What gears to use?

[justa6]

Nope, no low 10's just 10.8's so far but I'm working on it<G>

As far as the thermostat goes I think your right, heat up the block and the oil will also warm up.

Here is a question for you guys. I'm picking up my oil temp right as it goes back into the block from the cooler (and filter). So it is at its "coldest" temp. What do you think the "rise" is. ie at the oil pan where it goes back to the external oil pump. REMEMBER this is a dry sump system so that there is little or no oil in the pan when the motor is running.

Also, as long as we are "talking". Do any of you have any experience with a vacuum pump for the oil pan. ie running a vacuum in the sump so as to increase horsepower? Since my motor has a dry sump I can simply close off the valve cover vents and the dry sump pump sucks all the air as well as the oil out from the crankcase. I've read where it boost horsepower by around 15-20. When we dyno'd the engine we had vents in the valve covers while the Busch versions didn't so they could boost their power.

Regards,

[Back in Black]

I assume that if you were to install such a critter, made from aluminum sheet metal, etc....installed in the front of the radiator, it would cut off some air flow, and bring your temps up..!?

I would start with a piece cutting off 2/3 of the air, and then if that is too much, cut it down and try that. You can anodize the air dam to match what you want, even use a piece of fine extruded sheet aluminum, to cover the whole radiator would reduce air flow...something to experiment with! Sounds like it's right up your alley!

Other options would be a MUCH smaller radiator! Or no fan at all, or a much smaller fan.

My Scout 2 has a 258 CI straight six, and I run the fan but no cooling shroud, and it runs cool anyway ! I don't really even need the fan!


No need to thank me, as ERA535 said, any guy with enough B***s to put a 6 in a cobra deserves the help!!

[justa6]

Actually I don't have a cover on the radiator. The water thermostat change will fix that, in fact I might go to a 195 thermostat that should get the oil up to at least the same and when I race it won't hurt if the oil to gets up to 230 or so. I notice that after a 1/4 run the oil temp will get up to around 160 or so then come right back down. Water stays at 170. Not really a big deal but I've got to "get it up"

Regards,

[Double Venom]

Justa6,

FORGET changing the water themostat! Counter productive my friend.

Install an in line "OIL" thermostat. Believe it or not, our V-10's have the same problem. We couldn't get the oil past 140, even under hard racing conditions. Low oil temps are a problem! I'm glad someone has brought this up!

Think twice about adding that "cool" oil cooler on your cars people. In most instances, if you want the look, install but don't actually hook it up!

The sad part is, most people have no idea what temp. their oil is running!

DV 300 Cobras is NOT enough! Have you registered?

[blykins]

Man, that's weird. When I raced Vipers at Skip Barber, we had to run them with the heater at full blast, then we had to leave them running with the hoods up after we were finished to keep them from overheating.

Those Cobras must flow a lot more air around the radiator and engine compartment....that's pretty cool.

Brent

[justa6]

I'd like to add a oil thermostat but can't.

Since my motor uses a dry sump system the Pressure out line from the pump has to go to the filter and cooler before the engine gets fed. If I had any restriction (thermostat) then the engine would not get any oil until it "warmed up". It would "warm up" allright

I'm just going to bypass the cooler first and then put a warmer thermostat in also as the engine water temp is also very low.

Thanks for the help its appreciated.

Regards,

[Double Venom]

Blykins,

144 is our hottest recorded oil Temp. to date, without a thermostat.

DV -- 300 Cobras is NOT enough!

[aumoore]

blykins
You said "Those Cobras must flow a lot more air around the radiator and engine compartment....that's pretty cool. "

All cobras are is a big engine compartment with a big old hole up front, stuffed with a big radiator, with two side vents for good measure wih all this wraped around a big V8. Oh yeah they put a really small place behind the engine compartment and it is called a cockpit but is is more like a torture chamber.

there is more thought in keeping the engine cool but the driver is a after thought.

[CobraEd]

This may sound a little silly, but what about wraping the pan with that adhesive insulating material they sell.

Ed

[Back in Black]

Is the following comment (true) by AUMOORE:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
"Oh yeah they put a really small place behind the engine compartment and it is called a cockpit but is is more like a torture chamber.

there is more thought in keeping the engine cool but the driver is a after thought. "
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The West Coast has 1 inch cockpit walls of sheet metal (on both sides) in between? INSULATION. This is like a more modern car, even including real sportscar seats and cockpit, yet the West Coast retains much of the cobra look. I wanted a car I could drive anywhere, without catching my feet on fire, or being miserable in antique seats. I love the original cobras looks, for sure, but for anything but short drives, they can be uncomfortable. Sure, you can help the heat thing with modern sheet insulation, but I wanted a turnkey, ready to go, with no problemos

[Mike Braddock]

Bob,

Why does it matter whether you are running a dry or wet sump oiling system as to whether you can plumb an oil thermostat? You say your oil comes from the pump, through the filter, through the cooler and then into the oil galleries in the block. That's the same as we're running on our wet sumps. So why can't you replumb the oil cooler and install the oil thermostat? I don't understand why the dry sump system is any different (please excuse my ignorance if this is a dumb question ). Why would you have an extra restriction due to the thermostat? Until the oil reaches the oil t-stat opening temperature, it just bypasses the cooler and returns the (uncooled) oil directly back to the engine. Once (or, more appropriately, if) the oil warms up, the thermostat then routes the oil through the cooler and back to the engine. It would require replumbing the lines going from your filter to your cooler and from your cooler to your motor, but that's about it. What size oil line are you running?

Mike

[Dominik]

bob,
some posts ago I read that you measure oil temp at the oil cooler exit.

you want to know the temp in the pan before it leaves the block (well preferably at the bearings) to determine if it's to cold.

as for the vacuum idea for the dry-sump I never saw something like that at the Can-Am engines I worked on - although that does not mean it is a bad idea!

dominik

[justa6]

I'm sitting here in an internet cafe in Mainz reading Cobra forum. Internet is cool...

The question was why my dry sump can't use a thermostat. The way a dry sump works is the oil is sucked out of the pan and goes to a 3 stage oil pump. That pump then send the oil to an external oil tank. From that tank the oil return to the oil pump to be boosted up to around 90 psi. It then goes to the filter and cooler and continues to the inlet on the front of the motor. With a wet sump like most engines the thermostat simply stops the oil from going to the cooler until the oil is warm enough to open the thermostat. HOWEVER the oil pressure in the motor is normal while its waiting to warm up. ie no restriction. In my situation there would be no oil pressure until the thermostat opens. I could rig a bypass of some kind but it would require some kind of Y fitting that would still allow oil to get to the cooler but more importantly feed the engine while it was warming up. If you could see the oil lines (number 10 and 12 fittings) you'd understand why it would be very difficult to plumb this thing. It could be done but it would be easier to bypass the cooler altogether and up the coolant thermostat to make the block run hotter. I could also insulate all the stainless lines and the tank to retain heat. I'm going to switch to Mobil 1 5-30 oil to also mitigate the low temp.

Thanks for the help guys its really great to have input from different perspectives.

Hope to see some of you at this years Run & Gun in Sept. I'm really looking forward to it.

[Dominik]

in Mainz?

I mailed you a contact number. I used to live 15 minutes from there.
maybe you have time to visit peter with cris.
peter is the mc laren guy. he lives 40 minuets from mainz (but doesn't speak english)

dominik

[Mike Braddock]

Bob,

Oil thermostats have 4 fittings like this:



because they have the bypass built in. So you should never have a restriction or see a drop in oil pressure. I've plumbed them before with -10 fittings and I realize it's a pain any time you've got to redo oil lines, but it's not that big of a deal. I think it's well worth it since the engine oil will reach decent operating temps.

Mike

[justa6]

Dom, Yes I was in Mainz Yesterday but today I'm back home in Georgia. Next Friday night I've got the same flight back to Frankfurt and stay in Mainz Saturday then back home Sunday. I don't speak German but do drink their beer

Mike, my son had the kind of oil thermostat your talking about. I guess I should have written the problem better. (I was very tired as the flight from Detroit was an all nighter and I wrote that note with a couple hours of sleep so....

The thermostat your describing would work. But my problem is that the oil lines from the cooler go in two different directions like most Cobra's do. With that thermostat I would have to bring the one line all the way around and back to the thermostat. It could be done but it would be difficult and would be "less" than nicely done... Thank God I got rid of the 4th stage on the Weaver pump. As it would be even worse...

Anyway I may end up with the thermostat but I think I'll try a couple of simpler things first. The guy that did the machine work and balancing of the engine said just bypass the cooler completely as the motor is "loafing" all the time anyway. When I drag race it its only wide open for 10 seconds and when it goes to a road race track your on and off the throttle a lot so it doesn't run hot their either.

Thanks guys I really appreciate the help and comments,

[niles]

justa6;

You might not need a oil cooler; because a dry sump has more oil volume and the lines and sump are in effect an oil cooler.

BUT: Also DV; make sure to calibrate your oil sensor; just because it reads 140 deg? that means absolutely nothing; work on double checking and verifying the actual temperature.
Sensor and guages are notorious for leading one on all sorts of wild goose chases .
gn

[Dominik]

bob,

those trip are torture.
you may call cris IF you have the time ... - he speaks english.
may take you to peter where you can buy his M8F ;-)

dominik

Hi DV!!!

[Double Venom]

Niles,
I couldn't agree more. We use two guages for testing on all the DV cars. Just went nuts with my DV getting 75 to 80 lbs of pressure, brand new build, then immediately would drop off to 10 to 15lbs. We checked everything. Finally replaced the bypass springs and valves. Started, same problem, changed guage same readings! Grrrrrrrrrrrr

Pulled the front cover off, (Viper oil pumps are in the timing cover case and run directly off the crank.) replaced both oil gears, and springs and valves again. Knowing we had the problem licked we restarted it..........same problem. Now we went to a THIRD guage! Same problem.

Now I'm stumped! Hey, lets play, What was DV's problem?

You're going to have to be really sharp to get this one!

A brief review. New crank, bearings, etc., etc. ALL mic'd out perfect. Block line bored..perfect. Block was steamed and cleaned.

A couple of hints...NO leaking gaskets, or oil leaks anywhere. Not a Bearing problem of any kind!

If Bob is reading this, I'll bet he is the first one to come up with the answer.

DV -- 300 Cobras is NOT enough!

PS HEY Dominik! Howdeee!

[niles]

DV:

I didn't read where you changed out the "sender or transducer" -My vote.

Related tech story: back in another life on nuclear subs; all gauges and indicators were triple or quadruple redundant. Sounds and is expensive; but absolutely neccessary. one guage off scale- bad- but tells you nothing. Two gauges- one says A the other B. You still know nothing, other that one of them is wrong. Third gauge(source) indentifies which one is the likely providing faulty readings.
Forth guage confirms with high probablility the real answer. I had this exact scenario play out one night at test depth when the main depth gauge at the con indicated that we exceeded test depth and were about to implode. Thankfully the gauge went T.U. for no reason with no warning.

gn