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Discussion Starter · #1 ·
As many of you know I went with stage 3 cams in my engine this year. Sounds mean on initial start up with the LT un capped it rattled my whole house!

Now the issue I am having…

At under 1000 Rpm's I am dropping oil pressure. I do not have an after market oil pressure gage just factory set up.

If I give the gas a tap the pressure jumps right back up. I called crower and asked if they had ever heard of this kind of issue. Their reply was no! They did say that I would have to bump up the idle to about 1000 Rpm's to stabilize the idle.

I did that and let it run for about 15 min and every thing was fine oil pressure stayed up.

Problem solved right?

Wrong!

I shut the truck off went inside and got ready for work. Started the truck back up every thing was fine oil pressure was at about 5/8 of the gage. Meaning over mid range on the high side. I got about 15 miles down the hi-way and went to change lanes let off the gas at about 80 mph and changed lanes this time Rpm's were at 2000 and the oil pressure dropped out again. I put it in neutral gave the gas peddle a tap pressure jumped right back up strong. I got off at the first exit and took it back home and am trying to figure out what's going on!

I took the front of the engine off and am going to check the O-ring in the pick up tube as well as the check valve in the pump tonight.

Do any of you have any input on my dilemma, or has this ever happen to you?


Respectfully,

Jeronimo (Suavy)
 

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I would not think after increasing your idle to 1K the cams would have anything to do with oil pressure. I would check you oil pick up tube or even your oil pump is going south on you. I have personally never had any problems with cams causing a low oil pressure issue.

When you rebuilt your motor what compression is your motor at now?

How long have you been driving your truck since the rebuild?

Are you having any blow by in your exhaust? If you do not know how to check that take a piece of clean paper and put it on your exhaust while it is running if you have oil on your paper then I hate to say it but you do not have seated rings. I hope this is not the case.

I would also check the oil sending unit it could be shorting out also.

And last but ot least, for God Sake man get a real oil pressure gauge.

Hope this helps

Brent
 

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Discussion Starter · #3 ·
Avalanche said:
I would not think after increasing your idle to 1K the cams would have anything to do with oil pressure. I would check you oil pick up tube or even your oil pump is going south on you. I have personally never had any problems with cams causing a low oil pressure issue.

When you rebuilt your motor what compression is your motor at now?

How long have you been driving your truck since the rebuild?

Are you having any blow by in your exhaust? If you do not know how to check that take a piece of clean paper and put it on your exhaust while it is running if you have oil on your paper then I hate to say it but you do not have seated rings. I hope this is not the case.

I would also check the oil sending unit it could be shorting out also.

And last but ot least, for God Sake man get a real oil pressure gauge.

Hope this helps

Brent
I drove the truck for 30 miles total. The sending unit was replaced when we did the re nuild. The truck did not run with low pressure for over a second or two. There was no noise like knocking or ratteling.

My compression is set lower than stock so I can run my high boost.
I will be checking the oil pick up tube tonight when I get out of work. I will be replacing the snding unit again.
I am not having any blow by at my exhaust matter of fact this is my first rebuild that did not smoke. My other two engines had a little smoke all the time from start up to rebuild.

You would think after 20 K and 3 years I would have got another oil pressure gage? However, I will say this in my defence I have never had an oil distribution issue in 3 motors. Matter of fact I went back to a stock pump cuz the HO pumps would spit oil droplets out at WOT. My engine used to stay dirty.

Thank you for your help.

Suavy
 

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Hey now 30 miles on a rebuild is not alot. It takes around 500 to seat the rings . I know you know that.

I also thought of maybe when you had your heads done the oil passages in the heads got blocked by something. Maybe this is a guess.

When you take the oil pan off to look at the pickup tube I would also look at the screen on the bottom of the pickup tube, it might be clogged.

One more think and this is a question.

WHen the oil pressure drops does the motor act like it is starving? I mean does it strat to run rough?

I am trying to help you but with the motor not in front of me it is kind of hard.

Brent
 

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Sauvy,

I'd highly suspect a "leak" on the suckion side. It's most likely pulling air from the pickup tube somehow someway. Is the pickup "puck"-to-pan clearance within spec? To close will starve it... to far away and it'll starve on hard launches.

Other things it could be... but very unlikely.

Excessive clearances in the oil pump
Excessive clearances in the main bearings/journals
Water instead of oil in crankcase...(j/k)

Rich
 

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Discussion Starter · #6 ·
Avalanche said:
Hey now 30 miles on a rebuild is not alot. It takes around 500 to seat the rings . I know you know that.

I also thought of maybe when you had your heads done the oil passages in the heads got blocked by something. Maybe this is a guess.

When you take the oil pan off to look at the pickup tube I would also look at the screen on the bottom of the pickup tube, it might be clogged.

One more think and this is a question.

WHen the oil pressure drops does the motor act like it is starving? I mean does it strat to run rough?

I am trying to help you but with the motor not in front of me it is kind of hard.

Brent
Thank you Brent, I a blessed by your guidance.

I am not planing on dropping the pan if I don't have to. I was told by our repair bay tech's that the pump can be removed with pan on. We shall see. If need be I will remove the motor mounts and lift the engine about 2 in to get the pan down. The process engineer in my plant told me to make a probe and insert it into the oil galley plug hole to probe the rear of the block with out removing the tranny if the probe goes the full distance then the rear plug that is behind the the rear seal acrrier was not installed. If it is in then it's the pump it's self.
 

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Discussion Starter · #7 ·
wydopnthrtl said:
Sauvy,

I'd highly suspect a "leak" on the suckion side. It's most likely pulling air from the pickup tube somehow someway. Is the pickup "puck"-to-pan clearance within spec?  To close will starve it... to far away and it'll starve on hard launches.

Other things it could be... but very unlikely.

Excessive clearances in the oil pump
Excessive clearances in the main bearings/journals
Water instead of oil in crankcase...(j/k)

Rich
Rich, I am going to start dropping the pick up tube tonight and see if the O-ring was cut or not in at all. The master engine builder assured me that his clearances were to print. He also said the only thing it could be on his end is a cut O-ring on the pick up tube or a bad oil pump.

I am prepping the engine to remove the pump tonight.
I would like nothing more than to race my beast this year!

Pray for guidance & wisdome for me.

Suavy
 

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Discussion Starter · #8 ·
Here is an up date checked the front oil hole galley just under the water pump as Superfords suggested. It was in place.
Checked the heads to make sure the plugs were in, they were in also. I am going to change the pump out this weekend and the sending unit.

I was told also that it could be because I removed the driver side hose off of the valve cover and plugged it at the rubber boot. Also I added another oil breather cap in the place of the hose that went to the intake boot.

Pray for me this weekend that the problem is solved! I truly would like to race this thing this year!


Suavy
 

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Man this is not what I wanted to read Jeronimo  :sad:
Lets hope and pray it's a simple fix  :smt017

I remember post where certain pick up tubes were a problem ? Are you using the stock pick up tube ? stock oil pan, differant oil pump than we usually use ? any modification to the sump set up ?

Dam that is not fair @#()*[email protected]#($%@#[email protected]#$
I have faith in you Pal, next time I check this post GOD I hope to hear some good news.....
 

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Discussion Starter · #10 ·
Rob_02Lightning said:
Man this is not what I wanted to read Jeronimo  :sad:
Lets hope and pray it's a simple fix   :smt017

I remember post where certain pick up tubes were a problem ? Are you using the stock pick up tube ? stock oil pan, differant oil pump than we usually use ? any modification to the sump set up ?

Dam that is not fair @#()*[email protected]#($%@#[email protected]#$
I have faith in you Pal, next time I check this post GOD I hope to hear some good news.....
Thanks Rob, I have been blessed with being here with repair bay techs, dyno team, and process engr. The only issue is the things I was given to check out are ok. The oil pump and pick up tube O-ring will be changed tomorrow. I am going to check for the rear oil galley plug also. I will have a good report for everyone Monday. I have faith!

Suavy
 

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Discussion Starter · #11 ·
up date, changed out the oil pump and pick up tube o-ring did not fix my problem. I guess the motor has to come back out!
 

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Discussion Starter · #13 ·
I'm pulling it back out this weekend and it's going back to the engine builders.

Thanks everyone who tried to help.
 

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Hi Suavy,
Sorry to hear about the problem. I would be very suspect of malfunctioning factory gauge. I would put a mechanical gauge on there beforeI pulled the engine. Just hook one up under the hood. Might slove your problem. We used to run a under hood gauge as well as dash gauge.Real convinient for working under the hood and you can check one gauge against the other in case one of them fail. Good luck.
 

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Discussion Starter · #15 ·
jakdad said:
Hi Suavy,
Sorry to hear about the problem. I would be very suspect of malfunctioning factory gauge. I would put a mechanical gauge on there beforeI pulled the engine. Just hook one up under the hood. Might slove your problem. We used to run a under hood gauge as well as dash gauge.Real convinient for working under the hood and you can check one gauge against the other in case one of them fail. Good luck.
Thanks, I have one now but didn't have to use it the motor would not restart . I went to start it and move it in the garage to start pulling the engine it acted like it was gonna turn the locked up. I have it 1/2 wat torn out should be out in a day or two.

Thank for your input.

Peace,

Suavy
 
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