need advice! fitting my yt rockers ECOTEC

[vsdore]

i'm in the process of fitting my 1.9 ultra light rockers YT6651 (for the 2nd time).

i tried last weekend, and found that they all have about a 3mm clearance at TDC ie between pushrod and rocker tip. so figuring i had the wrong pushrods or something in the kit, i put the standard stuff back and rang YT on mon. they said yeah the ecotec lifters bleed down a bit, so just crank the engine with out the ignition & fuel pump relays they should come back up.

so, finally got some time this morning to have another go, same problem even after cranking it. now, the whole point of hydraulic lifters is to eliminate gaps, so i am worried about firing it up!

has anyone fitted these themselves and can give me any guidance??

thanks in anticipation...

[TheIceman]

in all my years as a motor mechanic never have i seen hydraulic lifters with clearance, even brand new ones, the springs in the lifters will close the gaps, the cranking the engine to pump them up is a wank wank as it wont close any clearance. only exception is if ya lifters are seized in their original spot but cant see 12 lifters all seized.
once you undo the standard rockers, the lifters will push up to their maximum lift and when you fit the new ones there should be absolutely no clearance what so ever, if there is it will never be taken up as the lifters are already at their maximum internal lift if u get what i mean. you need to know how lifters work to understand fully. at TDC doing the standard rockers back up would open the valve slightly until they bleed back down with the valve pressure on them.
u got the wrong rockers and pushrods by the sound of it. check your part number make sure they arent for a different model V6 or that the right package contents are in there. wouldn't be the first time ive seen mispackaged engine parts.

[VY CHRISSO]

Yeh Mine Bolted up Tight, straight away, Don't fire it up!!

Take em back with ur car and let them gaurantee they are the correct ones.......... Bet they are not!!

[vxcalais_01]

Someone else on this or another forum had a similar issue, only thing is his motor was sitting for a while and had the clearance gap. He just bolted them on, and yes they ticked for a few seconds but eventually the lifters bled up and all good now(just in the last week or so)........so there is also the possibility they are the right parts......

[VY CHRISSO]

So in saying that, with the lifters containing a metal spring to keep them at full hight, the lifters would need to experience Vaccuum instead of Oil Pressure to do this...????

OK, I could understand one or two lifters have been found to be at their lowest point, due to dirty oil etc, but not all of them at the same time......

Yes lifters can bleed down, Loose oil Internally, but this does not mean they drop to lowest point..as spring keeps upper seat at highest point, not only for assembly, but also to keep them together in a maintenance situation... OK one or two springs could be broken, But not all of them....


I wouldn't be firing it up, unless the first post is an exaguration of the truth.....

[vxcalais_01]

rotate the engine by hand and see how it goes ?

[TheIceman]

Originally Posted by vxcalais_01

Someone else on this or another forum had a similar issue, only thing is his motor was sitting for a while and had the clearance gap. He just bolted them on, and yes they ticked for a few seconds but eventually the lifters bled up and all good now(just in the last week or so)........so there is also the possibility they are the right parts......

if they are bled down there would be movement in the lifters but still be no gap unless you pressed on the rocker arms to move them and compress the lifter.
And yes they would be rattly for a few seconds after startup but at no point would there be a 3mm gap with it sitting there, lifter would take it up.

[vsdore]

thanks for the replies, first post was no exaggeration i can assure you.

i had turned it by hand, double checked all pedestal bolts, then cranked it again, still the same. and yes the pedestals were all seated perfectly in the alignment plate.

just put the standard stuff back yet again, no clearance at tdc again. cranked it by hand to check all the cyls, all good. fired it up, all normal thankfully.

so. i'll ring yt again on monday i guess, wish i was in vic so i could go see them. i can't believe they are the right parts.

still would like to hear anyone else's experience in fitting 'em...

[chargedvx6]

What other mods are done to ur engine, if any?

[vsdore]

engine internals are all stock, 127,000km, full service history. i've just done the usual since i've owned it - CAI & HM Headers, Redback exhaust.

[TappetHead]

We have found in a number of cases that the V6 lifters can stay compressed and do not always come up with just the internal spring, they often need oil pressure to pump them up.
The YT rockers are set up to have less lifter pre-load than the factory rockers so it's not uncommon to have some gap before the engine is fired.
The difference is not 3.0mm though, it's more like 1.0mm or a little under.
Here's a few things to check:
1) Make sure you remove the factory mounting guide and use the steel pedestals and aligning plate supplied.
2) Make sure the pedestals are fitting into the aligning plate and that they are the right height. They should measure 12.30mm from the bottom of the pedestal to the base of the curve on top.
3) Are you fitting the rockers with the trunnions the correct way up. The flat section goes up and the curved section goes down.
4) Check the push rod length, they should be 7.290"
5) If all the above check OK then there is something different in the engine set up to normal.
The most likely is a re-ground camshaft with reduced base circle, in which case the lifter preload will need to me measured carefully and longer pushrods used.
Other things that can affect the amount of pre-load are: Valve length, head gasket thickness, machined head or cylinder block joint faces.

Cheers.
Mark.

[vsdore]

Mark, thanks for your reply.

1) Make sure you remove the factory mounting guide and use the steel pedestals and aligning plate supplied.
- Yes I used all those parts, and of course removed the factory mounting plate - did you receive my email with the pic?

2) Make sure the pedestals are fitting into the aligning plate and that they are the right height. They should measure 12.30mm from the bottom of the pedestal to the base of the curve on top.
- Yes I tapped the pedestals into the alignment plate as was advised to do on the phone. That measurement is correct for mine.

3) Are you fitting the rockers with the trunnions the correct way up. The flat section goes up and the curved section goes down.
- Yes - you can make it out in the pic i emailed too.

4) Check the push rod length, they should be 7.290"
- Yes, mine match that.

5) If all the above check OK then there is something different in the engine set up to normal.
The most likely is a re-ground camshaft with reduced base circle, in which case the lifter preload will need to me measured carefully and longer pushrods used.
Other things that can affect the amount of pre-load are: Valve length, head gasket thickness, machined head or cylinder block joint faces.
- As per my email, the old couple that owned it the previous 8 years wouldn't drop in a reground cam! Plus, the exisiting rocker gear is all factory.

So even if the lifters do pump up if I was to fit the YT gear a 3rd time and fire it up, I just don't want the possibility of that sort of clearance everytime I stop the engine. It's just not worth the risk to a low km engine like that.

I'll PM you now about what can be done.

Thanks again...

[TheIceman]

Originally Posted by TappetHead

We have found in a number of cases that the V6 lifters can stay compressed and do not always come up with just the internal spring, they often need oil pressure to pump them up.

on what? engines that have done over 900,000km and serviced once every 200,000km and all sludged up??