1968 Hillman Minx Estate - 08/10/21 - Road Trip!

hey seth.. not sure which part of london you are in but planning on hitting eastbourne at some point over the christmas holidays which entails the wonders of the m40 and the m25 so a meetup is possible at some location if you wish?

A bit of progress on the engine front. I managed to get the front crank nut off which allowed me to strip the engine right back to the bare block.



Cam seems to measure up OK though oddly one lobe is smaller than the others - same lift but smaller base circle and height to the peak. I boxed the various bits so that I could bring a few home at a time to check/measure/clean.



I've already done the rockers and pushrods and now have the pistons, rods and oil pump. Then I came across some pistons on Ebay and buying them has changed the direction of the build somewhat....



They're +.020 1500 pistons, which, with their flat tops will enable me to build the 1725 with the larger Holbay type combustion chambers in the head while retaining a high compression ratio.



So rather than chucking the 1725 together as an interim engine I'm going to do it "properly" especially as the crank is in such good order anyway.

Today I thought I'd try something I remember reading in magazines - measuring the balance of the con-rods. An initial try with it just supported on a thin rod and ressting on a socket on the scales showed that actually there must be a "proper" way as it was difficul to get repeatable results. A quick look on the internet showed that the proper rigs have roller bearings and allow the rod to swing a little to find its proper resting position. I had a look in the shed and found a couple of small bearings so gave it a go with them and with care could repeat the measurements successfully.

Weighing the big end.



Weighing the little end.

Obviously it is sensible to take precautions when doing this in the house, hence a piece of kitchen roll on the kitchen scales and being the only person home at the time....



With those weights and the weight of the rod as a whole I can remove a little here and there and match them together with the pistons (one of which is a bit heavier than the others). I'm not going to go mental as I'm not building a race engine but a bit of "blueprinting" like this seems an appropriate thing to do.

Ditto on the heads. I thought I'd try out what tools I've got on one of the ports. There's a ridge with a sharp step about an inch in from the manifold face so I smoothed that a bit...



..and there's a nasty ridge particularly on the inside radius above the valve so I've blended that in a bit too.



Just following some leads for the more major machining now.

lol putting stuff in the dishwasher he wouldnt have use of his man vegetables evah ;D

Hairnet, we don't have a dishwasher

BC, little things like this won't make the engine build take any longer as it'll be a couple of months coming together and its nice to put into practice stuff I was first reading in magazines 15-20 years ago...

Mr C-W, thanks I'll take a good look at the dizzy drive. The fuel pump is driven by an eccentric. The small lobe is the one nearest the oil pump drive so maybe its for clearance? Though I can't imagine less than a mm making a difference. The guy I got the head from was explaining about the spigot rings in earlier manifolds.

Indeed. I'd strongly suggest getting in touch with the Imp Club Spares co-ordinator for a set of Viton O-rings - I've had a set on my Stroms for about 4 months now with no sign of leaking at all.

By comparison, the Nitrile ones I had before shrunk, presumably due to being immersed in petrol, and didn't fit the jet holder's groove properly.

Obviously, making sure that the float chamber sealing face is clean, and radiusing out any vertical scoring, helps the seal.

If you want the contact details, do let me know and I'll PM you.

this build reminds me of an article in hot car from the 70s. with david vizard giving the lowdown on building a topnotch bottom end for few pennies
each part should be matched like for like. so all pistons should be the same weight and all rods
also he blended away the lug on the small end (its only there for easy machine balancing)
the lug on the big end was profiled to more closely follow the radius of the bore and he ran a ball ended milling cutter through it so only the front and back were left
the next stage was to polish the entire rod with the exception of the inside of the rod
next the rod was shot peened to work harden the surface and strengthen the rod
final step was to check the rod for straightness and bend back if neccesary
don't know if your build is going to these lengths but if you do and have the crank balanced afterwards you will have a very smooth running engine
a friend had their essex v6 balanced and i could balance a 10p coin on the engine at tickover and rev up and the coin didnt move!
ttfn glenn

Thanks for the tips on the carb seals chaps. jrevvil, I'll PM you once I'm thinking about the carbs again.

Bob, I still like the idea of putting the 1500 back in at some point. Will see how this build goes first. I'm using the standard 1725's cam (twin carb version).

Glenn, I'm liking the idea of doing some basic balancing to this engine (and intend to get the crank/flywheel etc balanced once I've done the pistons/rods) but I'm not going to go mad refinishing parts. As you say, balancing should make a good difference to how even a non-race engine feels and ought to be good for longevity too.

Slacker, its my 'daily' in that I don't have a modern car to fall back on. Only other car in the household is my wife's Herald. But as I work from home I don't have to commute in it, though I would if I did if you see what I mean. It obviously gets used for all the typical trips most people would do in normal cars.

Why I oughta......

In other news I picked up some possible new winter wheels over the weekend....



Kinda depends if I can get tyres to sensibly fit. 7 x 14, ET -8. Might be tricky.

Saw those and instantly thought of KevFromWales' truck. Should fit them to the Hillman as-is for great lols.