Quick dumb question - rockers

[McMuttley]

When Macy says:

 

"When the #1 valve has opened fully and just starts to close..."

 

.... does that mean when the rocker arm has pushed the spring down furthest

 

..... or the other way round ?

[Geko]

yes, the first one

[RogerH]

Hi Austin,

yes.

 

Roger

[Peter Cobbold]

Austin,

Adjusting tappet clearance? - to be sure the clearance is fully open use 'sum of 9'. So when rocker 4 is pushing on its valve and 'on the rock' you adjust #5. Etc. Peter

[peejay4A]

I find Mark Macy's method more reliable.

[PhilipB]

What camshaft are you running? Not all valve clearances are the same. See the link. Most are 0.010 - 0.012 but the Revington /Kent cams are 0.022 - 0.026

 

http://www.tildentechnologies.com/Cams/TriumphCams.html

 

Phil

[McMuttley]

Thanks all, I wish I hadn't asked - see below.

 

Phil - no idea - all I have is a 1989 quote (not finished build spec) for a fast road engine - pretty good history file from then, but mention of a new cam - and just a few months before Steve Hall bought a computer !

 

However, measured, measured and measured again (wish I still had a fan blade as the ratchet didn't want to stay on the nut and my knuckles are shredded on the rad)

 

OK, so the first measurements (using a metric feeler gauge)

 

Front =1, back = 8

 

1 - 0.20 mm

2 - 0.15 mm

3 - 0.20 mm

4 - 0.40 mm

5 - 0.25 mm

6 - 0.25 mm

7 - 0.30 mm

8 - 0.15 mm

 

I then found another feeler gauge and wondering if there different spring compressions in the cycle measured three times (measuring at compression and just after) and got the following (in thou):

 

1 = 8

2 = 0 .........NO GAP (tried and tried again - but no gap) ???

3 = 8

4 = 11

5 = 10

6 = 9-10

7 = 12

8 = 6 - 7 t

 

What the heck is going on there ????

 

Notably the rocker where I could get no gap appears to be bronzy in colour - No.2 - second right.

 

The spark plug that was sooty was No.2

 

 

[Geko]

1/ The sooty plug means nothing relevant at this stage. Drive it as if you stole it for a long ride, then check again.

2/ Even the bigger valve clearance on exhaust cyl 2 is not relevant to the sooty plug.

3/ If you have the knack try to adjust the valve clearance with the engine running. Much easier ;-)

[peejay4A]

Back to the beginning Mac. Try the Macy method.

 

For cylinder 1 rotate the engine until the inlet valve just starts to CLOSE, ie just after full compression of the spring. Adjust the exhaust valve clearance for cylinder 1. Rotate the engine until cylinder 1 exhaust valve is just beginning to OPEN. Adjust the inlet valve clearance for cylinder 1. Repeat for the other cylinders.

 

There's more turning involved than for the rule of 9 method but less chance of forgetting where you got to but make sure you keep track of which is inlet and exhaust for each cylinder.

 

PS. I don't know if Stef was being ironic but don't bother with adjusting with the engine running.

Edited May 2, 2016 by peejay4A

[Lebro]

1 - 0.20 mm = 8 thou converted for comparison

2 - 0.15 mm = 6 thou

3 - 0.20 mm = 8 thou

4 - 0.40 mm = 16 thou

5 - 0.25 mm = 10 thou

6 - 0.25 mm = 10 thou

7 - 0.30 mm = 12 thou

8 - 0.15 mm = 6 thou

 

I then found another feeler gauge and wondering if there different spring compressions in the cycle measured three times (measuring at compression and just after) and got the following (in thou):

 

1 = 8

2 = 0 .........NO GAP (tried and tried again - but no gap) ???

3 = 8

4 = 11

5 = 10

6 = 9-10

7 = 12

8 = 6 - 7 t

 

 

Either you measured No. 2 while the wrong "other" valve was down (should be No. 7) or sommat's wrong !

 

Bob.

Edited May 2, 2016 by Lebro

[Peter Cobbold]

I'd be happy with the first set, ready to give the engine good shake-down run before re-torqeuing the head and readjusting tappets.

But I would not expect tappet clearance to cure that tickover misfire. Thats is either a duff plug or something along the way to the plug from the disy rotor arm.

Peter

Edited May 2, 2016 by Peter Cobbold

[McMuttley]

Thanks all, as much for practicing the adjustment as anything, I have been through using the rule of nine and set all to 12-13 thou, but couldn't run its as it was too late in the evening..

 

By rule of 9, I mean, No.1 compressed just about to open, then set gap on No.8; 2/7; 3/6......... 8/1.

 

I assume this is correct?

 

Not sure why the original settings were so different? Is there anything wrong with setting all to 13? Many historic threads refer to 10/12, 15/15 or 20+.

 

Despite suspicion of fast cam (noisy) my original settings would have been way way too low for the Raceytorations like suggestions of 20+.

 

I therefore assumed that 13 was a sort of safe bet ?????????

[Lebro]

13 thou is the correct gap for engines with aluminium rocker shaft pedestals.

 

(between you & me mine are set to 10 thou to make engine a bit quieter !)

 

Bob.

[peejay4A]

Thanks all, as much for practicing the adjustment as anything, I have been through using the rule of nine and set all to 12-13 thou, but couldn't run its as it was too late in the evening..

 

By rule of 9, I mean, No.1 compressed just about to open, then set gap on No.8; 2/7; 3/6......... 8/1.

 

I assume this is correct?

 

Not sure why the original settings were so different? Is there anything wrong with setting all to 13? Many historic threads refer to 10/12, 15/15 or 20+.

 

Despite suspicion of fast cam (noisy) my original settings would have been way way too low for the Raceytorations like suggestions of 20+.

 

I therefore assumed that 13 was a sort of safe bet ?????????

No. The valve you're not adjusting should be fully open. I use 10 thou for them all with my fast road cam. Edited May 2, 2016 by peejay4A

[McMuttley]

eck, now I am confused.

 

Macy's website reads:

 

"When the #1 valve has opened fully and just starts to close, adjust the #8 valve (1+8=9). "

 

I had read that as meaning, that at a moment after spring 1 has reached full compression (No.1 valve open?) I should adust the gap on No.8; which conveniently has a gap??

[Lebro]

Yes that is correct, just think of the camshaft have two cams - the 2 lobes being 180° round from each other.

when one lobe is upright (12 O'clock) the other will be at 6 O'clock.

well the valve you are looking at is connected to the 12 O'clock lobe, & the valve you are adjusting is the 6 O'clock one.

 

Well that is how the cams are arranged on the shaft, to find which cam is opposite the one you want to adjust use the rule of 9.

 

ie. valve 7 fully down (open), adjust valve 2 etc.

 

Bob.

 

 

 

" By rule of 9, I mean, No.1 compressed just about to open CLOSE, then set gap on No.8; 2/7; 3/6......... 8/1.

 

I assume this is correct? "

Edited May 3, 2016 by Lebro

[Geko]

To cross-check, get to the dummy method:

Balance/ Adjust

cyl 1/ cyl 4

cyl 2/cyl 3

cyl 3/cyl 2

cyl 4/cyl 1

Where "Balance" is the point where both valves are fully closed (one just closing, the other one about to open - on the same cylinder)

If you have one pesky valve clearance after that - which you shouldn't- try adjusting it with the engine running at idle (no oil splashing to the head below 1200 RPM). I does take some skills though....

[Andy Moltu]

The method Peter Cobbold describes is the simplest - simply number the valves 1-8 from the front - if say valve number 3 is fully depressed - take 3 from 9 and measure no6. if no8 is depressed measure 1.

 

With the 6 cylinder engine the rule of 9 becomes the rule of 13.

[McMuttley]

OK, I think I am doing it right (except for confusing spring opening with valve closing !)

 

I will look to close the gap from say 12-13 to 10-11 ish

[peejay4A]

Yes, you said in your post that the valve was just beginning to open when it should be fully open if you're using rule of nine. That's why I responded.

 

Try Macy's universal method as I outlined it above. It's really very easy.

 

PS if you don't have oil splashing around at idle then you have an oil feed problem. Also you wont be able to reliably adjust screw and locknut with the rocker bouncing around.

Edited May 3, 2016 by peejay4A

[Stevecross]

I have used the rule of 9 method for years.

 

I have a small tin of grease to hand and put a small spot on each rocker as I adjust it. Easy to see which ones have been done.

 

Stef's "running " method can be tricky when actually adjusting but is a great way for a quick check of clearances and identifies a noisy tappet straight away.

 

Steve

[stillp]

I wouldn't bother reducing those clearances. Too much (within reason) just means they might be a bit noisy. Not enough means the vanves won't close properly and will burn.

 

Pete

[RogerH]

Hi Bob,

due to a very small oversight I can state that the old tractor engine will run nicely for a fair few years with a 0.004" rocker gap.

 

My 0.010" feeler gauge turned out to be a #10 gauge on my metric feelers - #10 = 0.1mm = 0.004" (apprx).

 

It was nice and quiet though.

 

Roger

[tim hunt]

Really Roger, with you being an engineer and all I am surprised you didn't realise the gauge you were using for all that time couldn't possibly be ten thou!

 

Tim

[RogerH]

Hi Tim,

every now and then I surprise myself about how stupid I can be.

Thankfully no damage done.

 

 

Roger