1G 6 bolt oil pump support

[Turbski91]

Hey guys weird question that I haven’t seen and answer to.

I have a 6 bolt short block that I am rebuilding, and it has helical oil pump gears. The block still has balance shafts, and I was planning to do the balance shaft delete that supports the “stub” side of the oil pump, and I can’t figure out which one is better. The one in the pics has an oil groove, and the other doesn’t. In my mind I would think the oil groove would be better, but I also find it hard to believe STM would stock a bad part.

So what would everyone recommend? Any experience with these?

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[19Eclipse90]

Look at the other pictures. They both have the oil groove. It does look like that the Kelford version has a groove around the whole circumference whereas the GSC has only around half the circumference. Either will do the job.

 

[Turbski91]

Look at the other pictures. They both have the oil groove. It does look like that the Kelford version has a groove around the whole circumference whereas the GSC has only around half the circumference. Either will do the job.

Wow i can’t believe i missed that! Thank you. Do you agree that helical gears should get this shaft? Or should i just keep balance shafts?

 

[19Eclipse90]

I really don’t think it matters. Helical gears create axial loads. Journal bearings, like that at the end of the standard balance or race shaft, do not provide any support in the axial direction.

I like to minimize potential failures. The balance shafts are a subsystem that can cause significant damage if something goes wrong. The race shaft cuts the potential failure points down since the front no longer needs to be there or, at the very least, no longer needs to spin. The race shaft will also help keep oil pressure lower than a full-on BSE with stub shaft.

Ultimately, it comes down to your personal preference. Many keep them and their engines live long and happy lives. Nothing against that approach. It would be recommended to check the bearings if possible and replace as needed, then use a quality belt and tensioner.

 

[Turbski91]

I really don’t think it matters. Helical gears create axial loads. Journal bearings, like that at the end of the standard balance or race shaft, do not provide any support in the axial direction.

I like to minimize potential failures. The balance shafts are a subsystem that can cause significant damage if something goes wrong. The race shaft cuts the potential failure points down since the front no longer needs to be there or, at the very least, no longer needs to spin. The race shaft will also help keep oil pressure lower than a full-on BSE with stub shaft.

Ultimately, it comes down to your personal preference. Many keep them and their engines live long and happy lives. Nothing against that approach. It would be recommended to check the bearings if possible and replace as needed, then use a quality belt and tensioner.

Thank you. I was under the impression that helical gears with a stub shaft get pulled together harder than straight cut gears which restricts oil flow leading to oiling issues. I guess this is a myth.

 

[jdxnc]

In my opinion, those shafts don't help with the #1 issue we see, chewing up the housing, in fact I've seen the rear bearing seize up and spin just like on an oem balance shaft.

If you don't have oiling issues or belt tension problems, the oem stubby works perfectly fine.

 

[Turbski91]

In my opinion, those shafts don't help with the #1 issue we see, chewing up the housing, in fact I've seen the rear bearing seize up and spin just like on an oem balance shaft.

If you don't have oiling issues or belt tension problems, the oem stubby works perfectly fine.

So that’s the thing. Iv never even driven the car. I bought a shell, and a non turbo long block that i am doing a turbo swap on. Kinda not sure what to do. I was hoping for straight cut gears, but they are helical. When i disassembled the short block all bearings looked perfect. No oiling issues. So i was going to stick with the same oil pump setup, but wanted to do the BSE.

 

[19Eclipse90]

I would not let the type of gear I had on hand weigh at all on my decision to keep or eliminate the balance shafts.

 

[Turbski91]

I would not let the type of gear I had on hand weigh at all on my decision to keep or eliminate the balance shafts.

Yeah i was pretty dead set on deleting them. Was more concerned about using stub shaft or that race shaft, but @jdxnc talked me out of it with the fear of that rear bearing seizing anyway. So it sounds like i should use the stub shaft, and just make sure the timing belt is properly tensioned.

 

[CrackedDSM]

Not sarcasm here even though it sounds like it:


Jesus Christ, someone who asks for advice, gets a differing opinion than what they wanted, and actually TAKES the advice and changes their mind? Instead of just throwing a tantrum or raging?


Who are you, how did you find us, and how can we recruit more people that are like you? The amount of people who ask for advice, and get pissy after receiving real world experience advice trying to save them time in return, is astounding. Blows my mind.

I don't know you, but I'm proud of you.

 

[Turbski91]

Not sarcasm here even though it sounds like it:


Jesus Christ, someone who asks for advice, gets a differing opinion than what they wanted, and actually TAKES the advice and changes their mind? Instead of just throwing a tantrum or raging?


Who are you, how did you find us, and how can we recruit more people that are like you? The amount of people who ask for advice, and get pissy after receiving real world experience advice trying to save them time in return, is astounding. Blows my mind.

I don't know you, but I'm proud of you.

Haha i appreciate the kind words. All i know is if two dsm wisemen give you advise then your best bet is to listen.

 

[DSMPT]

Yeah personal preference like Brian said above. Assembly quality would be more important.
Some year's 4G61 came with the helical gear + stub shaft combo from factory. The 4G61 front case and oil pump gears are the same as 4g63. This fact may give you a little peace of mind in case if you are worried about it.

 

[CrackedDSM]

Just want to add that I really think straight cut oil pump gears are unnecessary for 99.98% of every DSM. Way too many putting stock in that particular fad when there's proof that even straight cut gears have issues with side load and eating the housing.

 

[donniekak]

We ran stock oil pumps with straight gears, oem stub shafts, and a stock timing belt tensioner on a 10,000 rpm setup with a mechanical fuel pump on the cam with zero issues.

As mentioned helical gears push the shafts away from each other axially. The thrust developed from this pushes the side of the gear against the case. Only a thrust type bearing will lower that force on the gear.