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4g63 oil pump pulley drama


bonkas

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Hey guys, have run into a bit of a snag in my 4g63 build. The oil pump I have seems to be a higher flow pump and the shaft where the drive pulley fits is too large and will not accept the drive pulley from the old pump. 

When I purchased the pump I was sure to order the pump that listed the -g63b motor as all other were listed for years '92 and up. 

Can I grab the pulley off an EVO or similar vehicle? Or if someone can identify the pump I have by the gears, see the differences below. The housing is the same bar the pump housing being a bit larger to accommodate the larger gear and additional bearing. 

I had thoughts of machining the pulley to fit but it may weaken it too much by doing this. 

@fuel maybe you are able to shed some light? 

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Yup it's the drive pulley on the oil pump, not the balance shaft.

I will measure the shaft and ID of the pulley as you can see a "flange?" in the pulley also that needs to fit withen the seal.

I am assuming there is two types of pulleys - The pump I ordered was supposed to definately for the 6-bolt engine so not sure why it is different, but if I can get the right gear and it fits right on I can move on.

@fuel and others - Is there any differences in the 6-7 bolt front covers/oil pupms that would cause concern with oil flow? as far as I can tell all the bolt on the block line up but readig online the tensioner mount may be different?

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pretty sure the oil thermostat fitting / orientation is fitternt on the DOHC turbo stuff between 6 and 7 bolt, and where the sump meets the oil pump cluster one is flat and the other has a curve or something - its a while ago since I did my VR4 sump mods for the mx5...

 

those pictures don't show enough cam pulles. :-)

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I will have to double check the fitment but all the bolts on the block line up, crank and balance shaft locations are all correct.

If I can confirm the sump bolts up OK I think just getting another larger pulley to fit the larger shaft will work.

I also found an article where Mitsubishi changes oil pump housings even on the 6 bolt stuff to helical gears - This involved changing the oil pump housing and gears but keeping the front plate - I am hoping I have a 6-bolt plate with 7-bolt housing.

NO.: TSB-92-11-002 REVISION 2

DATE: November, 1992

MODEL: See Below

This bulletin supersedes Technical Service Bulletin # TSB-92-11-002 REVISION (Dated June, 1992) and Advance Technical information Notice # ATIN-92-11-001 (Dated July 31, 1992). Please discard the superseded TSB and ATIN.

New information includes:

- Deletion of 1983-89 2.0L Truck from Vehicles Affected list.

- Addition of new drive gear for 1983 Cordia/Tredia (1.8L and 2.0L, SOHC), 1985-87 Galant (2.4L, SOHC), 1987-90 Van/Wagon (2.4L, SOHC), and 1990-92 Truck (2.4L, SOHC).


PURPOSE

This Technical Service Bulletin describes a new oil pump/gear assembly that may reduce engine noise on some 1.6, 1.8, 2.0, and 2.4 liter 4G6-Series engines.

VEHICLES AFFECTED

1983-88 Cordia/Tredia (1.8L and 2.0L, SOHC)
1987-90 Van/Wagon (2.4L, SOHC)
1985-87 Galant (2.4L, SOHC)
1989-92 Galant (All)
1989-92 Mirage (1.6L, DOHC)
1990-92 Eclipse (2.0L, DOHC)
1990-92 Truck (2.4L, SOHC)
1992 Expo 2.4L, SOHC)


DESCRIPTION

On some vehicles equipped with the 4G6-Series engine, you may receive customer complaints of a high-pitched whining noise coming from the engine. This noise most likely originates from the engine's oil pump and is particularly noticeable during cold starting.

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To help reduce the noise, a new oil pump is available. The new pump has helical gears as opposed to the former pump's spur gears. In addition, modifications were made to the engine front case to accommodate the redesigned gears.

All 4G6-Series engines built from 6/11/91 with identification code LX8939 and up, have been assembled using the new oil pump gear set and front case assembly.

When installing the new oil pump on a vehicle, be sure to replace the drive gear, driven gear, and front case as a set. These parts are not interchangeable with the former ones.

For information concerning the replacement of the engine oil pump, refer to the applicable service manual or engine overhaul manual.

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PARTS INFORMATION

WARRANTY INFORMATION
Position Code: 121010.
Use standard warranty procedures.

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The EVO one from @mjrstar fits.. just. I had to shorten it by 4mm and machine down the ID on the end to clear the pump housing itself.

That enlightened another dilemma... The OEM Cam Pulley is square tooth, the Adjustible Cam Pulley I got from @ToMitz is Round tooth.

The New pulley from the EVO is round tooth.

The OEM Crank Pulley is square tooth.

So I have two options:

  1. Find the correct square tooth 12mm Oil Pump Pulley with square teeth and run the OEM Cam and Crank Pulley's. - If there is such a thing.
  2. Machine the OEM Crank pulley to take a round tooth belt and use the adjustable Cam Gear - This is prefered.
  3. Find a Crank Pulley from and EVO (90's and up 4G63) and see if it can be modified to fit or may just be the same...

Here are some pics of the crank pulley which if I remember is 36mm crank. Maybe someone has something they can compare for me.

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Looks like I found the crank pulley I need, if you notice it has the round teeth and not flat:

image.png.ba4a0ac6380b4fae3a4e89a64dca840c.png

This is listed as "Generic Forklift 4G63 Timing Gear Sprocket MD120373"

Does anyone have a Crank gear laying around from a later model 4g63 or similar you can take a picture of for me?

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@mjrstar yup absolutely right, I "could" make this work by turning it down shorter ( the locating dowel looks to be in exactly the right place).

The only issue is the wide shoulder on the old pulley which keeps the belt in place, there is also a plate which covers the other side of the pulley so the belt cannot wander in either direction, I may be able to make up a plate to put in the side with the missing shoulder.

Will wait for this pulley to turn up in the mail, it may just fit with no modififications.

In the mean time I have alot to get on with on this build.. Intake, Carbs, Distributor Tuning, Exhaust etc etc...

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  • 2 weeks later...

Have received the oil pump pulley which is the correct part for a 6-bolt, oil pump is correct for a 6-bolt... surprise surprise this pulley does not fit either...

I'm stumped here.. If anyone can offer advice i'm all ears...

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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?

 

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
<
 
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