oil cooler or no oil cooler..... that is the question

[Scott Danforth]

working on my BBC build and have been vacillating with whether or not to add an oil cooler. the Gen VI block has two oil cooler ports in it and would make plumbing an oil cooler a breeze. I would put one in the supply hose to my crank mounted raw water pump, and have identified the oil cooler I would use.

however, does the motor really need an oil cooler?

those running oil coolers, have you monitored the oil temps? just curious.

 

[HT32BSX115]

however, does the motor really need an oil cooler?

those running oil coolers, have you monitored the oil temps? just curious.

Scott, I am tempted to do some measuring......My stock Bravo 454 DOES have an oil cooler. It's a fairly robust OEM cooler and remember that most Mercruiser oil coolers get cold (raw) water for cooling. This would tell me that Mercruiser thought the oil needed as much cooling as possible.

I don't think it would be all that hard to measure the temps though. Just use a cheap Harbor Freight Infrared "gun" and measure the inlet and output oil temps at the cooler.

I have to say that if Mercruiser thought a stock 454 needed a cooler, your hot-rod build would definitely need one.......

 

[Bondo]

I have to say that if Mercruiser thought a stock 454 needed a cooler, your hot-rod build would definitely need one.......

Ayuh,.... Gotta agree with that,.....

 

[gm280]

Bondo, I would think any time you could supply cooler oil to the engine would be a good thing. When you initially crank up any engine, the oil is cool and starts its job of lubing all the bearings and such but also removes heat from everything as well. So cool oil would be a good idea in my feeble thinking. On a lot of vehicles they have both an oil cooler AND a transmission fluid cooler built into the radiators. And cool oil doesn't break down as quickly either providing a much better friction reducing ability. JMHO

 

[Scott Danforth]

factory oil cooler plumbing is a differential pressure bypass system. only about 40% of the flow gets cooled, hence the reason for my question. factory cooler is a 2 x 6 or 2 x 9 (depending on year, etc) Volvo unit is a 2-1/2 x 6 for the early ones (didnt look up later units)

seakamp oil coolers on ebay in the $100 range. Thought of making one, however the materials alone are close to that.


OTS question - Anyone have experience running an HP500 cam in a 454 with carb vs a 502 with EFI? I have a really good line on a low hour take-out prior to the motor getting a set of heads, blower, and cam change.

588 lift intake 596 lift exhaust, duration at 0.050" is 228 intake and 232 exhaust at 114 degree lobe separation

 

[HT32BSX115]

factory oil cooler plumbing is a differential pressure bypass system. only about 40% of the flow gets cooled, hence the reason for my question. factory cooler is a 2 x 6 or 2 x 9 (depending on year, etc) Volvo unit is a 2-1/2 x 6 for the early ones (didnt look up later units)

Well, the above statement made me go out to the shop and look!

On my "stock" 1997 Mercruiser 7.4 Bravo, the inline oil cooler is plumbed in series with the oil filter.

Therefore ALL the oil that goes through the filter is cooled. The only bypass would then be if the oil filter became clogged enough to open the filter bypass. But it would still all be cooled.

Volvo didn't plumb the oil cooler in the oil filter circuit?

 

[Scott Danforth]

They plumbed the Gen V and VI motors to the oil cooler ports like GM designed them

 

[HT32BSX115]

They plumbed the Gen V and VI motors to the oil cooler ports like GM designed them

That would lead me to believe that Mercruiser had a pretty good reason for plumbing oil coolers for full flow (non-bypass) operation....

 

[Scott Danforth]

On a Mark IV block, that was common to do, however on a Gen V or Gen VI, not sure why Mercruiser wouldn't use the two oil cooler ports.

After reading countless articles on grumpys garage, I myself will be using the oil cooler ports for the oil cooler, and a remote oil filter head for the filter

 

[HT32BSX115]

not sure why Mercruiser wouldn't use the two oil cooler ports.

I think it's obvious IF the oil cooler ports don't flow as much oil as the oil filter. They obviously wanted as much oil cooler flow as possible.

Many heavy duty diesels use (internal) coolantil coolers. (my 6.0L Ford does this....with all kinds of unintended problems......I am going to replace it with an AIR:OIL type cooler) But that can only reduce the oil temp to somewhere near (& always above) coolant temps.

Mercruiser used (cold) raw water to cool the oil (and PS) most likely because "It's There" and easily available.... but it reduces the size needed to get adequate cooling.

For your application, It might even be easier to just plumb the oil cooler in series with the filter. GM designed that block for automotive/light truck (low duty-cycle) applications.

Since marine applications are always like pulling a MAX GVWR truck up a continuous grade at near wide open throttle, I would venture to guess that Mercury Marine wanted the max oil cooling available.

You're probably going to be "ok" doing it either way.......if it were me, I put the cooler in series with the filter.
Regards,

Rick

 

[Scott Danforth]

However oil thru an oil cooler on cold startup opens the bypass popet (30# in an SBC or BBC) and most of the oil then doesnt make it thru the oil cooler until its warm enough to drop the pressure across the cooler, which in turn means that the oil wouldnt be filtered either.

its not the ports dont flow the oil, its the pressure drop across the cooler and filter opens up the bypass popet.

at startup you want as much oil thru the filter as posible, as that is where the most wear occurs.

Diesels use a 2-port plate cooler stack in the block. much more efficient oil cooler than a shell and tube or an air to oil with less pressure drop. if your going external oil cooler, look for one that has minimal pressure drop on the oil side. Make sure you have significant air flow across the cooler.

All marine installations (CI or SI engines) utilize raw water cooling for the cooling media. even the heat exchanger on the water jacket side. why, because the lake or stream or ocean is the biggest radiator in the world.

 

[HT32BSX115]

at startup you want as much oil thru the filter as posible, as that is where the most wear occurs.

True........... Many engine manufacturers of course specify an oil filter with a bypass. (and anti-drainback depending on mounting position) Mine is upright but the Merc filter specified for most Mercruiser applications has an anti-drainback because Mercury mounts some of them upside down (MESSY to replace) !

I would expect the oil filter to produce MORE resistance to cold oil than the current crop of oil coolers though and since the oil filter doesn't appear to have a bypass, it must be in the oil pump?

Diesels use a 2-port plate cooler stack in the block. much more efficient oil cooler than a shell and tube or an air to oil with less pressure drop. if your going external oil cooler, look for one that has minimal pressure drop on the oil side. Make sure you have significant air flow across the cooler.

THat's exectly what my FOrd 6.0L (NAVISTAR VT-365) has. BIG fail for them! Because the coolant side becomes clogged with silicate drop-out in the coolant!!

 

[Scott Danforth]

on the mark IV block, its about 3" in the block above the oil filter. on the Gen V and VI (priority main oiling), there are 3 check valves in the system.

I have the links book marked at home, can post in the AM.

 

[Scott Danforth]

Here are some of the oil bypass links I had bookmarked

http://www.superchevy.com/how-to/4567-chevrolet-big-block-engine-generations/

https://www.google.com/search?q=big+block+chevy+oil+flow+diagram&ie=utf-8&oe=utf-8

http://www.offshoreonly.com/forums/general-q/248383-gen-vi-oil-filter-relief-valves-2.html

http://speedtalk.com/forum/viewtopic.php?f=1&t=34071

http://garage.grumpysperformance.com/index.php?forums/oil-and-lube-systems.54/

 

[Durango318]

I'm convinced that a lot of marine engines are warn out early from being too cold. It seems like raw water engines just don't last as long. Could it be from the coolant flow pattern and 140* (raw) vs a more uniform 160* coolant closed system....? I don't know. If the engine oil reads more than 190* off the side of the oil filter, I'd be thinking about running a cooler AND a Derale fluid Control Thermostat #25719 from Summit Racing. This would let the engine get to temperature quicker and not over cooled. [h=1][/h]