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Old 02-27-2010, 12:19 PM   #1
gr8hse67
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Need help with 327 valve adjustment

Working on a 1966 327. I have heard that their is a method to adjust the valves a side at a time by setting the first cylinder and so many portional turns down the line to get the adjustment. Anyone know what that formula might be and can pass it along?
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Old 02-28-2010, 08:18 AM   #2
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Re: Need help with 327 valve adjustment

Welcome to AF . None that I'm aware of are accurate. There's a spot that would position engine to set half the valves and then re-position the engine to set the other half. It would not be setting one "side" at a time though. The Motor manuals will explain how.
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Old 02-28-2010, 09:04 AM   #3
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Re: Need help with 327 valve adjustment

As said a good repair manual has that procedure in it.
HYD or solid lifters?
If HYD lifters.
I always use the old machinist true timing check method way.
Bring no 1 cylinder to TDC compression and make sure the opposite firing cylinder is on valve rock one opening and one closing.

On chev V8 the opposite firing cylinder on opposite the other on dist cap.

Like No 1 TDC compression the opposite firing cylinder is no 6 cylinder.

Then adjust valves one no one cylinder and the rotate and adjust valves in firing order when the opposite firing cylinder is on valve rock.

Some lifters are 3 turn to bottom lifters. and some may be more or less.
The good book says center the lifter haft way.
But I always leave the a little loser.
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Old 03-06-2010, 09:01 AM   #4
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Re: Need help with 327 valve adjustment

If the engine was apart, you have to do the initial lifter adjustment with the engine off. I don't think its 3 turns, but refer to a good manual, Motors or Chiltons should be fine.

You can bring #1 up to TDC like others suggest and go one by one. The firing order is 18436571.

You can do them in pairs as well, it saves turning the engine over a bunch of times:
1 with 6
8 with 5
4 with 7
3 with 2

Since all the spark plugs will be out, you can double check to make sure the right pairs are on TDC at the same time. I like to do this with the intake manifold off as well so I can SEE that the lifter is up on the top of the cam lobe.

After the thing is back together, do a running valve adjustment. Loosen the rocker nut until it clacks loudly, tighten it slowly until it quiets down. This is the "zero point". Tighten it a 1/4 turn, wait for the engine to settle down, go another 1/4 turn for a total of a 1/2 turn. Some manuals say go to 3/4 of a turn total, I play it safe especially if everything is used. Repeat for the other 7cylinders and you're good to go.

Bob
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Old 03-08-2010, 08:34 AM   #5
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Re: Need help with 327 valve adjustment

WAIT!! Firing order on GM V-8's is 1-8-4-3-6-5-7-2.
With all due respect, DO NOT follow the advice in the post just above this one! At least not the part about adjusting them in pairs. The cylinder pairs listed are both at Top Dead Center (TDC) at the same time. What that means, is while Cyl #1 is at TDC on the Compression (firing) stroke, with both valves closed, in perfect position for adjusting both valves, Cyl # 6 is also at TDC, but it is during the transition (overlap) period from Exhaust stroke to Intake stroke, meaning BOTH VALVES of Cyl #6 are partially OPEN, and CAN NOT be adjusted!
I do agree with the advice from same guy about not tightening Hydraulic lifters beyond 1/2 turn max, (after achieveing zero lash), I stay at 1/4 turn, with new OR used parts. Less chance for lifter pump-up to cause valve float at higher RPM's. NEVER exceed 1 full turn, which will bottom-out most hyd lifters!
Here is where you will find the advice you asked about - (And NOTE, there is NO procedure that lets you adjust a full side at a time - NOT possible). Go buy a copy of How to Rebuild your Small-Block Chevy, by David Vizard. It is either an HP Books publication, or a Peterson Pubs book. Available at most large parts stores, (Advance, Autozone, O'Reilly, etc), or from Amazon.com, where you can get used copies for a couple $. GREAT book for all SBC people. It will give you the procedure on how to adjust all 16 valves using only 2 crankshaft positions, which does save time. Some Cyl's you can adjust both Int & Exh at same time, but most are doing the Int at one crank position, and the Exh at the other position. I don't recommend adjusting while running, oil splatters everywhere, even with those worthless clips you can buy.
Option #2, more time-consuming, but nothing is more accurate: The EO/IC method. (Exhaust Open/Intake Closed). Engine builders do it this way in every major form of racing. You do one cylinder at a time. Remove all sparkplugs for ease of turning engine. If you can get a breaker bar & socket on crank snout, I recommend that method of turning engine, but you can bump the starter instead.
For each cylinder, turn the engine until the Exhaust rocker/valve just begins to Open. (EO). At this point, you adjust the INTAKE valve for that Cyl. Then rotate until the Intake valve you just adjusted opens, keep going until it just closes. (Intake Closed = IC, now you understand EO/IC). When it has closed completely, now you adjust the EXHAUST valve for same Cyl. Proceed to next Cyl. You can do them in firing order, or by one side then the other, or in ANY order you like, just do both valves for each cyl sequentially.
As for how to adjust the valves, when you get the crank positioned for a given valve, back off the rocker nut about 1-2 turns to loosen that valve, then slowly tighten it with a ratchet, while your other hand rotates the pushrod between thumb & forefinger. Just twist it back & forth, that pushrod will spin easily until the lash approaches zero, and it will snug up and get tighter, and harder to rotate. At that point, you've removed all the slack, (lash), and so now you just need to pre-load the hydraulic lifter by tightening the rocker nut 1/4 turn more. Stop, you are done. Move on to next valve. For solid lifters, you would not pre-load, but instead of the pushrod twist, you'd have the proper feeler gauge in between the rocker & valve stem. It is really simple, and once you do a couple of cylinders, it is an easy routine to follow. I highly recommend it, that is how I do them on new builds, and in-the-car.
Note: Once you have adjusted hydraulic lifters, there really should never be a need to adjust them again. Occasionally, a really old rocker nut may lose it's self-locking ability, and become a bit loose. But if one or more cam lobes ever wear enough to cause the lifter to lose it's pre-load and make noise, you have much more serious trouble than simply adjusting the rockers. They should stay quiet for well over 100,000 miles, as long as the oil is changed regularly. Good luck!
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Old 03-09-2010, 04:34 PM   #6
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Re: Need help with 327 valve adjustment

Best to do hyd lifters with the engine running. It is the easiest way.
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Old 04-04-2010, 02:28 PM   #7
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Re: Need help with 327 valve adjustment

I had a 1968 327 in the 1968 Impala that I used to have, it had hydraulic lifters to adjust them I rotated the engine until the push rod I was working on was a far down as it was going to go and then tightened down the lifter until it was no longer loose and wobbling around, I did that to all of the cylinders and then fired up the engine and then slowly tightened them until they stopped clicking.
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