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Discussion Starter #1
Hi All
I built my self a warm 351C mid last year, I don't drive it much as it is my week ender, I'm having a problem with my oil presure, when the engine gets over 170 degrees the oil psi fluctuates from 40 to 60. It could be my Auto Meter gauge stuff'n up. Has any one had the same problem ?
 

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74 XB Fairmont
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Flutuate from 40-60psi? You'd have to expand on that just a tad more.

Does it hold constant oil pressure @ a particular rpm? If not clevelands tend to push all the oil into the heads and leave none @ the crank. An oil restrictor kit will fix this and so will a 7lt sump.

As the rpm fluctuates so will the oil pressure. This is normal. More rpm = more pressure.

Brenden
 

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Discussion Starter #3
I have a restricktor kit in it.
Yes I understand that when the RPM goes up so does the PSI, but at constant RPM say 3000 RPM the gauge Flutuates from 40 to 60 PSI.
Any Ideas?
 

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If the problem occurs only at higher temps it sounds like oil viscosity isn't sufficient. What grade of oil are you using? In the summer heat I wouldn't go any less than a 60 grade myself..
 

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Two SC 61's = trouble
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What type of pump do you have and what size sump?
First I'd check pressure with mechanical guage even if fitted under bonnet..
The oil thickness shouldn't make any difference so lond as it's quality oil, other than being slightly lower at low rpm.With engine in good nick...

Try adding 1/2 litre of oil and see if it makes any difference??
 

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Whats traction?
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I just bought and fitted an autometer ext oil pressure guage.... its a piece of shit and total waste of $100.

Their top end guages are good but the cheapies are not worth having. Mine is off by 30psi @3000rpm, checked with a real guage.
 

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Slurry Boostin
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Fit a mechanical guage and actually check what it doing, at what revs, and at what temp :)
 

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I've just fitted all autometer mechanical gauges to my car (silver ultralites) - they are a dream and pleasure to watch - and don't tell lies!

Is your gauge electrical or mechancal? Try changing the sender if its an electrical job.

Mine sits steady at about [email protected] - Mellings HV pump.

Cheers
 

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Discussion Starter #9
First of all I use Penrite 30, I've never had any problem with this grade before, I might try a 50 grade oil.
The oil system consists of a modified standard sump with a windage tray By Russell oil pans, new stock Mellings pump with longer pickup, restrictor kit, slandered Rico filter & Pro Comp Auto Meter mechanical gauge.
Thanks for your suggestions, I will try a few . If any one has any other suggestions that would be great.
 

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Whats traction?
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TruBlu351 said:
I've just fitted all autometer mechanical gauges to my car (silver ultralites) - they are a dream and pleasure to watch - and don't tell lies!

Is your gauge electrical or mechancal? Try changing the sender if its an electrical job.

Mine sits steady at about [email protected] - Mellings HV pump.

Cheers
Yeah Ultra lites are one of the decent ones I'm refering too, mines a sport mechanical and with a real guage attached I got the exact same reading as you (same oil pump too BTW!) the autometer on the sill showed 30psi.

Not happy with it and its going back to the shop where I will spend the extra and get a decent guage.
 

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Clevo8 I still say if it only happens at higher temps then it is most likely an insufficient grade of oil, only being affected at extreme temperatures. I guess you've been running the same guage all along, so just eliminate what is obvious, and cheap first ie an oil change is very cheap compared to a new guage.

When you say Penrite 30 - do you mean HPR30? This is 50 weight oil I think. Why not try some HPR 50 - 70 weight.
 

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Old Ford Fan
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in my opinion, I dont think theres any way that temp/viscosity could cause fluctuations at steady rpm- thin oil will drop pressure for sure, but it will be steady at steady rpm. If your gage is electric, put a real one on, but if you have a mechanical pressure gage theres only a couple things I can think of that can cause this:

1) almost all your oil is in your valvecovers or valley, pump is intermittently sucking air. if so, checking oil level immediately after shutdown might show nothing on the dipstick(should be down a little, but not over a quart). you might be able to look in thru the PCV grommet (if not baffled inside) to 'check for flooding'.

2) your pump pickup may have come off/loose-causing above symptoms. only way I can think to check would be to pull distributor, get an engine primer to run the pump, pull the guage hose off and try to pump it dry- if you start seeing bubbles in the oil before you get 3 quarts out somethings amiss on your pickup. A clogged pickup could cause pump cavitation(vacuum/intermittent buzzing noise) but would seem unlikely.

**was pan/pickup clearance checked before assembly?

3) gasp- you could have a spun bearing intermittently blocking a bearing inlet- suggest running a magnetic drain plug for a while, and pray it dont collect
grindings.

one last thing- aftermarket dipsticks can be really off- next time you change oil/filter refill by owners manual stated capacity(include the filter) and double check the reading if you have a chrome one...I had one that was off almost a quart.
 
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