Re: [Amc-list] recently rebuilt 343 - No Oil Pressure

[Frank Swygert <farna@xxxxxxx>]

I missed that post somehow! I'm ranking about the same as Tom -- "experienced amateur builder". Those two plugs at the top near the front of the valley DO have to be plugged. IIRC they are 3/8" plugs, but I'm not 100% certain. Those plug the holes that are drilled through the block to the lifter galleries (and pump on one side). Without the plugs you were just running oil up into the valley. It wasn't building pressure because there was nothing slowing the oil's progress through the pump and out the top. 

If you used a good assembly lube you SHOULD be okay. Install the plugs, prime the engine with a drill before you start it to make sure you have oil pressure (the drill may not pump up much over 10 psi before it bogs down), then start it. 

I doubt you did enough damage to warrant disassembly. If you did, you'll know right after it cranks up and starts knocking. You may as well fire it up and see. At worst my guess is you took a few hundred miles off the bearings (assuming a good assembly lube was used). You should be fine on the camshaft also, as there was no oil to wash the lube away. 

Make sure you use a good break-in oil additive! With today's low ZDDP oils that's VERY important. I'd run the additive in the second batch of oil too (in the second oil change). Unless you are using stiffer than stock valve springs you should be fine after the second oil change with regular oil, but it won't hurt to run a bit of supplement from now on. 

----------------
Date: Wed, 12 Nov 2008 23:52:52 -0800
From: Tom Jennings <tomj@xxxxxxx>

Hmm, no engine builers replied... OK, I'm rank amateur engine builder, 
but... that sounds bad to me. The first few minutes are the most 
critical by far.

Usual practice is to spin up the oil pump with a drill and flattened rod 
until you see oil pressure, BEFORE you fire up... or at least spin it up 
until it "gets stiff" so that the galleries are all full of oil and the 
pump primed.

No way you wanna hear this... if it were me, I'd pull the engine now, 
with the assumption that if you don't, you will later, with ruined hard 
parts. Or see if you can get the pan off and pop a bearing cap or two. I 
dunno though, cam lube is dead critical at start up. Did you use 
high-zinc lube on everything at assembly?

Sorry, I think no one wants to say anything so depressing. Maybe the 
more-optimistic will slap me down here. I do tend to be on the paranoid 
side when it comes to assembly.





Greg DePratt wrote:

> > Finally got my 343 back together and in my Javelin.  Fired it up and found
> > that I am not getting any oil pressure....bummer.  So I checked my oil
> > pressure gauge and it is working.  Next I checked the oil pressure gauge
> > tube and also removed the tube from the port.  Some oil will come out of the
> > port while it is running but not a lot.  Next we removed the distributor and
> > turned the oil pump with a drill, thinking maybe the pump didn't get primed
> > properly.  Still no oil pressure.  After scratching our heads for a while we
> > remembered that the local machine shop sent the block back to us without any
> > of the plugs in it.  Usually they put the plugs back in the correct spots
> > before giving it back. We installed all the plugs we had but were unsure on
> > the two plugs at the front of the engine under the intake.  With the drill
> > turning the oil pump we see a lot of oil flowing while looking into the oil
> > fill tube.  Is this the souce of my low oil pressure problem?  Thought I
> > would ask the experts before I pull the intake and have to buy a new gasket.
> > 
> > The total run time for the engine so far was less than 5 minutes.  Do you
> > think I could have damaged anthing?
> > 
> > If it is those plugs that I need to fill, does anyone know what size they
> > are?
> > 
-- 
Frank Swygert
Publisher, "American Motors Cars" 
Magazine (AMC)
For all AMC enthusiasts
http://farna.home.att.net/AMC.html
(free download available!)

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