Does anyone have a GM service manual that gives the procedure for installing a new oil pump on a Gen V? I understand that you can remove/reuse your oil pump (like when you are changing cam shafts). But you MUST use the special fixture/indexing tools to insure proper alignment when reinstalling the old pump. If you don't use the fixture tool, then you MUST install a new oil pump. But I cannot seem to find out how exactly you go about installing a new pump. How do you properly index or align the new pump? Why does installing a new pump not have the same sensitivity to location as reusing the existing/old pump?

 

If you scroll down a bit this explains the process. https://www.corvetteforum.com/forums...all-guide.html
I started making some of the tools which seem to be working for people. About to try it myself next week during my cam swap. https://www.ebay.com/itm/LT1-LT4-L83...p/283567415908

 

Thanks, I've seen this thread. And I've got a set of those fixture tools on order. But that is for the removal & reinstall of an original pump. My question is - what is the process for installing a brand new pump? The Haynes manual I have indicates that if you intend to remove and not reuse the original pump, these fixture tools are not required. So then - how are you supposed to properly align and install a new pump? I expect the GM manual must have a procedure outlines for installing a new pump.

 

Oh, I thought you were still debating which way to go. I'm not sure with a new one, I can only guess that replacement of used needs the tools to put it back where it has settled so to speak, where a new one would be starting from scratch position-wise? Dunno. Curious to know as well. Maybe someone who works at a dealer will chime in.

 

I paid the $20 to get 3 days access to GM online service manual info. There is zero information in the manual about how you install a new oil pump. They only cover the installation of the original/used pump assuming you use the guide tool. So it remains a mystery on how you install a new pump.

 

Melling has a tutorial.. It takes about 3-4 .002-.003 feeler gages spaced around the assembly then tighten everythin.up..

 

I'm not questioning your knowledge, but isn't the Melling tutorial solely for the LS? Going directly to the Melling website reveals nothing in oil pumps for the gen V (LT). To the best of my knowledge there isn't any aftermarket support yet for gen V LT oil pumps.

 

I noticed that about the gen 5 pumps too. I just looked it up again to see if I can find any info in alldata and here is what it says. (so far I haven't seen anything that tells us why we don't need an alignment tool for the new pump.. maybe it comes with something??)


Note: If the oil pump is removed to perform a different repair and is going to be REUSED, the EN-51267 - oil pump alignment tool must be installed on the engine block BEFORE the oil pump is removed and left in place until the installation of the original oil pump. If the EN-51267 - oil pump alignment tool IS NOT installed prior to oil pump housing removal, AND left in place while other repairs are performed, a NEW oil pump MUST be installed.

 

I went ahead with the purchase of a new oil pump. I got one directly from a local GM dealer. There was nothing in the GM box besides the pump itself. No special install tool, no instructions, nothing. I will note that the variable oil pressure solenoid is not included with the pump (previously this was serviced separately).

I did purchase a set of the oil pump alignment tools. So I installed them prior to removing the oil/original pump. Since the alignment tool only references up/down position, I also took a reference measurement along the left side of the pump to the block. I recorded the distance/gap between the passenger side of the pump and the block (used a stack of feeler gauges). That proved worthless for 2 reasons. First, the new pump body, which is a casting, is slightly different in that area. Seems they have made some changes to the design of the pump body. And second, I really could not feel any left/right movement possible with the bolts loosely installed. Yes, you could move it up/down. Thus the need to hold the pump 'up' against the alignment tools. But side-to-side it seemed to be a net fit with no, or at least very limited, adjustment possible.

The engine is now buttoned up. I will say that initially, like the first 5mins or so, the pressure seemed high. It was around 60psi (as indicated by the gauge in the cluster). But after a few minutes it settled down and is now running where it was previously.

I will say that with the AFM/DOD delete and Texas Speed stage 1 cam, it doesn't run for crap. I purchased the DiabloSport i3 platinum tuner after talking with them about the content of this build. I knew a tune would be required in order to make it run properly. Plus the AFM/DOD must be turned off. Whoever I spoke with at DiabloSport tech support assured me the i3 tuner was exactly what I needed. Wrong. Loaded the canned 87 octane tune. Runs for crap (dies at idle). Raised the idle speed +250rpm manually with the tuner (one of the very few parameters the i3 allows). Can now get hte truck to idle, but very poorly. Still isn't a happy camper at idle. And frankly nothing noticeable in terms of power gain with the stage 1 cam.

A short talk with the DiabloSport tech line again. Now they tell me there is zero chance their canned tune will work. I must have a custom tune. I am referred to a person who does custom tunes that can then be loaded via the i3. Email back/forth with the person. Learn that he will not do a custom tune via email for any gen V engine, especially one that has an aftermarket cam.

So now I call Texas Speed. They no longer do inhouse tunes. They refer me to the person who used to be their inhouse expert. I was able to speak with him on the phone. Great guy. I learn that there are virtually no people doing tunes for gen V engines because they are so difficult and sensitive, especially one that has an aftermarket tune. Regardless, there is absolutely zero chance of getting an acceptable tun via the i3. So I spend $850 for HP Tuners and 1 custom tune. Tuner arrives today. Hoping to get this this tuned shortly. What a nightmare.....

Oh and by the way, does anybody want to purchase a slightly use i3 platinum tuner? Seems that was $400 that was a complete waste.

 

That sucks man hope you get the tune sorted

And hopefully one of us figures out what is behind this gen 5 oil pump thing it's been bugging me because I want to do a cam at some point.

 

As some of you guys may know, I've gotten to tear into one of these gen V engines to do a factory cam swap:
https://ls1tech.com/forums/fueling-i...out-ideas.html

Well, here are the results: by pure coincidence, we had another Gen V oil pump laying around*, and being fearful of screwing things up, I used that, instead of the original pump.

I just bolted the pump on finger tight, cranked the engine over by hand a few times, and then torqued it down.
No low oil pressure. Maybe I got lucky, maybe they're just trying to sell parts.

This is a variable displacement vane pump, not a rotor pump, so I'm sure that an egregious mismatch in position could result in lower pump volume.
Here is my recommendation for all of y'all in this situation: Scribe a few lines on the block in relation to the pump before you take it off, and then get the new/ used pump to match them.

It's a variable displacement pump, so a slight mismatch shouldn't make that much difference. The oil pressure control solenoid is SUPPOSED to handle the changes in pressure*.

Something that needs to be said: If GM, in their INFINITE wisdom, thought that oil pump alignment was so goddam critical, WHY DIDN'T THEY PUT IN SOME DOWEL PINS?

I've said this same thing about the Gen III/ IV oil pans/ front & rear covers, and NO ONE ever has an answer.
They just say that you should buy some company's alignment tools, or (the better option of the two) give you some helpful options for aligning everything.

The front timing cover and oil pan on these Gen V engines have dowel pins. So GM DID learn a few lessons, but not enough.

* GM will not sell you an oil pressure control solenoid on its own; you have to buy a whole new oil pump, which is a complaint I've had about dealer parts departments for a long time.
We had an oil pump sitting around because another truck with the same engine, owned by the same company, came in for an oil pressure control solenoid problem.
I took the new solenoid out, and put it into their used pump, while it was still in the engine.

 

Just realized I did not update this thread with the final solution(s). I ended up going with a new tune from mailordertuner.com. Tune is great with no issues. I did end up having to replace the ECM due to getting coolant into the front engine sub-harness connector (see separate thread for details). But everything is sorted now and the truck runs great.

Regarding the oil pump. I was able to locate an alignment tool from engineswapsupply.com for $50. They also have some videos for doing a genV cam swap.

I was able to locate the oil volume solenoid at a local dealer. These parts used to be available separately so there is some stock floating around. Now, as mentioned above, these are only available as part of the oil pump assembly. For those wanting to check stock here is the part number -

 

According to all data you need to apply upward pressure on the oil pump while tightening the oil pump bolts to 18 ftlbs

 

I have a feeling he got it done by now....

 

I was posting the solution because I have been researching and running into the same problem as OP.

 

Thanks for the information guys. At this point I'll take any information because this is still something I'll be facing and haven't gotten clear answers on.

But I fully agree about the dowel pins. They absolutely should have put dowel pins in if alignment is so critcal.

 

There isnt a real procedure like an LS. Just make sure the bolts that secure the oil pump to the block have the plastic guides on them. Hold upward pressure on the oil pump while tightening it down.

 

Facing this delema right now.. Any chages since 2020 or just use the right bolts with alignment collars and push up wile torquing ?