8BA Flathead overheating on highway

[40cpe]

Originally Posted by SonicRaT

I've been trying to reach Bubba, but haven't had any luck yet.

Charlie NY can fix you up with a converted Delco Distributor and he will get back to you.
[email protected]
716 440 8952
716 662 9159

[SonicRaT]

Originally Posted by 40cpe

Charlie NY can fix you up with a converted Delco Distributor and he will get back to you.
[email protected]
716 440 8952
716 662 9159

Thanks -- Bubba is swamped at the moment, so I'll see what they can do for me.

I did the compression test today (cold, due to weather turning on me). Each cylinder was pushing right around 120psi -- the widest variance was maybe 3 psi between the highest and lowest cylinders.

I'm still curious about what would cause the vacuum bounce when idling -- anyone have any ideas on that?

Earlier in the day, I did a WOT run up on a set of new plugs I swapped in after letting the truck warm up, they came out looking pretty good. Seemed to run a bit better under load with my advance limited to 24 degrees -- didn't get enough time for long term testing due to the weather.

Trans cooler arrives tomorrow and hopefully this weather will clear enough to take it for a longer drive and see how it performs. I'll be hooking up a temp gauge to the trans to keep an eye on both along the cruise, so hopefully I'll learn a bit more from that.

[Tinker]

Vacuum bounce could be sticky valves. Tight tolerance on a rebuild could make valves a bit stubborn. Good news is that driving it more, helps. Adding a upper engine lubricate doesn't hurt. What leaded fuel was for. Maybe a leak.


Lot's of basic charts online.
https://www.classiccarrestorationclu...oubleshooting/



I like to run a vacuum gauge next to a mechanical oil and 2 water pump gauges in the cab, just for fun.



120lbs is great, sticky valves usually show underload while driving. Good luck!!!

[Ol' Ron]

I'v been fowling this post,as I'm using a similar radiator in my roadster.
I've had some experience in tuning these engines, and have come up with the following advance curve that works well with most engine modes as well as stock. unfortunately it doesn't work with the Load a matic. Also today's gas makes it difficult to read the plugs, so I use an AF meter. Takes the guess work out of the equation. This way yo can see the AF under load as well as in cruise.
Also , I;ve run several engines with out a fan on the open toad with no cooling problems. The unknown here is the carburetor. I think a stock 8BA carb and distributor would solve your problem, but here's what I KNOW works

Ignition Mechanical advance 16-18 degs all in by 2000. Vac advance 6-8 degsa at hi vac.

AF 12.7/13.2 Power . 14.5/?? this can run up to 16 in a BUILT engine for economy. Working on that. In Richards engine he got up to 15.5 in cruise.

All these numbers vary abit under different atmospheric conditions

Good luck
OL' Ron

[SonicRaT]

Originally Posted by Ol' Ron

I'v been fowling this post,as I'm using a similar radiator in my roadster.
I've had some experience in tuning these engines, and have come up with the following advance curve that works well with most engine modes as well as stock. unfortunately it doesn't work with the Load a matic. Also today's gas makes it difficult to read the plugs, so I use an AF meter. Takes the guess work out of the equation. This way yo can see the AF under load as well as in cruise.
Also , I;ve run several engines with out a fan on the open toad with no cooling problems. The unknown here is the carburetor. I think a stock 8BA carb and distributor would solve your problem, but here's what I KNOW works

Ignition Mechanical advance 16-28 degs all in by 2000. Vac advance 6-8 degsa at hi vac.

AF 12.7/13.2 Power . 14.5/?? this can run up to 16 in a BUILT engine for economy. Working on that. In Richards engine he got up to 15.5 in cruise.

All these numbers vary abit under different atmospheric conditions

Good luck
OL' Ron

I have a wideband I could install on each bank, but the exhaust on the flathead doesn't have bungs and I've never had very good luck using them as sniffers in the rear. If worse comes to worse, I'll install a couple a bung and see how it's doing. I've also got some EGT gauges, but I'm not sure what the typical range is on a flathead, so I wouldn't really have any point of reference from the values.

I think this Edelbrock 94 and the Loadamatic are not playing well together -- my distributor seems to be more to blame at the moment though. I'm going to replace the advance springs later today and see if that brings it into spec. After I get the trans cooler installed, I'll hopefully be able to get in a longer cruise to see how it does.

[Ol' Ron]

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The AF readings are for any internal gas engine IT doesn't have to have two bungs one will do just keep it close to the engine. I don't see why you need a trans cooler.

[George/Maine]

When I installed a should with electric fan ,I did notice I would run hotter at high speed.
What did was cut the bottom of should off. Those flops are blocking air.
I tried ever thing when going up hill would run hotter. even with bubba chevy dist.
It never run over 210, I had mercury 8ba 2 97 c4 278 gear small tires would run about 2200 rpms. The engine 060 over always run hot even with stock trans.
Just a hot flathead. My 53 stocker my 47 run so nice a cool.

[Mike51Merc]

Have you checked your coolant for hydrocarbons? Or for pressure buildup?

The reason I ask is because a crack in the block can cause hot exhaust gasses to leak into the coolant passages causing hotter temps. This kind of leak will cause problems at cruising speeds and under loads.

[SonicRaT]

Originally Posted by George/Maine

When I installed a should with electric fan ,I did notice I would run hotter at high speed.
What did was cut the bottom of should off. Those flops are blocking air.
I tried ever thing when going up hill would run hotter. even with bubba chevy dist.
It never run over 210, I had mercury 8ba 2 97 c4 278 gear small tires would run about 2200 rpms. The engine 060 over always run hot even with stock trans.
Just a hot flathead. My 53 stocker my 47 run so nice a cool.

When you say it never runs over 210 -- was that before or after the shroud modification? What size fan/shroud setup did you have? I've got a 16" Spal, which takes up the vast majority of the core space -- the larger parts of the remaining shroud all have flow flaps which seem to be working, though they may still be adding a bit of restriction. I can always pull the fan and shroud off for a test drive.

Originally Posted by Mike51Merc

Have you checked your coolant for hydrocarbons? Or for pressure buildup?

The reason I ask is because a crack in the block can cause hot exhaust gasses to leak into the coolant passages causing hotter temps. This kind of leak will cause problems at cruising speeds and under loads.

The coolant test was negative for exhaust, so I don't think I've got a leak into the coolant passage. I do get a bit of pressure, but I'm running a pressure cap so that's to be expected. I'm not spewing coolant out other than what goes in and out of the expansion tank.

[SonicRaT]

Finished the remote mounted transmission cooler install yesterday, but due to weather didn't get a chance to drive it at all until today for a car show about 40 miles away. Let the truck warm up while I checked over everything and rolled out with it reading 195 -- about 10 miles later (at 55mph) it had crept up to 210 and stayed there. On the way home, I was trying to beat the rain back and ran about 65mph the entire way back, and it had just barely crept up over the 210 tick on the gauge by the time I pulled in, which was mostly due to a hilly area right before the house. Overall, these were the temps I noticed both in the morning and evening:

- Coolant: 210*
- Transmission Cooler Inlet: 190*
- Transmission Cooler Outlet: 165*
- Transmission Pan: 150*

I had no transmission issues at all on the entire duration which leads me to believe the transmission is much happier now running within its own system. Previously, it'd only make it about 15 miles before the transmission would start puking fluid.

Things I had done:
- Fuel pressure to 2psi
- Rebuilt carb
- New plugs all around, gapped correctly
- Fixed distributor advance to as close to factory specs as I can get it
- Remote mount derale transmission cooler (acting as primary cooler, with a derale heatsink cooler as a secondary)
- Running 80/20 water/antifreeze
- Retorqued all head bolts

Next up on the list will be swapping the radiator and flushing everything to see if there's any lingering sand or debris causing issues -- going to fab some new engine mounts, so I may pull an inspect the pumps at the same time.

[Tinker]

Looks like you have a plan and following it by checking everything. It does make it easier to isolate (fine tune) the issue with one change at a time, but it seems you are getting closer and understand mechanics, hence having a good grip on what's going on. Keep at it!

[Tinker]

Gauges correct . I'd still look at your ignition if you need it cooler (since this is fair from stock, maybe a weird fan/radiator issue). But maybe not. just armchair quarterbacking it.

[SonicRaT]

Originally Posted by Tinker

Looks like you have a plan and following it by checking everything. It does make it easier to isolate (fine tune) the issue with one change at a time, but it seems you are getting closer and understand mechanics, hence having a good grip on what's going on. Keep at it!

I'd have preferred to do some test drives after each change so that I can pinpoint exactly which changes have which effect, but the weather was not in agreement and I wanted to make the weekend show, so I threw a little bit of everything at it all at once.

A lot of things were simply exploratory and tying up loose ends -- such as lowering the fuel pressure slightly, new plugs, carb rebuild, and etc. I didn't suspect one of those particular things would suddenly solve the mystery, but I figured I'd address issues with each while I was doing everything else.

Originally Posted by Tinker

Gauges correct . I'd still look at your ignition if you need it cooler (since this is fair from stock, maybe a weird fan/radiator issue). But maybe not. just armchair quarterbacking it.

Yeah, I'll be planning to ditch the original loadamatic as soon as I can -- it just doesn't seem to behave well at all with my Edelbrock 94.

With fall fast approaching, I'll likely park it for the remainder of the year and start delving into some of the more time consuming projects I had planned, which should hopefully will reveal some more background as to what's causing the creeping.

[Tinker]

Each thing gets you closer. A friend one told me a basic stupid idea. You do, do, think or you think, think, do. both have their advantages.



You'll get it figured out.

[Mart]

It sounds like a vast improvement over what you had.

If you have a pressurised system, it raises the boiling point so 210 may be ok. The fact that it "stayed there" is good.

Big question, though, how was the weather when you did this run? Nice and warm? Blisteringly hot? A bit chilly? It could be significant.

Does your loadamatic actually work? If the vacuum can is shot you have no advance at all. This happened to me on a French motor which has vac only and that was broken.

It does sound like good, positive progress though.

Mart.

[SonicRaT]

Originally Posted by Mart

It sounds like a vast improvement over what you had.

If you have a pressurised system, it raises the boiling point so 210 may be ok. The fact that it "stayed there" is good.

Big question, though, how was the weather when you did this run? Nice and warm? Blisteringly hot? A bit chilly? It could be significant.

Does your loadamatic actually work? If the vacuum can is shot you have no advance at all. This happened to me on a French motor which has vac only and that was broken.

It does sound like good, positive progress though.

Mart.

The weather on the way in was about 82* with very high humidity and the trip back was slightly cooler, about 76 with high humidity.

The vacuum can was originally destroyed when I first started troubleshooting the issue, so I replaced it thinking that was the source of my problems but it didn't make a difference. The new can holds vacuum for quite a while and I can verify it's advancing -- a little too much.

I believe the griffin cap is rated at 15lbs, so I'm not getting to boiling territory, but I'd definitely like to find a way to bring those numbers down and be able to go up a hill without keeping a nervous eye glued to the temperature gauge.

[rotorwrench]

With a 15# cap, your boiling point will be near 250 degrees F so it should be OK for the time being. Getting a centrifugal distributor will help a lot and tuning a vacuum spark load control system to work with manifold pressure would be even a bit better. Mileage should also improve.

[Tinker]

It's interesting truck. But not very stock. Why the flathead?

[enzo321]

Hello SonicRaT, can`t send a private message for some reason. I have exactly the same problem on my 59AB engine. Did you find any solution? Did you pull the heads or find the problem elsewhere? Your reply/advice would be highly appreciated
Thanks, JM