Technical GMC SIX oil canister and generator questions

Hey guys.
I have better luck here than other sites with the questions besides this is more active and I check in more often.

I have a 270 GMC that im trying to put together for a 37 GMC truck in the near future.

I want to do the full oil filtration conversion and have a question.
IF I go with the new Remote/screw in type filter conversion, Can I get rid of the Stock oil Canister on the Passenger side of the engine?
I want this to look cleaner.

Also I have no wiring and want to run a 12vGenerator since an alternator looks out of place.
What would be the cons/pros?
Thanks.

1st pic is the engine and the rest is how the engine looks with no Canister.

 

Yes you can get rid of the oil canister if you go to the newer style filtration. And that 270 came with a generator, Pros of the generator are that you can charge a dead battery whereas an alternator cannot. Cons of the generator is that they are heavier, a little more complicated wiring, most will only put out a max of 35 amps or so (I think some early Olds and Caddy generators were in the 50-55 amp range, but not on these truck motors), the generators wont take as many RPMs as the alternator. Hope this helps

 

If you are asking about using a remotely mounted oil filter of the modern spin on type in place of the original one, the answer is yes. Just mount the spin on filter where you want and plumb it like the original one was done.

If you are asking about going to a full flow oil filtration, then the answer is probably not. This requires a major modification to the oil flow and may not be possible with this engine.

You are correct in thinking that the remotely mounted spin on, mounted out of sight, will give your engine a more attractive and cleaner appearance. I have a soft spot in my heart for those GMC sixes.

JWL

 

Have you looked at the generator appearing alternators? They are pricy, but look like a generator with the performance of an alternator. JWL

 

I thought the full flow was pretty easyhttp://www.inliners.org/tech/full_flo_GMC.html:

 

JWL, this full flow conversion has been done many times.



Ben

 

Yeah, do this conversion while you have the block tore down for new bearings. A couple of holes drilled, a pipe plug installed, then wash/blast the metal chips out. Just follow along on the Inliners Tech Archive. Also works on 235 & 261 Chevys. K6

 

Like this?

 

If you need the amperage an alternator is the only choice. Generators will do the job just fine if you don't, but they don't like to be wound out to high RPM. That's one reason hot rodders ditched them right away. Another issue is a good armature helps for highway speeds, if it's not perfectly true and supported by good bearings it will tend to push the brushes out and away from the commutator surface, tend to stick in the holders. Make sure correct diameter pulley is used.

 

Yep.........found this 0ver 30 years ago in the Bill Fisher book on GM inlines.....worked great!

Ray

 

I read somewhere that if the bypass gets deleted,theres a chance the top will get oil starved?
Is this true?
Btw.
Im planning a bare bone,hoodless, chopped,fenderless truck with a pretty stock 270,dual intake and dual esxhaust,nothing extraordinary

 

Not exactly sure what you mean by "if the by-pass gets deleted". It's been a long while since I worked on older Chevy and GMC 6 cylinder engines, but I am going to guess you may mean the small line that, as I recall, feeds an oil port in the head to supply rocker arm lubrication. Providing that oil line supply IS NOT dependent on using the by-pass style oil filter that was original to your engine. It DOES require installing such a line from the oil gallery to the head oil port. I do not recall if their is a metered orifice associated with that line, or if the line size itself provides sufficient volume control of the oil supply.

However, the diagram in the Inliner's article, taken from the Bill Fisher book, must be followed exactly if one wants to use a remotely mounted modern full flow and insure the engine bearings are adequately lubricated. The drilling and tapping on the external block gallery AND installing the tapped plug in the internal vertical connecting gallery must be done in the manner indicated to insure proper oil flow.

Hope my reply answered your question.

Ray

 

Ok here's the deal on stock GMC bypass filters. The oil gallery line at the left front of the block had 2 feeds. A small 1/8" line went to the right side of the cylinder head to feed the oil to the rocker arms. It aimed up. There is a second line from the same fitting which fed the oil filter, it aimed right, it was 3/16" or a 1/4" I can't remember. Anyway the return for the oil filter back to the block was the 1/8" hole under the disributor that just happens to point at the dist/cam gear mesh.....Imagine that. Even though ALL my GMC's had the pressure filter system this second line is put back on.

If you ask why, GMC engineers were a lot smarter than I am and I've never lost a steel stock gear on a stock steel billet cam since I figured it out. A stock gear would only last a year without the line. That's why it's smaller coming off the filter so it would squirt on to the gear mesh. I do now have a bronze dist gear but the oil line is still there.

If you take off the original bypass filter and use modern style or just move it to different location I would still have this feed line in the circuit to the cylinder head.

 

Thanks for the help so far guys.
I took all my oil lines off,canister,brackets water pump and termostat housing and gave them a good bath,they shpuld be ready to paint tomorrow.

My oil canister says:
"Military standar filter,Purinator"
Like this:

The filter looks like this:
But my engine is not sealed?
It came out of an army truck that delivered fuel but the rest is civilian with a governor on the carb.

I think im just gonna run it.

 

The full flow does so much better job - can't justify not protecting the $$$ a GMC bottom end costs today.

 

All full flow filters have a bypass built in. It is true that filtered oil goes to the main galleries from the filter directly from the pumps. However pumps have by passes also so actually there is a constant oil flow of oil being circulated which helps in the cooling of our engines.
As many won't say but know the best cleaner of oil is the bypass system built by Frantz; not talked about much any more but does still work amazingly well today.
With the advent of non-leaded fuel our oil does last longer by keeping contaminates in suspension. However most of these smaller demension oil filters are only good for 3-4000 miles. Sorry for the rant. I was just trying to save distributor gears.

 

Im more confused than when I started.

 

Im happy to report that theres no bent guides and everything looks pretty clean
Also gonna start on a split manifold next week.
Got myself a present.



Ill hang the engine on an engine stand to get the pan off

 

Do the full flow conversion, also use the tee in front of block to feed the dist. drive gear instead of the original canister ...
Those Zeniths will work better than anything but BXOV Strombergs. Adjustable main jets used to be around for them, & Hydramatic pickups used Sisson electric chokes.

 

Thanks for the response.
So when I do the full flow I just leave the T in front of the block alone?


On my Military Canister,the thin tube (from the "T") went up to the head and the thick tube(from the "T")came from the Top side of the canister,another line (from the "T")went to the drive side of the block at the rear,under the exhaust and ended with a small plastic tubing.
Im assuming that was the oil pressure gauge.

The bottom line on my canister went to the bottom of the block near the gas pump.
There was no oil line going anywhere near the distributor.
Green arrow: line with plastic tubing
Blue arrow:short rubber line to block.

My block was not like this:


It also looks like I have the big pan for the bigger trucks.

 

Right. On one end of the tube, use a fitting with the same restriction as the filter used. This affects the volume of oil to the valve train.

 

Hi any ideas on how to feed the dist gear if my block doesnt have a hole for it?
I seems like the oil drips from the holes next to the pushrods and thats how it gets oiled.

 

If it wasn't drilled from the factory, I wouldn't worry. Not all forms of the engine needed the added oiling provisions. The oil pours down over it returning to the pan.

 

Great.
Thanks.

 

Hey guys.
Im ready to do the conversion.
I bought a remote filter without hoses becuse I hate the SS braided hoses that come with it.

My questions is can I make my own hoses with some hose,fittings and hose clamps?
Or do they need to be high pressure?
Thanks.

 

it would probably work but i would rather have a crimped line. i worry about hose clamps coming loose.
does you return line go into the hollow bolt/nipple that holds the fuel pump on?

 

Thanks Ted.
Yes the return line went to that hole where the long bolt is sticking out to the right of the fuel pump hole.

 

that is different than the last one i worked on. it actually had a special bolt with a nipple built into it that held the fuel pump on. i had never seen it before that is why i asked.

 

As 33 said above, all the pre-war engines with factory GMC filter, at least in the smaller series trucks, discharge the oil thru a hollow bolt or fitting on the front of the fuel pump.
Over the years, holes of various sizes are tapped into the crankcase and are found in many different places ... check out a Korean war 302 ....

 

As for the lines, I.D use some low pressure hydraulic lines. They have nice brass fitting and are clamped like power steering lines. Otherwise you could use swagelock or Parker stainless fittings and lines. They look very clean and polish up nice.


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Also if you want a alternator that looks like a generator, the powermaster ones look nice except for the tag. There is also a guy on here by the name of rottenleonard that has basically the same units. I believe they are tractor alternators or maybe forklift units. I plan on using one on my Jimmy.