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Old 10-29-2012, 09:04 PM
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Pontiac 400 / Oil Pump Gasket Question?

Hey guys im new to the site , have been checking the site out for a while but just now registered as im in a bind.

OK i recently finsihed building my poncho 400 bored 040 forged pistons 6x heads shaved to 9.2CR , Perf RPM dual plane intake , lunati 233/241 503/527 110lsa cam , scorpion roller rockers etc.

I have never built a pontiac before only chevy's and i have never used oil pump gaskets, well i didnt use one on this Pontiac either.
I was talking to a friend who told me that Pontiacs require a gasket on the oil pump....

When i finished the motor after cam break in , i noticed that once it warms up to 190 oil pressure drops to ZERO on my auto meter 200ps gauge that was in the car , so i went and bough a cheap sunpro oil pressure gauge and its reading 55lbs on start up , once warm and in gear 20lbs at idle , if i bump the throttle it flys up to 60lbs.

Just trying to figure out if i need to lift the motor and drop the pan to put this gasket on the oil pump... Or if pontiacs are like Chevys where they will be ok without them .... I used the melling high volume pump.
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Old 10-29-2012, 10:40 PM
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I have always used a gasket between the pump and the block. I don't know if it won't work without one, but as long as you have sufficiant oil pressure, you should be okay.

Bill

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Old 10-29-2012, 11:09 PM
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I always use a gasket. Paper is OK but IIRC Melling has a copper one that's nice. Pumps are usually very flat but the block is another matter. I wouldn't risk not using a gasket.
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Old 10-30-2012, 04:40 AM
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Agreed with all above, I've built many a Pontiac motor and always use the gasket. Don't know if you'll be OK or not but, I do agree that if you have sufficient oil pressure chances are you haven't done damage.

Rule of thumb in the future, if a buddy says you don't need something, but, whatever he says you don't need to put on doesn't take a pile of time, you already have it, and it won't stop your car from going fast...put it on.

Just sucks that you may need to pull the pan.
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Old 10-30-2012, 05:05 AM
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Thanks guys figure i better pull the pan....
Im sure it did no damage as it has enough oil pressure for the few test drives i took .....

I appreciate the quick replys.
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Old 11-01-2012, 09:35 PM
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Quick question.
Since im pulling the oil pan and taking off the oil pump its a Melling 60psi MEL-54DS the stock replacment.

They make the MEL-54F which is a 80psi pump which would raise the pressure 30%.

My question is if i went to this 80psi pump is there any bad it could cause?
They say its for 455 motors but the 400 is basicly the same block.....

Just trying to get all my ducks in a row before i lift the motor and pull the pan.

Advice? Thanks
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Old 11-01-2012, 09:53 PM
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You don't need an 80# pump unless you are running a 421, 428, or 455 block, 3.25" mains, with lots of bearing clearance. The RA IV (60#) pump is optimum for all other applications.

Bill

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Old 11-01-2012, 09:53 PM
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A 60 pound pump is all your going to need. Unless you have everything upgraded to handle the extra pressure I wouldn't use it and again, looking at the parts you have installed stick with what you have.
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Old 11-01-2012, 09:58 PM
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Quote:
Originally Posted by WDCreech View Post
You don't need an 80# pump unless you are running a 421, 428, or 455 block, 3.25" mains, with lots of bearing clearance. The RA IV (60#) pump is optimum for all other applications.

Bill

Hey Bill, we posted the same comment at the same time, it must be true, great minds think alike.

Ray
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Old 11-01-2012, 10:13 PM
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That, or we both think Pontiac!

Bill
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Old 11-01-2012, 10:15 PM
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but im only getting 18/20lbs of pressure at Warm Idle.
Your telling me this will not help?
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Old 11-01-2012, 10:21 PM
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What is your idle rpm, and what is your pressure at 2500?

Bill
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Old 11-02-2012, 04:59 AM
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About 850-900rpm @idle and around 50lbs at 2500rpm
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Old 11-02-2012, 05:40 AM
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Quote:
Originally Posted by oneluv1979 View Post
About 850-900rpm @idle and around 50lbs at 2500rpm
Your idle pressure and pressure at 2500 rpm is totally adequate. Keep the pump you have- there is no need for the additional pressure!
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Old 11-02-2012, 07:05 AM
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Quote:
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That, or we both think Pontiac!

Bill
That probably make more sense
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