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 Post subject: Re: Vacuum pump
 Post Posted: Sun Mar 21, 2010 6:33 pm 
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Chuck, What did you get for hose and fittings??? Have any pictures of your set up =;

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 Post subject: Re: Vacuum pump
 Post Posted: Sun Mar 21, 2010 6:45 pm 
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Beretta wrote:
Chuck, What did you get for hose and fittings??? Have any pictures of your set up =;


I went with the black fragola push lock. No pics yet, I'll try to remember to take some when I finish it.

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 Post subject: Re: Vacuum pump
 Post Posted: Sun Mar 21, 2010 6:51 pm 
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gearhead1011 wrote:
Beretta wrote:
Chuck, What did you get for hose and fittings??? Have any pictures of your set up =;


I went with the black fragola push lock. No pics yet, I'll try to remember to take some when I finish it.



That's funny as I was looking at them also..How did they work for you?? Im going to need 3 90* and 1 120*.plus the hose..$$$$$$$$$$$$ :-

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 Post subject: Re: Vacuum pump
 Post Posted: Sun Apr 04, 2010 2:23 pm 
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I got the car fired up last night and it looks like the oil pressure is down 6 lbs at 4K RPM. I haven't had a gauge on it yet so I'm not sure how much vacuum it's pulling. Does this lower oil pressure cause any problems or should I do something with the oil pump? It has a standard volume pump in it now.

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 Post subject: Re: Vacuum pump
 Post Posted: Sun Apr 04, 2010 11:42 pm 
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gearhead1011 wrote:
I got the car fired up last night and it looks like the oil pressure is down 6 lbs at 4K RPM. I haven't had a gauge on it yet so I'm not sure how much vacuum it's pulling. Does this lower oil pressure cause any problems or should I do something with the oil pump? It has a standard volume pump in it now.


There are two very different things that can cause oil pressure drop when a vacuum pump is installed. # 1 is to be expected, #2 will hurt the engine.

1. If the engine has a typical internal oil pump with internal bypass valve, the bypass valve is sensing/controlling pressure between the oil discharge passage and the crankcase. Crankcase vacuum will lower the pressure in the oil passage relative to atmosphere and therefore on a gauge on the outside of the engine since gauges are referenced to atmosphere. The oil differential press across the oil system (bearings) inside the engine will be the same and this should not cause any bearing related issues. This type of oil pressure loss will follow the vacuum created. If you pull 15"hg of vacuum, the oil pressure reading will drop by 7.367psi. (1"hg (mercury)= 0.491psi)

2. The other oil pressure drop that sometimes accompanies vacuum pump installation is caused by cavitation. If the absolute pressure at the suction of the oil pump drops too low, the oil entering the pump can briefly turn to vapor or entrained air will expand into much larger air bubbles as the oil enters the pump cavity. Either of these will reduce the volume of pressurized oil flow out of the pump since the pump cavity is not filled completely due to the air or vapors created taking up pump space instead of oil. A blocked pump inlet, insufficient oil pickup size, oil that is too thick, excess oil flow etc. All of these things can lower the suction pressure at the pump. Without significant crankcase vacuum these have to be severe problems before cavitation will be severe enough to be noticed. Once the crankcase pressure has been lowered enough (ie. high vacuum) the oil pump has to pull from a much lower absolute pressure and anything that creates a lower pressure at the pump inlet can push it over the edge into cavitation. This will be seen as fluctuating pressure and sometimes the engine will reach a certain rpm where the pressure drops suddenly and lowering rpm will return the pressure to normal.

If you had perfect vacuum (absolute pressure of 0psia) a pump can't even function unless it is below the level which will allow gravity to fill the pump inlet.

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 Post subject: Re: Vacuum pump
 Post Posted: Mon Apr 05, 2010 11:58 am 
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Thanks Rick. I am running a std volume off the shelf oil pump (mellings I think). Will shimming the pressure relief spring help or does it matter? I still need to get a vacuum gauge on it but if the vacuum pump is doing what it is supposed to it sounds like you're about right with the amount of oil pressure drop I am seeing.

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 Post subject: Re: Vacuum pump
 Post Posted: Tue Apr 06, 2010 4:30 pm 
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gearhead1011 wrote:
Thanks Rick. I am running a std volume off the shelf oil pump (mellings I think). Will shimming the pressure relief spring help or does it matter? I still need to get a vacuum gauge on it but if the vacuum pump is doing what it is supposed to it sounds like you're about right with the amount of oil pressure drop I am seeing.


If it is only caused from #1 from my earlier description, it really doesn't need helped. The bearing "sees" the same pressure difference and therefore flow that it has w/o a vac pump. Shimming the press relief spring will raise the oil pressure like any oil pump. Whatever pressure it would have w/o the vacuum, it will have that same amount of d/p from the oil discharge to the crankcase pushing the oil, so the oil flow will be the same.

If it makes you feel better, shim it til you're comfortable. How much oil pressure is required to give the needed flow is something that you have to figure out on each engine. (ie experience and testing).

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 Post subject: Re: Vacuum pump
 Post Posted: Sun Apr 25, 2010 11:32 am 
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gearhead1011 wrote:
I had a little trouble with my motor smoking last year and while discussing the problem here it was mentioned that I need to have a vacuum pump on it. My motor is a 370" SBF 14 to1 NA with a single .043 compression ring, & a 3/16" low tension oil ring. I shift it at 8,200.

I'm sure there's stuff I missing so I will appreciate any advice.


Are your pistons gas ported? I would think that running just 1 compression ring you would see some gains. Especially if it's a light tension ring. Running light tension rings, with only 1 compression ring along with vacuum pump is a very good set up.

Just a suggestion.

Goodson tools sells a tool you can do this yourself. It's very easy.

Have you ran this since adding the the vac. pump? Did it do what you wanted? Did you see any gains in ET? Lowering crank pressure may help out with your valve cover gasket issues also.

Don

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 Post subject: Re: Vacuum pump
 Post Posted: Sun Apr 25, 2010 1:25 pm 
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want-a-be wrote:
gearhead1011 wrote:
I had a little trouble with my motor smoking last year and while discussing the problem here it was mentioned that I need to have a vacuum pump on it. My motor is a 370" SBF 14 to1 NA with a single .043 compression ring, & a 3/16" low tension oil ring. I shift it at 8,200.

I'm sure there's stuff I missing so I will appreciate any advice.


Are your pistons gas ported? I would think that running just 1 compression ring you would see some gains. Especially if it's a light tension ring. Running light tension rings, with only 1 compression ring along with vacuum pump is a very good set up.

Just a suggestion.

Goodson tools sells a tool you can do this yourself. It's very easy.

Have you ran this since adding the the vac. pump? Did it do what you wanted? Did you see any gains in ET? Lowering crank pressure may help out with your valve cover gasket issues also.

Don


I hadn't thought about gas porting the pistons. Maybe next time it's apart. I have not had the car out yet. I had truck transmission problems on my way to the 1st test-n-tune last week and our 1st UMTR race got rained out yesterday. If the weather is decent next Friday I will probably take it to US60. Hopefully I will know something next week :-$

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 Post subject: Re: Vacuum pump
 Post Posted: Sun Apr 25, 2010 1:54 pm 
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Get a gauge on it yet??? 10 to 12 is max for us bracket racers... =;

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 Post subject: Re: Vacuum pump
 Post Posted: Sun Apr 25, 2010 2:09 pm 
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Beretta wrote:
Get a gauge on it yet??? 10 to 12 is max for us bracket racers... =;

I hooked a gauge to it in the garage but haven't put a transducer on the logger yet. Looks like it is right at 12 now, I figured that would be a good place to start.

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 Post subject: Re: Vacuum pump
 Post Posted: Sun Apr 25, 2010 7:08 pm 
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Chuck, If your at 12 at idle that is way to much as it will increase as you go down track.....If you feel ok with it rev it to 5000 and see where it is and go from there or call Greg he will help you out..........

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 Post subject: Re: Vacuum pump
 Post Posted: Mon Apr 26, 2010 12:09 am 
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That was with it revved up. It was lower at idle and seem to hit the highest at 4,000. Didn't change from 4,000 to 6,500.

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 Post subject: Re: Vacuum pump
 Post Posted: Mon Apr 26, 2010 8:55 am 
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gearhead1011 wrote:
That was with it revved up. It was lower at idle and seem to hit the highest at 4,000. Didn't change from 4,000 to 6,500.


Keep in mind that free wheeling the engine up that high isn't going to produce much blow by around the rings and pistons. Now if you had a Glide with a 6500 stall torque converter you could check it under load on the transbrake! O:) I'd venture to guess that it will be lower under WFO conditions down track unless it has a pop off valve to stop it at 12 in hg. ;-)

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 Post subject: Re: Vacuum pump
 Post Posted: Mon Apr 26, 2010 10:01 am 
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Ken0069 wrote:
gearhead1011 wrote:
That was with it revved up. It was lower at idle and seem to hit the highest at 4,000. Didn't change from 4,000 to 6,500.


I'd venture to guess that it will be lower under WFO conditions down track unless it has a pop off valve to stop it at 12 in hg. ;-)


It does. I figured that's why it seemed to stop at 12.

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