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Discussion Starter #1
Now that the brake system is back up to scratch I have a valve lifter that is "tapping" and is irritating. In my Chiltons manual is states to make the adjustment with the engine "off". I have been told that with hydraulic lifters it is best to adjust them with the engine running.
Which is the best method?
 

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Hydraulic Valve Lifter Adjustment

Um, cold or hot, it doesn't much matter for hydraulic lifters. See section 60-10 of the Opel Factory Service Manual. Set # 1 piston at TDC, firing position. Loosen valve train pivot nut until rocker arm is loose, tighten to eliminate looseness, then another full turn tighter. Repeat on other valve. Rotate to next firing order TDC. 1,3,4,2. Some prefer 1/2 or 3/4 of a turn, but the effect is the same.

All you are doing is compressing the internal spring a bit by depressing the lifter plunger. The spring then supplies a minimum "force" on the valve when they are closed, and the oil in the lifter transmits cam lift (and hence force) to the valve to open it.

If the lifter continues to tap, the valve may be sticking (not fully closing). Or the lifter is worn out, and won't hold oil pressure.

HTH
 

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Remember the oil deflector!

Please remember to put something over the timing chain if you decide to do the lifters while it is running. I have the actual Opel "tool" but anyone can make a quick and dirty oil deflector out of sheet metal or the front of a steel Kadett/Manta valve cover.

The mess if you don't cover the timing chain is awful. :eek:
 

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Another tack you can take is to cut the top off of an old valve cover--just the ribbed section at the top--& use it for running valve adjustments. The rocker arms can kick a lot of oil around, too.
 

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Hydraulic Valve Adjustment

So, why do you want to adjust the valves with the engine running? I do recall seeing an aftermarket service manual showing the chain splash guard and describing adjusting the valves with the motor running, but I believe this only applied to the early, non-hydraulic lifter (solid lifter) engine. The 1970-1973 Factory Service Manuals DEFINITELY state that the hydraulic lifters are to be adjusted in the manner I described above, and it also states that they can be adjusted hot or cold.

Or is there a secret here?
 

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Discussion Starter #7
Hyd Lifter adjustment

Very interesting;
This is why I posted this question because several mechanics told me that hydraulic lifters were adjusted with the engine running. What would be the does and don't of adjusting them with the engine running?
 

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FWIW, I've never adjusted Opel valves with the engine running. I've seen it done, marveled at the mess it created, and vowed to always do it on a non-running engine because of it! This would apply to both hydraulics and solids.

Bob
 

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i do hyd with the motor hot and running

i use a shield over the timing chain not that big of a deal

pretty sure Todd from Opels unlimited does it that way

and Marty also


Davegt74
 

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valve train pivot nut slipping?

As was mentioned in this thread and in the chilton manual I got with my '71 Opel GT the idea is to turn the engine to TDC for each cylinder then adjust the valve train pivot nut until all the "slack" is taken up and adjust one full turn after that.

Oddly, the car did not run at this setting.

Suspecting that the valves where not seating I re-did these to 1/2 turn (no-go) then finally 1/10 of a turn.

Ran like a top for about 5 minutes then I could hear that a couple had come back loose (tapping)

So.. the question.

Any tips on "locking" these nuts? Any reason why the car will not run at 1 full turns compression?

*I don't have a complete history of modifications on this car having owned for all of two weeks.

Great forum BTW!
 

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just went thru this over the weekend with my daughter Emily (11), who changed out a mushroomed lifter on Maggie the Opel.

The mess:

the timing chain acts as a pump, slinging oil all over the place. to stop this, cut a strip out of a milk carton and use the two front mounting bolts for the valvetrain cover to hold it in place. This eliminates 90% of the spray. A couple of towels in the engine compartment (away from the fan) pick up the rest.

The reason the motor won't run after the adustment:

If you do it 'by the book', the lifter does not have adequate time to discharge its oil, and it will lift the valve off its seat. Once off its seat, there's no compression, and the motor won't run. A 'hot' adjustment is best, but you have to approach the correct adjustment in 1/8-1/4 turn increments with a minute or two between adjustments to allow the lifter to pump down.

As for the nuts:

If you have an unlimited budget - buy new OEM Opel valve train nuts. If you're on a limited budget (or just plain cheap - like me) you can get the nuts to hold by re-compressing the cone.

The top of the nut has a tapered cone section. If you look closely, you'll see this cone is not round - it's kinda triangular. This is beacuse the nut was squeezed at the factory to help it 'lock' onto the stud. If you have a v-block and a drift, you can impart some more squeeze by giving it a couple of good whacks with a hammer. The same may be true with a vise - anyone have luck doing this another way?

BTW, Emily was so proud of her accomplishment that the old lifter is now sitting on her bed stand. Betcha she's the only 11-year-old in the country with an Opel lifter in her bedroom!
 

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A cheaper, more readily available alternative to the Opel locking nut is to use Chevy 60 degree V6 (2.8 litre) locking nuts. They're 10 mm X 1.00 thread like the Opel, and are longer-lasting as well.
A full set is dirt cheap.

Bob
 
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How to check if the locking nuts are backing off?

Just a tip.

I put a paint mark line on the lock nut and stud using red fingernail polish. If the nut loosens then you can see it when the line becomes broken due to the nut rotating. The fingernail polish is not bothered by the engine oil..........

Paul Crane
 

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Thank you

Thank you all for the tips. Still waiting for the chevy lock nuts (my favourite little shop had to order them) but I will be sure to post back when I get 'er running again!
 

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Well that was easy for a change.

1. Removed the dizzy cap and turned the engine over till the rotor arm pointed to no 4 plug wire.

2. Loosened off both rockers on no4

3. Squeezed the hydraulic tapper in a vice to discharge the oil.

4. Refitted and tightened down the rockers so they both had 3 threads protruding.

5. Ran the engine and it started and ran beautifully albeit tapetty.

6. As the oil warmed up the hydraulic tappers filled and she runs quite now.

Have ordered a vaccum gauge so I can check all that and do final timing tuning.

Still got a 5 second hiss coming from the brake booster/servo when I turn the engine off I think it's coming from where the elbow joins the servo.
 

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I think I've seen FirstOpel post this, but incase anyone missed it. A very easy way to get each cylinder to TDC is to put the car in 4th gear and then you can push the car while looking into the spark plug holes. There is a sweet spot where you can rock the car back and forth and it will feel lighter and the the piston will be at the top. I have a double pulley so this is the only way I can do it accurately without removing my radiator.
I adjust my hydraulic valves without the car running yesterday. I simply tighten until you can't shake the rocker and then turn 3/4ths. Works great with no ticking
 

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I use a 0.002 feeler gauge. Tighten the rocker till it just starts biting the gauge, remove it, then tighten the rocker nut another 3/4 turn. Simple, quick and consistent.
 
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