How To: Restore a Morris or keep fit

[Mike K]

The 1937 to 41 military CS8 truck engine had it's genesis in the family of pre-war Morris 25 engines, the Morris 'big six' sedan of 1937 to 39 utilized the 25hp 82mm bore engine, the basic block was used in both civilian and military vehicles with variations in the cylinder heads, pistons, manifolds , carby and water pump. They are similar to other pre-war engines: poured big end bearings as used in the CMP Chevrolet 216.

I found a 25 engine out of a civilian Morris truck, the crankshaft and bearings are good enough for my needs . I plan to make up a engine from the two engines I have stripped down. I have new valves , pistons and valve guides (made by me). Just need to find a good engine machinist ..

These engines have a few peculiarities i.e. there isn't a rear main crank seal in the normal sense, they used a large flange with a threaded o.d. that throws the oil back . The dynamotor is chain driven by the duplex timing chain. The crankshaft has no counterweights.The military carburetor is a special updraft Solex-dustproof. Fuel is gravity fed to the carb from the Autovac vacuum unit that is mounted on the dash panel.

Another oddity is: the Leyrub joints, these are rubber 'universal joints' on each end of the prop shaft.. These joints are still available new. .

[Mike K]

Been held up with the big problem . How to repair the broken M6 bolts , there are 28 of them broken off in the side of the engine block. The jacket side cover has 32 of the M6 bolts and 28 of them have broken. This is a common problem with this type of vintage engine.

Looking into the options I have decided to drill out the bolts and use M6 heli-coils. This process requires very accurate drilling...more about that later on.

Good fortune: I found a 1930s era film made by Morris Motors (Morris had their own in house film unit). By a stroke of good luck the film depicts a Morris 6 cyl. engine , drilling and assembly. Basically it is the same engine that I am currently working on ! The film reveals how they drilled out the 32 holes in one process, and to such a high degree of accuracy. https://www.youtube.com/watch?v=ieF3d_YBUh4

Another issue I have is: a replacement head gasket. As of now, there aren't any replacement new head gaskets available, only a very few old stock gaskets exist and these cost a small fortune and are of dubious condition. I believe a few Morris 25 car owners have had gaskets hand made. I have made enquiries to overseas gasket makers, the prices are very high, maybe a run of 50 would be viable.

[Bob Carriere]

For the head gasket may I suggest you contact antique engine clubs..... there are suppliers they get gasket material from which they cut they own head gasket....... comes in sheets of compacted asbestos or ceramic cloth held together by a high temperature bonding agent..... various thickness and can be backed up with soft pure copper sheet. Seems it works well on single and double cylinder engines... rather hard to cut but made one for a Fairbanks 5hp magneto hand started engine and it worked. For a 6 cyl head I would consider two soft copper sheets with ceramic cloth in between so you have something to compress with the head bolts. Collectors/rebuilders of old steam engines maybe another source.

[Mike K]

Hi Bob

Yes I have looked into buying copper sheet and the composite material and then making up the gasket myself. Maybe I could get the sheets CNC cut , I would need to provide a computer file in the commonly used CNC format, something like G code ?

Yes the stationary engine guys and clubs would be a good place to ask.

There are a few people who can hand make vintage car gaskets for the car restorers but these guys are very expensive $$$$. There is a on-line business in Thailand that manufactures head gaskets for vintage car owners, I got a quote some years back... upwards of $300 plus $100 shipping for just one 6 Cyl. head gasket. https://gasketstogo.com/

Auto surplus, a business here have NOS Morris head 6 cyl. gaskets for the 1933 to 36 models, but Morris changed the gasket shape in 1937 and I need the 1937 onwards gasket.

Back to the broken bolts, I have drilled out one of the broken M6 bolts and it worked out OK. I have not used heli-coils before, so this has been a learning experience ! In order to achieve a nice and accurate hole, I bought a cheap mag drill. The drill has a electro magnetic in the base , so that you can, with a switch, turn on-off the magnet, the drill has to sit on a flat even steel/iron base, it can be used horizontally too. I made a little aligning tool out of angle plate, the holes in the plate are the correct distance from the block deck. The clear plastic rod has cross hairs like a rifle sight . How it works: you look down the rod and line up the cross-hairs in the centre of the broken bolt. You then align the drill in the mag drill in the angle plate hole and drill out the broken bolt. The Heli-coil set comes with a special sized drill and tap and the little stainless steel coils. BTW there are many cheap copies of heli-coil sets around, the Chinese sets are of dubious quality , I found a brand that is actually manufactured here in Aust.

[Mike K]

Asking around, some restorers are using solid copper head gaskets on old vintage cars. Apparently the copper gaskets have been performing OK.

A business in Brisbane CNC cuts these solid gaskets , the copper needs to be annealed before fitting. Might be worth considering going down this route.

[Mike K]

I managed to drill out all of the broken M6 bolts and tapped new threads to accept the heli-coils,

This was a long and tricky job.. the Mag drill did the job well.. I bought a cheap Mag drill on Epay but it worked out OK .

The original little M6 bolts have oversized heads .. for 3/16" BSW size spanners . I will buy some 8mm bolts and machine them down to M6 and rethread them. This sounds crazy but the larger heads are needed to seal the gasket .

Morris inherited Metric tooling when they took over the WW1 era Hotchkiss factory , the Morris oversized metric bolt heads were made to suit the common U.K. Whitworth spanners.

[David Herbert]

Re. mismatched heads vs. threads: I had a 1921 German Jung steam locomotive that had whitworth threads but metric heads. I have a Japanese bench grinder made in the '70s with whitworth threads.

David