Tech Tips:
Inserting a later engine into a Mk Minx

From: Keith Johnson [keiths55(at)bigpond.net.au]
Sent: Monday, 2 February 2004 10:38 PM
To: hillmanlist
Subject: Re: "Hillman – " Progress report

This message forwarded by the Hillman List.

––––– Original Message ––––– From: "Chuck Hillman" <hillmanminx(at)hermon.net>
> Hi Keith,
> It is always good to get your update report.  I have to ask, how much
> would it take to put a later engine like the 1490 in my '51 Minx?  Is it
> the same drill you are describing here?  I assume a 1390 is a good upgrade
> over the little flathead.  Can I keep the original transmission if I can
> get the column shift working well?
> Chuck

Hi Chuck
This is a good swap.
But like all things Rootes has several traps.

Firstly the easy way :–)
Get a donor Mk VIII use the front suspension cross member, radiator, engine and gearbox.
The 51 column shift will fit up to the Mk VIII gearbox.

Next the "hard" way.
I will list the things that are different.
The first is the front crossmember, the engine mountings are different.  They are a different angle and closer together.  So you need to weld new mountings to use the original.  All the other parts of the front end are the same which is why I said the easy way is to swap in a Mk VIII crossmember.  Just bolt it up and you are ready to install the engine.

Radiator is different, mounts the same but has different outlets, it is taller and narrower than the series radiator.  I have a spare Mk VIII radiator but the cost of getting it to you would be excessive.

Engine: The easiest 1390 to swap in would be the Mk VIII again.  Things that are different to the more common series engine are: the front engine mounting plate, the front of the sump, the fuel pump.  These are the differences that would affect installing the engine in place of a sidevalve.

If your 1390 comes from a series car then this is the approach I would take.  Remove the front engine mounting plate (lives behind the timing chain) and modify the place the front engine mounts fit so that it will fit up to your original front mounts on the sidevalve crossmember.  If you have a sidevalve front plate you can use it as a template.  See one little change solves two problems and the car itself has not been modified should you "repent" of your modifying ways :–) Doing it this way means that the front crossmember doesn't need to be altered, just a part that bolts on to the replacement engine.

The sump is too long and needs to be either replaced with a Mk VIII one or have about 4" cut out of the front.  This is for steering clearance only.  It is just the deeper part that needs to be cut back.  The oil pick up is under the distributor so it is a simple job to get done.  I had to do the same thing to put a 1600 in my original Californian back in 69 as the original 1390 sump had several large bullet holes in it from engine self destruct.  Ouch!!!

The fuel pump cannot live on the front of the engine it needs to be in the mounting at the rear by the distributor.  However the series fuel pump doesn't work in this location so you must use the Mk VIII item or substitute an electric pump.  This is what Ian did with the 1600 into his Mk Ute.  I like the electric pump because it automatically primes the carb making starting easier.

Other differences that would not affect you are the manifolds and dipstick location, just leave them as is.

Gearbox: the early sidevalve gearbox has a different input shaft to the overhead valve models.  You have no choice but to find a bell housing and gearbox for a Mk VIII.  The gearbox mounts are the same, the gear linkages and drive shafts will bolt right up and the clutch chain just hooks on like the original.  Don't know about the speedo cable.

A very worthwhile swap, do it this way it will look like it was made that way in the factory.  Any Rootes engine 1390 to 1725 can be installed, the Hunter/Arrow 1725 requires a front engine mounting plate and electric fuel pump as they are not provided with the rear fuel pump mounting as are some of the 1600 blocks.  The accelerator/throttle linkages are easy if you use Mk VIII parts otherwise you will need to invent something suitable.

The exhaust would best be fabricated same as the Mk VIII again from the manifold on the left side, cross over under the gearbox and join the original muffler on the right hand side.

Brakes are similar through the whole mark range, need plenty of pedal pressure to get anything happening.

Tell me what model engine you want to use and we can get into more detail.  Be warned that those front engine mounting plates were changed slightly by Rootes every few years to make sure we were paying attention.

55 Californian

Several months later, Keith's theory (above) was put to the test when he enquired about putting a 1725 cc engine into his 1955 Hillman Californian.

From: Keith Johnson [keiths55(at)bigpond.net.au]
Sent: Sunday, 24 October 2004 5:30 PM
To: minx [hillman@can-inc.com]
Subject: "Hillman – " Progress????

Afternoon All,

For future reference don't believe anything I have to say :–)
Check on it first.
I have been busy preparing a 1725 ex Hunter to transplant into Californian.
Now I knew that the front mounting plate and water pump would need changing.
As did the sump.
For those with series Hillmans or Alpines all the steering stuff goes behind the engine, on Mk cars it goes under the front of the sump.  This means the Mk sump is cut away to clear the steering linkages.  Easy, I think, remove sump on surplus Mk VIII 1390 and attach to 1725 block.  Problem solved???
Fortunately I had a spare Hunter sump which I thought I would slip on the 1390 engine to keep the dirt out and make it easier to move about.  On offering it up I found the holes down one side didn't line up.  It appears that the 1725 block is 1/4" wider than the 1390.  I am glad that I didn't become aware of this little piece of Rootes "product improvement" after pulling the engine out of the Californian.  Checked my sump gaskets and they align with the 1725 but not the 1390..

Brings to mind discussions with Ian on the 1600 into Mk VIII swap.  I was convinced that I used a fuel pump in the rear mounting which doesn't appear on the 1600.
I didn't swap the 1390 sump to the 1600 as it had so many "bullet" holes in it I cut down the original 1600 sump to suit.

The last swap I was involved in with the 1725 into an early model, was into a 57 Series 1.  I can't remember what sump was used in that case, probably a remanufactured Hunter one again as the original engine had also grenaded.

One for the number gurus:  AB74750857.  An alloy head lump out of the 66 Vogue.  With all this self doubt that is going around what do the numbers say?
I thought it was a 1725 but is it in fact a 1600?
If it is a 1600 perhaps it can go back in the Vogue and at least make it mobile under its own power.  Still needs some paint.

All so depressing.  I will now need to manufacture a new sump.  Down to the car graveyard and see if I can find something I can cut the bottom from and weld it into the Hunter top half.  Neat welding and a coat of paint (covers a multitude of sins :–) and nobody would ever know.

I see that the Sceptre on Ebay sold at AUS$4000.

55 Californian
57 Rapier
78 Mercedes :–) Hers

From: kkj [kkj(at)privat.utfors.se]
Sent: Monday, 25 October 2004 3:52 AM
To: hillman@can-inc.com; Keith Johnson
Subject: SV: "Hillman – " Progress????

You said: "It appears that the 1725 block is 1/4" wider than the 1390."

That was something new to me! But on the other hand, it has been decades since I had a 1400 block in front of me, but I have always thought they had the same outside dimensions.

Kristian J

From: Vic Hughes [v.hughes(at)student.canberra.edu.au]
Sent: Monday, 25 October 2004 9:22 AM
To: Keith Johnson; minx
Subject: Re: "Hillman – " Progress????

This message forwarded by the Hillman List.


  From the engine number it's a Vogue III (pre-September 1965) which would make it a 1600.  It may well have been registered as a 1966 model because in those pre-compliance plate days, the 'year' was generally recorded as the year first registered (my HSC built in Sept '63 was registered in January 1964 as a 1964 car).    A Vogue IV (1725) engine no. should start (for Australia)  AB774.....

But..... Can't a 1725 be distinguished from a 1600 by the dipstick? – ie doesn't it go straight into the block on a 1725, but into a sump tube on a 1600?

Cheers, Vic

From: Keith Johnson [keiths55(at)bigpond.net.au]
Sent: Monday, 25 October 2004 4:52 PM
To: minx [hillman@can-inc.com]
Subject: Re: "Hillman – " Progress????

This message forwarded by the Hillman List.

Sigh  :–(
it has the little tube out of the sump. I guess it is a 1600.
Suppose this means I can fit all the high rev stuff to it :–).


From: Graham Robinson 62 Husky [Leslie3008(at)bigpond.com]
Sent: Monday, 25 October 2004 5:04 PM
To: Vic Hughes; Keith Johnson; minx
Subject: Re: "Hillman – " Progress????

This message forwarded by the Hillman List.

Vic & Keith,
Being a 1600 and probably alloy head for the Sceptre or Sports model the top end and camshaft should be the same as a 1725 alloy head version but the bottom ends are different with holes and cutaways for steering arms etc.
Sump gasket sets we sell to members has two sets of sump gaskets to cater for that variation in hole locations and shape of the outside rim.  The Humber should have a full bottom where the 1725 is shaped as you found out.
Don't disgard the Humber block as it should have the larger bigend bearings and is quite a good motor for rebuild purposes.
Basically the same donk as used in the 1600 Sunbeam Alpine.
From one Sage to another.

From: Keith Johnson [keiths55(at)bigpond.net.au]
Sent: Monday, 25 October 2004 8:41 PM
To: minx [hillman@can-inc.com]
Subject: Re: "Hillman – " Progress????

This message forwarded by the Hillman List.


I take it then that the 1600 sump is the same as the earlier 1390 and 1500 models.
Ian would have figured this out with his 1600 in the 55 Ute.??????

Holes in your memory can be a worry :–)  I was convinced I used a rear fuel pump on my 1600cc powered 55 Californian many years ago.  It definitely had a mechanical pump, so I must have used the front mounted pump of the 1600.  My faulty memory being that the original pump didn't fit there.  looking at my Mk VIII it appears that the front pump will actually fit if you relocate the coil bracket.  As the 1600 doesn't have a mounting for the rear pump I couldn't have used it then, could I :–)

So a 1725 into my Californian needs a special sump, while putting it in the Rapier or Vogue can use the original or one from a 1725 Alpine or series V or VI.
Easy when you get it figured out.  The series installation doesn't have the problem with the steering under the front of the engine that I have to contend with in the Mk VIII.

I found the 1600 a very good engine, the larger journals made it far more robust and the shorter stroke than the 1725 allowed it to rev harder.  From a racing point of view there is less rotating inertia or drag in the engine, so it will build revs more quickly.
So I get a Californian time warp with a 1600 engine just like my old one :–)
Scary stuff :–))
Actually with the Holden twin choke carby that the previous owner fitted to replace a broken Solex it probably will go harder than the progressive 28/36 Weber that I favour.  This engine is an alloy head version as well.
The whole thing starts to look like a much more viable swap into the Californian.  I need to do it soon as the present engine is loosing oil pressure for some reason.

Has anybody in Brisbane got a surplus driveshaft for a series Minx???
Condition of the UJ's doesn't matter as it would need to be shortened and rebalanced to match the overdrive to the Mk VIII rear end.  The driveline people replace the UJ's as a matter of course before doing the balancing bit.

Keith 55 Californian

From: "DOUGLAS EDWARDS" [hillmanfromhell(at)hotmail.com]
Sent: Tuesday, October 26, 2004 1:51 AM
To: keiths55(at)bigpond.net.au
Subject: Re: "Hillman – " Progress????

Keith.  Whats your problem with a 1600 cc  There a dime a dozen over here because everyone wants 1725cc engines.  I m putting a 1600 in my kids ser 5 alpine because its what I have sitting in the garage right now .  If it turns out its no good I'll drop the 1600 cast iron head out of my sedan in it .  Then I'll put the weber manifold on it from grant and go play with everyone anyhow.

From: Keith Johnson [keiths55(at)bigpond.net.au]
Sent: Tuesday, 26 October 2004 8:31 PM
To: minx [hillman@can-inc.com]
Subject: Re: "Hillman – " Progress????

This message forwarded by the Hillman List.

I have no problem with the 1600.  it just wasn't what I thought I had.

The 1600 has some advantage over the 1725, being shorter stroke it revs much better.

So nobody has answered the burning question...... does the 1390 sump fit???
If so all I need is the right sump gaskets to change it and in it goes.  I can fit the overdrive later.

Sufficient for the day is the evil thereof :–)


From: Graham Robinson 62 Husky [Leslie3008(at)bigpond.com]
Sent: Wednesday, October 27, 2004 3:35 PM
To: Keith Johnson; minx
Subject: Re: "Hillman – " Progress????

This message forwarded by the Hillman List.

Two emails to answer all on tricky subjects!
  ... (snip) ...
On sumps– it all depends which oil pump you want to use- then find the sump that fits that and the block or chop it about to fit the oil pump.  Easy to change the drive cog over to the other pump anyway.

From: Graham Robinson 62 Husky [Leslie3008(at)bigpond.com]
Sent: Wednesday, October 27, 2004 9:02 PM
To: Keith Johnson; minx
Subject: Re: "Hillman – " Progress????

This message forwarded by the Hillman List.

Sumps– I have heard all say that 1725 sumps wont fit the earlier blocks so one assumes all the other sumps will fit one to the other but not to 1725.  I haven't had enough engines together to compare – just one at a time.  I do know that the Humber Sports sump being 1725 has the internal earlier baffles with extra cutouts for the later oil pump and dipstick but for some reason used the earlier oil pump.  That is what I found when I pulled it down a few weeks ago to salvage the camshaft for Jin Artz.  I kept the sump for later use.

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