Bulltear Products?

[Fast79Chief]

Anyone have experience with Bulltear oil pump products?
They have a pump lower housing that says "it eliminates the bypass valve under the filter".
Is this good thing?
Why would we want to eliminate that valve?
Anyone know?

Thanks

[weeegoneeer]

I think the main though about eliminating the bypass is that it will recirc oil when it gets above 65(?) PSI? From what I've read.

In later years the bypass was eliminated. I actually have a blockoff plate on mine (purchased from bulltear).

In general bulltear stuff is great (have bought a few things from them) - but they don't move as quickly as we expect in the Amazon era. I cut them some slack on it though because they are actually manufacturing stuff for AMC and aren't just repackaging stock chinese stuff that may or may not work (like TGW).

[mjdriver]

The bypass valve on the filter adapter housing was eliminated, however that style takes a filter with an internal bypass. So it is still there.

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[Fast79Chief]

Thanks weeegoneeer, so can the bypass valve operation affect your running oil pressure?
How about the other plunger and spring setup?
Can that setup affect running oil pressure?

Thanks,
Fast

[Stuka]

Thanks weeegoneeer, so can the bypass valve operation affect your running oil pressure?
How about the other plunger and spring setup?
Can that setup affect running oil pressure?

Thanks,
Fast

The bypass valve is to allow oil to bypass the filter when the internal resistance of the filter gets too high. This includes when the oil filter is dirty, but also at higher RPM. If the bypass valve is blocked, it is absolutely required that the oil filter has an internal bypass (most all made these days do). If the built in one is blocked, and the filters bypass either does not exist, or is inadequate, the engine can be starved for oil in some situations.

I think the second item you mention is the oil pressure relief valve. This is to prevent oil pressure from getting too high. If it is, it allows oil to go back into the oil pan. This is important so seals don't get blown. But, it can also be bad if the spring gets weak (which can happen over the decades).This can allow oil to always bypass and cause oil starvation.

Below is a diagram which has both by the bypass and pressure relief valves shown:

[Fast79Chief]

Thanks Stuka,
So if I run a NAPA 1258 filter (has it's own bypass valve?) along with the factory bypass valve intact ... am I creating a low oil pressure situation at operating rpms?

Thanks

[Stuka]

Thanks Stuka,
So if I run a NAPA 1258 filter (has it's own bypass valve?) along with the factory bypass valve intact ... am I creating a low oil pressure situation at operating rpms?

Thanks

You are not. The bypass will only allows oil to bypass the oil filter, allowing for higher volume to the oiling system. The downside of this is the oil is not going through the oil filter. But there are times where having the higher volume of oil is more important than having it constantly filtered.

The pressure relief valve is the only part that could cause oil pressure to go down, as it can allow oil to go back into the oil pan. But this should only happen if pressure is actually too high (in which its good that it is relieving it), or if the spring has gotten weak and is activating before it should.

[Fast79Chief]

Thanks Stuka,
I appreciate your knowledge on the AMC systems. I'm getting a good education here. Spent my life with the small block and big block chevys, never took one of these external AMC's apart.
So here's a question for you: I bought the replacement lower pump housing, and the rebuild kit from Crown. It comes with a new Oil Pressure Relief Valve Assembly. It has two (2) plungers in the box for this assembly. I mic'd them to try and figure out why the heck did I get 2 plungers. One plunger is 10 thousandths smaller in diameter on the SMALL end than the other. No difference in the barrel diameter of the plungers. Then I mic my 42 year old factory plunger from AMC ... it's larger on the small end by another 6 or 7 thousandths. I didn't know what to do so I installed the old factory plunger and the new spring.

Why do you think Crown included 2 plungers in this kit?

Do you think that the small end of the plunger can have some effect on oil pressure while running?

[Stuka]

You can thank Dohler Jarvis for the AMC engine design. He is the same guy that designed the Buick V8's, which have the same external oil pump and timing cover design.

I am unsure as to which plunger you should use. The last time I rebuilt an AMC V8 oil pump I used a kit from Napa, it only came with a single plunger.

My guess is that at some point it was changed, and crown includes two for that reason. I am not sure why neither matches what your engine has.

I am inclined to think that the thin part regulates how much oil is able to pass by. The larger one should allow less oil by, and the smaller one would allow more oil by. But it could be only one fully fits your timing cover.

One thing to check while you have things apart is if you have any gouging in the timing cover where the gears go. Both on the end plate, and inside the housing. Any gouging will result in lower oil pressure.

[Fast79Chief]

Since the assembly is fully contained inside the lower cover, the plungers all fit, just various size small ends.
I'm going to try and contact Crown to see if their techs know anything.
My lower pump cover was scored inside so I replaced it with a new unit. My old gears looked like some debris had chewed through there in its 42 year life. I replaced those. The upper pump internal surface has raised bosses where the gears ride, they were clean. Inside the walls of the pump housing were not bad.
These gears, by virtue of gravity, are going to ride primarily on the lower cover surface, but I'm sure with oil in there, there is 'float' within. I may go with a thinner lower gasket to try and bump pressure further.
Thanks.

[Stuka]

Let us know if crown knows anything. Though I wont be surprised if they do not.

[Fast79Chief]

Will do ... and I agree with you.

[bigun]

Bulltear is still in business?
Does anybody know if he ever completed the transfercase shifter box he kept saying was coming out just any day?

[Fast79Chief]

Hey begun,
You be highjackin bro.
Lol

[SuperStockAMX]

Just an FYI on my own experiences, the latest and greatest Oil Pressure Relief Valve Assembly found in all but Bultear packages are made in China. For just about anybody, that may not be a problem but IF that spring breaks, you will loose ALL oil pressure QUICKLY. Had that happen during a burnout on my NHRA ’70 AMX drag car. Didn’t realize the problem (my stupid) and didn’t make it to the 60’ clock. After doing some investigating, found this was not an AMC issue; found various Chevrolet’s, Ford’s, Chryslers with same issue. China steel springs not properly tempered. Your choice is Bultear springs or used originals from the wrecking yard; which are better than new China part.
My first post...just bought a ’79 J10 with a 401 and 4-speed. A lot I don’t know about with trucks!

[Lti57]

This is a great discussion
Rebuilding my pump is in my list this winter
Among other things
That’s for the people willing to share their knowledge

[Fast79Chief]

Thanks superstock,
Now I'm thinking I'll put the old factory spring back in.
lol
I did hear from a Crown techy who did some research after I first called. He says the most important spec is the diameter of the plunger barrel. The larger part of the plunger. According to this guy, you want a close tolerance slide fit inside the lower housing for optimum operation. I did notice that one of the new plungers did not easily pass into the new lower housing.
I initially put the factory plunger in the new housing until I heard back from this guy. Next cool day I'm going to take the large plug off, and see which of the 3 plungers I have is a closest tolerance slide fit in there, then put the factory spring back in.
Anyone know where we can get a new crush washer for that assembly? That's one thing they didn't include and my original is leaking.
Thanks to all for contributing here!

[killerinstinct]

Great Discussion ! Can I ask what happens is the plunger gets stuck and you can’t remove it?

I ordered a new cover but mine has 3 holes in the oil filter side can I leave it like that or do I need to plug the top hole on the new cover or can I leave it like that since the oil filter already has a bypass valve?




Thanks
Cesar


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[coolhand75]

Bull tear makes a bypass block off plate.


1975 jeep j10
360 4bbl
Turbo400
Qudratrac w/part time kit
Dana 44’s front and rear