05-26-2013, 09:05 PM #1
- Join Date
- May 2013
Weber MPE 750 turbo - factory changes _after_ the Polaris MSX version
can anyone tell me what changes were made to this engine in the second generation ?
how is the gen2 weber engine better ?
Last edited by K447; 05-27-2013 at 08:28 AM. Reason: Thread title
05-26-2013, 11:57 PM #2
I'm not sure which years or applications are considered the 2nd gen... but I'm aware of some differences on later model Weber engines after the '04 MSX 110s & 150s.
The Nicasil plating process was improved and made more reliable... less plating failure issues.
The waterpump was redesigned. It now used a plastic impeller in the waterpump and housing was revised to include a built in pipe that connected to the coolant rail on the intake side of the block. The 1st gen used a rubber hose. The gears that drive the waterpump (counterbalance shaft, drive gear, waterpump shaft gear) were revised and were now all metal... removing troublesome plastic drive gear from the 1st gen.
The oil tank was redesigned. The old heavy metal tank was redone in lighter plastic. It removed the separate oil separator cyclone and built it into the top of the tank. It also removed the high pressure valve that opened the tank to atmosphere when the engine was running (worked off oil pressure line). It also added a secondary tank on the side of the oil tank called the rollover tank which helped prevent oil ingestion in the event of a rollover.
The oil filter housing is metal on the snowmobiles... plastic on the MSXs... not sure of other applications.
The pistons and rods used in the Polaris FST snowmobiles are slightly different (beefier?) than the MSX watercraft version. Not sure if this became norm for all the Weber engine variations.
In some applications the engine was cooled via open-loop fresh water system... no closed-loop cooling system like the MSXs. The Hydrospaces were like this to cut down on weight.
I think the MSXs were the only ones to use throttle by wire with an electric throttle body. I believe the other applications used a throttle connected to the throttle body.
In some application the magneto system was replaced with an external alternator... in the snowmobiles for instance.
The intercoolers were different in different applications.
The ECU and engine management system where different in different applications. Bosch vs Walbro vs ???
The exhaust outlet off the turbo came in a longer version (like the MSXs) and a shorter version... for different applications.
That's all I can think of.
09-21-2015, 07:17 AM #3
What are the upgrades offered? Water pump, oil pump, and tank correct? We are at the point where I have 3 of these motors ready for rebuild. Nikasil failure in all of them seems to be the culprit.
09-21-2015, 11:34 AM #4
See your other thread for Weber MSX suggested updates/upgrades.
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