Ian Wood
Guest
I own and live in a Mercedes Hymer S660 in the South West of England. I really love the van & the deep quality engineering that is behind it. I bought it with the intension of not travelling more than a county (ish) in each direction from my base, the forecourt of a warehouse. Recently though I have had the idea of touring to France, but the thought of doing this with the normally aspirated engine was not that appealing. If I really logically think about the van it is not that slow on the flat, it’s just the reality of hitting a hill & you tumble down the gears. If I was a little bit patient this would be fine, but I’m used to having a turbo’d transit & I wouldn’t want to go back to my old transit without turbo. You so get used to that power! So why not buy a newer MH? I looked at newer Hymers, (I’m sold on them a bit like Apple Mac’s v Windows I like quality & the benefits that design & build quality bring, I’m not interested in other makes of older van) and considered spending an additional £14k (£27k rather than £13k) on a turbo’d modern Fiat base vehicle, tempting but some how I’ve invested so much time in this van making it suit me and I actually love it in a strange way! So I decided to really research the possibility (or not) of fitting a more powerful engine and higher gearing to match the extra power.
So I’m going to share my experience and journey with you, so are you sitting comfortably? I set my self a budget, excluding my time, of £3k surely that should do it! Also I had a free month coming up between projects/events in my life, September 2014, lets do it, why not, it’s going to be tough & there will be lots & lots of hurdles to cross, I was going into this with my eyes open. Here are some facts:
The engine I have is the 5 cylinder 2.9L (OM602). Base vehicle is a Mercedes 410D, 1989.
So a lot of time was spend on research, here are my results:
The next generation of this engine (phase 1 Sprinters) had a turbo option (129bhp) but it had a complex electrical control system and injection pump that makes it almost impossible to retro fit into a Hymer.
The South Korean four wheel drive manufacturer Ssangyong had a deal with Mercedes where they assembled engines from Mercedes parts. Their version of the OM602 is known as the OM662. The interesting thing is they made their own turbo version of this (120bhp) engine with a mechanical injection pump. Also the turbo on this engine is self controlling/regulating which also saves a lot of work with sensors etc.
So great it looks like there is an option and also there are a lot of these engines available. I bought one on ebay for £700 with 83k miles. I wanted to find out if one would fit and the only way to do that was to have it on the floor to measure off. Well what a disappointment there is no room for the turbo because of the bulkhead & engine cover. Maybe these could be cut to make room. I was not rushing to this conclusion, I did not want to risk more noise in the cab, it’s loud enough as it is. So I looked for somewhere to remount it and decided on the space that was available lower down & just in front of the bell housing, it was just possible to squeeze it all in there.
The engines have the same mountings points and same main features like exhaust & inlet mountings on the engine, but lots of detailing is different.
The things used from old Hymer engine:
Inlet Manifold (with 5 small holes welded up) and attached fuel lines and accelerator linkage).
Oil Filter Housing.
Fuel Filter Housing.
Sump.
Steering pump (so as not to have to disconnect & then bleed it).
The Old Oil Dip Stick Assembly (with a new hole drilled into the crankcase for it).
The Internal Oil Pump that sits in the sump.
Some of the old air intake pipe work was very handy.
The Oil Filler.
The things used from the Ssangyong engine:
The Injector Pump.
The Vacuum Pump.
Exhaust Manifold.
The Intercooler and pipe work.
Things bought new:
Clutch kit.
New Pinion & Crown wheel (different ratio wanted +25%) from Mercedes.
Ssangyong exhaust this was cut to fit the Hymer. Bought because I wanted to keep the same backpressure, ie it is a larger diameter than the Hymers to allow more exhaust gas to flow.
Ssangyong workshop manual.
Mercedes 410D workshop manual (Peter Russex).
Lots of hoses & aluminium bends from Viper Hoses.
Things made / fabricated:
An extension to fit between the exhaust manifold & the new position of the Turbo.
A new mounting for the steering pump.
Reworking of the 4 wheel drive exhaust to fit the motorhome.
A mounting bracket for the Turbo.
The EGR cut off & sealed off.
A heat shield to protect wiring from the new Turbo.
Things needed:
Large space with room to work on two engines alongside each other on pallets.
Really good light.
Relaxed time frame, time to work through problems without pressure.
A skilled friendly fabricator.
A skilled friendly mechanic.
A small fork lift. The space in the engine bay is very tight & the arms of the fork lift just fitted in a treat. Not sure how you’re supposed to get the engine out without one!
Comprehensive tool kit.
Things to Note:
The fibre glass bodywork cross member across the front of the Hymer is not removable (well without major work).
The Turbo has to be mounted with the core so adjusted that the oil feed in is at the top and the oil feed out is at the bottom.
The bottom of the Turbo must be above the level of the oil in the sump so it can gravity feed back into the sump. I did not know this and by sheer luck it was mounted 2cm higher, phew that was a close one.
I changed the whole engines over because apparently the heads are different internally to allow for the increased pressure of the gasses. I don’t know if this is true but I didn’t want to risk it.
Because of the different shapes of the chassis cross members the sumps are totally different. The Hymer is deep at the front & the Ssanyong deep at the back. So you have to change over the sumps and the matching oil pumps, this was relatively simple to do.
So it all went well. The turbo is tucked away by the gearbox and works well, I’ve just done some comparisons of a hill climb with the old engine (66 k/hr) & the new engine (78 k/hr). That was the kind of improvement I was looking for so I’m pleased with that. I haven’t checked the new fuel economy yet. The differential ratio gets changed next weekend. Including this work the total cost has been around £4k. Would I recommend it, ‘NO’ unless you love solving oily problems, which if that is the case then you will be like a ‘pig in £$%^’!
Please see attachments for photos.
Good Luck!
So I’m going to share my experience and journey with you, so are you sitting comfortably? I set my self a budget, excluding my time, of £3k surely that should do it! Also I had a free month coming up between projects/events in my life, September 2014, lets do it, why not, it’s going to be tough & there will be lots & lots of hurdles to cross, I was going into this with my eyes open. Here are some facts:
The engine I have is the 5 cylinder 2.9L (OM602). Base vehicle is a Mercedes 410D, 1989.
So a lot of time was spend on research, here are my results:
The next generation of this engine (phase 1 Sprinters) had a turbo option (129bhp) but it had a complex electrical control system and injection pump that makes it almost impossible to retro fit into a Hymer.
The South Korean four wheel drive manufacturer Ssangyong had a deal with Mercedes where they assembled engines from Mercedes parts. Their version of the OM602 is known as the OM662. The interesting thing is they made their own turbo version of this (120bhp) engine with a mechanical injection pump. Also the turbo on this engine is self controlling/regulating which also saves a lot of work with sensors etc.
So great it looks like there is an option and also there are a lot of these engines available. I bought one on ebay for £700 with 83k miles. I wanted to find out if one would fit and the only way to do that was to have it on the floor to measure off. Well what a disappointment there is no room for the turbo because of the bulkhead & engine cover. Maybe these could be cut to make room. I was not rushing to this conclusion, I did not want to risk more noise in the cab, it’s loud enough as it is. So I looked for somewhere to remount it and decided on the space that was available lower down & just in front of the bell housing, it was just possible to squeeze it all in there.
The engines have the same mountings points and same main features like exhaust & inlet mountings on the engine, but lots of detailing is different.
The things used from old Hymer engine:
Inlet Manifold (with 5 small holes welded up) and attached fuel lines and accelerator linkage).
Oil Filter Housing.
Fuel Filter Housing.
Sump.
Steering pump (so as not to have to disconnect & then bleed it).
The Old Oil Dip Stick Assembly (with a new hole drilled into the crankcase for it).
The Internal Oil Pump that sits in the sump.
Some of the old air intake pipe work was very handy.
The Oil Filler.
The things used from the Ssangyong engine:
The Injector Pump.
The Vacuum Pump.
Exhaust Manifold.
The Intercooler and pipe work.
Things bought new:
Clutch kit.
New Pinion & Crown wheel (different ratio wanted +25%) from Mercedes.
Ssangyong exhaust this was cut to fit the Hymer. Bought because I wanted to keep the same backpressure, ie it is a larger diameter than the Hymers to allow more exhaust gas to flow.
Ssangyong workshop manual.
Mercedes 410D workshop manual (Peter Russex).
Lots of hoses & aluminium bends from Viper Hoses.
Things made / fabricated:
An extension to fit between the exhaust manifold & the new position of the Turbo.
A new mounting for the steering pump.
Reworking of the 4 wheel drive exhaust to fit the motorhome.
A mounting bracket for the Turbo.
The EGR cut off & sealed off.
A heat shield to protect wiring from the new Turbo.
Things needed:
Large space with room to work on two engines alongside each other on pallets.
Really good light.
Relaxed time frame, time to work through problems without pressure.
A skilled friendly fabricator.
A skilled friendly mechanic.
A small fork lift. The space in the engine bay is very tight & the arms of the fork lift just fitted in a treat. Not sure how you’re supposed to get the engine out without one!
Comprehensive tool kit.
Things to Note:
The fibre glass bodywork cross member across the front of the Hymer is not removable (well without major work).
The Turbo has to be mounted with the core so adjusted that the oil feed in is at the top and the oil feed out is at the bottom.
The bottom of the Turbo must be above the level of the oil in the sump so it can gravity feed back into the sump. I did not know this and by sheer luck it was mounted 2cm higher, phew that was a close one.
I changed the whole engines over because apparently the heads are different internally to allow for the increased pressure of the gasses. I don’t know if this is true but I didn’t want to risk it.
Because of the different shapes of the chassis cross members the sumps are totally different. The Hymer is deep at the front & the Ssanyong deep at the back. So you have to change over the sumps and the matching oil pumps, this was relatively simple to do.
So it all went well. The turbo is tucked away by the gearbox and works well, I’ve just done some comparisons of a hill climb with the old engine (66 k/hr) & the new engine (78 k/hr). That was the kind of improvement I was looking for so I’m pleased with that. I haven’t checked the new fuel economy yet. The differential ratio gets changed next weekend. Including this work the total cost has been around £4k. Would I recommend it, ‘NO’ unless you love solving oily problems, which if that is the case then you will be like a ‘pig in £$%^’!
Please see attachments for photos.
Good Luck!
