Yella Terra Roller Rockers (LS1)

[SSUte01]

Last night I decided to fit up some 1.8:1 YTRRs that I purchased to the ute. It turned out to be a fairly simple procedure, much more simple than I remember from the old Small Block Chevs - no setting the lash or anything, simply remove and replace.

Here is how it went for those that are interested:

Start

http://www.trackchat.com.au/media/data/500/medium/100_1614.jpg

Remove coil packs and rocker cover - a total of 11 nuts/bolts and unplug coil packs and leads for each side, about 15-20 minutes if you pissfart around and take your time like me.

http://www.trackchat.com.au/media/data/500/medium/100_1615.jpg
http://www.trackchat.com.au/media/data/500/medium/100_1616.jpg

Remove std rocker gear one at a time, when the final rocker is removed, you can remove the guide plate that the rocker gear is seated on.

http://www.trackchat.com.au/media/data/500/medium/100_1617.jpg

The guide plates aren't used with the new rockers instead they are seated on the below collet-like washers.

http://www.trackchat.com.au/media/data/500/medium/100_1618.jpg

Fit each of the new rockers (in pairs) and tighten evenly is advisable on the supplied mounts with a washer between the head and mount.

Once they're are all back on they will look like so.

http://www.trackchat.com.au/media/data/500/medium/100_1620.jpg

Get a 24mm socket (from Dave if you dont have one yourself :beer: ) and manually wind the engine over (take the plugs out unless you feel like compression testing your motor lol) this is probably not necessary but I just wanted to make doubly certain everything was 'seated' correctly and all worked in 'slow' environment.

Re-assemble and it will look like the start again.

They will be a bit noisy initially, but that settles down once oil up the top end and warm. Also a re-check the this morning found they were fractionally loose after initial 'run-in'.

Now for the re-tune and overall opinion. I tried to complete this morning until I fcuked my WB sensor on the driveway :headbang: so now I need wait for a replacement sensor until I can do the touch up and will report back.

All up took a bit over two hours to fit and test and then a further 30 minutes to pull covers back off and test after run in and settled to make sure all is well.

Initial impression is that nothing signigicant has changed, but I will reserve judgement for when tune is optimised - if nothing else they look better.:)

Luke :)

[DaveHAT]

NOICE one Hector ... :bravo:

Might have to get some of these and give them a try ... :headbang:

Oh wait ... I said I was done didn't I? :lol:

[BOMI]

WOW good stuff mate, I always thought that there was far more to it.

Thanks for posting.


Troy :)

[VooDoo]

Changing rocker ratio also changes the geometery of the valvetrain. In some cases its good, adds some extra lift etc but on some cams it can be bad including valves hitting pistons, destroying valve guides etc. Ask Sonny about them, he isnt a huge fan but done right they can be good

[Sonny@AutoWerks]

Luke ,

Great write up :),though wat about the valve springs ? and lastly,ur not supposed to use the washers :),check ur valve geometry

regards sonny

[SSUte01]

Changing rocker ratio also changes the geometery of the valvetrain. In some cases its good, adds some extra lift etc but on some cams it can be bad including valves hitting pistons, destroying valve guides etc. Ask Sonny about them, he isnt a huge fan but done right they can be good

Very true, hence my winding over by hand just to triple check all calculations, sometimes theory is great but I always like to see it for my own two eyes to back the theory up.

Given my cam is very far from radical, in fact I believe the Z06 (LS6) cam had more lift std (0.525" @ 0.050" IIRC), my cam is a Crow item 218/224 114LSA @ 0.050" 0.521/0.521" lift, so as I said pretty mild. So on a high duration cam these rockers may run you into trouble or close to it.

I now effectively have very close to 0.551" on both int and exh which is still a fairly mild amount of lift, adding 0.030" extra. I am not sure on the exact limit of lift/duration prior to generally running into piston-valve clearance issues on LS1s but I know 218/224 isn't enough even with the rockers in this application. Always check and re-check I guess is the moral of that story.

I guess we'll just have to find out if they are any good.:)

[SSUte01]

Luke ,

Great write up :),though wat about the valve springs ? and lastly,ur not supposed to use the washers :),check ur valve geometry

regards sonny

Cheers :)

Changed the springs about 10K ago, Crow items aswell, cant remember the part no.

Thanks for the heads up, will do.

What are the washers for then??

Luke :)

[Delft Maloo]

good stuff. now hurry up and get that wideband fixed and get us some feedback:whip:

[SSUte01]

Luke ,

Great write up :),though wat about the valve springs ? and lastly,ur not supposed to use the washers :),check ur valve geometry

regards sonny

I just went and checked everything again, thanks :)

It seems that mine still needs the shims/washers, with them in I get right on the recommended (waiting for YT to get back to me to confirm what I have sourced elsewhere) amount of thread (turns) of pre-load. Without the shims, I will go close to running outta thread - thanks for your advice

Do you still think I should run without the shims or do you think it will be ok as is in accordance with the recommendations.:teach:

Thanks again for the help :bravo:

Luke :)

[SSUte01]

I took Sonny's sound advice following the response from YT saying it would be fine either way and that I would fall between their recommended tolerances either way about the fitting of the washers/shims.

Moral of the story - take good advice when it comes your way

I owe Sonny a beer or two :beer: :cheers:

Very many thanks.

P.S. Got replacement WB sensor today :yahoo: - out to the garage for a play, beats the shit outta accounting study, (no offence Nick)

[bluess57]

Any loctite required on rocker bolts?
And for anyone contemplating removing their rockers, get a 6 point socket 8mm (I think from memory).

[SSUte01]

Any loctite required on rocker bolts?
And for anyone contemplating removing their rockers, get a 6 point socket 8mm (I think from memory).

Yep 8mm for the rockers and 10mm for the coil packs and that is essential tools you need, some others are handy too.

Loctite, is recommended although not essesntial, I guess at least with rocker gear if it does come a little loose it gives you fairly obvious warning.