Saracen exhaust running HOT

[peter clemmer]

I have a 1956 Saracen that I am slowly getting to run properly. When I run the engine over about 2100 RPM for awhile, it gets the muffler so hot that it tries to set the tires on fire.
I have a manual, but it does not cover this situation. I suspect it is timing or distributor setting.
Any one out there have any ideas?

[Les Fisher]

Usually there is two main reasons for a hot exhaust. One is ignition timing and the other is a plugged exhaust.

[Phil Waterman]

Hi

Agree with Les, timing and plugged exhaust. Critters once loaded the muffler on my HUP with acorns which in a very short run had the muffler glowing red.

Cheers Phil

[colin jones]

Hi Peter, you may also want to check if your model has the reverse cooling system. If it does then that would certainly make it run hot.
Colin.

[peter clemmer]

Thanks for the replies. It does not have reverse cooling so we can rule that out.
I haven't taken the muffler off to check for plugging, but I suspect that is not the problem since the exhaust pressure seems to be ok, could be wrong though.
When I get some time will try to check it out.
Peter

[Phil Waterman]

Hi Peter

With my HUP it wasn't that the muffler was plugged it was that the little critters had loaded it with acorns. That burned like charcoal with the force draft of the engine, which still had enough oxygen for the muffler to glow merrily a couple of inches from the fuel tank. Out of the exhaust pipe came the fall smell of burning oak leaves. Shoving a hose up the tail pipe and turning on the water resulted in an explosive cloud of steam. Fire was out but the muffler was ruined with the seam split.

But back to your problem if you have a IR thermometer checking the exhaust manifold and along the pipe should show a steady drop in temperature. I'll check my engine test notes get some temperature numbers at particular RPM to compare to. I us my IR gun to check manifold port temperatures, good check for intake leaks which can cause high exhaust temps.

Cheers Phil

[Hans Mulder]

If it isn't timing it could be a blockage - put a few strips of masking tape along the length of the exhaust when cool. Fire it up and watch the tape as she idles...the masking tape will start discolouring/burning first in your problem spot.

[peter clemmer]

Thanks for the temperature information. I will try the IR thermometer and the tape trick.
Let you know what happens.
Peter

[peter clemmer]

Well, I tried the tape and IR test. After idling it at about 1500 RPM for several minutes. Hopped out and ran the IR. the temperature was pretty even all along the pipe. The tape didn't show a hot spot either.
Went back and tried to run the engine faster. Can't seem to get it much over 1500 Rpm, just tries to stall. shut the engine off and went outside and both the tires were burning pretty good and the grass below and between the tires was pretty scorched. I had a garden hose handy and put it out. There must be something like a flame thrower effect going on. I didn't run the motor for much more than 4 or 5 minutes.
Got any ideas on this one?
Peter

[maple_leaf_eh]

Your rubber tires caught fire? Yikes! Time to strip the exhaust out from the manifold out.

[cletrac (RIP)]

If the motor is running lean it will make the exhaust hot too.

[jeff davis]

If the Timing is to far advanced the exhaust will heat up red

[peter clemmer]

Hi,
I am not sure when I will be able to check some more things out. This is the start of the usually rainy Oregon winter. The Saracen is under a tarp, so I need decent weather to work on it.
Let you know when something comes up.
Thanks so far for all the help.
If someone comes up with something else, let me know.
Peter

[peter clemmer]

Here is photo of the Saracen with the hot exhaust.