The black art of cooling grey motors

[Harv]

I can better understand the lumpy humpy trick of drilling the head and making a "coolant manifold" now.  It'd tend to equalise the flow of coolant inside the head, and perhaps most importantly, minimise the average path length that coolant would take between entering and exiting the cylinder head.  Are the holes generally drilled above the 2-3 and 4-5 exhaust ports?

In the photo below (sorry about the link), the middle photo shows an unbranded finned upper thermostat blanking plate to suit the Holden grey motor. These blanking plates replace the upper thermostat cover, preventing water flowing out of the cylinder head. These were used in conjunction with drilling two or three holes in the cylinder head top surface, down to the water jacket. The holes are tapped, and piping connected to the tappings. With the thermostat cover blanked off, water now flows through the two/three tappings back to the radiator instead of via the thermostat cover.
http://s929.photobucket.com/user/V8EKwagon/media/7_zpsj1wle0lh.jpg.html
More discussion on it here:https://www.fxfjholden.com/forums/viewtopic.php?f=37&t=2470&p=19493&hilit=humpy+still+racing+cooling&sid=482e6f34dca38638baea1da11d08499e#p19493

To the best of my (scanty) knowledge, the modified head gasket 7424869 was never used in production.  I think it was one of those "hidden knowledge" things that Holden dealers had up their sleeves to fix overheating and cracked heads in near-new Holdens.  Coincidentally, when I got to Ceduna in 2012 with an overheating car, the guy in the next-door motel room had done his apprenticeship at a Holden dealer in the early '60s.  He said that there was a fix for the J-series motors involving drilling out passages and a different head gasket.  First I'd heard of it.

I need to talk to Dad... he was a GMH mechanic around that time. Wonder if he knows about this one?

Rather than doing all the fiddly work with sheet Teflon and scissors, maybe one could go to the gasket manufacturer (AA Gaskets in Melbourne)with a normal grey head gasket and a 7424869 and say, "I'd like to get a special run of head gaskets made with these twelve punch dies removed."  It's just a question of cost and minimum production quantities after that.

I'd be interested in doing that, or at least approaching AA Gaskets... fancy lending me a 7424869 ?

Cheers,
Harv

[zulu]

Harv,

Pretty sure I have a NOS 7424869 in the shed, you are welcome to a loan of it and depending on the price of the gaskets, I may be interested in 1 or 2

Gary

[Harv]

Thanks Gary - appreciated.

I'll make some calls next week and get a rough idea on pricing.

Cheers,
Harv

[KFH]

Harv.  Depending on price I would be interested in one or two as well if it is possible to get them made.

Keith

[Old_Mt_Isa_Boy]

SPECIAL DUTY CYLINDER HEAD GASKET
FOR HOLDENS, PRIOR
TO 'EJ', OPERATING
UNDER ARDUOUS CONDITIONS
A revised type cylinder head gasket is now available from NASCO Distributors for use on 48J21 5 up to 'EK' Holden vehicles that are continually operating at high speeds or under conditions where severe operating temperatures are experienced. The purpose of this new gasket is to direct a greater flow of cooler water to the rear of the engine. To achieve this, a number of cooling holes in the cylinder head and block are blanked off by the gasket, while the two rear holes are increased in size. This new cylinder head gasket is now available from all NASCO Distributors.
PART No. • 7424869
LIST PRICE £0 18 0 plus tax

Found this on the net.

[Old_Mt_Isa_Boy]

The actual ad.

[mcl1959]

This is from the July 1963 GMH service bulletin





Ken

[Harv]

Thanks gents - appreciated.

I've sent a query to AA Gaskets - I'll let you know how I go. If there is a minimum run number, I'll call for expressions of interest.

Cheers,
Harv

[DJ]

What an interesting & informative post.
Thanks for the collection of experiences gents.
Looking forward to a reply from AA Gaskets Harv.

[Old_Mt_Isa_Boy]

Hopefully you get a quick response Harv, I could do with one now. Have the engine out at the moment.

Regards

Wayne b

[Maco]

I will have one too please Harv.

Cheers
John

[Harv]

I got a very quick response from AA Gaskets. They are more than happy to make the gaskets, using non-asbestos material 1.4mm thick (+/- 5%), and silicone coated. Lead time is 6-8 weeks to allow for retooling. The finished gaskets are a reasonable price ($40), though we would also need to cover the cost of the tooling changes ($800-$1500). They need a minimum order of 50 gaskets, so if I spread the $1500 tooling cost out over 50 gaskets, the cost would be $70 per gasket. As a sense check, a standard head gasket from eBay is $35-60, depending on quality (the AA Gasket type quality is around the $60 mark).

So the long and the short of it is that I need to find about 50 people willing to pay $70 per gasket for better cooling. Say another $10 for postage.

I'm happy to act as the focal point for this one, similar to what I did with the hydramatic service kits. I'll raise a separate post on each of the FX/FJ, FE/FC, FB/EK and EJ/EH forums, calling for nominations on who wants a gasket. I'm not doing FaceBook (me and FaceBook don't talk), but happy if anyone wants to spruik a link to the forums. I'll let the nominations run for two weeks (end of January), and hope we get 50 nominations. I assume some blokes will want two or three, and I'll probably take 5-10 (some for me, and some for the inevitable latecomers  ). Provided we get 50, I'll place the order then manage the distribution. Not sure how I'll post these out without them getting bent... need some advice here please. If someone can scan me up a good copy of the GMH Service Bulletin, I'll include a print of that too in each parcel.

Righto, time to make some nomination postings  .

Cheers,
Harv

[Fraze]

I'll take one thanks, Fraze

[Harv]

No problem Fraze. Please post to the thread in the "for sale" section, and PM me your details.

Cheers,
Harv

[ardiesse]

Harv,

Thanks for moving so quickly. Good news that AA Gaskets are co-operative.  I'll pm you . . .

Rob

[ardiesse]

Next Instalment:

I got in touch with Renner Radiators in Fyshwick last week, and asked them whether they'd take the tanks off my radiator and clean the tubes out . . .   No problem, they said.  OK, I live in Sydney, so why am I going to a radiator place in Canberra?  For a start, Renner Radiators do all the work on the National Museum's historic vehicles, and they came highly recommended on the Forum.  Also, I was going down to Canberra last weekend (actually, just got back a few hours ago), so it was no trouble for me to take the FC's radiator, and a festy, but basically sound radiator that came out of an EK "shooting landau" at Parkes.

Same day service.  $140 each, including repair of a couple of weeping leaks on the FC's radiator.

I asked if my oxalic-acid bath and home-reverse-flush actually did anything.  Maybe, but nowhere nearly enough.  "Pretty dirty inside."

Once I got home, I installed my newly serviced radiator, with (hint) the toe-end of panty hose in the top radiator hose fitting to act as a scale filter.

And I repeated the St Ives run from last July.  Ambient temperature: 25 degrees.

Top tank: 63 (i.e. ambient + 40)
Bottom Tank: 59 (i.e. ambient + 35)
Rear cyl head: 68 (i.e. ambient + 45)
Front cyl head: 70 (i.e. ambient + 45)

The radiator temperatures are the same, relative to ambient.  But the coolant temperatures inside the cylinder head have been lowered 15 degrees, and are now much closer to the temperature of the top tank.

When I got home,

Top tank: 63 (i.e. ambient + 40)
Bottom Tank: 57 (i.e. ambient + 35)
Rear cyl head: 66 (i.e. ambient + 40)
Front cyl head: 67 (i.e. ambient + 40)

These are the sort of numbers I got with a motor idling in a test stand, after I did the Teflon cure.  Does having your radiator professionally cleaned out make a difference?  Shit yeah.  Best $140 I've spent in a good while.

Rob

[Harv]

and a festy, but basically sound radiator that came out of an EK "shooting landau" at Parkes.

The "shooting landau" is an official GMH Rural Division body style  . Sometimes confused with the Cow Feed Carrier and Paddock Basher variants.

Does having your radiator professionally cleaned out make a difference?  Shit yeah.

Agree. When I bought the FB, it had a relatively new radiator in it. I dropped the water and flushed the hell out of the block and radiator. Ran OK around town, but under load (trailer on the freeway) the temperature light would flicker on. Had the radiator cleaned out by PJ Radiators in Tamworth, and never missed a beat since.

Cheers,
Harv

[Old_Mt_Isa_Boy]

So I have the engine out and was thinking of drilling the water jackets bigger while it was out. What is the consensus of then putting the head back on and waiting for the new gasket to arrive. No other changes and keep driving the car.

Regards

Wayne b

[ardiesse]

Wayne,

If you want to get the car back on the road before (say) April, your best option may be to make up the blanks and use them with a standard head gasket.  I used 1 mm Teflon sheet because we had some at work.  I don't know about brass or copper (would the cast iron act as a sacrificial anode?).  Perhaps stainless steel?  It's pretty hard to work with though.

Rob

[RET]

Here's the reference to it from the Master Parts Catalogue, for what it's worth:



Given the reference to "Special Service - Enlarged rear water ports", I'm really interested to know what the impact of using this head gasket on an engine where the rear holes weren't enlarged. Rob, you mentioned that you only did the 7/16" modification. What are your thoughts?