Cylinder Head Torques.

[rocketsteve]

I have a small oil leak on the left cylinder head on the lower corner just below the ignition switch, it was leaving a bit of mist before but today it's let out a few drips.

Not what I'd call major but I'd like to nip up the head bolts on that side - if anyone has the cold torque figure it would be much appreciated...

[V8Bikers]

Is it a ZZ4 or LS ?

[GordonBH]

It's a ZZ4 385cam

[rocketsteve]

Yep that's the one, year 2006.

[V8Bikers]

I did some researching and it is 65 ft lbs.

[GordonBH]

Steve,

Check the rear of the manifold, mine has a weep from there that runs down to the head's mating surface with the block.

If it is a head bolt job remember the sequence (tons of internet pictures are there for reference)

[rocketsteve]

Thanks Bill, I'll remove the manifold and check them all before anything else.

Was hoping it's the rocker box gasket Gordon which would have been easy to fix but that's all clean. Oil leaking from the exhaust manifold would be very alarming, worn ex valve guide possibly! but it's the head gasket area without doubt.

Looks like all the Brits are in the wars at the moment

[GordonBH]

Hi Steve,

Keep us posted if you find any loose ones, the recommended procedure is do them in 3 passes, increasing torque until the 3rd pass is at 65 - but that's from totally loose. You'll be clicking that wrench for the whole weekend!

I am hoping mine (reverse) is an electrical issue as the alarm is also acting up wierdly - e.g. re-arming when idling! and once went off during idling so I'll tear into that first. I am assured that as long as I have a neutral light it won't impede the starter but the alarm is highly likely to be the starter issue culprit. Will keep you posted...

[The Mindless Philosopher]

I had recently re-torqued mine for a similar reason (mine was slowly oozing oil).

An internet image search for ZZ4 cylinder head torque sequence will yield plenty of accurate results. I had a link to a .pdf file but it expired, however, 65 lb / 88 nm is indeed the magic number.

[rocketsteve]

Okay, I found a Youtube video for SB Chevy and will take some time out to release then re-tightening all 17 bolts as indicated.

https://www.youtube.com/watch?v=f5SsJJDQLq0

[The Mindless Philosopher]

Okay, I found a Youtube video for SB Chevy and will take some time out to release then re-tightening all 17 bolts as indicated.

https://www.youtube.com/watch?v=f5SsJJDQLq0

Out of interest MP - did re-tightening your bolts fix your leak?

Yes, it did. No more annoying mild oil seeping.

[rocketsteve]

That's good news, there's hope for me yet...

[rocketsteve]

My plan of action this week is to remove all left bank roller rockers and exhaust manifold, torque down in 3 stages as suggested and if no bolts move at 65 ft/lbs ~
I'll be left with no other option than a top end strip down and new gaskets.

Lets hope those rear head bolts move before the wrench starts clicking!

[rocketsteve]

Update from this morning;
Lower bolts 4 & 7 below the Exhaust were loose on the 2nd pass at 50 ft/lbs and all 8 lower bolts below the Exhaust were loose on the final pass at 65 ft/lbs.

The two hexagon nuts on the Exhaust manifold were also loose and might explain the different Exhaust note noticed on the Left side.

I've asked Tom at Mountain Boss Hoss if he can let me know the Rocker Bolt tightening technique so I can get the bike back on the road soon, lets see if the lower loose bolts were the cause...

[GordonBH]

Hi Steve,

Sounds like that would cause it.

I'll do mine in the winter as it's barely noticable but still not bone dry.

Stupid question time - you removed all the rockers because you can't get to ANY of the headbolts? or you can on some but you wanted to do a proper job?

I could do without setting the preload on all the rockers if I could get away with it.

[GordonBH]

Hi Steve,

There are loads of videos on youtube eg:
https://www.youtube.com/watch?v=LpkrNouFauA

or
https://www.youtube.com/watch?v=8ROU7D-6meY

Also I found this tip:
When setting the valves in the number 1 firing position you may adjust
Exhaust 1, 3, 4, 8 Intake 1, 2, 5, 7 the number 6 firing position is one revolution from the number 1 firing position.

In the number 6 firing position you may adjust
Exhaust 2, 5, 6, 7 Intake 3, 4, 6, 8 this information was in my Chevrolet shop manual.

I'd welcome any comments on this minimal engine turn technique as it saves a lot of time and hassle TDC-ing 8 cyls.

To all:
Any tips on turning our bike engines to get #1 at TDC firing position - there is no access to my harmonic balancer it looks like only slowly turning my alternator nut is an option. I plan on marking my balancer to determine a further full revolution of the crank to get to #6 firing position.

And...

with a 385 cam how about a 1/4 turn of pre-load to maximimise power, will I get a lot of tappet noise when warm? (I can accept cold start up taps)

[Orlando606VetteTrike]

When replacing my cam on my 502, I originally used the top dead center technique and in doing so broke a rocker stud. Replaced all studs with ARP and performed the EO/IC method. Exhaust Open/Intake Close. No issues after that. Google it.

[rocketsteve]

Hi Gordon, Rocker arms do need removing to gain access to inner Head bolts.

https://res.cloudinary.com/dgn40u2mq/im ... jmsynp.jpg

This guy seems to do a good job and makes good reference to hydraulics that we have at the end of the vid;

https://www.youtube.com/watch?v=9mbxIkb4JTM

Simple enough to do with this guy's 2nd technique above - you don't need to know cylinder TDC's which is good for us and just flick the Kill Switch to jog the engine over on the Starter.

My only question is - is it 1/4, 1/2 or full 1 turn on the Rocker Arm bolt - I'm waiting for Toms reply...

[knockdolian]

Gordon, this is a a question as I don't know. To turn the engine can you not pull the plugs, put it in gear and raise the back wheel. Is the gearbox mechanical. Other than that can the starter motor be removed and turn the engine with a screw driver. No idea if either is possible especially starter removal as obviously turning the engine via transmission won't work with a trike.

[GordonBH]

Hi Paul
The auto transmission means a fluid link so I intend to bump it with the starter and plugs out. I will use the EC/UP method as that seems a safe and accurate, after all I am not dialling in a can.

I am just awaiting the preload advice. Steve is running zero lash I feel some lash would be good for the lifters so I'm leaning towards 1/4.

[rocketsteve]

Just a quick note about Wag's advise in the BIG book, a torque value of 75 ft/lbs (101 nm) is mentioned.

I only noticed this late last night.

[GordonBH]

Hmmmm I've only seen 65 j must look up the book when I get back from a very hot London.

[rocketsteve]

The wait continues for Tom at MBH to confirm the lash on our Factory fitted Hot Cams...

[rocketsteve]

Tom got back to me late last night with apologies - he's had a busy time with his Open Day lasting 1 week

So, Tom recons a 1/2 turn in from the point of Zero lash.

I don't want to risk burning the edges of the valve skirts so
I'm thinking of trying it at Zero first - as the worst thing that can happen is I get a tapping noise which can then be fixed with a 1/4 to 1/2 turn back in the workshop.

Happy days.

[Imzz4]

I would use Tom's suggestion of 1/2 a turn and not zero. Hydraulic preload is the distance the pushrod plunger is depressed below the retaining lock. Preload should be between .020"-.060" for the lifter to perform properly. With too little , the valve train will be noisy and the retaining lock may fail (break or pop out) due to excessive hydraulic force against the retainer. Too great a preload (more than .060") will produce excessive lifter pump-up, causing the valves to open longer and lift higher.
If your rocker studs are 3/8-24 , then each full turn of the nut is .041" . That means 1/2 to 5/8 of a turn puts them in the right place so long as you are at zero lash and at the right lobe position ..