1.9:1 ratio rockers to suit Buick (non ecotec) V6's

[Immortality]

any head work, decking of block and/or heads will effect rocker geometry and lifter pre-load.

were the valves refaced?
did you have the valve seats ground?
how much lifter pre-load does it have?
are you sure it is hitting the rocker covers?

 

[LX_HATCH]

I think the valves were refaced.
The valve guides were done not sure on the seats.

How can you determine lifter pre-load?

Im pretty sure the rockers aren't hitting the covers as I have put the original covers back on and the noise comes back when it gets warm.

Im thinking as the engine warms up the valves pistons etc are expanding and I recon the valves are touching the pistons.

Plan is to put the stock rockers on which is a bummer as I have a drag day on Saturday.

Then pull the heads off next week and check if there is any marks on valves/pistons. And check the clearance with modelling clay.

Your thoughts?

 

[Immortality]

With a stock cam i would be very surprised if you have a PTV clearance issue.

To check lifter pre-load you need to undo one rocker when the lifter is on the base circle of the cam. slowly tighten the rocker until there is no play between the lifter/push rod/rocker. then you need to measure how much you tighten down the rocker until it is locked up. to much pre-load will cause the push rod to bottom out in the lifter.

Have you checked for coil bind at max lift?

 

[LX_HATCH]

No I haven't checked for coil bind.

How do I go about that?

Do I just check for clearance when the valve is fully open.

 

[LX_HATCH]

Whats acceptable lifter pre load. The crane cams website says 0.02"-0.06" (0.508-1.524mm)?

 

[Immortality]

No I haven't checked for coil bind.

How do I go about that?

Do I just check for clearance when the valve is fully open.

yep, exactly

when you installed your new valve springs, did they come with new retainers/locks or did you use the original ones?

Bart

 

[Immortality]

Whats acceptable lifter pre load. The crane cams website says 0.02"-0.06" (0.508-1.524mm)?

it varies between lifter manufacturers. will need to double check with Steve what pre-load they set it up with.

Bart

 

[LX_HATCH]

I used the original retainers.
I will be contacting steve next week, if he does not reply here

Will be fitting the original rockers this arvo, fingers crossed!

 

[MACE]

I think you'll most likely find that the oil you're currently using may be too thin. An indication of this is the tapping sound that occurs when engine is warm, when engine oil pressure drops.

It would be extremely unlikely that you have PTV clearance issues (unless you've shaved heaps off the block and deck) as the car would probably be running much worse given the loss in compression do to bent valves etc.

Coil bind definitely won't be an issue with the standard springs and retainers let alone with the crow ones you've been supplied.

The factory lifter crush we've found on a standard engine was around the 1.5 -2 turns of the rocker bolt or approximately 0.094" to 0.125" As the thread of the rocker bolt is 3/8" BSW 16TPI

Please keep us posted.

Cheers
Steve

 

[MACE]

I used the original retainers.
I will be contacting steve next week, if he does not reply here

Will be fitting the original rockers this arvo, fingers crossed!

Of course I'll reply here

I would try changing the oil to factory spec first though.

Cheers
Steve