Newly rebuild 1.5 BMC engine overheat and stops after a few minutes [VIDEOS]

[Tony Brooks]

7 minutes ago, Tracy D'arth said:

The precombustion Riccardo chambers originally do protrude slightly from the head face when new but heads are often skimmed with them still fitted because they are difficult to remove, so that they are then flush. This does not generally cause a problem.

 

They should not fall out and the remaining one looks all wrong, the flame port should be rectangular, not the shape of that one. What state are the others in ?

 

I agree, the hole looks too large to me. I wonder if the ones that fell out are genuine BMC ones, Just maybe Perkins ones would fit but be loose. Then there is the question about if this is an Indian of UK made head and I think Turkey may have made some as well, but I am not sure that was for 1.8s. With the variety of sources it makes chambers for one source less likely to be a good fit in a head from another source.

[Tracy D'arth]

20 minutes ago, Tony Brooks said:

 

I agree, the hole looks too large to me. I wonder if the ones that fell out are genuine BMC ones, Just maybe Perkins ones would fit but be loose. Then there is the question about if this is an Indian of UK made head and I think Turkey may have made some as well, but I am not sure that was for 1.8s. With the variety of sources it makes chambers for one source less likely to be a good fit in a head from another source.

The 1.5D tooling is in India as far as I remember.  The 1.8D is I believe tooled in Turkey exclusively.  Many bits of Perkins appear  to fit the BMC engines but are not correct and cause many problems.

To help we need to know what parts were changed or if they were found to be in this engine before it was worked on. As a start I would get the head checked for cracks and distortion, skimmed if possible. Then new combustion chambers fitted properly.

There is obviously fair compression as it did start with at least one cylinder below par so bores and pistons would seem to be serviceable.

[Tony Brooks]

Tracy, I agree with that as well.

[RLWP]

My understanding is, if the chamber inserts are loose, you cannot skim the head. If you leave them in, they interfere with the tool tip.

 

If you leave them out, they stand too far off the face of the head when you put them back in and the gasket will blow around the inserts. 

 

Richard

 

 

[Tony Brooks]

3 minutes ago, RLWP said:

My understanding is, if the chamber inserts are loose, you cannot skim the head. If you leave them in, they interfere with the tool tip.

 

If you leave them out, they stand too far off the face of the head when you put them back in and the gasket will blow around the inserts. 

 

Richard

 

 

 

I think that depends on the tool used. Back in the day when we were frequent users of machinists I got shown the head skimming machine and it was a spinning abrasive "ring" about an inch wide set into a surface plate. I concluded the ring could move up and down. I don't see how fixed inserts would trouble  it. Loose ones probably would.

[john.k]

having watched all the Pakistan truck repair videos,this one is obviously a job for them.

[Tony Brooks]

20 minutes ago, john.k said:

having watched all the Pakistan truck repair videos,this one is obviously a job for them.

 

My thoughts entirely but felt it wiser not to say so, I did hint at it though.

[Tracy D'arth]

43 minutes ago, RLWP said:

My understanding is, if the chamber inserts are loose, you cannot skim the head. If you leave them in, they interfere with the tool tip.

 

If you leave them out, they stand too far off the face of the head when you put them back in and the gasket will blow around the inserts. 

 

Richard

 

 

True if you are using a fly cutter, it will break it. We used a surface grinder with a large flat stone.

[john.k]

Back in the day,when diesel Landrover heads cracked,the simple cure was to fit a petrol head ,carby and dizzy......I'd say youd probably do the same with an Austin motor.

[TNLI]

Silly question, but are the various nuts and bolts used on the outside of the BMC 1500 imperial fine or coarse threads (UNF or UNC) ???

 

 

[Tony Brooks]

Mainly UNF but one end of any studs could be UNC but then BMC tended to sprinkle the odd BSF/Whitworth thread about on their products so probably not 100% UNF.

[Tracy D'arth]

36 minutes ago, Tony Brooks said:

Mainly UNF but one end of any studs could be UNC but then BMC tended to sprinkle the odd BSF/Whitworth thread about on their products so probably not 100% UNF.

BMC machined most of their own threads on studs and nuts, hence the brass full nuts that they had the good sense to use on manifolds. This did however lead to some odd vehicles with a mixture of standard threads.  The Whitworth and UNC thread forms in smaller sizes are very close which also leads to confusions.

[john.k]

In any case ,as the various BS and Unified fasteners use different sized hex heads,the simple application of a wrench will show if the fastener is Unified or BS......if you want genuine confusion ,get BSC and UNF fasteners mixed up.....

[MtB]

3 hours ago, john.k said:

In any case ,as the various BS and Unified fasteners use different sized hex heads,the simple application of a wrench will show if the fastener is Unified or BS......if you want genuine confusion ,get BSC and UNF fasteners mixed up.....

 

 

Jeez that word grates.

 

Please, it's a "spanner" when you're working on a British engine! 

[TNLI]

23 hours ago, Tony Brooks said:

Mainly UNF but one end of any studs could be UNC but then BMC tended to sprinkle the odd BSF/Whitworth thread about on their products so probably not 100% UNF.

 

Thanks, luckily I'm not replacing any steel bolts, just some of the mostly half inch nuts with stainless lock nuts and washers. That way I know they will never rust on, and like the new shiny rocker cover, will look cool.

  Biggest issue I have at present is removing the old black furnace paint from some metal parts. It responds to paint stripper, but I have then discovered some original green paint underneath. The alternator was anodized dark grey, so I can't use a wire brush to remove the paint. 

  

If anyone is replacing steel bolts or other parts with Chinese or Indian stainless steel, don't forget that some types of cheaper stainless have a very poor fatigue life and can very occasionally suffer from casting or stamp flaws. I snapped a 12mm stainless bolt once whilst tightening it by hand. I knew it was from a dodgy chandlery and had looked it over before fitting, but that incident, (Radar arch fitting plates), put me right off using stainless for anything serious. 

[Tracy D'arth]

7 hours ago, john.k said:

In any case ,as the various BS and Unified fasteners use different sized hex heads,the simple application of a wrench will show if the fastener is Unified or BS......if you want genuine confusion ,get BSC and UNF fasteners mixed up.....

Unfortunately not always correct with BMC engines. Because they made their own, the nuts may be 1/2" AF but can be BSW or BSF threads!

Edited January 1, 2022 by Tracy D'arth

[Victor Vectis]

3 hours ago, MtB said:

 

 

Jeez that word grates.

 

Please, it's a "spanner" when you're working on a British engine! 

And please use low sulphur fuel in it when travelling to the railway station, not forgetting to take your driving licence after checking that your registration plates are in place.

[Mad Harold]

6 hours ago, MtB said:

 

 

Jeez that word grates.

 

Please, it's a "spanner" when you're working on a British engine! 

Once was asked by a Brummie if he could borrow my "keys".

Puzzled I queried this and it turned out he meant spanners!

[bizzard]

35 minutes ago, Mad Harold said:

Once was asked by a Brummie if he could borrow my "keys".

Puzzled I queried this and it turned out he meant spanners!

An American with a lisp would say, ''Can I borrow your wench''.

[TNLI]

Has anyone got a picture or diagram of how the Morse cable (Throttle part) and stop lever are connected to the HP pump ??

 

My engine had no mounting plate or cables connected and the BMC manual I have is for a car, so does not show how it is connected. 

[Tony Brooks]

1 hour ago, TNLI said:

Has anyone got a picture or diagram of how the Morse cable (Throttle part) and stop lever are connected to the HP pump ??

 

My engine had no mounting plate or cables connected and the BMC manual I have is for a car, so does not show how it is connected. 

 

I think that I answered this question for you some time ago when you were on about the four studs sticking out of the end of the injector pump. Those studs are used to secure a double return sided r two brackets (probably home made in your case) to which the cable outer clamp saddles are secured to the returns. No image because there have been many designs.

 

I found the image below on the net, i shows what looks like an automotive cable bracket to me and that would make fixing the throttle cable anchor in line with the pump lever very difficult. It also has a welded in outer clamp for a Bowden stop cable. However you can see where it fits and get an idea about how to make one. Personally I would make two each being secured by the left or right hand side pair of studs. I would use strip steel the same width as the Morse cable anchor ou intend to use bent into an inverter L shape.

 

Edited January 2, 2022 by Tony Brooks

[TNLI]

Does anyone know if the BMC 1500 should have a covering cap near the top of the dipstick to stop water dripping onto the engine going into the crankcase ??

[Tony Brooks]

I can't recall one back in the 60s and 70s but I suspect later engine may have had one, pretty much like cars and vans.

[TNLI]

7 hours ago, Tony Brooks said:

I can't recall one back in the 60s and 70s but I suspect later engine may have had one, pretty much like cars and vans.

It might have had a simple lump of rubber or similar on the dip stick shaft that has fallen off. Can't seem to find a new dip stick anywhere.

Edited January 4, 2022 by TNLI

[Tony Brooks]

4 hours ago, TNLI said:

It might have had a simple lump of rubber or similar on the dip stick shaft that has fallen off. Can't seem to find a new dip stick anywhere.

 

Drill a small tap washer to be a stiff fit on the stick. There are some small ones, not the conventional 1/2" ones) that should be almost the ideal size.

Edited January 4, 2022 by Tony Brooks