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Rocker slipping


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#21 bullzed

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Posted 30 December 2010 - 07:34 PM

Cheers Steve, much appreciated  :)

I have checked the valves and they're all good, getting some new rockers on Saturday and then I'll have to see what happens after they're in.

I've got another Z mate trying to find out what's caused all this. I shall update as things happen.

Cheers

Zac

#22 bullzed

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Posted 30 December 2010 - 11:29 PM

Haha, I've been helped out quite a few times on this forum already. I need to find out how to adjust the pivot height. Is it simple? Would it be possible for you to give me a short run through?

:)

#23 RB30X

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Posted 31 December 2010 - 07:27 AM

Those bolts with the round head on them that one side of the rocker sits on like a cup, those bolts can be lifted or lowered by screwing them in or out. The other nut on those bolts is to lock them in position once set. If you look back at your own pictures you can see that these bolts are all different heights which is what these gurus picked up on straight away. I believe you adjust the height according to your valve clearance. With both ends of the rocker touching the top of the valve and the top of the ball headed bolt, you wind the bolt up so the is X amount of clearance between the cam lobe and the lash pads.

How did you go with finding replacment rockers?  I've got two complete L28 heads which I'd prefer not to separate but I could remove the rockers for you if you're desperate.

#24 bullzed

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Posted 31 December 2010 - 09:49 AM

All the valve clearances were fine, what would you use to measure the distance between the cam lobe and the lash pad seeing as they're not directly under each other?

I've sourced replacement rockers from Paul in Brisbane, he has a Z graveyard which has helped me a lot in the past. So far I've only checked 2 rockers for their condition, hopefully they don't all have deep wipe patterns.

#25 RB30X

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Posted 31 December 2010 - 10:04 AM

Valve clearances are fine? How did you measure that.

The lash pads "should" be directly under the cam lobes and you use feeler gauges to measure the gap. Clearance specs are in the gregories manual.

#26 Enzo

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Posted 31 December 2010 - 10:54 AM

Hey RB30X,
              Your quote (The lash pads "should" be directly under the cam lobes) 
As Gary Coleman would say:
                    "What chew talkin bout"
The Lash pads are on top of the valves. Directly under the cam lobes is the rocker wipe pad.

Bullzed.
        Valve clearences should be checked between the back of the cam lobe and the rocker wipe pad. That is with the lobe facing away from the rocker.
Also since you have a oiler cam, check with a thin piece of wire that the oil holes are not blocked on the lobes that have worn rockers. And as Salty has suggested check all the rockers for a wipe pattern that does not extend off the ends of the hardended wear area. The lash pads look to be reasonably tall so I presume this is an aftermarket camshaft. With standard valve spring retainers the maximum thickness of the lash pad should not exceed 170 thou.
Regards
David.

#27 RB30X

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Posted 31 December 2010 - 12:08 PM

Whoops. Me no speak no americano.

#28 bullzed

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Posted 31 December 2010 - 01:40 PM

Thanks for clearing that up guys. I've checked the oil holes (when we had it running without the rocker cover on), they're all working perfectly. The wipe patterns are really deep and some of the rockers are chipped. It's apparent that there's something wrong there as others said they'd never seen the 'deep' wipe patterns before. This is an aftermarket cam however all the work was done by the owner of the motor before me. The cam is an E30, i'm not up to date with all that so I would have no idea what lash pads are needed. What measurement shouldn't exceed 170thou?

I measured from the bottom to where the rocker sits in the lash pad and it's 6.76mm (0.266 inches [is this the measurement that shouldn't be exceeded?]). Another thing worth noting is that the lash pads spin freely, is this normal? The rockers are bouncing out so much that it's giving the lash pads time to spin.

#29 bullzed

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Posted 31 December 2010 - 01:47 PM

for about 15 seconds yeah. Didn't know which valves were affected

#30 PZG302

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Posted 31 December 2010 - 02:00 PM

Where in Brisbane are you? I'm not sire of my movements over the next few days, but I should be able to take a quick look at what's going on with these rockers. What you're describing should not be possible with everything working as it should. Sounds like whoever set up the head got something very wrong.
Matt

#31 bullzed

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Posted 31 December 2010 - 02:04 PM

I'm over in Chapel Hill. Your help would be massively appreciated. I can tell there's something incredibly wrong with the state of the rockers and the fact that the rockers are jumping out of the lash pads!!

I'm home the 1st and 2nd of Jan but work 9am - 1pm on the 3rd. I'm only 17, so, don't be surprised hahah.

The name's Zac.

#32 PZG302

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Posted 31 December 2010 - 02:08 PM

No worries Zac, pm me your contact details and I'll try to get over on the 2nd. Tomorrow looks like it will be a lazy day to recover from tonight  ;D

#33 bullzed

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Posted 31 December 2010 - 02:13 PM

PM sent

Haha, enjoy your New Years, quiet night in for me  ::)

Cheers again.

#34 xa1973

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Posted 31 December 2010 - 09:23 PM

  when i set up motors with ground cams i sometimes end up with 6 to 8 different size lash pads, that my friend is a good job, there are so many variations wouldnt it be nice if they were all the same , lash pads come in 10 thou increments , this is the idea ,adjustment, if there all the same obviously not much adjustment has been carried out , i have a kit that has 14 different size lash pads to juggle and set up cams with,, mind you checking each valve requires a somewhat patient attitude


Ditto... ;)

Im more concerned about this " new cam grind " and the valve train as a whole, sounds like someone bit off more than they could chew and only did half the job required to match the new cam specs, driveway warranty at its best...Im also curious to read the verdict

#35 peter mc

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Posted 31 December 2010 - 09:55 PM

Dazzed and Salty you are both correct in what you are saying the valves do have to be exactly the same height to start with but the lash pads need to be individually fitted as there is no predetermined thickness lash pad to use with a reground cam because many variables effect the thickness needed.
The only sure way to determine the correct lash pad thickness is to check the cam lobe wipe pattern on the rocker arm rubbing pad.
Therefore it must centered other wise the wipe pattern will go off one end of the rubbing pad resulting in the destruction of the cam lobe and rocker arm. 
There is all so other checks that help, i like to be sure that i have the same lift with a dial indicator if you have diffrent lift numbers you have not done it right. As your rocker arm ratio will not be right, the max variation between valves should not vary by more than 0.005 inch

#36 peter mc

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Posted 31 December 2010 - 10:41 PM

yer it nice when the valves are the same height it makes the job a hole lot nicer. its when you put a cam in a engine that has been around and you have to have 12 diffrent shims that when you earn the big bucks....hahhah

#37 bullzed

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Posted 31 December 2010 - 10:56 PM

so far you keep spitting out rockers , now your running out to get another set to spit out  and , why dont you get a specialist to set it up properly so you can gain the maximum benefit from the cam and tune it up , another set of rockers will not help you.


No offence but I find your tone a little condescending. In no way do I intend to just swap my rockers out and think it's solved the problem, I'm not that ignorant. I intend to let Matt have a look at the head to determine what really needs to be done.

I don't want this thread to turn into an argument about personal setups, I will update everyone as I learn more about the head setup from Matt.

I appreciate most of your guys patience with me and my lack of knowledge but I would prefer to be treated with more respect by others.

Cheers

Zac



#38 peter mc

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Posted 01 January 2011 - 09:41 AM

yer it hard to give addvice and try to explane things to people that have not got the experience and time under the bonnet i find it very hard to give a simple explanation to a very complex problem  with out sounding like a prick...

#39 Lurch ™

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Posted 01 January 2011 - 11:05 AM

Lose the attitude you lot or I'll lock this topic.

#40 bullzed

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Posted 01 January 2011 - 01:53 PM

Cheers heaps Steve, I'll definitely read up on these things.

Apologies Lurch.  :-\




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