Out with the 318, hello 360 engine!
After a slow build and tedious installation into the small engine bay of the Dodge Dart, the 360ci engine has finally found its way into the car.
Had my first long drive today with the engine, and just so happened it was a warm day here (25°C / 77°F), so this was also a good test for pinging but I didn’t notice any during the trip. But I didn’t really let the engine work hard yet. Some short 3/4 throttle sprints at most.
As a precaution I took some 4° out of the max. timing, topping at 28° advance @ 2800rpm (compared to 32° with the previous low cr 318 engine).
Maybe that AirGap intake with its blocked heatriser works nicely after all at keeping the charge cool 🙂
However I’m still dealing with some idle issues however where the vacuum needle is fluctuating rapidly between 19 and 21″. This usually points to a problem with the valves.
As I converted the hydraulic lifters to solids (on a hydraulic CompCams XE256 cam) I suspected a too tight lash eventhough I reset the lash twice on the engine stand to a tight .003″. Rechecked the valves today while it’s quite a bit warmer. Found some a tiny bit too tight but even after relashing them to .004-5″ the issue still remained. Maybe I should up the lash to .006″ but I don’t the lifters to ‘overshoot’ the initial ramp in the cam lobes.
When the engine is warmed up to 160-180°F the vacuum fluctuation at idle widens to 18-22″. The needle does smooth out at higher revs however.
With iron heads and block, the lash should grow slightly with rising engine temps. I plan to check lash with a hot engine to make sure and then do a compression test if needed also.
The heads were rebuilt with bronze guides, seats refreshed, new exhaust valves. Backcut intake valves, 1.6:1 rockers.
Before installing the heads, I ‘leak’ tested them by spraying some brakecleaner in all the ports and found it took some 20 seconds or more before just a very thin wet line appeared on the chamber side at the valve heads.
Did notice during the trip that the engine temps are higher at idle than with the 318, but that might also be because of the valve/vacuum issue where the engine isn’t running that well now.
In any case a ‘working’ viscous-thermo fan is needed, as the one currently installed is just freewheeling along with the engine, just like it has done for years with the 318ci engine.