What exactly Is a VM Diesel

[volvopaul]

I had a pair of 180hp 6cyl in a Halmatic 34 semi displacement on shafts.

They had VM on the Blocks, BMW stickers and Mercruiser stickers.

VM Is an italian engine manufacturer and sold engines to BMW for their marine engine range (petrols and diesels) BMW lost their shirt on it and sold range to Mercruiser as their range was all petrol at that time and yanks did not know how to build small diesels ( still dont).

This engine range ran for about 8 to 10 yrs in production.

I had overheating problems with mine and they made a fine set of deadmen when chain was added.

The early BMW variant was renown for overheating, but once the oil cooler mod was carried out it was sorted, ive rebuilt a few of the bmw motor, there not that easy to work on in a boat, bench rebuild in my opinion is the answer.

 

[davey]

Gemini is no good but the parts are cheap.

Davey,

The header tank was raised to ease the coolant fill. One of the problems with the VM overheating was that is was extremely difficult to fill and get rid of the air blockages. Raising the header eased this issue.

The VM was not a patch on the LR home designed and built 2.5 litre Gemini, intorduced with the first Discovery. Gem 2 was my perference, in the 1993 facelift Disco and Rangie. This replaced the VM in the Rangie, with a DI Diesel rather than the IDI VM enigne.

Jag tried the VM in the early '80's, and it worked quite well, but never went into production.

Not the currently defunct LDV Maxus used a VM engine. The van is about to reappear made in Shanghai.

*******************************************************************

Regarding the Gemini engine (and I’m actually talking about the 300TDi) it is in my honest opinion an outdated piece of s#1t and I speak from bitter experience. The number one problem is that its heritage goes back to a petrol engine that had the centre two exhaust ports next to one another. This was done in order to heat the carburetter hot spot. Allegedly about 300 modifications were done to the petrol engine in order to make it into a diesel but it is still a piece of junk. It still has two exhaust ports next to one another and the Siamese ports produce uneven heating. When (not if) the head gasket fails it always fails at the centre. The high mounted water pump is also bad news and the engine has a cam-belt (duh!) Allegedly the 300TDi is just about tolerable in a Defender as the bonnet shape allows the header tank to be higher up. The Discovery has its header tank at a height equal to or lower than the water pump. One can only assume that the designers were young dudes who believed that metals and gaskets always make 100% perfect hermetic seals but in real life this is not so. In a badly designed cooling system a microscopic leak of gas - even 1cc per hour - will eventually create an air-lock and cause overheating. In a well designed cooling system this gas will be vented-off harmlessly from the header tank. As I have a spare Discovery bonnet I plan to incorporate a bulge to get the header tank higher up but these cars are still a heap of junk unless one has the much lower petrol V8 engine where the water does circulate properly. Forget the school run, the proper test of a 4x4 is to hang 3.5 or 4.0 ton on the back and traverse a few long steep hills (the A35 at Chideock for example) Allegedly the American 6.5 litre turbo 4x4s are now quite good and some have a 12,000lb rating. The Gemini engine is IMHO a has-been that never was and it doesn't have a tunnel-bore block or self adjusting tappets. Unfortunately G-Wagens and Unimogs cost too much.

 

[Latestarter1]

*******************************************************************

Regarding the Gemini engine (and I’m actually talking about the 300TDi) it is in my honest opinion an outdated piece of s#1t and I speak from bitter experience. The number one problem is that its heritage goes back to a petrol engine that had the centre two exhaust ports next to one another. This was done in order to heat the carburetter hot spot. Allegedly about 300 modifications were done to the petrol engine in order to make it into a diesel but it is still a piece of junk. It still has two exhaust ports next to one another and the Siamese ports produce uneven heating. When (not if) the head gasket fails it always fails at the centre. The high mounted water pump is also bad news and the engine has a cam-belt (duh!) Allegedly the 300TDi is just about tolerable in a Defender as the bonnet shape allows the header tank to be higher up. The Discovery has its header tank at a height equal to or lower than the water pump. One can only assume that the designers were young dudes who believed that metals and gaskets always make 100% perfect hermetic seals but in real life this is not so. In a badly designed cooling system a microscopic leak of gas - even 1cc per hour - will eventually create an air-lock and cause overheating. In a well designed cooling system this gas will be vented-off harmlessly from the header tank. As I have a spare Discovery bonnet I plan to incorporate a bulge to get the header tank higher up but these cars are still a heap of junk unless one has the much lower petrol V8 engine where the water does circulate properly. Forget the school run, the proper test of a 4x4 is to hang 3.5 or 4.0 ton on the back and traverse a few long steep hills (the A35 at Chideock for example) Allegedly the American 6.5 litre turbo 4x4s are now quite good and some have a 12,000lb rating. The Gemini engine is IMHO a has-been that never was and it doesn't have a tunnel-bore block or self adjusting tappets. Unfortunately G-Wagens and Unimogs cost too much.

Gather you have no liking for the motor then............

Which one are you talking about Gemini 200TDI or Romulus 300TDI?

 

[talltim]

VM Head Gaskets

These are/were supplied in 3 different thicknesses. So you had to dismantle and check if you had no, one or two small holes in a certain area of the gasket so you knew which gasket to order.

I also remember there being numerous bulletins in the BL workshop

 

[Elessar]

*******************************************************************

Regarding the Gemini engine (and I’m actually talking about the 300TDi) it is in my honest opinion an outdated piece of s#1t and I speak from bitter experience. The number one problem is that its heritage goes back to a petrol engine that had the centre two exhaust ports next to one another. This was done in order to heat the carburetter hot spot. Allegedly about 300 modifications were done to the petrol engine in order to make it into a diesel but it is still a piece of junk. It still has two exhaust ports next to one another and the Siamese ports produce uneven heating. When (not if) the head gasket fails it always fails at the centre. The high mounted water pump is also bad news and the engine has a cam-belt (duh!) Allegedly the 300TDi is just about tolerable in a Defender as the bonnet shape allows the header tank to be higher up. The Discovery has its header tank at a height equal to or lower than the water pump. One can only assume that the designers were young dudes who believed that metals and gaskets always make 100% perfect hermetic seals but in real life this is not so. In a badly designed cooling system a microscopic leak of gas - even 1cc per hour - will eventually create an air-lock and cause overheating. In a well designed cooling system this gas will be vented-off harmlessly from the header tank. As I have a spare Discovery bonnet I plan to incorporate a bulge to get the header tank higher up but these cars are still a heap of junk unless one has the much lower petrol V8 engine where the water does circulate properly. Forget the school run, the proper test of a 4x4 is to hang 3.5 or 4.0 ton on the back and traverse a few long steep hills (the A35 at Chideock for example) Allegedly the American 6.5 litre turbo 4x4s are now quite good and some have a 12,000lb rating. The Gemini engine is IMHO a has-been that never was and it doesn't have a tunnel-bore block or self adjusting tappets. Unfortunately G-Wagens and Unimogs cost too much.

what on earth has any of that got to do with VM diesels?

 

[desmodromic]

Much prejudice presumably due experience on this thread! When slating VM don't forget the 4 cyl model is used in the London Taxi (and Chrysler Voyager and Jeep Cherokee) so noone can say it's not durable. Like anything else there are good/bad ones, good/bad maintenance, good/bad usage. I've got one - VM that is - which though it's in a LDV Maxus van (the Lada of the van world) has proved very reliable, smooth, easy to work on and above all tractable (torque) and economical (30mpg on a run). A lot more reliable than the Td5 (Discovery2) despite that being based on the well-reputed Rover L series engine (Rover & Prima Perkins). Not everybody's Maxus is reliable I recognise (!) but if maintained well and driven considerately (i.e. not like the works van it usually is) it can be as reliable as a London Taxi. So the point is that the VM-derived Mercruisers (bigger VM engines but same design) are as good as other Mercruisers (1.7dti was great for me but again not everyone), Yanmar or Volvo (remember the awful - for most people anyway) Volvo 2003T?? Additonally I've had a much better life with Mercruiser legs (all ALpha Gen II) than Volvo DP....So often it's not the engine/leg but what the manufacturer - or you - do with it.

 

[Barleycorn]

*******************************************************************

Regarding the Gemini engine (and I’m actually talking about the 300TDi) it is in my honest opinion an outdated piece of s#1t and I speak from bitter experience. The number one problem is that its heritage goes back to a petrol engine that had the centre two exhaust ports next to one another. This was done in order to heat the carburetter hot spot. Allegedly about 300 modifications were done to the petrol engine in order to make it into a diesel but it is still a piece of junk. It still has two exhaust ports next to one another and the Siamese ports produce uneven heating. When (not if) the head gasket fails it always fails at the centre. The high mounted water pump is also bad news and the engine has a cam-belt (duh!) Allegedly the 300TDi is just about tolerable in a Defender as the bonnet shape allows the header tank to be higher up. The Discovery has its header tank at a height equal to or lower than the water pump. One can only assume that the designers were young dudes who believed that metals and gaskets always make 100% perfect hermetic seals but in real life this is not so. In a badly designed cooling system a microscopic leak of gas - even 1cc per hour - will eventually create an air-lock and cause overheating. In a well designed cooling system this gas will be vented-off harmlessly from the header tank. As I have a spare Discovery bonnet I plan to incorporate a bulge to get the header tank higher up but these cars are still a heap of junk unless one has the much lower petrol V8 engine where the water does circulate properly. Forget the school run, the proper test of a 4x4 is to hang 3.5 or 4.0 ton on the back and traverse a few long steep hills (the A35 at Chideock for example) Allegedly the American 6.5 litre turbo 4x4s are now quite good and some have a 12,000lb rating. The Gemini engine is IMHO a has-been that never was and it doesn't have a tunnel-bore block or self adjusting tappets. Unfortunately G-Wagens and Unimogs cost too much.

I'm just a thick farmer, knowing little of the politics of engine production, but I do know that with a bit of servicing the 200 and 300 tdi engines are bombproof, they regularly go over 200,000 miles. Whenever we have had a head gasket it was due to overfilling the oil. The td5 was a disaster, and tidy Landrovers with tdi engines fitted are currently very sought after.

 

[nicho]

I have a Sealine fitted with two 3.6 Mercruiser engines but I keep hearing a reference to them being VM Engines. Research shows VM engines are made in Italy or that they are fitted to Land Rovers. I thought mercruiser were American! Whats the truth or am I on the wrong track completley?

Just to confuse the issue, I thought the Mercruiser diesels were the old BMW units?

Edited to say ignore post - Didn't see Volvopauls post above

 

[Jurgen]

Have seen many comments on the Mercruiser (VM) v VP debate over the years.
fact is that both engines have suffered their problems. Any poorly maintained engine will give you grief as will early designs.
I have 2 Merc 4.2 that have wanted for nothing, yes the odd niggle but otherwise sound. Each engine is 17 years old with circa 1800 hrs each.
keep them maintained and loved and they won't let you down

 

[gordontytler]

Davey,

The header tank was raised to ease the coolant fill. One of the problems with the VM overheating was that is was extremely difficult to fill and get rid of the air blockages. Raising the header eased this issue.

The VM was not a patch on the LR home designed and built 2.5 litre Gemini, intorduced with the first Discovery. Gem 2 was my perference, in the 1993 facelift Disco and Rangie. This replaced the VM in the Rangie,...

This is a great thread in my search for cheap parts.

Would a cylinder head gasket set for a Range Rover 2.4TD 2.5TD 2.5 TD VM 1986-94 VRS fit the BMW D636 engine? The Range Rover gaskets on ebay are 1.62mm thick.

Here is the Range Rover gasket set



and this a page from the D 636 workshop manual



The holes seem to be in the right places.

thanks

 

[jon and michie]

Really good engine - had one in my frontera and once the swmbo ran it with no coolant in as there was a hole in the radiator.
Got home and temperature off the scale.
Got a new rad and topped up and still ran like a dream as it had separate heads for each cylinder therefore there wasn't any warpage
Jon

 

[CLB]

This is a great thread in my search for cheap parts.

Would a cylinder head gasket set for a Range Rover 2.4TD 2.5TD 2.5 TD VM 1986-94 VRS fit the BMW D636 engine? The Range Rover gaskets on ebay are 1.62mm thick.

Here is the Range Rover gasket set

View attachment 76715

and this a page from the D 636 workshop manual

View attachment 76716

The holes seem to be in the right places.

thanks

I think they will fit, but of course you will need to get two lots as you need six and the RR only had four. Just make sure yiu get the right thickness.

 

[novanta]

I think it must be around 98 or 99, we had a new Targa 37 with D250's (yes, a few of them were build, including Morse electronic gearlevers) and a new T37 with KAD44's. Although I liked the Mercruisers they were no match in compare with the VP's. Acceleration with the compressor was much faster and overal feeling was more sportive. The Bravo 3 drives struggled to get the power in the water, if you looked at the trimswitch it would start to cavitate... Because of the larger distance between the stern of the boat and the engine, space in front of the Mercruisers was almost zero. We did a comparison test but the VP boat was the best!