for Imp-anoraks only... crankcase & crank query (stamps)

Thanks Darkspeed

I visit that site quite often but your link led me to read more of it lol

Anyway it doesn't have the answer for what I'm trying to establish.

Basically my engine has 875 cast into the block (where the engine number is stamped) and very early Imps didn't have this. Someone is telling me only Chrysler-era blocks had 875 on them That would be 69/70 onwards I think

Thanks for the advice but detecting a bit of impatience with remark at end.

That's the problem with being an expert I guess

Likewise - '67 Chamois Coupe had 875 cast - which I believe was on all the MK2 straight edge blocks. I have had sport engines from '67 to '73 and they were outwardly all the same. I have 4 here at the moment spanning 68-73 those years and they are all pretty well identical square edge 875 cast 180 head motors.

The main Chrysler differences were the oil drains, sport cams and double springs as stock with the later I4 engines - which I think came with the 533 or 553 head casting number.

There are early sport head casting numbers and if your car is an early sport that may be the better way to investigate it - find out exactly when the 180 sport head was introduced. The Imp club forum would be a far better place to ask.

Again from the link above.

All the sport heads have the oil drain (from head to crankcase) and they all use the same valve sizes.
Sport head casting numbers (not a Rootes part number) with last digits
....107 : the very early sport head, possibly for use with competition cars and the dry-liner 998 Rally Imp from the end of 1965
....162 : 162 fitted to early production Sports up to 1968; the Rallye head casting, basically the same as the 180 cylinder casting but ported and chambered for 150 CD Strombergs and 998cc.
....180 : the most common. It was the later sport head, used until the end of production. It is a thicker casting than the 107, giving more scope for modification.

The search for clues to the age of my bottom-end goes on and is actually at the terminus now.

I've checked every component and there is nothing with that might be date-related on it.

However the crankshaft has something stamped on it. As well as the casting marks (although I've been told you can't call them this as the crank is forged) it shows D 85

Now this could mean anything really but it's been hand stamped and looking at a listing on Ebay it shows a quite different number P ****

So it's possible this could be letter for year followed by sequential numbering. Who knows...


I've been told transaxles has sequential numbering stamped on this. this is mine which fits in with Apex book estimates that around 160000 Imps made/sold pre-67



stamp on crank might also be sequential



from the makers of Devon Custard?



D85 stamped and S58 cast. what does it all mean? lol

No but there is a nick on the top of the lug. It's in a box in front of me.

I looked again and there is a very thin crack to the right of the lug. It encroaches about 3mm into the casting's bottom-face

Cheers colnerov

The reason I'm doing all this research is that my car was modified by Rootes workers before being registered and gained quite a few bits n pieces, including the unstamped Sport engine. So it's getting a bit of special attention from me lol

As you say Imp engines tended to get changed & modified and mine definitely lost its original head. The guy who did it told me he put it on a Chamois and there was also a small tow-hitch that he put on a Transit apparently.

Funnily enough last week I got an email from someone who's family business owned my Imp in the 80s and he remembers it always overheating (not uncommon I believe) and last night I found one end of the water-jacket completely blocked. It's clean as a whistle now but they weren't to know that back then lol


anti-freeze jelly on top of solid gunge in water-jacket. it wouldn't help car run at correct temp