Opinion on Trimming Oil Pan (Page 1/2)
Notorio NOV 07, 08:15 PM
You are looking at the template that comes with the high-volume oil pump for the 2.8. It is telling me to cut along the red lines which will leave a good section free-standing and eliminate one of the dimples that strengthen the fold (I think.) It seems like a lot of the baffle to remove but I don't want to try several cuts, trial and error. What are your thoughts?


olejoedad NOV 07, 11:05 PM
Why are you installing a high volume oil pump?

Why are you questioning the instructions from the manufacturer of your oil pump?
Blacktree NOV 07, 11:24 PM
Yes, the trimming is necessary for a high volume oil pump.
Notorio NOV 07, 11:33 PM
Why the high-volume pump? Well, I'm tiding over this short block (100Kmiles) until I can afford a 3.4 short block, so leaving the crank and cam bearings as is (while porting/polishing heads and manifolds, and going to 1.5 semi-roller rockers). The oil pressure if I remember back to 18 months ago now was around 10 psi at idle and I thought the high-volume pump would give me a bit of margin.

Why questioning the instructions? It seems like a lot to remove compared to the increased size of the pump vs stock, when compared side-by-side. Maybe I'll get a picture of that so folks can see both together.
pmbrunelle NOV 08, 12:19 AM
I was able to fit my "high volume" pump without trimming the 85-86 2.8 pan... but maybe I unknowingly installed a standard volume unit, or the pump was mislabeled.
I ordered a Melling M95HV from Rockauto.

Why don't you first try installing the pan without trimming, then if it doesn't fit, trim if required?

If you're going to be cutting the stock baffle, you have to make sure that you get out all the metal and abrasive dust from the pan.


quote
Originally posted by olejoedad:
Why are you questioning the instructions from the manufacturer of your oil pump?



It's not because a given piece of advice comes from the part manufacturer that it's good advice...

[This message has been edited by pmbrunelle (edited 11-08-2019).]

olejoedad NOV 08, 08:24 AM
I would trim the baffle to insure an adequate supply of oil to the pickup screen.
Notorio NOV 08, 11:59 AM

quote
Originally posted by olejoedad:
I would trim the baffle to insure an adequate supply of oil to the pickup screen.



Ah hah, I was not thinking about it that way, just from the clearance standpoint. I've got three views of the two pumps side by side and it is clear that the high-volume pump is a little bit bigger, certainly not so much so that one would need to cut so much of the baffling away. But I think I'll go with the manufacturer recommended baffle mods with a view toward the less obstructed returning oil flow ...






olejoedad NOV 08, 12:16 PM
I suspect that the high volume 2.8 pump is actually a stock 3.4 pump....
pmbrunelle NOV 08, 12:47 PM

quote
Originally posted by olejoedad:

I suspect that the high volume 2.8 pump is actually a stock 3.4 pump....



I think the 2.8 high volume (aka the Melling M95HV) pump is the same as the later-generation stuff, except for the pump cover and pickup tube.
The gear housing of the HV/later stuff looks a bit longer than the Fiero stuff, giving more displacement.

The pickup tube on the HV is the same as the Fiero pickup tube (its shape and diameter). The later-generation stuff has a larger diameter pickup tube, with different bends.

The pump cover on the HV has a smaller hole in it than later-generation stuff to accommodate the smaller diameter pickup tube.

Summary: I think that putting a Fiero pump cover and pickup tube onto a later-generation oil pump yields the 2.8 HV pump.

[This message has been edited by pmbrunelle (edited 11-08-2019).]

Notorio NOV 08, 01:00 PM
Another difference, perhaps due to wear on the old 2.8 pump, is that the shaft turns very easily by hand. On the new HV pump it takes a serious effort ...