300ex oil pump in a 350x

[i58829]

Ok i was talking to the engine guy and he said he never heard of this swap before. He also said the stock pump can be rebuilt? Can someone explain the gear swap to me so i can relay it to him. I was wondering if the drive gear mounts on the shaft with a spline type setup or if you just install the gear/shaft from the X into the ex pump. Anyway a better explanation will help or even a pic or two would be greatly appreciated. Also is the pump a 100% direct fit in an 86 350x once the gear is swapped? Thanks TC...

[Dirtcrasher]

I believe SWIGIN says you merely need to use the 350X drive gear and otherwise it is available and a 100% swap.

[The Goat]

there is also the option of slightly grinding the cases for clearance I believe.

[i58829]

I believe SWIGIN says you merely need to use the 350X drive gear and otherwise it is available and a 100% swap.

Maybe he will chime in and explain how you 'use' the drive gear and attach it to the pump safely to keep it from spinning on the shaft after years of use. I'm concerned it may cause the oil pump to not work 100% or at all if it slips on the shaft and therefore starve the top end of oil.

there is also the option of slightly grinding the cases for clearance I believe.

If you need to grind the cases for clearance the gear must be larger in diameter than stock so what gear do you use on the other end to make it turn? Is it a complete drive/pump swap from the EX motor?

I'm not trying to argue i just simply dont understand how this works, and i know nothing about the internals of a 350x (which is why someone else is doing the rebuild). Anyway thanks for the input and maybe we can get a few things clarified so anyone can do this. Thanks again, TC...

[Louis Mielke]

I believe its actually a nub on the center of the gear that needs clearance. i'm pretty sure the diameter of the gear is the same. Otherwise it would not fit and mesh with the old gears.

[i58829]

Oh ok thats a big help, so i can just take an end mill and plunge into the cover a little for the clearance. That makes a lot more sense i was thinking diameter wise not length. I dont know why i had it in my mind that it was a diameter issue...

[JohnR.]

What is the advantage to doing this extra work to put the EX pump in? Are the X gears no longer available?

John

[Louis Mielke]

The body of the oil pump for the 350x is no longer available, wouldn't be surprised if other parts are gone now as well. The 300ex is a direct swap other than the drive gear shaft is slightly different.


I just want to clarify that I don't know this to be the exact difference, just what i can tell from observation. I plan on installing this 300 pump i have as soon as my timming chain shows up.

SWINGING would be able to verify/ tells us exactly is the difference.

[i58829]

The X pump is discontinued and the ex pump is available from the dealers new. I dont know the advantage but i've seen this in several posts and was trying to figure out how hard it is to do, what mods it requires and what the advantage is...

[JohnR.]

Cool. I figured that there had to be either some NLA parts or the EX was just a better pump all around.

Thanks.

[The Goat]

oil pumps are not easily found in working condition for the 350x...I think I have a good one in my glove compartment...that's the last place I saw it at least. lol.

If I wasn't running a NOS one, I'd do the EX swap for sure.

[SWIGIN]

Maybe he will chime in and explain how you 'use' the drive gear and attach it to the pump safely to keep it from spinning on the shaft after years of use. I'm concerned it may cause the oil pump to not work 100% or at all if it slips on the shaft and therefore starve the top end of oil.



If you need to grind the cases for clearance the gear must be larger in diameter than stock so what gear do you use on the other end to make it turn? Is it a complete drive/pump swap from the EX motor?

I'm not trying to argue i just simply dont understand how this works, and i know nothing about the internals of a 350x (which is why someone else is doing the rebuild). Anyway thanks for the input and maybe we can get a few things clarified so anyone can do this. Thanks again, TC...

did you search this at all? i've gone over this a few times now.

you are thinking to hard..... the pump is the same, its the shaft that goes through the pump thats different.

but to use the 300ex gear/shaft combo you just clearance the BEHIND the pump.

[i58829]

I did a search and read most of them and all i see is that the case needs to be machined, or have the gears swapped. There aren't any pics or idiot proof descriptions of what to do when installing it either way. I may have overlooked the important post. My motor runs great so maybe its not worth the hassle of trying to figure out what to do and why i can't stuff a late model pump into it without mods...

[Dirtcrasher]

I did a search myself and I'll post what each post stated by SWIGIN, just trying to help

1) also get a new pump...honda stoped making 350x oil pumps but a 300ex pump works as long as you use the 350 drive gear in the 300ex pump

2) if they are scuffed up you need a oil pump witch honda no longer makes nut a 300ex pump will work if you use your gear on the new pump

3)you will find out that they are disscontinued but a 300ex pump will work if you use the 350x oil pump drive gear or machine the case for the 300ex gear to work.

4)we also found out that 300ex oil pumps bolt right on if you use the 350x gear

Thats what I found.......

I didn't find anything about grinding or any other issues when using the 300EX oil pump body other than listed above.

Sounds to me that the gear is a direct swap, HOWEVER the 300EX gear can be used if you grind the case. I'm unsure HOW a different gear can be used UNLESS it is merely fatter in some aspect of it's design which requires grinding and not greater in the amount of teeth.

If there is more to this swap than stated above, I did not locate that particular piece of information. If thats the case, no pictures are needed....

Sometimes ya have to do it to see whats up, then share the results with us

I hope this clears it up


EDIT - BTW, I'd never rebuild a tired engine and NOT change the oil pump. They are under 75$ in every case I've seen and well worth the piece of mind!

[SWIGIN]

nice job DC....lol

the 300ex gear/shaft sticks out of the back of the pump where as the 350x gear/shaft is flush.

hence a slight clearance job is needed if your using the whole 300ex unit. but like DC said, if you just get one you'll see how simple this is.