Harv's grey motor Yella Terra head thread

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Harv
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Harv's grey motor Yella Terra head thread

Post by Harv »

Ladies and Gents,

I was wrong. Really wrong. :oops: I believed that there was no such thing as a Holden grey motor Yella Terra head. I thought many of the heads seen on the market were "Dulux overhauled" with a yellow rattle-can.

There actually was (is) a grey motor Yella Terra head. Maybe my search skills got better with all this Guide writing, or maybe more info has come to hand in recent years. In any case, apologies to anyone I’ve blown raspberries at for claiming they had a Yella Terra head... they just may have.

As penance for my error, I’ve started this thread. I’m not writing a Tella Terra Guide... I’ve got enough on my plate as it is. The aim of this thread is to collect together the evidence supporting the Yella Terra grey motor head. I seem to collect grey motor info as I go along, so will post what I find here. We will probably touch on the red motor as we go along. Where possible, please back up your posts with support material – photos, scans of advertisements etc. I know this sounds finicky, but the Yella Terra head has been a bit like the Canadian block... so surrounded in “I once knew a bloke” stories that it is hard to sort the wheat from the chaff.

From the Perfectune website (http://www.perfectune.com.au/), Perfectune was established in 1962 by Dave Bennett. This was still in the years of the grey motor, with the red appearing a year later. Perfectune was the first engineering company in Australia with CNC machining capabilities. During the late 1970’s to the mid 1980’s, the company was a supplier to Holden for OEM engine components. During this time Perfectune launched Yella Terra as a brand of high performance racing parts. The brand continues in use today (http://www.yellaterra.com/).

Now for the evidence that the grey motor Yella Terra existed.

The ads below (the first from the Australian Motor Manual magazine of November 1972, the second from an unknown source in 1972) shows that Perfectune would take your grey motor cylinder head with a $25 exchange deposit in case your exchange head turned out to be unrecoverable. They would then machine and fit components (valves etc) to your head. They offered a Stage 1, Stage 2 and a Stage 3 (Yella Terra) option for between $85 and $175. The ad clearly tables the Stage 3 head for the grey motor as a Yella Terra (stage 1 and Stage 2 were not). Stage 1 gave a 22% power increase (the stage 3 on a 186S red motor head was giving 32%... no data reported for the grey motor Stage 3). The Yella Terra (Stage 3) was machine ported, had modified ports, valve throats and combustion chambers, oversized inlet and exhaust valves, double valve springs, compression raised (shaved) and ports matched to standard gaskets.

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By 1983, Perfectune was offering only one model of exchange grey motor head (part number H4863), as shown in the advertisement below (I suspect this is an in-house Perfectune brochure). The single offering for grey motors is despite having separate heads for Economy, Towing, Performance and High Performance for other engines - probably due to the declining grey motor go-fast market in the 80's.

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I also have a Perfectune brochure (which I will scan and post once I’m home again) that indicates cylinder heads for red and later engines, but nothing for the grey. It does however indicate the following parts:
a) grey motor inlet valves (part number YT1601, 1.440" diameter, compared to standard grey at ~1.35"),
b) grey motor exhaust valves (part number YT1603, 1.270" diameter, compared to standard grey at ~1.22"), and
c) grey motor inner springs (part number YT1501).

Cheers,
Harv
327 Chev EK wagon, original EK ute for Number 1 Daughter, an FB sedan meth monster project and a BB/MD grey motored FED.
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Re: Harv's grey motor Yella Terra head thread

Post by parisian62 »

Nice work Andrew. :thumbsup: 8)
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Re: Harv's grey motor Yella Terra head thread

Post by Craig Allardyce »

Top work Harv!
I think you should change your name to Sherlock. :thumbsup:
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Re: Harv's grey motor Yella Terra head thread

Post by fingers »

Hey Harv the man mostly responsible for the development of the grey yellow terra heads was Eddie Wood who now owns Head Stud Development in Melbourne ..and very respected in appendix J racing circles ......he worked for Dave Bennett for years ...check out his facebook page ........https://www.facebook.com/HSDcylinderheads
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Re: Harv's grey motor Yella Terra head thread

Post by GreyEJ »

Top stuff. I knew it ( well felt it in my bones ) but having Harv prove it well that's undeniable.

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Harv
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Re: Harv's grey motor Yella Terra head thread

Post by Harv »

Cool.

I really shold be doing the Norman stuff... but might have to take a short detour into Yella Terra terrritory. I'll post what I find. If I'm not back in six months, send a search party.

Cheers,
Harv
327 Chev EK wagon, original EK ute for Number 1 Daughter, an FB sedan meth monster project and a BB/MD grey motored FED.
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Re: Harv's grey motor Yella Terra head thread

Post by 850man »

I am about to go and purchase an EJ head and embark on a porting and larger valve modification frenzy with advice from a couple of old head modifiers that did lots of grey heads back in the day. Rob Webster now owns and runs Martini heads in Bundoora was a former employee of Perfectune and knows his stuff, he has welded up chambers in grey heads and done some great mods to them, Ron Brownrigg is retired now but was and still is famous for his head mods and hand made extractors.
I will have a chat to Rob and see what he has to say about the YellaTerra grey heads.
Its a shame Kevin Igoe isn't on this forum, I worked with him at RPM engines for a few years and he is another very knowledgeable grey builder.

http://www.martiniheads.com.au/
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Re: Harv's grey motor Yella Terra head thread

Post by 850man »

On my way down to see Greg at Hydroblast with my EJ head today I called into Perfectune to talk about grey heads and would they be prepared to do a run of them.
The first guy didnt know what I was talking about so he went and got a more knowledgeable bloke that said that they rarely do cast iron heads now, and that when they did do grey heads it was always your own head that they would modify, rather than a change over basis. He said that if I wanted a good grey head done I better go and see Eddie at HSD http://www.headstuddevelopment.com/home.aspx which I already knew. I did try to get them interested in doing a run of Grey heads again, if we supplied some but they didnt seem interested.
What they did tell me that is worth getting excited about is that they have almost finished the R&D of Grey motor roller rocker sets and they should be available soon.
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Re: Harv's grey motor Yella Terra head thread

Post by GreyEJ »

850man wrote:What they did tell me that is worth getting excited about is that they have almost finished the R&D of Grey motor roller rocker sets and they should be available soon.
You are a bad bad man. This is goign to cost me .
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Harv
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Re: Harv's grey motor Yella Terra head thread

Post by Harv »

GreyEJ wrote:
850man wrote:What they did tell me that is worth getting excited about is that they have almost finished the R&D of Grey motor roller rocker sets and they should be available soon.
Had the same thing confirmed by email from George Petrakis (the Engineering Manager for Perfectune Engineering and Yellaterra Manufacturing) last week. Roller rockies and pedestal cradles. Happy days.

Cheers,
Harv
327 Chev EK wagon, original EK ute for Number 1 Daughter, an FB sedan meth monster project and a BB/MD grey motored FED.
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Harv
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Re: Harv's grey motor Yella Terra head thread

Post by Harv »

Ladies and gents,

Attached below as promised a scan of the brochure which shows the grey motor inlet valves, exhaust valves and springs (se the 6th image - I've included the other material here to put in context the other gear that Perfectune was selling by this time... very little relatively speaking for the grey):

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Attached below is the article from Modern Motor of January 1978 (together with the Perfectune advertisement from the same issue… still selling exchange heads for “all Holden 6” in 1978). Whilst the article has no grey motor info in it, it does describe how Perfectune started out, and how the Stage 1, Stage 2, Stage 3 and Yella Terra names described above came about:

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Cheers,
Harv
327 Chev EK wagon, original EK ute for Number 1 Daughter, an FB sedan meth monster project and a BB/MD grey motored FED.
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Harv
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Re: Harv's grey motor Yella Terra head thread

Post by Harv »

A little bit more of the grey motor Yella Terra story. This one is a workshop poster from mid-1977, and describes the typical flaws that would prevent an exchange head from being Yella Yerra'd. Note the reference to grey motor heads at the bottom left.

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Cheers,
Harv
327 Chev EK wagon, original EK ute for Number 1 Daughter, an FB sedan meth monster project and a BB/MD grey motored FED.
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Re: Harv's grey motor Yella Terra head thread

Post by GreyEJ »

A boot full of them
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Re: Harv's grey motor Yella Terra head thread

Post by parisian62 »

Score. Yours?
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Re: Harv's grey motor Yella Terra head thread

Post by GreyEJ »

Just 2 of them. One I got as a bare head. That one will be used shortly. Now runs black 202 valves turned down a little as the head was already to big for red motor, new spring, new guides also. Total cost $100 for the head, $80 for the springs and the rest was just the time it took my dad to re-cute the valves and valve seats. The guides were a swapmeet find so I assume they were dirt cheap.
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