Well, thought I had my overheating issue solved with Tim's "cleveland correct" thermostat, but I'm still having problems. Hadn't really gotten any extended drive time on the truck till this weekend. I drove it about 20 miles to a friend's house outside of town Ambient temps in the 80's; truck seemed to run pretty comfortably most of the trip, but toward the end, temps crept up past 210-215. Shut it off & it sat for about an hour & it cooled back down. No coolant out the overflow. On the way home, it heated up again & got to almost 240 before I was able to pull into a parking lot & shut it off. It did puke coolant this time. Waited about 20 minutes for a buddy to bring out my trailer. When I started it back up to load, temp was back to about 195. Also noticed some knocking when the engine warms up, which seems to get worse the hotter the temp gets. Seems to be coming from the top rear of the passenger valve cover. (lifter or rocker?) I KNOW this engine shouldn't be heating up like this. I've got a brand new champion aluminium radiator, new high volume water pump, new 180 degree thermostat. I believe timing is set correctly; where should i start troubleshooting this? Here's a link to my previous thread: https://www.ford-trucks.com/forums/1...g-a-400-a.html

 

One year later !!!!

Per your earlier thread, ''newly rebuilt'', and adjusting the timing with guesswork, could be issues.

But the easy stuff first.

Does your vacuum advance actually work, with 10* to 20* additional timing at idle (if still connected to manifold vacuum) ?

Are the fans on the engine side of the radiator ?

If yes, put a sheet of paper in front of the grill with the engine running. Does the sheet stay in place ?

If yes, the fans are wired correctly. If not, the fans are pushing instead of pulling.

Either get yourself an infra red temp gauge, or go to a radiator shop, and test the temps at the t/stat, top hose, and lower hose.
For curiosity, see if the highest temp matches your temp gauge.

And last easy test.

Ask a radiator shop to test the coolant for exhaust gases.

Then give feedback on those four tests.

At what temp on your gauge do the fans kick in, and do they both actually kick in ?

 

Fans are operating correctly. right now they're wired to operate with key on all the time. Could heater hoses be a culprit? One thing I never did was verify in/out on heater core & water pump.

 

This will help. Try connecting distributor to manifold source vacuum.

Make sure mechanical advance is operating smoothly and advance plate isn't sticking. Should be 34° to 36° BTDC timing, somewhere in there, all in before 3000 RPM without vacuum advance connected.

 

Just another thought - I am running a ProForm HEI distributor for a big block - https://www.summitracing.com/parts/p...view/make/ford In item description, it lists this part for the 335 motors, but is it possible its advance settings might be different enough from the stock Duraspark system to cause a problem?

 

A typical HEI has 20-22* of mechanical advance and another 20-22* of vacuum advance. This can be changed with A HEI distributor kit with weights, springs and a vacuum advance limiter.
https://www.summitracing.com/parts/sum-g5212/overview/
https://www.summitracing.com/parts/c...00-1/overview/
I have used these.

 

Don't believe so but it is important to check the total mechanical advance timing. Want to see about 34° or 36° BTDC at the far end. That would be without vacuum advance.

The vacuum advance is sort of hard to measure accurately in that it is load based, but there isn't any load in neutral. The vacuum advance only adds to whatever mechanical advance there is under steady state level ground cruise. If you connect to manifold it will have a lot of advance in neutral too. This will keep temps down.

Remember too, when the timing degrees are talked about with a distributor it is 1/2 the number that shows up on the crank, since it turns at half the speed. So you'll hear something like "I'm using the 10L slot" (for example) and that equals 20° timing on the crankshaft. Sorry for veering way off into the weeds here (unusual for me, though it happens) the point being if the ignition timing is retarded enough it will cause an overheating condition that can be hard to disgnose.

 

Sorry, but I'm almost completely ignorant of ignition timing - I mostly work on diesels besides this pickup. When I was setting the initial timing, I wasn't even able to get a smooth idle without connecting to the carb vacuum port - why would that make a difference if there's little to no vacuum at idle anyway? I think I ended up setting it at about 14* initial. I had a mechanic check the ignition timing & he said he only had to make a minor adjustment. Can you guys point me to a good tutorial. I get the concept of varying the spark on the compression stroke based on engine speed & load, and how the mechanical & vacuum advance components work, but how are measurements & adjustments made, except but rotating the distributor slightly until the motor "sounds right"?

 

That just got me thinking about the clatter I was hearing from the engine when it got hot - could that actually be pinging instead of a rocker or lifter? I do think there is a valvetrain adjustment that needs to be made, as I can heat a slight tapping from the rear of the passenger side valve cover, even when cold, but it turns into a full blown clatter when the engine gets to about 200. Also only evident when into the throttle.

 

Here's a link to a good overview of ignition timing.

http://www.hotrod.com/articles/set-i...rformance/amp/

 

So after reading this, I'm beginning to think I might need more mechanical advance, since the engine runs fairly cool & quiet in high vacuum situations, but starts rattling & heating up when vacuum advance is taken away. Should I try adding more initial advance, or do i need to look at distributor kits to increase mechanical advance? Anyone know the advance settings on the ProForm HEI distributor for big block fords?

 

Generally the routine is tune the distributor first, with the vacuum advance port disconnected and plugged.

The total advance at the far end is what's important. Rev it up (carefully!) with a timing light and see where it stops advancing. Turn the distributor wherever it needs to be to get the number you want. Usually more than 10°, maybe 15° BTDC, somewhere right in there, is typical to get to 34° or 36° BTDC. There isn't anything "wrong" with more idle timing than that, but you'll likely find it difficult to turn over the engine due to starter kickback. And with that much lead then the distributor would have to be limited on the far end a bit. Lots of different ways you can slice the timing "pie" depending on application.

Some racecars with lots of base timing i.e. probably 20° + had a button to temporarily disable the ignition so the engine would start spinning to get it started.

 

@ Tedster9

I like that attachment.

@ Byrd.dog

Heating up sounds about right when removing the vacuum advance (basically it's retarding the timing), but the 'rattling', if pinging, would occur with advancing the timing.

Try and determine what the noise is. Google a you tube video of pinging if you can, to determine if that's the sound or not.

Read the attachment again if need be to fully understand what's required.

Is the rattling at WOT or partial throttle ?

What octane gas are you using ?

What are the new engine specs ? The OE total timing of 34-36* (ignoring vacuum advance) might be too high if the new engine has e.g. higher compression than OE.

 

Engine noise is apparent with any application of the throttle once engine is up to operating temps, but sounds almost like an old idi diesel when temp got up above 210. I run 90 octane; engine was rebuilt with TMeyer .020 over pistons, straight-up cam timing, and an rv cam.

 

whats the DCR? That will determine fuel octane and how much timing you can run. Combustion chamber design and squish also has an effect on timing. TFS 195 powerports seem to like 26-28* and stock open chambers like 32-34* of timing with around 40-50 thousandths of squish, if the correct octane is used, if using too low of octane, you will need to retard timing more to avoid pinging.I'm sure your answer is somewhere in the math...