Cylinder Head Torques.

[GordonBH]

This is getting like an oil thread...

I got a response from Rhodes Performance in PA. It's where MBH goes for their engine work. they set the 385cammed SBs at 1/8 - 1/4. Note that they are performance machinists and power is their God.

Am I right in thinking we run 1.6:1 rockers? if so I don't want to over lift the valves AND I also definitely don't want to risk a retainer clip failing on me as I quite often play hard in 1st so I'm leaning towards the 1/2 zone.

I reckon I won't know the power difference between 1/4 and 1/2 turn but will notice if a retainer clip busts!

[rocketsteve]

Jeff; the theory is all good and I follow the logic but the dilemma is now that while waiting for Tom to reply I removed the Right Rocker cover and checked the Push Rods & Rockers on that side - and they were all Zero lash which brought me to my current reasoning of duplicating it on the Left side...

Gordon; There were no Clips removed during this process - what Retainer Clips do you mean?

[GordonBH]

Hi Steve,

The retainer clips or "uper snap rings" or IMZZ4's "retaining locks" (like circlips) are those that hold the hydraulic lifter plungers inside the lifter body, the pushrods sit in the plungers.

IMZZ4 and Internet research inform that the preload avoids the hydraulic pressure and possible plunger striking its retaining clip on upwards travel at higher revs - when it can either be pushed out or break under strain. More preload reduces power through extra work operating the lifters (increased pump up) and also can increase valve lift/opening - and more besides I'm sure, the experts can chip in...

I keep seeing references to increasing power and rev limts through smaller turns and zero lash - I've seen quotes of up to 500rpm more at peak revs - everyone to their own but I am tending towards the 'normal' power of our engines and longevity, which is enough for me.

[Imzz4]

Gordon, I agree. Most of us are not into squeezing every Hp out of our fun toys. Some yes ,and thats great.
Who knows if whoever set those rockers were really at zero in the first place, or, perhaps over time ,the valves simply worked themselves into the head a bit , or both ?
What I enjoy is that everyone always questions exactly what is the best way or the right way to fix or adjust something especially when it comes to "their" bike or trike. That's what a lot of the fun is ,when you finally decide for yourself that you've searched enough and it's time to put the wrench on it and move on. And everything will be fine until it isn't and then you start the process again !!! How many V8 owners have excellent hind-sight?

[rocketsteve]

Good points raised there, one thing I hadn't taken into account was wear & tare over time.
I'll get to resetting a 1/2 turn before the next ride.

Always open to good ideas, applied logic and fore-sight ~ I think this is why we've achieved the milestones of 55+ years riding and survived this long.

[GordonBH]

Good point IMZZ4, who knows who adjusted them last, or if they used the TDC on 1 and set 8 valves then the turn to get #6 on TDC and set the others, maybe one wasn't perfectly on TDC and the cam not on its heel.

A number of factors can induce a difference. You only truly know when you do it yourself. I may not be the best mechanic but I am the one I trust the most

[rocketsteve]

So, after all this time it's confirmed the oil is (now dripping) from the Intake Manifold at the rear.

Top Man Tom from MBH, bless him has sent me an Inlet Gasket set free of charge so I can take care of the fix, next Spring now, but UK Customs & Excise are keeping it because they want £30 Import duty!

This was free = there was no exchange of money = no cost incurred!!!

So WTF is that about?

[knockdolian]

So, after all this time it's confirmed the oil is (now dripping) from the Intake Manifold at the rear.

Top Man Tom from MBH, bless him has sent me an Inlet Gasket set free of charge so I can take care of the fix, next Spring now, but UK Customs & Excise are keeping it because they want £30 Import duty!

This was free = there was no exchange of money = no cost incurred!!!

So WTF is that about?

The should have put gift or exchange item on the custom form. God bless UK customs !!

[Jack]

How does tightening a head bolt stop an oil leak anyway? I know you've since come in and said that it didn't, but I don't know how it could have in the first place.

[rocketsteve]

Would have helped Paul but I suppose I'll have to talk to them now.

Jack, I have very sneaky oil and it's been carefully running down the back of the heads to make it look like the head gasket is going/gone.

The black sealant used front & back of the Inlet manifold has let go and I don't want to lift the manifold to put new sealant in without having a new gasket set standing-by.
I'll be ready for any torn gaskets during dis-assembly now.

[Jack]

Got it Steve, thanks.
My valve covers leak... just can’t find a replacement set, so I need to glue them on.

[Orlando606VetteTrike]

My 502 was seeping oil too and driving me nuts. I too found it was from the manifold rear rail area. I cleaned off all old sealant and oil residue. Placed a vacuum on the motor, and used Three Bond 1184. It's slightly runny, so I applied it multiple times. No more leaks.

[rocketsteve]

I worry about those rocker cover gaskets, they're very soft and just hope they last. You'd think Chevy stuff would be easy to get hold of especially in the States?

Good fix there Gerry, I've got some Soudaflex 40FC Mastic Polyurethane, similar to the black stuff already on the manifold so hope it works.

Wonder why they didn't put a gasket back & front.

[Orlando606VetteTrike]

I was told by numerous engine builders that those rubber gaskets that were used in there were not as good at sealing. So most just use a thick bead of sealant.