MB 1120 Coming to America! Purchase, Build and Now Travel!

Alloy

Well-known member
Little update, we parked the truck a few weeks ago in order to fly east and visit family and in September to visit a friend in Spain. We spent the better part of a year in Spain while sailing and loved it. Now we get to visit again for a few weeks but get to be hosted by an overlanding friend who is from Spain. Should be great fun.

So, I did end up ordering the replacement radiator, I was told by Nissens USA that the drawing is old and the reduction is not there. I am very skeptical but I did learn that this is the replacement radiator for the OM366LA with 240hp (ours is the 200hp) so I am hoping it will work. I think (key word here) this was also the "HD" radiator option for the 200hp engine. Fingers crossed.

HOLSET 4040429
View attachment 677086

And I have finally gotten off my butt and ordered the replacement turbo. Not really sure why but the turbo is way less expensive in Europe, like half to a third of the cost. Unfortunately they will not ship to the USA (the one shop I looked into that had the best price along with some other needed bits), so the turbo is coming back in luggage when we return from Spain :D. At the same time I will finish the install of the EGT and boost gauges. After an injector pump change we will hopefully see 230-240hp. Will be really nice in the hills. Will likely install it in Tuscon AZ in October as there needs to be a little aluminum welding done and the guy that worked on our truck last year is there. Plus I am redesigning our entry ladder to make it more stable, have 3 steps with a wider tread. This will hopefully remove the need for the small step ladder which works fine but takes up storage space in the gear garage and adds the possibility of introducing bugs.

Have to admit, we are both missing the truck.

Will be interesting to learn what the larger radiator and increased HP does to the cab temp? Any insulation in the floor now?
 

VerMonsterRV

Gotta Be Nuts
Will be interesting to learn what the larger radiator and increased HP does to the cab temp? Any insulation in the floor now?
The cab does have the factory rubber insulated floor mats plus a layer of RattleTrap (which I doubt helps much here) and carpet (I know, kinda soft). Given the exhaust manifold is rusty I am considering getting it ceramic coated inside and out. I don't have any first hand experience with this but I have a hobby car (MGB) that other owners have done a JetHot coating to reduce under bonnet temps. If I can move this heat towards the exhaust it might reduce the temp under the cab. Not sure if this is a good idea or not, a 1.8l NA gas engine is a bit different than the OM366LA (and a lot easier/cheaper to experiment).

On a side note (and you all may know this already), these trucks also came with a 240hp version of the OM366LA (though there are some different internals as it was a bit newer), the 1124. Really wish I could have found one of those with the 6-speed.

I also know that the same engine was used as a marine engine that was built to 300hp, so I am hoping my upgrade will not stress things too much.
 

Joe917

Explorer
I believe there is also a 7 speed that will fit.
My truck was custom ordered as a motorhome with many rare goodies. I never understood the choice of the 5 speed. There may be other factors such as dependability or ease of service? I curse the 5 speed every time I am stuck between 3rd and fourth. Many times in the mountains I have revved the #^%@ out of it in third and slammed it into fourth only to hang on for 10 seconds or so before giving up and finishing the climb in 3rd. I suppose that is what the hazard lights are for.
 

Alloy

Well-known member
I believe there is also a 7 speed that will fit.
My truck was custom ordered as a motorhome with many rare goodies. I never understood the choice of the 5 speed. There may be other factors such as dependability or ease of service? I curse the 5 speed every time I am stuck between 3rd and fourth. Many times in the mountains I have revved the #^%@ out of it in third and slammed it into fourth only to hang on for 10 seconds or so before giving up and finishing the climb in 3rd. I suppose that is what the hazard lights are for.

Same for catching gears downhill.
 

Alloy

Well-known member
The cab does have the factory rubber insulated floor mats plus a layer of RattleTrap (which I doubt helps much here) and carpet (I know, kinda soft). Given the exhaust manifold is rusty I am considering getting it ceramic coated inside and out. I don't have any first hand experience with this but I have a hobby car (MGB) that other owners have done a JetHot coating to reduce under bonnet temps. If I can move this heat towards the exhaust it might reduce the temp under the cab. Not sure if this is a good idea or not, a 1.8l NA gas engine is a bit different than the OM366LA (and a lot easier/cheaper to experiment).

On a side note (and you all may know this already), these trucks also came with a 240hp version of the OM366LA (though there are some different internals as it was a bit newer), the 1124. Really wish I could have found one of those with the 6-speed.

I also know that the same engine was used as a marine engine that was built to 300hp, so I am hoping my upgrade will not stress things too much.


Ceramic coating reminded me of the custom exhaust blankets. Before the blankets were around we used Asbestos and coated it with Water Glass. These days fiberglass tape and Water Glass is used but it is not serviceable like the blankets are.


1629507385342.png

 

VerMonsterRV

Gotta Be Nuts
Here is the Jet Hot website. Mostly for hot rods but they claim a 56% reduction in under hood temps. Just don't want to pass on so much heat that it causes other issues downstream.

I haven't heard of a 7 speed but there are 2 different 6 speeds. The one that came on any 4x4 was still direct drive in 6th (guess they figured 4x4's don't need to go fast). They did however make a version of it for over the road 2wd trucks with the 6th gear being an overdrive. If you have the 6 speed already the swap to the overdrive unit is relatively easy. If you are starting with the 5 speed then things are trickier as the 6 speed is larger so more needs to be changed. I am hoping the extra hp helps in that 3rd-4th shift and makes up for the 5 speed. With any luck we will be able to move a bit quicker uphill.
 

Alloy

Well-known member
Here is the Jet Hot website. Mostly for hot rods but they claim a 56% reduction in under hood temps. Just don't want to pass on so much heat that it causes other issues downstream.

I haven't heard of a 7 speed but there are 2 different 6 speeds. The one that came on any 4x4 was still direct drive in 6th (guess they figured 4x4's don't need to go fast). They did however make a version of it for over the road 2wd trucks with the 6th gear being an overdrive. If you have the 6 speed already the swap to the overdrive unit is relatively easy. If you are starting with the 5 speed then things are trickier as the 6 speed is larger so more needs to be changed. I am hoping the extra hp helps in that 3rd-4th shift and makes up for the 5 speed. With any luck we will be able to move a bit quicker uphill.


 

VerMonsterRV

Gotta Be Nuts
I ha my manifold, turbo, exhaust brake housing and dump pipe all ceramic coats, sure does keep the heat down.

View attachment 677914

View attachment 677915
Now we're talking with the ceramic coating, probably go with a black if possible though! Your turbo install looks interesting. So on the outlet side the common way to do my upgrade is to cut the end off the charged air pipe and weld it back on at a slightly different angle. This is the most complicated bit as I don't have access to an aluminum welder (not to mention I do not know how to weld). I can have the guy in Tuscon do the welding for me as he has said it would be ok for me to do the turbo swap in his yard and I have another project for him anyways. Now If I could just cut the end off (it is a cast aluminum pipe with a flange and gasket) and put on a silicone adapter then that would remove that complexity. So, do you have a flange on the charged air box (intercooler?) off on the right in the picture? If not any issues?
 

Geo.Lander

Well-known member
Here is the Jet Hot website. Mostly for hot rods but they claim a 56% reduction in under hood temps. Just don't want to pass on so much heat that it causes other issues downstream.

I haven't heard of a 7 speed but there are 2 different 6 speeds. The one that came on any 4x4 was still direct drive in 6th (guess they figured 4x4's don't need to go fast). They did however make a version of it for over the road 2wd trucks with the 6th gear being an overdrive. If you have the 6 speed already the swap to the overdrive unit is relatively easy. If you are starting with the 5 speed then things are trickier as the 6 speed is larger so more needs to be changed. I am hoping the extra hp helps in that 3rd-4th shift and makes up for the 5 speed. With any luck we will be able to move a bit quicker uphill.

Can you explain what you mean by overdrive? I find no mention of our trucks having been spec'd with an "overdrive". Then again I find no real technical explanation of the term and it being rather ambiguously referred to.

To my knowledge there were 2 x 6-speeds (i have one of them), a 5 speed and a 6 speed with split gears. I suppose the 6th gear on the 2wd higher geared than on mine, as the change from 5th - 6th is not a great jump. I find all the gears rather close apart from 4-5th..
 

VerMonsterRV

Gotta Be Nuts
Can you explain what you mean by overdrive? I find no mention of our trucks having been spec'd with an "overdrive". Then again I find no real technical explanation of the term and it being rather ambiguously referred to.

To my knowledge there were 2 x 6-speeds (i have one of them), a 5 speed and a 6 speed with split gears. I suppose the 6th gear on the 2wd higher geared than on mine, as the change from 5th - 6th is not a great jump. I find all the gears rather close apart from 4-5th..
Yes, when I refer to overdrive I am referring to the split gear 6 speed. It has a final drive ratio of .83 in high gear. The 5 and regular 6 speed have a final drive of 1.0. The .83 would be nice to either bring the revs down or increase the top speed.
 

Iain_U1250

Explorer
Now we're talking with the ceramic coating, probably go with a black if possible though! Your turbo install looks interesting. So on the outlet side the common way to do my upgrade is to cut the end off the charged air pipe and weld it back on at a slightly different angle. This is the most complicated bit as I don't have access to an aluminum welder (not to mention I do not know how to weld). I can have the guy in Tuscon do the welding for me as he has said it would be ok for me to do the turbo swap in his yard and I have another project for him anyways. Now If I could just cut the end off (it is a cast aluminum pipe with a flange and gasket) and put on a silicone adapter then that would remove that complexity. So, do you have a flange on the charged air box (intercooler?) off on the right in the picture? If not any issues?

I went with the silver ceramic coating as it has the last radiant heat - helps keeps thing cooler. The turbo is a GT2860RS "Disco Potato" Garrett GT28RS Turbos 739548-1 and 739548-5 GT2860RS Dual Ball Bearing Measurements in MM Turb...jpg

I had to get a T5 to T25 adapter for the old turbo, and then make an adapter for the turbo outlet from 5 bolt to the 4 bolt exhaust brake housing - all the bit between the two flange I made from weld material - took a while with worked great.

DSC00041.jpg


I think it would be OK to cut the flange off, an weld on something, but that depends on how good your welder friend is, aluminium is tricky to weld, and he would need to know what type of aluminium the compressor was made from. The silocne pipe only came off once, on the first long test drive, but since I tightened up the clamp properly about 6 years ago, never had a problem.
 
It’s irrelevant whether the top gear is direct (1:1) or overdrive (0.80:1 for example). What matters is the total final drive ratio (top gear times axle ratio), as far as highway driving. And equally important, the total ratio ratio (lowest gear divided by the fastest gear) and the gear “spreads”; the N-1 root of total ratio ratio, N = number of gears. The fastest/tallest ratio taking into account tire diameter of course.
 

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