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Discussion Starter #1
Well, I pulled my motro this morning, broke it down. Did not find any significant wear on any of the bearings. No copper showing. No metal in the pan. Cam bearings looked fine.

I pulled it apart cause my oil pressure went from 80cold/40 hot, and climbed as the RPM did, to 80 cold, 20 hot, and would not climb about 40 psi, even at 7000.

So I am at a loss today. The oil did have a good bit of fuel in it, leading me to believe the rings did not seat very well. In the middle of the season last year, I changed to domed pistons, but did not hone the block. That is the only thing I can think of.

Any thoughts???
 

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It's a little after the fact...but did you change out the oil 1st and test it?

And are you SURE that your gauge is correct?

And yeah, if you swapped out rings w/o breaking the glaze on the cyl walls...lack of ring seating could be a factor.
 

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If you do not have a bypass on the filter mount and, the filter gets dirty, the pressure relief valve on the pump will open up, dropping oil pressure as rpm increases.And seen as the gauge is after the pump relief-you see low pressure, accept the pump itself is making tons of pressure but it all goes back in the pan. just another two cents-Doug
 

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Discussion Starter #4
I have changed the oil repeatedly, initially its fine, then within about 5 miles it start again. I plan to hone the block well, and put it back together.

The oil always is dark black and thin, has fuel in it. Hoping that better ring seal will cure it.
 

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I think your on the right track 10sec, get those rings sealed up and keep the oil clean, run a wix or napa filter you should see more steady pressure. and for the extra money a new oil pump might be worth putting in while you're down there. Just make sure you inspect the pump before you install it.
 

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Discussion Starter #7
Well, I honed the bores, took emy paper to the crank, have a new oil pump that I blueprinted, and started filing the rings last night..

I replaced the valve springs (little heavier) for the new cam, time consuming (I measure each and shim to the same installed height). Also sent my converter out to be freshened.


I'll get her back together this weekend.
 

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Ron Slabaugh said:
After the hone job, how do you prep/clean the bores prior to assembly?

Personally I would give the block a good wash down after doing any machining work on it. Then I would use ATF and clean paper towels to clean the bores with...you keep wiping down the bores with the clean paper towels and ATF until it will nolonger pick up any dirt/grit from the honing...that should get you ready for reassembly

Also note that after you wash a block the machined surfaces will want to flash rust almost immeadiately...you need to spray on a water displacer/oil on them almost the second the water stops running to ward off this rust...then you can begin drying the cast areas of the block...:)
 

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Discussion Starter #10
I honed it, used WD40 done the bores to remove the remaining residue.

I found the oil pressure problem. The pink spring in the oil pump was broke. Hence no more then 40 psi of pressure.

I always dissemble new pumps and measure the gaps between the gears and the base, inspect the spring, and debur the gears, so I guess it just was a bad spring.
 

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nova10sec said:
I honed it, used WD40 done the bores to remove the remaining residue.

I found the oil pressure problem. The pink spring in the oil pump was broke. Hence no more then 40 psi of pressure.

I always dissemble new pumps and measure the gaps between the gears and the base, inspect the spring, and debur the gears, so I guess it just was a bad spring.
So after all of that, you could've just pulled the oil pump :eek:



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69NovaSS has the correct way to clean the bores after honing. Use the ATF and clean white rags or paper towells until you get nothing more out of the cylinder. Change rags/paper towells often. When they come out as clean as you put them in, you are ready.
 
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