1.7 and 2.0 O series compatibility. Replacement or replacement parts

[david painter]

In my opinion that is a RWD block if it was a O2 from a Montego the drilling of the dipstick would be facing the bulkhead and would be covered by the manifolds possibly a later Sherpa block I have seen a few of those offered for sale recently being ex military parts stock
Dave

[ClaytonSpeed]

If you look at the drivers side of the block in the pictures it tucks inwards showing that it is mirrored. O2 blocks, M series and T series are all like this.

RWD sumps in that configuration are difficult to get hold of. Enthusiasts sites are possibly your best bet. When was the last time you saw an O series Sherpa? Or a Discovery MPI?

[locost_bryan]

Google searching found this link, a German guy saying he had a Rover engine with LCF10067 on the block and serial number 20T4HH84. Googling 20T4HH84 shows it is a Rover 220 T-series 16v

Would it be feasible to cut the existing sump, and re-weld it to suit the reversed block? Perhaps a good idea to get a fwd drive sump, and compare to the Marina sump?

[ClaytonSpeed]

Or just use a FWD sump if you don't have an ARB. You could cut and shut if you cut them exact and maybe TIG it all back together.

[Mikeyp]

Sorry being thick - FWD ?

[Mikeyp]

Ps found a very useful engineering shop that will manufacture the dipstick plug

[ClaytonSpeed]

Sorry being thick - FWD ?

Front wheel drive

[Mikeyp]

Doh - any other thoughts on possible models as sumps for 2.0 MPi are rarer than hens teeth

[ClaytonSpeed]

First things first, make sure you have all the other pieces that will bolt onto the block you have.

I’ve got a front wheel drive steel sump that might help convert your original to the new block. I might even be able to convert it for you.

[MarinaCoupe]

I'll leave this information here as it is the most comprehensive chat on O Series parts, also to settle some previous assertions about the O Series cylinder head and its unleaded capabilities. I have checked the parts manuals for the Marina MK3 1.7 and the Ital 1.7/2.0. All version of all years used Steel/Stellite valve seats in the cylinder heads.

Inlet valve seat 12H 4915
Exhaust valve seat 12H 4916 / CAM 7493

The old style BMC/BL part numbers would suggest that they were also used on something else previously, but I can find no cross-reference to another engine or vehicle. Also I can't find any supplier with stock of these parts against these part numbers.

In my searches, I came across the Serdi website, they list valve seats by dimensions both metric & imperial - so it should be possible to identify suitable replacements if necessary https://www.serdi.co.uk/engine-componen ... t-inserts/

Enjoy!

[locost_bryan]

Same part numbers in the Rover SD1 2000 parts manual http://www.vintagemodelairplane.com/pag ... iche02.pdf

[sherpa]

hi, just joined on here, im into MK1 sherpas myself, own 2 of them, one did have the 1700 original O series in it, but took it out 2 years ago as leaked oil from everywhere and had constant head problems even after fitting new old stock heads to it, anyways recently i landed on a very clean looking early 1700 sherpa O series with the oil filler on the cam cover, bought it blind as the seller had allready stripped all the external fittings off it which made me concerned i was buying a scrap engine but as it wasnt much ive took the chance on it, ive removed all the missing bits off my original O series which has now seized up due to standing since 2023, think water got in one of the bores, so ive built up this new acquired O series, it spins over normal, its got a spark fuel is getting into the manifold but dont seem to be getting to the plugs, ive fitted new plugs leads points, it has comprression though it is down a bit not not massivly, the engine could have stood un used a long time, but its been kept in the dry as its not corroded at all its very clean even the head.
some idiot has decided to remove the dowl pin on the flywheel end of the crank and to remove it heated the end up with gas bottle gear its got so hot its melted a blob on one side ! ive ground it off, but its basically ruined the crank, i do have the original crank in the original O series, but thats got scores on the end where the oil seal has rubbed on it years so leaked badly when last in use,
the Pair of cranks photographed together on the start of this post, which one is the 2 litre one and which one the 1700 one? i can see a slight diffrence on the casting but they do look about the same.
any advice on this 1700 O series im trying to start up would be welcome, if i can get it to run, i plan to get someone to totally rebuild it assuming i can get a set of low compression pistons for it, i have all the parts to do the head up have a full set of new old stock valves and have most the gaskets, bear in mind all sherpa 1700 O series were made as low compression engines not high compression as used in the cars

[MarinaCoupe]

Your picture hasn’t uploaded.

The 2.0 crankshaft is part number BHM 1152 it should be cast/stamped into the crankshaft somewhere and the 2.0 high compression (car) pistons are CAM 1382.

The con-rods are common to both 1.7 & 2.0 engines. The bore is the same for both engines, the difference in capacity is achieved by different crank throws and difference in piston height (from the centre of the little end to the piston top.

You must use 1.7 pistons with the 1.7 crank and similarly 2.0 pistons with the 2.0 crank.

[locost_bryan]

I think Sherpa was referring to Kilroy's photos on the first page of this thread, showing the differences between the 1700 and 2000 cranks and pistons.

[sherpa]

since i last wrote ive bought a brand new crank in wax paper in a wood crate, but after putting it in my original 1700 block and noting the throw on the piston off th 1700 crank to the one ive just bought i now realize iv bought a brand new 2 litre original O series crank.
also picked up at the same time a factory spare new O series engine, been stored decades in damp conditions so has surface rusting on it, but again after stripping, this turns out to be an austin princess new short engine, block pistons and crank, even says 2 litre penned on the front, ive also been told that the part number is whats showing on the princess microfiche slides, the oil pick up is within the oil pump area, not from the sump like on marina ital and Mk1 sherpas, so bought an an engine thats no use to me too , i want to sell it if anyones interested
ive cleaned it up, no pitting in bores, or on head or sump
not sure what to do now, toying with the idea if making this rebuilt 1700 into a 2 litre now ive a crank and pistons, but they are high compression pistons, and a sherpa 2 litre should have low compression pistons, ive read both high and low 2 litre pistons differ only by the depth of the depression in the piston crown? low ones having a deeper drepression in them?