Non-original motor identification

[JConstable]

Greetings to Alpinists with greater experience than my own. Recently I purchased a Series V (Chassis #B395009988) with a non-original engine. As a neophyte I thought this was not a problem, but now I am trying to learn more about the engine. It appears to be a 1725 with an aluminum cylinder head, suggesting suitability for a series V. However the engine number (B006041094 LSX H) according to what I have found on the web is a high compression 1725 from a Hillman Minx. If I am correct this suggests a significantly lower compression than for which the Alpine was intended and a concomitant reduction in power (~65 bhp rather than the targeted 92+ for an Alpine 1725). I seek any assistance in gaining information about the engine and will attempt to place some pictures to aid identification. Thank you.

John

 

[Series3Scott]

John - you're correct. Your 1725 engine is from a 1965 Series VI Hillman Minx DeLuxe. LSX is left hand drive saloon bound for North America. The extra H is for high compression, as you noted.

 

[JConstable]

I was hoping that I had made some errors in identification, however, a lower power and torque engine appears to be the conclusion. Although I would not qualify as a speed demon, the greater output of the correct 1725 would be appreciated. This brings up a second issue, is there a way to determine the gear ratios in the transmission to determine if the transmission is an Alpine version or a Minx version? Any information would be appreciated.

John

 

[RootesRooter]

Series IV Minx' came with 1725's?? I always thought only the VI's had them.

John - you're correct. Your 1725 engine is from a 1965 Series IV Hillman Minx DeLuxe. LSX is left hand drive saloon bound for North America. The extra H is for high compression, as you noted.

 

[Series3Scott]

Series IV Minx' came with 1725's?? I always thought only the VI's had them.

Oops, typo - I fixed it.

 

[Dr.NO 007]

wordsmith

"concomitant" reduction in power

(bite my dickshunary, butt) this English sure sounds like it's getting close to Hollywood. just joking JC. we are never too old to learn a new word. please expound on the exact meaning.

 

[lemansvk]

John,

You say the car has an alloy head, so it seems that what you have is an engine block from a Minx VI, not the complete engine. Minxes came with iron heads and a single carb (not alloy heads and multiple carbs) and the cam was 'milder' - hence they had lower power than Alpines. Iron head cams will not work with an alloy head, nor will the carb/manifold (different valve sequence) So, if your car has the alloy head and twin Strombergs it's safe to assume that only the block was replaced (a common event, - I know of several Alpines with Hillman Hunter/Sunbeam Arrow blocks).

The 1725 blocks are the same for Minx or Alpine, it's the other bits that make the power difference. Same with 1592 blocks, my Alpine III has a block sourced from a Hillman Super Minx, but with all the important Alpine bits fitted

Given this, It would seem most likely that the gearbox is also the original Alpine one.

Cheers, Vic

I was hoping that I had made some errors in identification, however, a lower power and torque engine appears to be the conclusion. Although I would not qualify as a speed demon, the greater output of the correct 1725 would be appreciated. This brings up a second issue, is there a way to determine the gear ratios in the transmission to determine if the transmission is an Alpine version or a Minx version? Any information would be appreciated.

John

 

[Tom H]

Vic, So you say if he has a Minx block, but an Alpine cam, head, manifold, carbs, he essentially has an Alpine motor. Do I understand correctly? That's what I thought.

For Dr. No; From Webster's:
con·com·i·tant
: accompanying, especially in a subordinate or incidental way

Tom

 

[lemansvk]

Tom,

Yes, that's what I'm saying. There may be some debate over the "originality" aspect but that's not what I'm talking about.

With my car, the original Alpine 1592 block had badly ovalled bores - when it was taken to 60 thou over it revealed an internal corrosion problem - water in the bores. I got a bare Super Minx block from a mate, had it bored 20 thou and fitted all the Alpine internals.

Cheers, Vic

 

[husky drvr]

Vic, So you say if he has a Minx block, but an Alpine cam, head, manifold, carbs, he essentially has an Alpine motor. Do I understand correctly? That's what I thought.

For Dr. No; From Webster's:
con·com·i·tant
: accompanying, especially in a subordinate or incidental way

Tom

( bell ringing ) We have a winner.

The high compression Minx engine would use the same pistons as the Alpine. The iron head is different to give the difference in compression.

I believe the Minx engine only used a pulley on the crankshaft as opposed to the Alpine's pulley and dampener. Checking that item might give an idea if the entire bottom end or just the block was used for the engine.

 

[JConstable]

It appears that I have opened a can of worms from which relatively good news could emerge. The next step is to check the bottom end and determine if I have a pulley (Minx) or a pulley and a dampener (Alpine) on the crankshaft. Should the clouds part to reveal an essentially Alpine correct engine, then life is good. And to conclude for Dr. No 007, I’ll try to constrain my verbiage to negate further obfuscation of this engine identification matter.

John

 

[mikephillips]

Be aware that the pulley/damper assembly is one piece, check to see if it has a rubber ring in it. If it doesm it's the Alpine unit.

 

[P. Scofield]

Speaking of Iron heads..............

I just got one with a parts deal. Are they worth keeping or should I chuck it in the pile of metal scrap?

Paul

 

[JConstable]

Block ID and cranking pressure

All,
Thanks for all the information you provided. To conclude the crankshaft has both a pulley and a damper as one connected piece supporting the conclusion that the block is a replacement from a Minx, but all the important add-ons, so to speak, are Alpine.

Now for the bad news. A compression check indicated cranking pressures of 120, 102, 117, and 135 psi - what is the correct cranking pressure of a fully functional 1725 engine? After the addition of a healthy dollop of oil in each cylinder the pressures increased to 145, 130, 195, and 170 psi. This suggests the need for rings and the whole 9 yards. Assuming the block has not been bored what is the safest maximum increase in bore that can be accommodated without sacrificing block integrity? As usual any and all information is appreciated.

John

 

[jumpinjan]

Speaking of Iron heads..............
I just got one with a parts deal. Are they worth keeping or should I chuck it in the pile of metal scrap?Paul

Well, I don't know....yeah, junk all that stuff...
(then I'll corner the iron head market on Ebay...Mull-haha!)

 

[alpine_64]

All,
Thanks for all the information you provided. To conclude the crankshaft has both a pulley and a damper as one connected piece supporting the conclusion that the block is a replacement from a Minx, but all the important add-ons, so to speak, are Alpine.

Now for the bad news. A compression check indicated cranking pressures of 120, 102, 117, and 135 psi - what is the correct cranking pressure of a fully functional 1725 engine? After the addition of a healthy dollop of oil in each cylinder the pressures increased to 145, 130, 195, and 170 psi. This suggests the need for rings and the whole 9 yards. Assuming the block has not been bored what is the safest maximum increase in bore that can be accommodated without sacrificing block integrity? As usual any and all information is appreciated.

John

175 psi up would be a start... but yes.. you are going to have to go the full rebuild.

60thou over is easy and pistons are out there.. 20 30 and 40 are also around. Check where your bore is at.

Now motor advice time... you should really upgrade some things.. but at minimum..

have the block hot tanked.. before doing this run a wire brush down all cooling passages and pull the welsh plugs.. will be loads of rubbish/casting sand in them. then repeat once block is back.

Deck the block, rebuild the oil pump.. replace it.. or upgrade it.

Head.. do the vizard modification to lower compression and increase flow, 3 angle valve grind and true it. Have lifetrs resurfaced 9delta do this.. you may want to up the cam at the same time).

internals.. balance all moving components..

look into chev rods.. stronger lighter better..

bunch more stuff.. but the basics.. clean, check clearnces, and assemble carefully.. balance all moving bits.. polish if you have the time..

 

[lemansvk]

From memory healthy cranking pressures should be in the 170-190 range, so you have a problem. Assuming you just want to build a stock motor, I think 060 is the maximum OS. Sunbeam Specialities list pistons for 010, 020, 030, 040 and 060.

There are people on this list who can help you build something 'special' - there was a thread a while back on "Building a 1725" that you could look through

Cheers, Vic

All,
Now for the bad news. A compression check indicated cranking pressures of 120, 102, 117, and 135 psi - what is the correct cranking pressure of a fully functional 1725 engine? After the addition of a healthy dollop of oil in each cylinder the pressures increased to 145, 130, 195, and 170 psi. This suggests the need for rings and the whole 9 yards. Assuming the block has not been bored what is the safest maximum increase in bore that can be accommodated without sacrificing block integrity? As usual any and all information is appreciated.

John