4g63 Oil Pump Pulley Drama

[bonkas]

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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[Tanro]

Did you change the front cover? Or just swap gears?

don't try and run those helical gears in the housing for the straight cut gears. It won't be good...

Sorry I can't be of more help. I've never had this issue my self. Always had the same sized gears.

 

[bastarddsm]

You got something wonky going on there bud. The larger of the 2 looks like what a dsm normally uses.

what year motor is this? Sohc? That sprocket looks like it's for a really narrow belt.

 

[bonkas]

It is a very early SOHC, '87 or so I think.

The description of the pump I ordered was "87-91 Dodge Plymouth Colt Vista Mitsubishi 1.8 2.0 2.4 8V G62B G63B Oil Pump"

The gears came with the front cover/housing as a whole unit, I removed the main gear from my old housing and the new housing to take the picture, everything else is identical just the shaft size is different.

I may have found myself with a later model front cover/housing - I would like to use it though as it looks to have a better built pump with a better support drive gear and higher volume, only other option is to reuse the old pump which I cannot find another of.. this opens up another can of worms of mis-matched pulley teeth types.

If anyone has a pulley laying around thier house which they an take some basic measurements - shaft size, length, ID that would be a huge help.

Or if someone would have one they could send overseas "For Science" that would be great too.

The Evo one I had to machine shorter to fit down the the shaft and then had to increase the ID to fit over the pump housing. I have ordered a md135005 which I hope will fit straight on as asking an ebay member who had this part number listed he confirmed it is 12mm. There has to be a pulley that fits straight on to this front cover... Once I find that and confirm the belt alignment then I am all set to proceed with this build.

Would you guys be interested in my 4g63 build up? I am doing a few things a bit differently with custom pistons, custom cam, custom valves, springs, retainers etc etc.

 

[motomattx]

People are always interested in builds on these types of sites, that said I wouldnt monkey with rigging up a pulley for that pump, its too important of an item to chance a failure.

 

[bonkas]

People are always interested in builds on these types of sites, that said I wouldnt monkey with rigging up a pulley for that pump, its too important of an item to chance a failure.

Yeah exactly why I am trying to track down what type of pump I have and the respective pulley that goes on the shaft, I wasnt too keen on modifying an evo on either - I also have not been able to find another the same...

 

[pauleyman]

It is a very early SOHC, '87 or so I think.

The description of the pump I ordered was "87-91 Dodge Plymouth Colt Vista Mitsubishi 1.8 2.0 2.4 8V G62B G63B Oil Pump"

The gears came with the front cover/housing as a whole unit, I removed the main gear from my old housing and the new housing to take the picture, everything else is identical just the shaft size is different.

I may have found myself with a later model front cover/housing - I would like to use it though as it looks to have a better built pump with a better support drive gear and higher volume, only other option is to reuse the old pump which I cannot find another of.. this opens up another can of worms of mis-matched pulley teeth types.

If anyone has a pulley laying around thier house which they an take some basic measurements - shaft size, length, ID that would be a huge help.

Or if someone would have one they could send overseas "For Science" that would be great too.

The Evo one I had to machine shorter to fit down the the shaft and then had to increase the ID to fit over the pump housing. I have ordered a md135005 which I hope will fit straight on as asking an ebay member who had this part number listed he confirmed it is 12mm. There has to be a pulley that fits straight on to this front cover... Once I find that and confirm the belt alignment then I am all set to proceed with this build.

Would you guys be interested in my 4g63 build up? I am doing a few things a bit differently with custom pistons, custom cam, custom valves, springs, retainers etc etc.

If you have a 4g63 why did you order that pump? Just order the pump for a 4 G63. What you have is incorrect

 

[1cleangsx]

Hey op I’m running an acl oil pump on my fresh 6 bolt rebuild with great success so far, might be a easier and safer alternative to rigging up something on such an important part of the motor that may or may not work

 

[pauleyman]

Here is everything you need.
www.streettunedmotorsports.com/engine/dsm_engine_page1.htm

 

[bonkas]

The engine is technically a G63B, this was the naming convention for these blocks until around '84.'85?

That pump was ordered as later model pumps ('91 onwards) have tensioner mounts and some other differences, rest of pump is identical.

If you strip down a G63B, and a 4G63 and put the blocks, head etc all side by side - you'll find they are identical. GxxB is the old naming system, 4Gxx is the new naming system.

From my research mitsubishi changed the oil pump configuration from straight cut gears to helical gears in around '87, I am unable to get a straight cut gear set and housing (10mm shaft, maybe you guys never got the 10mm shaft there?) only the later model helical gears (12mm shaft) this change in shaft size is where I am getting stuck. I would also like to use the 12mm pump I have due to larger pump gears, beefier bearings on the pump shaft as my engine is probably making 3 times the stock power levels and with some of the clearances on my build good oil pressure and flow is important.

I need to find a later model pulley from a 12mm pump so I can use on my motor, I only machined the original EVO part to see if it was possible to use that part if I had no luck sourcing an original part, the EVO part was damaged so I was never going to run this.

Thanks for the link pauleyman, I have visited that page many times, and found the part numbers for the pulley but they were not able to confirm for me whether it is suitable for the 12mm shaft, but an ebay seller has confirmed the part no MD135005 is a 12mm part number, I have ordered this, hoping it will fit straight onto the pump. If you look carefully at this part you can see where the ID is tapered near the block side of the pulley to clear the housing, I had to do this same thing to the EVO part I had, so hoping it is the correct part and will just slip on to this pump.

Keep firing your input and questions! I think I am getting nearer and nearer to a solution.

 

[bonkas]

Hey op I’m running an acl oil pump on my fresh 6 bolt rebuild with great success so far, might be a easier and safer alternative to rigging up something on such an important part of the motor that may or may not work

Yeah I dont want to rig anything up either.. I am just trying to find the correct pulley for this pump, that is the next piece of this not so simple puzzle!

 

[1990TSIAWDTALON]

My 2 cents.
Aren't you over thinking this whole thing.
Why not run a conventional 4g63 oil system? Readily available. Those of us that are tickling the 600hp mark or more are.
I see the value in VOLUME of oil that you are chasing after but the passages can only flow so much of that. Add any other factors in like, are you taking out the balance shafts? That is a big bump in pressure right there. Too much of either and you can wash a bearing out. I, myself, am on the limit on pressure and need to reduce it but I don't really know how much more volume these motors can flow.
Just something to think on.

 

[motomattx]

We did have straight cut gears on the early 4g63 6 bolt.

 

[bonkas]

I cant use the later model pumps due to belt tensioner mounts being different. Also cant go back to old pump as it runs a square tooth pulley and not round - Due to various modifications (Cam pulley has been changed to a later model round tooth one as the old one was flogged, have ordered a crank pulley to suit a round tooth belt), means I will be hunting for yet another unobtainium pulley.

The new pumps are all 12mm shaft also which puts me in the same position of finding a pulley and relocating the tensioner mounts.

If I can just find the pulley that fits on this pump, I am confident the correct pulley is the part number above - hoping this is the same as later model pumps.

Will find out once it arrives, if it fits then there will be no modifications and using all OEM equipment.

 

[1990TSIAWDTALON]

Yes we did.

 

[bonkas]

We did have straight cut gears on the early 4g63 6 bolt.

I dont suppose you recall the pulley size on these? I wonder if my original pump is not the correct one for this engine in the first place.. making part finding difficult.

 

[motomattx]

Im running one in my car actually, but I dont know for sure what size they were, I suppose you could get the specs on the inside diameter of the oil seal on the pump drive pulley and that would tell you if its the same as the newer 7 bolt one or even the actual inside seal diameter.

The seal part numbers are the same from 90'-99' so they were the same no matter whether they were straight cut or helical as far as shaft diameter where the seal rides.

 

[chrysler kid]

Good grief that's a narrow pump shaft.

An eclipse oil pump pulley should work just fine. I don't recall the size but it wasn't 10mm

Reference on why he wants a bigger pulley

https://www.evolutionm.net/forums/v...english-racing-underdriven-oil-pump-gear.html

 

[bonkas]

I received what is supposed to be the pulley for my year engine and also for your eclipse's but, surprise! It does not fit either.

Here are some photos to make it a bit clearer where I am at.

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I did find another part number... MD122692 Found this here: http://projectzerog.com/sohc-dohc.shtml

This does actually look a little narrower... Just need to confirm shaft size, can anyone get more detail on this part number?

Found the following table, not sure wether one of these is 10mm shaft and the other is 12...

MD122692 - Camshaft & valve for Eterna Sigma TNPWP2


No PNC# OEM part number Required
per car Name Spec Notes Color
1 04044 MD096389 01 SPROCKET,ENG OIL PUMP
1985.05.1 - 1988.09.3 ALL
Replacement MD122692

2 04044 MD122692 01 SPROCKET,ENG OIL PUMP
1988.10.1 - 1990.03.3 ALL

 

[motomattx]

Can you use a Dsm pump shaft to fit that pulley? or is the shaft size going to be too big to fit into the front cover?

 

[bonkas]

From pictures I have found my shaft looks to be the same as the DSM version, if someone has one around I would be keen to compare measurements.

 

[donniekak]

That huge bolt thing looks like an issue with any gear. Use the castle plug instead.

http://www.streettunedmotorsports.com/parts/oem_dsm_front_case_plug.htm

 

[motomattx]

From pictures I have found my shaft looks to be the same as the DSM version, if someone has one around I would be keen to compare measurements.

It pretty much cant be if that pulley doesnt fit it properly?

 

[pauleyman]

That huge bolt thing looks like an issue with any gear. Use the castle plug instead.

http://www.streettunedmotorsports.com/parts/oem_dsm_front_case_plug.htm

I'm in agreement. What is that thing? Should look like this.

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[brian9397gsx]

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?