Correct flathead operating temperature?

wearymicrobe

wearymicrobe

Member
What exactly is the correct operating coolent/head/oil temperature of a mildly built Flathead. I have ~600 miles give or take on the motor, mild cam, mild carb (Triple 97's). Stock compression for a 60hp version. I have no thermostat valve that I know of. Think the HP is in the 70-80hp range to the rear wheel.

It seems to be jetting right and its idling right around 750 rpm reliably though I can go down as low as 600. Off Idle is reasonable and air fuel mixture is set right and the plugs are showing clean running. I have a stock sized 28 radiator with 4 cores.

Temp's that I am getting on a 60F day after ~30 miles of driving and 10 more of idling in the driveway

135f on the outer heads near each plug hole
145-150 on the radiator metal itself
115-120 on the coolant
No hot spots on the radiator that I can see with a probe.

Oil temps are unknown because the gauge that I have in the car I don't know the calibration on. Its showing 165 at the highest.

Car definitely runs better warmed up a bit but it still stumbles like its cold in the 1/4-1/2 throttle position. I have a progressive linkage on the car and its definitely set correctly for the motor build.
 
wearymicrobe said:
What exactly is the correct operating coolent/head/oil temperature of a mildly built Flathead. I have ~600 miles give or take on the motor, mild cam, mild carb (Triple 97's). Stock compression for a 60hp version. I have no thermostat valve that I know of. Think the HP is in the 70-80hp range to the rear wheel.

It seems to be jetting right and its idling right around 750 rpm reliably though I can go down as low as 600. Off Idle is reasonable and air fuel mixture is set right and the plugs are showing clean running. I have a stock sized 28 radiator with 4 cores.

Temp's that I am getting on a 60F day after ~30 miles of driving and 10 more of idling in the driveway

135f on the outer heads near each plug hole
145-150 on the radiator metal itself
115-120 on the coolant
No hot spots on the radiator that I can see with a probe.

Oil temps are unknown because the gauge that I have in the car I don't know the calibration on. Its showing 165 at the highest.

Car definitely runs better warmed up a bit but it still stumbles like its cold in the 1/4-1/2 throttle position. I have a progressive linkage on the car and its definitely set correctly for the motor build.
Click to expand...

Tripple 97s on a "mild" 60, and 70-80 rwhp? :eek: What make intake are you using?
I think your temps are way too cool-170-180 on the road would be better for the engine and oil. IMO. :)
 
Fort comparison, these are the temps I recorded on my 8BA on a 90-deg. summer day, fully warmed up.

Location.................... temp
Top tank ....................173-179
DS head (center).............183
PS head (center)..............183
DS thermostat housing .....173
PS thermostat housing.......179

These were taken with an infrared non-contact thermometer.

Your oil temps are supposed to be a minimum of 180 fully warmed to boil off condensation.
 
V8 Bob said:
Tripple 97s on a "mild" 60, and 70-80 rwhp? :eek: What make intake are you using?
I think your temps are way too cool-170-180 on the road would be better for the engine and oil. IMO. :)
Click to expand...

Its just your basic 60hp with offenhauser triple, offenhauser cam, carbs and headers and late 50s edelbrock heads. Plus dumps when I need them. No stroke or real changes to the primary design of the motor.

Probably makes 110 at the motor, running it through a 34 transmission's and 39 rear end though and they suck power down quite a bit. I have seen over 25% on a dyno in the past on this style of drive train.

As for the progressive I have to use that or I get way to much air into the motor on acceleration and it bogs like crazy. I restricted the idle valving on the front and rear carb. Then use the progressive to match the flow on the outside to what the motor wants in terms of CFM. I could probably run the car on a single 97 with the other two blocked off but whats the fun in tuning something like that.


1928_Model_A_Roadster_Brookville_Flathead_Silver_Rumble_Seat_For_Sale_Engine_resize.jpg
 
Ross F-1 said:
Fort comparison, these are the temps I recorded on my 8BA on a 90-deg. summer day, fully warmed up.

Location.................... temp
Top tank ....................173-179
DS head (center).............183
PS head (center)..............183
DS thermostat housing .....173
PS thermostat housing.......179

These were taken with an infrared non-contact thermometer.

Your oil temps are supposed to be a minimum of 180 fully warmed to boil off condensation.
Click to expand...


Thank you! That's the way I way measuring the heads as well. Looks like I am running way to low there as well. normally I would say way to much fuel but my carbs are not icing down to a decently low temp they are floating in the 90-100 range which is decent in my book which is my first sign. Plus the plug are running super clean.

Might throw a inline thermostat in tonight and set it for ~180 see if I can get the temps up that way.

I will also take a quick oil sample and see if it has any foaming or water traces.

FYI this is my first Flathead. So trying to dump years of conventional wisdom that I use of big blocks is taking some time.
 
That is not a V8-60 in that picture. Your first post sounded like you had a 60 hp engine. Those fittings on top of the heads are thermostat housings and you need to get some in there.
 
Yo Weary, if you posted your location in your name box, you might find a fellow barner to chime in who is in your area. That way, you'd have someone close by to check notes with. That's not to say that it is good for you to post on here looking for info, I'm just saying it is always cool to find local info and talent.
 
San Diego is where I am located.

I am more then happy to bring the car over to someone who knows Flathead's and pick there brains on getting it up to temp. I will bring the beer/soda and heck I will polish tools at this point to learn what I need to know.

I did ordered two 180 degree stock thermostat's and will be picking them up at napa tonight on the way home. See it that helps a little bit. I have been reading on the HAMB and almost everything is trying to keep a Flathead cool not warm one up!! Might be a restrictor in a hidden place that I am unaware of as well.

Additionally I might switch the system over to a higher ratio of water to see if I can bring the temps up a little bit more. I did grab another probe temp gauge at the office that is calibrated up to 500f so I should be able to get direct temps on the oil and a fe other things tonight.
 
Alright I bow down to your superior wisdom. Thermostats were the answer. I actually found what looks like a 1/2 inch restriction in the radiator hoses so I pulled those out and popped in 2 180 degree thermostats. Then I fused the whole system and started running a 80/20 water/freeze mixture as well. It was 20/80 before based on the color before.

I put a colorant in the motor to see if the thermostats would open and they sure do.

Let it idle and holy crud the motor actually warms up. Let it sit for about 20 minutes to get up to temp and puke out the extra fluid through the overflow and drove it around the block.

I have so much better throttle response off idle, I have power above 1/2 throttle, I actually have enough power to light up the tires a good bit. Which I could never do before. I actully dialed in a bit more advance on the carbs.

So new temps

Location.................... temp
Top tank ....................165
DS head (center).............167
PS head (center)..............172
DS thermostat housing .....181
PS thermostat housing.......182

I can barely hold onto the radiator hoses anymore and I can feel heat off the motor which I never was able to before.
 
The 60HP is a smaller version of the 85HP engine built from 37 to 40, It only had about 137 cubic inches and 60 HP at the flywheel.
Y blocks started in 1954 and are overhead valve. 51-52 mercury is 256 cu.in.
Bill
 
bbrocksr said:
The 60HP is a smaller version of the 85HP engine built from 37 to 40, It only had about 137 cubic inches and 60 HP at the flywheel.
Y blocks started in 1954 and are overhead valve. 51-52 mercury is 256 cu.in.
Bill
Click to expand...


Cool. Thanks for the info. I always think in final output not source power due to work. .
 
OK spent some time timing the motor a bit better and working on the progressive link. I now have a leak free vacuum advance system as well. Plus found a few smaller air leaks that I have patched up.

I also put in head temp sensors on both sides of the motor. I am getting reading of ~165 on the driver's head and ~140-142 on the passenger head. This corresponds with the readings that I am getting with the laser temp gauge. Any real worry with ~20 degree differential on the heads.

Also front cylinders also seem to be running a good bit hotter then the rear ~15 degrees.

Does not seem to change in differential of temp across the two heads with load or extended idle. I guess one of the water pumps could be more effective but I am amusing at this point that the idle needle valves that are under the carbs are not synced up properly and I am getting excess fuel delivered to one side of the motor cooling everything on that side down.

Does that sound reasonable.
 
since your using progressive, only the center carb idle adjustment screws should be working, the outside carbs are dumpers and there is no need for their idle circuits to be working, you do not want them to work. the adjustment on the center carb should be approx 3/4 turn to a bit over 1 turn out each, and they should be about even. If one side has no effect then there is probably a blockage in the idle circuit on that side of the carb, could be the cast iron base idle circuit blocked or the main body blockage.
 
Wearymicrobe,

I am a curious sort of person. I have always pondered this for a while.

It sounds like 180 degrees is the winning operating temperature! If you don't mind, I would like to add?

When it comes to the BEST way, to gauge the engine temperature in our flathead V8's, should we rely on Coolant Temperature OR Oil Temperature?

Depending on which you feel is best, how did you come to that opinion & would the 180 degree operating temperature, still apply to each method?


Thanks Men,
Chris Kennedy
 
You must log in or register to reply here.
Back
Top