods and rockers with a dob of assembly lube on valve stem tip and top of push rod,
replace balls and nuts

then proceed to adjust rockers as follows

from my collected engine notes


Step-by-Step:
• Park the car on a level surface. Set the parking brake and block the tires. On manual cars, put the trans in neutral.
Pull the coil wire that goes from the distributor cap to the ignition coil (on HEI cars, disconnect the connector out of
the distributor) and ground it.
• Turn the engine over until you can see the timing mark on the harmonic balancer. Using a piece of chalk or other
visible marker, place three more timing marks on the balancer: one mark every 90 degrees around the balancer (one
exactly opposite the factory mark, and two in between these marks: just get it pretty darned eye-ball close, it doesn’t
have to be exact.)
• Remove the valve covers. You may have to remove some accessory brackets in order to do this.
• Rotate the engine over (either by “bumping” the starter or by inserting a socket and breaker bar onto the harmonic
balancer bolt) until the factory timing mark lines up with “0.” Observe the pushrod for the exhaust valve on the #1
cylinder: if the pushrod moves as you come up on Top Dead Center, you’re on the exhaust stroke, and you need to
rotate the crank one more time. If neither pushrod moves as you come up on the timing mark, you’re on the
compression stroke and ready to go.
• Loosen the adjustment nuts on both the rocker arms for cylinder #1 using a deep socket and a ½” drive ratchet.
One at a time, adjust them as follows:
• Place the pushrod between you thumb and forefinger of your left hand (or right hand if you’re left handed…).
Rotate, or “twirl,” the pushrod back and forth between your fingers and notice how lightly and easily it spins. As
you do this, slowly tighten the rocker arm nut. The instant you feel the “twirl” friction change between your fingers,
you are at “0” lash. STOP. Now, notice the position of your ratchet handle. Tighten the nut exactly ½ turn from
your current position. Do the same to the other rocker arm for #1 (when doing this, make sure that the friction you
feel as you swirl the pushrod is not caused by your ratchet and socket pushing or binding on the rocker arm – keep
things straight and aligned, and watch for false indications caused by your tools). That’s it for #1.
• Now, here’s the trick:
What’s the firing order for a GM V8?
1-8-4-3-6-5-7-2
How often does a cylinder fire in a V8?
Every 90 degrees
That means we can now rotate the crankshaft 90 degrees at a time, and go right to the next cylinder in the firing
order for the valve adjustment, with confidence that both of the valves for that cylinder will be closed and ready to
adjust.. So rotate to your next chalk line, and adjust #8 as described above. Rotate to the next line and adjust #4.
After you’ve rotated the crankshaft twice over (using the starter and “bumping” is the easiest way), you’ve finished
your valve adjustment! No oily mess, no worrying about if you missed a valve. Just a nice, simple, structured
procedure!
• Pop your valve covers back on with a fresh set of gaskets, re-install any accessory brackets you’ve removed, and
start it up with confidence. You now have a correctly adjusted valvetrain that will operate quietly and with
outstanding performance and reliability.:
Speed has never killed anyone,
Suddenly becoming stationary that's what gets you.

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Postby 68ragtop » Thu Jul 05, 2012 9:44 pm

Thanks for that post riverracer. Was sorta what I had figured out already. Finally got the time and tool this evening to start having a crack at things. Got air compressor, spark plug adapter, spring compressor, new standard springs, new o-ring and umbrella seals (just in case one or the other was needed)

Took out plugs, removed fan, removed rocker covers and started turning crank via bolt holding balancer. First handy thing is that TDC was correctly marked as well as every 90 degrees. Also some off marks about intake valves opening anc closing but not sure which they match up to yet as it isn;t quite #1
Image

So got things at TDC on #1 and powered up the compressor. Tried to build up some pressure but found leaks in the adapters at both ends of the hose meant 90psi was all it will build up to. Still was enough to hold the valves up while replacing the springs for #1 cylinder.

Took off the rockers and springs ok. Found trick flow 7.200 pushrods in there that look to be wearing/rotating just fine. Found that the guides on the heads look to have been machined down to .580 so I can probably go with some viton seals in the long run. Took a pic here.
Image

The seals that were in there seemed to be solid plastic things but were about .600id so actually just seemed to float on the valve stems. Not sure what whey were. Threw on the rubber umbrella seals as figured they'd be a better option than the old ones. Adden the new springs and put the rockers back and adjusted to 0 last + 1/2 turn.

Just in case you were wondering what the state of the bits I removed was, here's a sample. Fortunately the valve stems still look ok despite the bits and pieces rattling round.

Image

So 1 cylinder down, and that's about where I stopped for the evening. Have a few questions I need to look into.

1. How the hell can I get the ait tool adapter into the plug hole for #3 cylinder. Appears I have a nice big steering box in the way.
2. New springs are about 1/16" shorter than the old ones. Old ones seem marginally stronger as well. Not sure if this will matter too much or if the new will be strong enough for the job at hand.
3. Where are the misisng bits of plastic seal hiding in the oil galleries of the engine? Could be time to pull the filter and sump and go hunting.

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riverracer
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Postby riverracer » Thu Jul 05, 2012 11:50 pm

with all the plugs out, i just turned mine over by the alt pulley nut

as for the air adapter, the one i used was only about 1" long with about 12" of hose then the air compressor snap fitting
about the same size as a spark plug
didnt have any problem of getting it in on any of the plug holes

the brownish seals are like what i removed/found and replaced with new on mine

the bits are probably rock hard/brittle and sitting in the bottom of the sump
possibly caught up in the filter mesh

change your filter if you like, then cut it open with a can opener
pull the paper filter folds open and look for the bits....

as for the springs, not sure, maybe give the supplier a ring and ask them
Speed has never killed anyone,

Suddenly becoming stationary that's what gets you.

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68ragtop
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Postby 68ragtop » Fri Jul 06, 2012 9:04 am

My problem is that the adapter plus the hose fitting I've borrowed is about 1/2" too long to get in teh gap between the plug hole and the sterring box.

Image

Have found a solution with a swivel fitting that shoudl allow me to get in tonight/tomorrow and finish things off enough to get me mobile to get to the show on Sunday.

Image

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riverracer
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Postby riverracer » Fri Jul 06, 2012 9:16 am

where the teflon tape shows between the spark plug adaptor and the air compressor adaptor, i had a 12" hose
Speed has never killed anyone,

Suddenly becoming stationary that's what gets you.

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australi
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Postby australi » Fri Jul 06, 2012 11:08 am

That adapter looks the plan! :o :o

Jesus - your seals were KNACKERED weren't they!? :shock:

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DOC
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Postby DOC » Fri Jul 06, 2012 6:42 pm

Never had a problem in my 77, Must be just a bit more room for some unknown reason, but also you can get a 90 degree fitting to go into the plug hole fitting. But your swivel looks the go as well.

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68ragtop
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Postby 68ragtop » Fri Jul 06, 2012 9:51 pm

Swivel fitting worked brilliantly. Until i got to #4 cylinder and had a hard time trying to get anything in behind the a/c unit. Anyone got a contortionist midget they can lend me to get their hand into these neat places. Got it in the end after much swearing. Now gotta take the hard fuel line out of the carby as its in the way of the spring compressor.

Slower progress but am learning a few things as i go which is always good. Should be able to finish things off tomorrow afternoon.

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DOC
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Postby DOC » Sat Jul 07, 2012 7:17 am

Yup, I remember the fuel line being in the way as it were on the wife's car. There's always something. But it is good to learn. And when your all done you will be just that little bit prouder of your car.

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ernbuild
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Postby ernbuild » Sat Jul 07, 2012 8:02 am

Anyone got a contortionist midget they can lend me to get their hand into these neat places.

No Midget, how about a trained spider with a rubber spanner?? :-x
adventure before dementure

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australi
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Postby australi » Sat Jul 07, 2012 11:08 am

:-x :)

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68ragtop
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Postby 68ragtop » Sat Jul 07, 2012 8:21 pm

All springs and seals finally done. Havent fired it up yet as have misplaced my new sparkplugs and threw the set i pulled away. For your entertainment or horror i present to you the full set of components found lurking under my rocker covers.

Image

Bazzas77
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Postby Bazzas77 » Sat Jul 07, 2012 9:45 pm

what a scrap metal collection :-x

you sound like me , leaving stuff all-about the sheds and not remembering where you left it ::

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riverracer
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Postby riverracer » Sun Jul 08, 2012 4:26 am

seals, they get old n brittle, to be expected, nitrile rubber/viton hardens with age
me thinks you mite have/had a coil bind problem...
to much lift on the cam for the installed height of the springs.
or the rocker geometry is out heaps, ie: to long a push rod
:x- :evil: :x-
Speed has never killed anyone,

Suddenly becoming stationary that's what gets you.

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68ragtop
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Postby 68ragtop » Wed Jul 17, 2013 11:31 am

Thought I'd update this post with the latest round of info.

After getting it all back together back then with new plugs I turned it over and set about adjusting the rockers. When putting it back together I has adjusted them so that I could just twirl the pushrod at TDC for that cylinder. then I got the car idling with the covers off and adjusted each rocker until they weren't chattering. Next I put the covers back on (still with the old gaskets) and ran her long enough for the engine to get up to almost normal running temp. At this point I took the covers off, and with her running I adjusted each of the rockers again, backing off and then tightening until there was no more chatter. Then I put about another 1/2 turn on each nut, sealed it up and it had been good ever since.

Until a few weeks ago when this happened...

Image

One of the nuts had backed off allowing the rocker to come free. Lucky nothing was bent or broken really. Tried putting it back in place and tightening it but after 2 minutes of test running it was coming loose again. Fix was to take the nut off completely, clean the oil off the threads and put it back together with some medium strength loctite I had in the shed. Ran it and tightened down the nut to stop the chatter just as before and then left it for a day for the loctite to cure. Checked it the other day and it's still holding on there nicely (and more importantly didn't come loose during my stint on teh track at Lakeside the other weekend).

Moral of the story, double check the valve lash again a month or so after adjusting the rockers. And possibly use new nuts on there if you're unsure of the ones that are on there.

Azza

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Postby Wayno77 » Wed Jul 17, 2013 7:35 pm

Bloody hell Aaron, that was lucky... :shock:

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DOC
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Postby DOC » Wed Jul 17, 2013 7:54 pm

The real trouble is, Arron didn't build this franken Engine. He bought it.
And really has no Idea of the Cam specs. Not really sure if he's running 1.5-1 or 1.6-1 rockers. Makes it hard to buy the right springs.

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Postby 68ragtop » Wed Jul 17, 2013 8:36 pm

Actually I measured and it was just 1.5:1. However it could really do with some pushrod guides to straighten/tighten everything out. Or just new alloy heads and hardware :)

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DOC
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Postby DOC » Wed Jul 17, 2013 8:43 pm

I hear ya! I've been dreaming of good alloy heads for going on 20 years now.
If only the bills would just go away!

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australi
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Postby australi » Thu Jul 18, 2013 12:03 pm

Bills NEVER go away Doc; they simply morph into other forms of bills or copies of the same ones with different due dates! :evil: :cry:

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Postby sirfixalot » Tue Jul 23, 2013 11:47 pm

The reason why the fourth rocker is loose it is probably on the back side of the cam for that cylinder Im sure if you turn the engine over it will change & you'll find a different one rocks side to side


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