FWP
CRS
Carb'd 350, ran around 180-190 with the stock manifolds. Put on Thorley tri-Y headers and new exhaust yesterday. Going down the freeway it's up around 220, cools off to 190 at idle. Suggestions?
CK5
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Running hot after header install?
- Thread starter FWP
- Start date
Make sure your carb is tuned properly?
Running lean (which should be the case now) is the only thing that could reasonably be associated with a header swap and running hot while cruising, assuming nothing else got messed up, or failed coincidentally when the headers were installed.
Even then, running cool at idle but hot at cruise after a header swap really seems to point towards a fueling issue, and not a radiator, cap, thermostat, sending unit, etc. problem.
Running lean (which should be the case now) is the only thing that could reasonably be associated with a header swap and running hot while cruising, assuming nothing else got messed up, or failed coincidentally when the headers were installed.
Even then, running cool at idle but hot at cruise after a header swap really seems to point towards a fueling issue, and not a radiator, cap, thermostat, sending unit, etc. problem.
FWP
CRS
Thank you Dorian, You are one of the guys on here I pay attention to, I appreciate your input.
I thought the same thing, even went so far as to shoot the motor with an IR gun to make sure it was real feedback. It was real so...
Upped the jet size to a 71 and will test tomorrow...Hotrod Baby
Will post the results.............
I thought the same thing, even went so far as to shoot the motor with an IR gun to make sure it was real feedback. It was real so...
Upped the jet size to a 71 and will test tomorrow...Hotrod Baby
Will post the results.............
FWP
CRS
Oh, BTW, I'm at 5200 ft Elevation, Have to tune for both High altitude and low desert wheelin and try to find a happy median.
be a good time to throw a brand new set of plugs in and do some plug readings to help verify too...
You are welcome. I induced a lean condition on my truck by removing the EGR (back when it was carbed) and not re-jetting the carb. Without O2 feedback, a carb has no way of correcting for the increased airflow headers tend to create on the SBC, so it's up to the operator.
I hope it's a simple fix for you! As much as a hassle as it would be, would be interesting to use an O2 sensor to measure the differences between jets.
I hope it's a simple fix for you! As much as a hassle as it would be, would be interesting to use an O2 sensor to measure the differences between jets.
FWP
CRS
Re-jetted- temps back to normal- yeah!
BTW- this motor is new, less than 500 miles.
BTW- this motor is new, less than 500 miles.
Any noticeable change in power?
Glad that worked for you!
Glad that worked for you!
FWP
CRS
A bit more power, but I have the original stock air cleaner on. I may put a K&N on in the summer and put the stock back on in the winter. With the stock Thermac on will help to warm the intake/ fuel up a bit faster in the cold- It's 10-30 degrees here in the winter.
Always a good idea. I have one of those colortune setups that replaces a sparkplug and lets you know how the engine is running. Not as precise as a wideband O2, but it lets you see if you are running lean, rich, or stoichiometric. For 50 bucks its an easy to use tool that can help you tune or track down problems, and has the advantage of being able to test individual cylinders.
