Back to the Drawing Board

[DougF]

Drove the TR6 on a little lap around town that included a two mile spurt on the local interstate. It ran fantastic!

Pulled into the gas station for a fill up and noticed steam coming up between the hood and fender. Found that it was coming from the overflow bottle. Temperature gauge was reading a little past normal, and it took the fan over a minute before shutting down. After the mile trip home, same steam and minute of fan before shutting off. The fan was set at 180. It's now at 150. There was no transfer of fluids.

The head was magnafluxed and checked for square. Installed a Payen head gasket, the fourth one on this engine in two years. The previous gaskets didn't blow in the same spot. The engine has about 40 miles on it since this work was done. I don't think it would have developed an air pocket after travelling this distance, or could it? I haven't found it to be leaking antifreeze.

So far, I've pulled the thermostat; topped the antifreeze; and retorqued the head after adding a flat washer to each stud to assure that the nuts weren't bottoming out on the threads. The nuts spin freely on the ARP studs. The timing is spot on to cam specs.

Any other thoughts on things to do before I turn the key?

I bought a different style head gasket that can be used with a gasket sealer...just in case.

 

[tr6_easyrider]

You say the timing is spot on. Have you had the harmonic balancer rebuilt, could have slip a few degrees after 40yrs.
I'll vote air pocket.Maybe running lean.
Do you have one of these.
https://www.harborfreight.com/infrared-thermometer-93984.html

 

[DougF]

Yes, thanks. I had Damper Dudes rebuild it last winter. I have an infrared, but didn't get it out. Good idea to have it on hand for the start up.

I'll Colortune it this weekend. I richened the carbs a bit over where they were last year. I may have go some more.

Thanks

 

[This14u]

Radiator cap?

 

[Brosky]

Pressure testing the cooling system will eliminate or confirm any internal leaks in the system, so try that to get that part behind you.

Air pocket is possible. Be sure to run the car with the heater valve wide open to get everything circulated out of the heater core.

 

[TomMull]

Agree with infrared thermometer. "A little past normal" is not all that specific but usually will not cause a purge of steam or antifreeze. A combustion leak of course will. So will an overly full system.
I'd start with trying a bit less coolant, carefully measure the temp, and if still steaming, get it tested for combustion gasses in the coolant.
Tom

 

[CJD]

Radiator cap?

X2

 

[sd80mac7204]

Loose nut behind the wheel?

Seriously though, I'm suspect of your rad cap in combination with an air pocket. Sounds similar to what the PPV did last fall.

 

[DougF]

I know a little beyond normal operating temperature is vague. I'll use the infrared to get a better idea. The radiator was pressure tested this spring and passed. There is a small crack in the flange of the radiator mouth. The owner of the shop didn't feel it was an issue. The crack is below the sealing surface, on the leading edge where the lip of the cap first makes contact. It's probably less than a 1/4" long.

I'll pick up another cap. The one I have is new, but leaves a little to be desired.

Hopefully, it's something minor as I do not want to pull the head yet again. Though some club members have volunteered to help if necessary and lend additional eyes to the situation....and maybe clean out my beer supply.

 

[TR3driver]

You didn't mention checking that the top of the block was flat, especially around the stud holes.

Also, twice now, I've had radiators that held water, and flowed OK (according to the radiator shop), but didn't transfer heat worth a <censored>.

This last time around, I had it back in the radiator shop twice before I finally insisted that they go ahead and "rod it out". When they did, they discovered that, although none of the tubes were completely blocked, all of them had a layer of a mud-like substance on the inside of the tube (probably leftover stop-leak mixed with rust particles and hard water deposits).

After a re-core, all my cooling problems suddenly disappeared.

A radiator shop can do a simple check, to see if combustion gases are getting into the coolant (indicating a crack or leaking gasket). ISTR mine charged about $18 last time I had them do it. Or you can buy the tool and do it yourself. I found a used one on flea-bay for $25 including a partial bottle of chemical.

Finally, "infrared" thermometers are inherently inaccurate, especially if you try to shoot natural aluminum (like the Tstat housing). I can change the reading on mine by 20F or more, just by moving the spot a fraction of an inch. So at least shoot something that is not aluminum (or painted). In a pinch, even a strip of tape will help.

 

[TomMull]

I get consistent readings on the hoses with mine. Shoot the hoses to get a good idea of coolant temp and the difference between upper and lower will give an indication of radiator cooling capacity. I don't know if there is a number but 30 degrees would be good IMO.
Tom

 

[DougF]

My infrared is listed at +/-10% accuracy, so it's probably almost equivalent to an unmarked temperature gauge, give or take 37 degrees.

The radiator was recored probably 15-20 years ago, so it could be suspect. I was considering one of the aluminum units on flea bag if this one was determined to be a leaker. The frustrating part is the shop installed mounting brackets to the rad frame for the fan. I had to make alterations to make things work, and I don't want to have to make more adjustments.

The deck was checked at the time of rebuild 2 years ago. I was going to have it cut but the shop didn't want to because there wasn't much metal to work with.

Modifications can be a real pain.

 

[DougF]

My infrared is listed at +/-10% accuracy, so it's probably almost equivalent to an unmarked temperature gauge, give or take 37 degrees.

The radiator was recored probably 15-20 years ago, so it could be suspect. I was considering one of the aluminum units on flea bag if this one was determined to be a leaker. The frustrating part is the shop installed mounting brackets to the rad frame for the fan. I had to make alterations to make things work, and I don't want to have to make more adjustments.

The deck was checked at the time of rebuild 2 years ago. I was going to have it cut but the shop didn't want to because there wasn't much metal to work with.

Modifications can be a real pain.

 

[TR3driver]

My infrared is listed at +/-10% accuracy,

That is the accuracy of the unit itself; but it does not measure temperature directly. Instead, it measures how brightly the surface glows in infrared, which is related to the temperature by a factor known as emissivity.
https://en.wikipedia.org/wiki/Emissivity

More expensive units will have an adjustment for emissivity, but generally the cheaper units assume a fixed value (mine assumes .95).

The problem is that the emissivity of aluminum varies widely depending on the surface condition. And unless you know what it is, you can't get an accurate reading.
https://www.engineeringtoolbox.com/emissivity-coefficients-d_447.html

Here's a more detailed (and technical) discussion if you are interested:
https://www.omega.com/literature/transactions/volume1/thermometers1.html#the_n_factor

 

[DougF]

Thanks Randall for the info. I will read it.

I use mine primarily as a sales sample and also to show surface temperatures when demonstrating freezing penetrants. Not to stray, but these penetrants work very well on brake lines and exceptionally well brake bleeders and are available in many auto parts stores. I did use it once to find a dead spark plug.

I'll be starting the car this evening and will post the results.

Thanks everyone for your input.

 

[TR3driver]

I use mine primarily as a sales sample and also to show surface temperatures when demonstrating freezing penetrants. Not to stray, but these penetrants work very well on brake lines and exceptionally well brake bleeders and are available in many auto parts stores.

Are you talking about "freeze spray" or something different? I'd be interested in learning more, although perhaps it would be best to start a new thread in the 'Tools' forum.

And of course you need to stay within the "no free advertising" guidelines.

 

[DougF]

I can't sell to the public, so advertising is not a problem. I know there are retail products similar to what I have. Ours is a freezing spray with lubricants. I will enter something in Tools section.

 

[DougF]

Car started right up. Ran it for five minutes with no pressurizing. Ran it again to temperature with no pressurizing. Started it again with some difficulty, it had idled to temp so I wasn't concerned. So far no problems. I'll put about an hour on it and retorque it again.
So far, so good.

 

[DougF]

Ran the car for another 15-20 minutes in the driveway and all was fine.

Took it out on the road and back into town, about six miles total with a ten minute stop in between, and it overheated. Sat for about 5 minutes with the fan running while the radiator was spewing heavily into the overflow bottle. After about ten minutes, I started it up and headed for home. Stopped once to let it cool off a little while I waited for a spot in traffic and for the light to change.

The water pump that is on the car is one I was testing for someone who wants to market it. I am going to refit my old one. Also the electric fan doesn't seem to been working up to snuff. When first installed, you could feel air coming off of it while standing back by the windshield. Now you have to put your hand behind it to see if it's working. It's a Hayden fan with a DeRaille adjustable thermostat relay.

Haven't looked at anything. Not in a good frame of mind to be near it.

 

[JerryVV]

Doug do the combustion gas test ASAP. Available at good Parts Stores, if I was closer you could use my stuff.