Tall rocker covers + Yella Terra platinum rockers for Buick?

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Tall rocker covers + Yella Terra platinum rockers for Buick?

Postby vlad01 » Sun Jun 19, 2022 5:32 pm

Have a bit of a conundrum, I am looking to use the Yella Terra platinum adjustable rockers for my next engine build as you might know the cam is the Formula Holden cam which needs mechanical roller lifters and thus needs adjustable rockers.

These are the ones but the pics are are ecotec ones but similar.

https://store.yellaterra.com.au/holden- ... io-yt6307/


The question is what to do with rocker covers? There is next to no options out there bar a few, unlike the L67 which has more options.

I found these and have been talking to the manufacture but it's apparent they made them unnecessarily tall which interferes with the booster, coil packs, power steering high pressure line, thermostat housing and worst of all blocks the entrance of the throttle body which I can't see a way around (literally).

https://www.aussiespeedshop.com/product ... er-covers/

The stock rocker covers are 60mm tall, these are 98mm which are way too tall and will cause the above issues. The throttle body will be clipped by almost half vertically and 1/3 front to back.

So does anyone know of the height of the platinum rockers? and how others get around these issues? They mentioned machining down the fins on the covers but I don't think that's enough and the amount of mods needed to them, would it be better to get custom CNC'd ones? and that can also allow them to be made with factory O ring and seals in mind over the backwards paper gaskets these use.
I'm the director of VSH (Vlad's Spec Holden), because HSV were doing it ass about.

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Re: Tall rocker covers + Yella Terra platinum rockers for Bu

Postby immortality » Sun Jun 19, 2022 10:12 pm

I thought someone made spacers to suit.

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Re: Tall rocker covers + Yella Terra platinum rockers for Bu

Postby vlad01 » Sun Jun 19, 2022 10:38 pm

Yes there are spacers but I think they are only tall enough for the run of the mill yella terra rockers, not the platinum race ones which are flatter across the top and have the adjusting nut sticking out, the normal yella rockers are closer to the OEM shape (trapezoid shape). So as far as I know the stock covers with spaces don't work with the platinum rockers due to the shape and being ever taller. But Gareth made the spacers work with the Kilkenny castings covers as they are a box shape, not trapezoid like stock.

I am not keen on using the KC covers as I feel like they are a big step backwards, shitty cork gasket and 1970s style oil cap.

I have asked the Formula Holden guys on FB what rockers they use as their covers are the original ACL ones made for that series that are OEM shaped but maybe 10-15mm taller, and they clear the throttle fine.
I'm the director of VSH (Vlad's Spec Holden), because HSV were doing it ass about.

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Re: Tall rocker covers + Yella Terra platinum rockers for Bu

Postby charlay86 » Wed Jun 22, 2022 10:13 am

Maybe something like this: https://zzperformance.com/products/polished-aluminum-valve-covers
Then apply grinder tig grinder process to the top until they fit.

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Re: Tall rocker covers + Yella Terra platinum rockers for Bu

Postby vlad01 » Wed Jun 22, 2022 11:57 am

Actually, come to think of it. Those are the ones Gareth used on his current engine with spacers with the platinum rockers but he has the ZZP alloy L67 heads, these won't fit the Buick heads as they don't have the injector bosses in the casting. I was thinking of cutting up a few stock covers and stack a section into it like you suggest just to see what height is needed and clearance etc... which i can do with the VN early alloy covers but in the end of the day I would prefer CNC'd custom covers based on the factory plastic covers and alternations to make them as low as possible and cut away for the throttle if needed.

I don't like the seals for the bolts the early VN alloy covers use, kinda crap and the plastic later covers addressed the issues and are much better. I suppose I should get the platinum rockers first so I have something to work with.

Also the Holden Formula group is pretty useless, they seem very secretive and won't answer questions which is no surprise given what FB users are like. I miss the days of dedicated forums when people were more helpful and cluey. :thumbdown:
I'm the director of VSH (Vlad's Spec Holden), because HSV were doing it ass about.

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