Repco head.

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pdq67
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Repco head.

Post by pdq67 » Fri Nov 30, 2018 11:09 pm

How is the design of this head?

https://primotipo.com/2015/06/26/repco- ... ower-head/

It's down in the link.

"‘The valves were arranged in two rows with the 1.375 inch exhaust valves vertical and on the near side, while the inlets were inclined at 25 degrees on the opposite side, their heads being 1.56 inches in diameter’.

‘The 6 circular exhaust ports were short and direct, while the rectangular shaped inlets were arranged in two groups of 3, springing from the 2 galleries, these formed partly in the head and partly in the manifolds. The manifolds were simple open sided castings, made in several types to suit vertical or horizontal carburetors’."

Seems to be designed kinda like the 318 Poli-head.

Please look and offer comments.

Thanks,

pdq67

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Re: Repco head.

Post by Geoff2 » Sat Dec 01, 2018 2:53 am

The Aussie Chrysler head that came along a few years later [ 1969 ] was better. It had a pentroof combustion chamber & made more hp/ cu in.
Compare the #s.

Repco engine 142 ci, 133 hp. 1/4 mile 17 secs in a light car
Chrys engine 265 ci, 302 hp. 1/4 mile 14.3 secs in a full weight street car, Valiant Charger.

Both engines used Weber carbs.

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Re: Repco head.

Post by gruntguru » Sat Dec 01, 2018 4:15 am

Geoff2 wrote:
Sat Dec 01, 2018 2:53 am
The Aussie Chrysler head that came along a few years later [ 1969 ] was better. It had a pentroof combustion chamber & made more hp/ cu in.
Compare the #s.

Repco engine 142 ci, 133 hp. 1/4 mile 17 secs in a light car
Chrys engine 265 ci, 302 hp. 1/4 mile 14.3 secs in a full weight street car, Valiant Charger.

Both engines used Weber carbs.
Hardly comparable engines.
4 main bearings vs 7.
2 x progressive downdraft carbs vs 3 DCOE side drafts (1 choke per cylinder)
1972 was the release year for the E49 you quoted - 13 years after the Repco modified engine (a 1940's design BTW)

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Re: Repco head.

Post by pdq67 » Sat Dec 01, 2018 11:15 am

"Seems to be designed kinda like the 318 Poli-head."

Is it any good, chamber eff-wise?

I for one like the poli- heads chamber design and valve layout. Just wish it was made in a ball and stud rocker design.

pdq67

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Re: Repco head.

Post by PackardV8 » Sat Dec 01, 2018 11:45 am

Here's the Repco:
Image

and here's the Mopar polysphere:
Image

No matter how nostalgic pdq67 gets for his poly, that it was never widely copied, not even by Mopar on their next generation of the same engine, is the best analysis of the desirability, efficiency and power production or lack thereof.

Similarly, we recently rebuilt an American Lafrance V12, which evolved from the 1932 Auburn design. It has many unique features. That they've remained unique for eighty-eight years is evidence they were a technological dead end.

Image

Image
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Stan Weiss
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Re: Repco head.

Post by Stan Weiss » Sat Dec 01, 2018 1:08 pm

One of the big differences is the valve train and a dual rocker shaft (REPCO) verses a single rocker shaft (Poly).

Also in a hi-performance engine who does not replace the ball and stud rocker design with shafts?

Stan
ab-poly.gif
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Re: Repco head.

Post by 202ci EH » Sat Dec 01, 2018 7:22 pm

My memory keeps telling me the repco was modelled after a Massey Fergusson tractor 4 cyl engine, it was an improvement over the grey head because a brown dog could design a better cylinder head than a Grey.

A mentor of mine ran one in a circuit race car, he built an intake manifold with tongues to stick into the ports to separate the runners to be IR with sidedraft weber carbs.

Still lack lustre compared to even a basic siamese port Red motor.

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Re: Repco head.

Post by Olds455 » Sat Dec 01, 2018 9:23 pm

There are pics of the chamber plus a bunch of other interesting stuff at this forum

http://www.fbekholden.com/forum/viewtop ... 45050dabec

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Re: Repco head.

Post by travis » Sat Dec 01, 2018 11:09 pm

PackardV8 wrote:
Sat Dec 01, 2018 11:45 am
Here's the Repco:
Image

and here's the Mopar polysphere:
Image

No matter how nostalgic pdq67 gets for his poly, that it was never widely copied, not even by Mopar on their next generation of the same engine, is the best analysis of the desirability, efficiency and power production or lack thereof.

Similarly, we recently rebuilt an American Lafrance V12, which evolved from the 1932 Auburn design. It has many unique features. That they've remained unique for eighty-eight years is evidence they were a technological dead end.

Image

Image
Holy connecting rod length, Batman :shock:

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Re: Repco head.

Post by desoto30 » Sat Dec 01, 2018 11:43 pm

AHHH, Back in the days when Repco was a great company, as opposed to now when they have sold out & only sell Shit and glitter,,,, very sad really

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Re: Repco head.

Post by PackardV8 » Sat Dec 01, 2018 11:57 pm

travis wrote:
Sat Dec 01, 2018 11:09 pm

Similarly, we recently rebuilt an American Lafrance V12, which evolved from the 1932 Auburn design. It has many unique features. That they've remained unique for eighty-eight years is evidence they were a technological dead end.

Image

Image
Holy connecting rod length, Batman :shock:
[/quote]

Only 9.438" center-to-center.
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Re: Repco head.

Post by hoodeng » Sun Dec 02, 2018 12:22 am

Interestingly , the Rolls Royce Merlin Mk 1 engine used the same ramp head as they called the design used by Repco ,it did not go past development ,the mk2 that did go into production had parallel vertical valves [both were four valve].

In the 70's i worked part time for a race car builder called 'Elfin Sports Cars' here in Adelaide ,their 'Formula 5000 MR5' open wheelers were powered by the Repco developed adaptation of the Australian 'Holden 5 litre' V8 engine, i remember early ones being built here and then tested at Repco in Melbourne by a chap known as 'Dyno Don' ,they made 500hp and 400ftlb,tested engines were shipped back to Adelaide and installed back in the tubs.

Repco also built a number of Formula 1 engines for Jack Brabham know as 'Repco Brabham' engines as well as customer engines for chassis builders.
https://primotipo.com/tag/elfin-400-repco/

Cheers.

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Re: Repco head.

Post by Geoff2 » Sun Dec 02, 2018 4:03 am

GG,
Veeeeery comparable engines. Both inline 6 cyl, both OHV. Next you will be saying they are incomparable because valve sizes were different.....

The Chrys engine was released & fitted to cars in 1969, as I stated. Webers came later. Weber cars came with 4 spd manual, tractable enough to be driven at 30 mph in high gear.

142 ci, 133 hp = 0.94 hp/ci
265 ci, 302 hp = 1.14 hp/ci.

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Re: Repco head.

Post by Geoff2 » Sun Dec 02, 2018 4:31 am

Correction to post above. Engine first appeared in 1971 as 215 ci, advertised as a 'Hemi' head; then later bored out versions of 245 & 265 ci.

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Re: Repco head.

Post by cjperformance » Sun Dec 02, 2018 4:57 am

In fairness to the repco 6 V's the 265 , these are 2 different beasts from 2 different time lines, use the side draft carb version of the repco with same CR as the 265 6 pack and maybe more cam to match the 265 and forgetting any strength issues , looking purely at hp/ci I say the repco would be line ball with the 265. Not taking anything from the 265 but the repco in its 133hp trim is hardly a "tune matched" engine to the 6pack, where as top end repco is getting a little closer and im sure the Chrysler Aust engineers gleened a few ideas from the repco 6 among others.
Craig.

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