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Oil pressure

Old 05-14-2012, 11:33 PM
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Gas is cheap, engines are expensive. The amount of savings you would garner from a 5w-20 motor oil are not going to outweigh any potential long term issues you might have.

I would imagine the primary issue with using 5w-20 would be longer change intervals where fine material getting passed by the filter could slowly grind away at your bearings because of the thinner oil film. That said, we at BHR have yet to see a rash of engine failures brought about by bearing wear.

I would bump up to a 5w-30 since that is the suggested viscosity for the rest of the world via Mazda. It has long been believed the 5w-20 was used to squeeze some extra MPG figures for sales and to combat the reputation of being an inefficient motor.

I suppose a few of your heads would explode knowing I use a 2-stoke OMP injection oil with a cSt of 7.5 @ 100 degrees Celsius (bottom of the 5w-20 scale) and my housing clearances were well within spec when the motor came apart after 100,000 overall miles with about 40,000 of them using the Sohn adapter.

Argue on "experts"!
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Old 05-14-2012, 11:35 PM
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Why will u want to get a tune up if ur getting 180mile to 1/4? LOL
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Old 05-14-2012, 11:39 PM
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Thanks for your comments, Would you recommend 10w-40 for the summer? and 5w-30 for winter? It's going to get 90f+ in my part of the world.
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Old 05-14-2012, 11:49 PM
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Originally Posted by Everest^ View Post
Thanks for your comments, Would you recommend 10w-40 for the summer? and 5w-30 for winter? It's going to get 90f+ in my part of the world.
Actually, this is a common myth that you have to have winter and summer oils. Technically, you shouldn't have to switch unless you see vastly different oil temperatures during the seasons. Typically, the conditions inside your motor don't change from summer to winter. Your engine coolant still runs at 180 degrees and your oil typically follows your coolant.

Even here in Arizona, I don't often see oil temperatures above 220 degrees in the summer and it usually takes ambient temps of 110 to 115 to make that happen.

There is a wealth of oil information on this site so read through it and you'll better understand what information you need to have to make an educated oil decision.
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Old 05-14-2012, 11:57 PM
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220f? goddam and i thought 200f was hi. I'll switch to 5w-30 went my next service is due.
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Old 05-15-2012, 12:35 AM
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I see 220 oil temps regularly if I beat on my greddy turbo for 5 mins straight ... time for FC oil cooler add-in :P
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Old 05-15-2012, 02:54 PM
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Originally Posted by Everest^ View Post
Why will u want to get a tune up if ur getting 180mile to 1/4? LOL
I was suggesting it to you.
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Old 05-15-2012, 03:11 PM
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Well, Houstonrx8er and I both had between 30k-40k on our Mazda Remans when they died, both were driven hard and meticulously maintained. He used Castrol 5W-20 and I used Mobil1 0W-40. His bearings were toast, mine were in great condition.
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Old 05-15-2012, 04:13 PM
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Originally Posted by stinksause View Post
I see 220 oil temps regularly if I beat on my greddy turbo for 5 mins straight ... time for FC oil cooler add-in :P
With ambient temps around 90F and beating on my 4 port (5K-8K rpm)
for 5-10 min in the Canyons I typically reach 210-215F.
And I have installed a second oil cooler too.

10-40 Castrol!! ftw
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Old 05-15-2012, 04:14 PM
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Originally Posted by 9krpmrx8 View Post
Well, Houstonrx8er and I both had between 30k-40k on our Mazda Remans when they died, both were driven hard and meticulously maintained. He used Castrol 5W-20 and I used Mobil1 0W-40. His bearings were toast, mine were in great condition.
Yet both were still just as dead.
Does that make your engine the better crappy engine?

What was the cause of failure for both engines? (I don't have your stories memorized, so that's an actual question)

BC.
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Old 05-15-2012, 04:18 PM
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As far as the low pressure reading it could be the sending unit (sensor) and not the gauge it self. Just a thought.
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Old 05-15-2012, 04:31 PM
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TX

Originally Posted by Bladecutter View Post
Yet both were still just as dead.
Does that make your engine the better crappy engine?

What was the cause of failure for both engines? (I don't have your stories memorized, so that's an actual question)

BC.
Yeah it's a matter of what is reusable during the rebuild and what is not. Mine didn't absolutely fail but it would have soon enough. I test my oil and found traces of coolant in it and when the engine was pulled (I had another 2008 engine rebuilt instead of my Mazda reman) it was discovered that coolant was leaking past the coolant seal into the combustion chamber.

Houston's died of a loss of compression and he ended up needing new housings, bearings, etc. His bearing wear likely aided in the premature death of his engine. Excessive bearing wear throws off the balance of the rotating assembly.
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