4g63 Oil Pump Pulley Drama

19Eclipse90 · Feb 12, 2018

I modeled up the DSM drive gear shaft (helical) some years ago. While I'm sure it isn't exact, it is a pretty decent reference and should tell you what you need to know, dimensionally, about the DSM shafts. Dimensions are in millimeters.

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bonkas · Mar 23, 2019

Just wanted to update you guys on this...

This was my conclusion...
I had to replace the cam pulley as it was trash, I could only get a square tooth version not the round tooth version the motor originally had, didnt realise this until much much later in the build and after receiving the new oil pump realized my old pulley was not going to fit anyway (8mm vs 10mm oil pump drive shaft). Confirming with a colleague who also has a g63b... he was running a square tooth belt also so I know there MUST be a pulley out there that fits this pump but I am still yet to find one.

After ordering a second oil pump locally specifically for the model of vehicle the engine came from... surprise, surprise.. same drama with different shaft size... none of the original parts fit...

In the end to make all this work I have had to go to a wider timing belt, different tensioner to fit the wider belt, machine down an EVO Crank and Oil Pump pulley to fit, now all my belts line up, all teeth on gears are correct etc.

Sorry if this is a bit unclear, this build has been going on for about 2 years now so my memory is getting a bit hazy but the engine is now running! as can be seen here:

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ThunderChild · Mar 25, 2019

Wonder if the g4js Kia optima motor would have the right pulleys, they have a squared 8mm timing belt tooth pitch vs the dsm round 9.5mm pitch. Idk the width of the top of my head, 29mm I want to say.

The castle plug is definitely a main issue I saw, it seems like alot of the hassle could have been avoided by using all 4g63 stuff, hard to say without having it in hand.

brian9397gsx said:
What kind of pump is that ? I've never seen one with the oil galley casting visible on the front? It's not an off brand is It?

This is a 2g pump. 1g just has a hump channel that the oil follows.
I'm assuming it's another relief valve, perhaps for the piston squirters?

Omarcito787 · Aug 26, 2019

bonkas said:
Hey guys,

Great community! I have been a long time lurker but first time poster as I have run into a snag which I hope someone from this community can help with.

I am in the process of building up a early 6-bolt 4g63(G63B) and have run into an issue with the oil pump drive pulley.

My old stock pump ran straight cut gears with a 10mm shaft, the new pump is the newer helical gears with a 12mm shaft, as such my original drive pulley/sprocket will not swap over.

I managed to find one from an unknown model Evo which was longer but with a bit of time on the lathe to shorten this and increase the ID where it meets the pump housing I have got this to fit onto the shaft but it sits 1-2mm proud of the pump from the old pulley location.

Do your DSM's run a 10mm or 12mm shaft? and if so do you have a part number for the 12mm pulley?

I have managed to find a few part number but nobody can confirm the shaft size...
MD135005
MD124762

I have confirmed with the pump seller it is a 6-bolt pump, mitsubishi are telling me the old 10mm pumps are no longer available...

Here is an article where they talk about the pump gear changes but there seems to be no discussion on shaft size...
http://www.dsmtuners.com/threads/2g-oil-pump-staight-cut-or-helical-gears.464223/page-2

Pics of new pump gear vs old gear and pulley:
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Sorry to bump this, but I can get you the correct pulley for this
OEM from japan

bonkas · Aug 28, 2019

ThunderChild said:
Wonder if the g4js Kia optima motor would have the right pulleys, they have a squared 8mm timing belt tooth pitch vs the dsm round 9.5mm pitch. Idk the width of the top of my head, 29mm I want to say.

The castle plug is definitely a main issue I saw, it seems like alot of the hassle could have been avoided by using all 4g63 stuff, hard to say without having it in hand.

This is a 2g pump. 1g just has a hump channel that the oil follows.
I'm assuming it's another relief valve, perhaps for the piston squirters?

The Castle nut is present on the original pump, my spare and this new one.

Omarcito787 said:
Sorry to bump this, but I can get you the correct pulley for this
OEM from japan

Please let me know the details on this, it seems there is a different pulley which is suited for a smaller belt so it will not foul with the oil pump housing. If you can give me a part number I can match it to the parts numbers I already have.

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4g63 Oil Pump Pulley Drama

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