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helrazr3 09-09-2012 07:25 AM

lost oil pressure
 
i have a 68 327 block with 70 heads, lower end is all stock and i have a comp cam (mild) edelbrock intake and carb early 80's hei dist. started the motor last summer and have been slowly rebuilding the rest of the car so it was never driven on the road until a few weeks ago it has maybe 2 hours total running time in the yard tuning and moving the car around and a trip to the alignment shop and the muffler shop maybe a total of 8 to 10 miles this whole time i have had no issues the motor runs strong, no leaks, and no ticking or knocking.

the other day when i returned from the muffler shop i thought i heard a noise from the motor yesterday i did hear a knock (not loud) and the oil pressure light came on i installed a mechanical gauge and nothing no oil in the tube (and no knock at restart) all of a sudden oil pressure is just gone:eek: the machinist who built the motor did tack the oil tube so it wouldn't fall off. any suggestions would be helpful. thank you.

ssmonty 09-09-2012 08:54 AM

You might try a prelube tool that simulates the distributor housing and is turned by a drill to see if the pump is working correctly. You'll have to remove the distributor to use it.
The intermediate shaft that engauges the bottom of the dist. and the top of the oil pump may not have had enough engaugement with both and stripped or become disloged. The prelube tool can be a good test.
Have you changed the oil that was first installed for break-in? If not the filter may have become clogged from the moly additives in the break-in oil?
The oil filter bybass valve in the oil filter adapter should have let the oil pressure rise though.
Perhaps the oil pump is bad. The prelube tool would be a good test.
Might be able to borrow a pre-lube tool from Autozone? Spin it clockwise with the drill and have someone turn the key to "on" without turning it far enough to engauge the starter, and monitor the oil gauge.
FWIW
ssmonty

helrazr3 09-09-2012 09:40 AM

took the dist.out i can feel resistance on the shaft when i turn it and i measured the distance from the shaft to the base of the intake there is about a 3/4 inch overlap so i believe the shaft was engauged properly.i'll check with az to see if the have a priming tool.

thanks for the help

66GMC 09-09-2012 09:58 AM

Quote:

Originally Posted by ssmonty (Post 1589329)
...
Might be able to borrow a pre-lube tool from Autozone?
...

I work at a NAPA store here in Canada, and the expectation of "free" everything kind of floors me!

We have installers that buy $1,000's of dollars per month of parts from us.
I don't understand why a parts store would risk "biting the hand that feeds them" by enabling the guy that *might* buy something?

Yes, we used to bench-test an alternator or starter when we had our own shop and qualified technician ... for a fee. We would then waive that fee if the test results indicated that a replacement was needed, and that we got to make a sale.

We still do free battery load-tests to determine if the battery needs replacing (this takes about a minute or so) but no, we do NOT install batteries for nothing!

We have been also installing wiper blades for free (usually standing in the rain) but even that is getting to be a time-consuming process because of all the new attachment styles.

But yeah ... the free tool rental thing is the one that still amazes me. I had a customer come in looking for a tool because:
A.) "The Canadian Tire one was a POS"
B.) "Their mechanic had a GOOD one, but refused to sell it to me!"

Really? :confused:
Did you REALLY expect that they should have? :rolleyes:

I'm also going to repeat something that I said just a few days ago.
The best advice that I can give my customers is to stop asking parts people for mechanical advice.

Parts people SELL parts, mechanics (technicians) INSTALL parts.
Free advice is often worth less than what you paid for it.

cdminter59 09-09-2012 10:19 AM

lost oil pressure
 
If you installed a mechanical oil gauge and oil did not flow through the tube, you either have a screen plugged or pump failure. Unless you want to rebuild the motor again you need to drop the oil pan and do some checking.

PatM 09-09-2012 10:27 AM

Did you use an intermediate shaft with the nylon coupling? Combining these with high volume or high pressure pumps has been known to result in coupling failure.

PatM

helrazr3 09-09-2012 01:56 PM

thank you all for your opinions and help. well i decided to sit down and think for a few minites and mull over everything that has happened in the last day or so and decided before i tore things down any further do keep it simple and start with the oil and filter so i drain the oil and it was dirty but i felt no grit at all in the oil took down the filter and it was heavy so it was full.slight gray tinge to the color but again i didn't feel any debris in the oil. now here's the kicker took the oil and put it into a gallon jug to dispose of it and if i was lucky there were only about 3 quarts in there!!!!! so i guess my dipstick is wrong i need to re mark it! so being down a couple quarts would make me loose oil pressure and the light would come on and the gauge would read zero. i put it all back together but i screwed up the mark on the dist. so i need to reset the timing at tdc and i didn't have the patience to do that today so i will set it on sat. and let you all know how a made out thanks again for the input!

S10 Racer 09-09-2012 02:05 PM

If the pickup tube is located to high from the bottom of the pan, being 2 quarts low may be an issue but if the tube is where it should be (3/8") from the pan bottom, it should not give you indications of "0" oil pressure. If you are using a Fram oil filter, CHANGE IT!!! Get a Wix, Purolator or any other "good" filter.

beertracker 09-09-2012 03:32 PM

X2 with CD above. bt

78novaman 09-09-2012 09:39 PM

Rich, setting the timing back to TDC should be fairly straightforward without taking anything further apart.

*I'm assuming the spark plugs are still connected to the cap in the correct order.

1.) Hand crank the motor so the timing mark on the balancer lines up with the TDC mark on the balancer. Remember this does not mean we are on the compression stroke.

2.) Follow the #1 spark plug wire back to the distributor cap. Install your dizzy so that the rotor points to the #1 wire on the cap. Install cap.

3.) Attempt to start the engine. One of three should will happen:
a.) It starts. Horay! You got lucky (25% chance). If it stumbles/runs rough you just need to tweak the timing in.
b.) It backfires (25% chance). You are 180* off on the timing. Pull the dizzy and move the rotor so it points to the opposite direction from where it rests. Reinstall cap with the same orientation as last starting attempt. Repeat step 3.
c.) It does nothing but crank (50% chance) then reinstall the dizzy so the rotor points 90* to the left or right from where it rests. Reinstall cap with the same orientation as last starting attempt. Repeat step 3 (should now start or backfire).

If you do this a couple of times without success you will need to pull the LH valve cover so you can rotate the engine to TDC on the compression stroke. The #1 valves will both be closed when the timing mark on the balancer is lined up with the 0* mark on the cover on the compression stroke.

jessedenny47 09-09-2012 10:13 PM

NO OIL Pressure
 
First did you bleed the oil tube going back to your pressure guage? next check to see if the hole in the block is not stopped up. Then I would recommend measure the distance from the intake to the oil pump shaft slot and (I use a screw driver shaft on a drill) to spin the oil pump to check the oil pump itself. I know this sounds beginning 101 mechanics but some times it the easiest to start with. Hope this helps. Jessedenny47

helrazr3 09-10-2012 06:20 PM

thanks novaman i can get the timing reset i was just real tiered and a bit cranky so thats usually when i mess things up i'll get it done saturday when i go back up there.

as for the dist. i did measure everything and its ok its not like i never had oil pressure all along its been fine i had to re adjust some of the rockers when i first got it running and those rockers made quite a mess w/o the cover on.

bleeding the oil line for the gauge was the only other thing i didnt know about. i basically had the line off the back of the gauge and still nothing.

killerformula 09-10-2012 07:47 PM

Hey Rich!

No oil pressure eh? Here are a few thing I would think of if I was troubleshooting my own mill:

First, do you know an actual PSI value of oil pressure that the car used to have? Maybe it just runs low at idle, many chevy motors do and its not an issue.

I would think if you were getting zero oil pressure you'd hear a hell of a racket from the lifters. I'm not clear on how long you had it running with the oil light on? Did you measure the distance from the pickup to the bottom of the pan? Are you using an aftermarket pan at all?

I would certainly try priming the pump with a priming tool. You can make one out of an old distributor if you want, grab one from a bone yard. Get a drill motor and hook it up, see how much oil pressure you're getting. Even with only 3 odd quarts in there, you should still have enough to keep pressure. If you're confident, run the mechanical gauge out under the cowl and pin it under your windshield wiper. See if you're losing pressure steadily or what's going on when you're driving with your full oil pan.

K

helrazr3 09-10-2012 08:19 PM

thanks erik, i mounted the gauge and connected it and nothing came up into the tube as to how long it ran i heard a slight knock and saw the oil light on and shut it right off when we started it back up there was no noise from the motor and we let it run for about 3 or 4 min. checking the gauge then we shut it off and that's where we are now. its a stock pan and i haven't pulled it down yet i was going to try and start it one more time with the fresh oil and filter when i reset the timing, if i get nothing then i'll pull the pan

i still don't understand how it could just stop pumping all of a sudden. its so weird i can feel resistance on the shaft when i spin it with a screwdriver so it appears to be working mechanically. i don't think i'm ever going to get to drive this car:mad::mad:

spinn 09-10-2012 09:25 PM

Did you spin the oil pump drive the correct way when priming? Dont laugh someone did this in front of me.

Is the oil pick up a pressed in one, it may have came off or not sealed. That would be a instant oil psi loss.

Even a bearing or bypass or screen would have some pressure.

Does the distributor sit high and need shims, could be the oil pump drive gear is not engauged.


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