Hi all, I live in Brisbane, Australia and am doing up a 1725cc motor for some Sprint & a little hill-climb racing. I want to bore it out a little bit (say 3 1/4" ) and am also considering say 100 thou extra stroke. have any of you guys done this? If so, what pistons did you use? Also con rods?
So far I have looked at Mitsubishi 4G64 and 4G52 pistons. Also the Toyota r21 engine pistons. I'd like to use 1.5mm wide rings (not 2mm wide).
Con rods - what about Chev 350 ones at say 5.7" or 6"?
At the moment I run a lumpy (sort of) cam, twin 40DCOE carbies, std. bore and 44 year old pistons with new rings, slight port & polish, fully balanced etc.
Any thoughts or ideas would be greatly appreciated.
For rods you want the 250 chevy 6 cylinder units, the V8 rods are not wide enough on the big end. I think there is also a ford rod that can be used. Actually you are in the hot bed of big bore and stroked motors there down under
There are quite a few motors in AU that run 2120cc they are the starion turbo based rods and pistons, there are guys running volvo rods and pistons and i have heard of other combos.
Might be worth contacting bob (kean keon sp?) in NSW or simon noske of all hunter spares in melbourne.
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Michael King
1963 Alpine SII - 1965 Alpine SIVGT
1965 Tiger MKI - 1966 Tiger MKIA
I used Chevy rods from the 6 Cyl. Those rods have a smaller big end than the stock 1725 and allowed me to regrind the crank with 0.100" added stroke. I also did the Vizard mod on the head, bored it out to 3.248 , which is 82.5 mm so I could use common standard metric rings.
I had custom pistons made by Venolia, in order to match the exact compression height and dish on top to give me the CR I wanted. The custom pistons were only slightly more expensive than standard ones.
There are 2 articles on Chevy Rod conversions on 1725's in the Marque magazines on this site. Do an advanced search on Chevy or Marque and you'll find posts about these articles
Engine:
Sunbeam Alpine 4 Cylinder 1725cc
Venolia Pop-top Pistons
Eagle Connecting Rods (Ford Pinto 2300cc)
Crane Cam - custom grind
Datsun 1600cc Valves
BMW 1600 Schrick double valve springs
Sumbeam Alpine 1600 oil pump
Custom deep sump oil pan with baffle
Mocal oil cooler
3 qt Accusump
Gilmer Belt drive water pump
Weber 40 DCOE Carb
Custom intake manifold
Custom high efficiency raditor
Mallory dual point distributor
* 135 hp at 6200 rpm *
Bill, you say you used the 1600 pump.. why would you be using that.. i would assume you have fiited it with the MG mod to make it higher volume.. but why early pump in a late car?
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Michael King
1963 Alpine SII - 1965 Alpine SIVGT
1965 Tiger MKI - 1966 Tiger MKIA
Hi Michael,
I have no idea why the racing shop and previous owner went that route. But judging from the $10,000 of receipts there must have been a reason. That is a lot of money for the engine alone. Your guess is as good as mine, better probably.
Bill
Sorry I cannot answer your questions. The race shop is no longer, hence I remain in the dark.
The only engine mods I did once receiving the car was to change the intake manifold, add some quality headers, add a larger Weber, (45DCOE), add a light weight racing alternator, twin cooling fans and engine vibration dampner similar to what the factory suggested years ago.
1725cc racer
Linear Mode
