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Post by seth on Oct 18, 2008 21:06:39 GMT
My Arrow Minx has an iron head 1496 engine. As far as I am aware these engines are direct derivitives of the earlier Audax engines (as are the 1725s) but this has a different bore and stroke to the 1494cc lumps fitted to Series 2 Rapiers (and equivalent Minxes?) So are they actually the same blocks with different cranks? The Arrow cars engines are canted over a bit but I've heard you can convert 1725's from mid sixties cars using appropriate sumps/mounts etc. Would an alloy head from a 1725 fit on an iron head 1500 block? The to connfuse matters there's the Avenger 1500 engine but I think that is totally different? Why did they do that? Would love to know the actual similarites/differences with all these engines as it would come in handy when finding parts etc.
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Post by briandamaged on Oct 18, 2008 21:31:05 GMT
The Avenger engine came in both 1248 and 1498cc, later enlarged to 1297/1599...but you're right Seth, these engines are totally different (much more efficient breathing, and shorter stroke) from the 1496/1725cc donkeys as fitted to the Audax/Arrow cars.
I find it odd though that Chrysler oversaw an entirely new range of engines for the Avenger that were in basic design terms breaking no new ground at all. Still OHV pushrod and not even Crossflow!!!
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Post by v8sceptre on Oct 18, 2008 22:00:35 GMT
OHV / Pushrod engines with chains were also used in the later Alpine / Solara range - by which time nearly every other manufacturer was using OHC belt drive engines !
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Post by Davenger on Oct 18, 2008 23:06:32 GMT
The Avenger engine was a wierd one. The camshaft is really high up in the block so as to give the benefits of overhead cam without actually doing it. Ended up with really short pushrods
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Post by seth on Oct 18, 2008 23:34:02 GMT
OK, so the Avenger 1500 is acutally the bigger version of a small engine. Also looking into dates the Arrow cars pre-date the Avenger by a few years hence why they never stuck the Avenger 1500 in the base model Minx/Hunter.
So how abut similarites/differences between Arrow and Audax/Superminx engines?
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Post by briandamaged on Oct 18, 2008 23:46:12 GMT
OHV / Pushrod engines with chains were also used in the later Alpine / Solara range - by which time nearly every other manufacturer was using OHC belt drive engines ! They were the old Simca jobbies, weren't they? They sounded like someone lobbing a bucket of bolts down a stairwell, and that was when they were new! The 1442cc Alpine engine went into that weird Matra Bagheera thing with three-abreast seating IIRC. Went like stink, but rotted even faster.....
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tommy
Talbot Sunbeam
Posts: 3
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Post by tommy on Oct 19, 2008 9:16:04 GMT
If swapping between alloy and iron heads on 1500/1725 engines and their predecessors the matching camshaft to the head must be used as the valves are laid out differently on each head. Many a time the head swap has been done and confusion reigns when the engine will not start. Tommy
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Post by Davenger on Oct 19, 2008 10:30:53 GMT
I read that the avenger engine was developed specially for it, and as such, the parts are n't interchangeable.
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rod
Talbot Sunbeam
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Post by rod on Oct 19, 2008 12:09:43 GMT
I always thought it odd that the Avenger engine was such a basic design. I suspect it was Chrysler influence to save a few pennies! After all at the time the Americans must have seen overhead camshafts as a funny foriegn idea. Seems a pity with the simple yet effective Imp design to work from.
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tommy
Talbot Sunbeam
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Post by tommy on Oct 19, 2008 16:59:40 GMT
I think after all the bother Rootes had with the imp it was probably once bitten twice shy on all alloy OHC engines. I think the avenger engine is over engineered which makes it nearly indestructable as a road engine whereas an imp engine needs sympathetic maintenance and careful building to keep it reliable. Rootes also got a leading motorcycle race engine designer to work his magic on the cylinder head which is why it breathes so well and didn't need to be crossflow. 70000 miles and a F**d crossflow is tired but an Avenger engine is barely run in. Avenger engine is a cracker with the only downsides being its weight and a tendency to crack heads between the valve seats. Tommy
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Post by seth on Oct 19, 2008 21:25:56 GMT
If swapping between alloy and iron heads on 1500/1725 engines and their predecessors the matching camshaft to the head must be used as the valves are laid out differently on each head. Many a time the head swap has been done and cunfusion reigns when the engine will not start. Tommy Ah, yes! Discovered that different port layout only recently.
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Post by sunalp63 on Oct 25, 2008 12:03:05 GMT
My Arrow Minx has an iron head 1496 engine. As far as I am aware these engines are direct derivitives of the earlier Audax engines (as are the 1725s) but this has a different bore and stroke to the 1494cc lumps fitted to Series 2 Rapiers (and equivalent Minxes?) So are they actually the same blocks with different cranks? The Arrow cars engines are canted over a bit but I've heard you can convert 1725's from mid sixties cars using appropriate sumps/mounts etc. Would an alloy head from a 1725 fit on an iron head 1500 block?/quote] First of all the Avenger motor is not related to the motors used in Audax Minxes (the 56-67 ones) and Arrows/Hunters. Now for a short history of the Hillman OHV 4 cyl. Started as a 1390 cc engine in the 1956 Series I Rapier/Minx, with iron head and 3 main bearings. Bored to 1494 cc for the 1958 Minx III. in this capacity it was also fitted with an alloy head for the first Alpine and the Rapier III (Minxes/Gazelles/Huskys continued to use the iron head. It was bored to 1592 for the Alpine II and this block also used in Minxes, Super Minxes, Vogues, Septres etc. In about 1965 it was revamped into the 1725 (actually 1724cc ) version. It has the same bore as the 1592 but a longer stroke - this is a different block, having 5 main bearings instead of 3 and is easily identified - on the early versions, dipstick goes into a tube attached to the sump, on 1725s it goes straight into the block. 1725s have other internal differences like the oil pump/dissy drive. The first 1725s were used in Alpine V, Minx VI, Super Minx/Vogue IV, Sceptre II. The Arrow/Hunter range also used 1725 but they were canted over and mounted differently. You can easily use a Hunter block in an early (Audax) car, but it's near impossible to put an Audax block into a Hunter. During the lifetime of the Hunter the 1496 version of the 1725 was made by reducing the bore - this was to make a more economical motor. Finally, you can't just bolt an alloy head onto a block originally fitted with an iron head. The valve sequence is different, so you have to change the cam and inlet/exhaust manifolds. The carbs are also different. Hope this helps Vic 1963 Alpine III (1592 alloy head, although the block has been replaced by a one from a Super Minx, by using the Alpine cam, manifolds, carb) 1969 Hunter (1725 Iron head, all original)
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rod
Talbot Sunbeam
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Post by rod on Oct 25, 2008 13:44:07 GMT
I didn't really mean that Rootes should have copied the all alloy design of the Imp, just used an OHC. There was a prototype, the Hillman "Swallow" which used the larger Coventry Climax engine (presumably the "production" 1220cc. Lotus Elite version rather than a racing engine) maybe with a thought to develop a new range of medium sized units from this. This was before the Imp was released, so I guess Imp problems put them off. The semi-mid engined Swallow of course metamorphasised into the Hunter. So what is the history of the Chrysler 180 engine? I had an Avenger "Tiger" spec road rally car for a while. Lovely, strong, seemingly unburstable engine but G*d was it thirsty!!!
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Post by seth on Oct 26, 2008 22:35:16 GMT
Wow, thanks for such a good summary! So if I understand you right, the 1500 in my Arrow Minx is a short stroke 1725 lump with the 5 bearing crank.
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rottie
Dodge Spacevan
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Post by rottie on Nov 27, 2008 23:10:56 GMT
hi seth. the piston height is different on the 1725 to the 1500 as well so simply getting a crank wont up the capacity.. the heads are a direct swap as said above as long as you have the cam as well (and manifolds) other differences are earlier motors have heater output from middle of head between cylinders 2 and 3 whereas later hunter motors dont. the water pump differences are all directly swappable the early engine had mounts on a steel plate behind the timing gears but I wouldnt have thought this would get in your way should you find an earlier engine..
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