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

[David Mack]

13 hours ago, TNLI said:

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 ??

When I had one it didn't. One of the core plugs rusted through and the resulting jet of cooling water impinged directly on the dipstick, turning the engine oil into mayonnaise!

[TNLI]

2 hours ago, David Mack said:

When I had one it didn't. One of the core plugs rusted through and the resulting jet of cooling water impinged directly on the dipstick, turning the engine oil into mayonnaise!

 

Did the core plug rust through from the inside, or did the coolant freeze or something ??

 

I'm going to fit a washer as per the TB instruction, BUT will put a rubber grommet under it.

[David Mack]

1 hour ago, TNLI said:

 

Did the core plug rust through from the inside, or did the coolant freeze or something ?

Rusted through from the engine side. It was a badly done home built conversion of an ex-vehicle engine, with raw water cooling. The thin pressed steel core plug was never intended to work with a continuous supply of oxygenated cooling water.

[TNLI]

36 minutes ago, David Mack said:

Rusted through from the engine side. It was a badly done home built conversion of an ex-vehicle engine, with raw water cooling. The thin pressed steel core plug was never intended to work with a continuous supply of oxygenated cooling water.

 Thanks, sounds like the boat might have been in salt water without engine anodes, unless they used some kind or real Iffy plug material.

 

Does anyone know if these are the right plugs:

 

MGA 1500, 1600 & 1600 MkII BMC ENGINE CORE PLUG SET | eBay

Edited January 4, 2022 by TNLI

[David Mack]

4 minutes ago, TNLI said:

Thanks, sounds like the boat might have been in salt water without engine anodes, unless they used some kind or real Iffy plug material.

No engine anodes, but knowing the previous history of the boat, I very much doubt it had ever been anywhere near salt water.

I would never again use direct raw water cooling with an engine designed for closed circuit cooling, as vehicle engines invariably are.

Edited January 4, 2022 by David Mack

[TNLI]

12 minutes ago, David Mack said:

No engine anodes, but knowing the previous history of the boat, I very much doubt it had ever been anywhere near salt water.

I would never again use direct raw water cooling with an engine designed for closed circuit cooling, as vehicle engines invariably are.

 

Yes, I don't like direct cooling either.

 

Salt or fresh water can cause trouble with raw water cooling as explained in this article:

 

The lowly engine zinc - Ocean Navigator

[TNLI]

Just serviced and modified my beloved dipstick. All it needed was a rotary wire brush to remove the dreaded black paint that some dipstick abuser had sprayed on it, AND one 12v switch cover I already had in stock. All you do is cut the very end of the rubber section off and then slide it over the stick and adjust to the length of the tube. Hey presto one water resistant dipstick.

 

Heavy Duty Toggle Switch / Flick 12V ON/OFF Car Light SPST Missile / Water Cover | eBay

 

Total cost of cover only: 1.25 quid.

 

 

 

 

Edited January 4, 2022 by TNLI

[TNLI]

Just re assembling the fuel injection pipes after finishing painting the block and box. Can't understand why the fuel return pipe goes to the secondary fuel filter, BUT has a double ended banjo fitting that then has a pipe to the tank. What is the advantage of doing that ?? I was thinking that as a great believer in the KISS principles of marine engineering, I might just chop the return pipe off, and fit a stainless braided flexible pipe, (The fuel lines around and in the engine bay should be fireproof). So any objections or reasons for such odd plumbing of the low pressure fuel pipes ??

[Tony Brooks]

18 minutes ago, TNLI said:

Just re assembling the fuel injection pipes after finishing painting the block and box. Can't understand why the fuel return pipe goes to the secondary fuel filter, BUT has a double ended banjo fitting that then has a pipe to the tank. What is the advantage of doing that ?? I was thinking that as a great believer in the KISS principles of marine engineering, I might just chop the return pipe off, and fit a stainless braided flexible pipe, (The fuel lines around and in the engine bay should be fireproof). So any objections or reasons for such odd plumbing of the low pressure fuel pipes ??

 

I don't think that you mean the fuel return pipe, I think you mean the leak off pipe for the injectors. The fuel return pipe form the injector pump runs back to the engine filter.

 

The banjo bolt that holds the fuel return pipe onto the filter is hollow and it should have a 0.5mm hole in the side. This allows a small  amount of fuel to constantly return to the tank by the pipe on that banjo. The reason for this is to allow any small amounts of air that finds its way into the system to leak back to the tank and not build up in the filter head. If it did build up the engine would eventually just stop with an airlock.

 

This is not an odd system to those who understand the CAV DPA injection pump systems. It is perfectly standard.

[TNLI]

Thanks, only seen CAV filters in use for a primary, and although I've converted to a spin on fuel and oil filter, the top part is the same as a CAV in plumbing terms, so as it seems to be needed to vent the actual filter, I will connect it back as it was. 

 

 

Edited January 15, 2022 by TNLI

[TNLI]

Good series of You Tub clips of a full rebuild for a BMC 1500, and i would note that this professional did send his crank shaft off to another company for it to be inspected and polished, something very few engine rebuilders bother to do. He obviously knows just a problematic a tiny scratch can be in the long term. 

 

 

Edited January 20, 2022 by TNLI