I installed a 302 in my 55 ford I am having trouble with it overheating, i
have a new waterpump hoses tried many different thermostats and put electric
fan on for extra air cooling. nothing is helping engine get up to 240-250.
could it be my manifold being plugged somewhere? it is also new but i
thought maybe silicone is blocking a port or something like that. It is in
good time and runs smooth. please help if have any suggestions.
First, do you know for sure that the guage is correct? Have
you subbed in a mechanical guage or other known guage? Many
shops have a temperature guage that can check it w/o
touching it. This can be used to find hot areas or even a
If you have confirmed that it is really hot, and you have
done the regular checks like a new thermostat and a correct
pressure cap, it is time to look at the basic setup.
Do you have a shroud for the fan with the fan properly
positioned about 1/3 into the shroud. Is the fan clutch
operating as it should? Do you have the correct fan clutch
installed? There are 2 basic types. On is strictly
tempreature limiting in which case it only operates when the
air tempreature it sees is too hot. This may not be good
enough. The other is more expensive and is torque limiting
where it senses temperature for full engagement but, pulls
air all the time. It locks on high temperature but pretty
much unloads at higher speeds. Is the clutch even operating
as it should? Do you have the correct fan installed for the
direction it turns? The air should blow front to rear with
the engine running. Wouldn't be the first time this
happened on an engine swap.
Another area to look at is the water pump itself. There is
both the early model normal rotation and the late model
reverse rotation which is used with the serpentine belts.
If you are using regular V belts, you must use the early
Is the radiator setup in a way that would create or allow
air pockets in the engine? An air pocket in the water pump
may prevent proper circulation. How many coats of paint are
on the radiator? Some folks go a bit overboard when
resto'in a car.
Is your ignition timing correct and, is the advance system
working as it should. A frozen advance or incorrectly set
timing can result in bigtime overheating along in poor
performance and fuel economy.
How about your fuel system? Could it be running lean or
rich? A rich fuel mix generally will not cause an overheat
condition but, too lean could cause problems. The carb may
be fine a certain speed ranges while being completely out of
whack at others. Does the overheating occur only at certain
speeds/loads? If this is setup as a performance engine, it
will be more sensitive to this and may require recal of the
Is the engine freshly built? If so, are all of the
components like the heads, cam and intake compatible units?
Another area to look at is gasket compatiblilty and
installation. This is particularly true of head and intake
gaskets. Common mistakes include wrong gaskets or wrong
orientation of head and intake gaskets. Make sure the water
passages line up properly before installing any gasket.
Don't forget that many times, a gasket will cover a passage
intentionally to make sure water flows the correct direction
in the engine. If there is an open hole that should not be
open, water may bypass a hot area of the engine.
Another problem area is the camshaft and it's
installation/breakin. The cam timing can be a problem
especially if it is late timed. Some cams are not properly
marked by the manufacturer. I always check a new cam for
proper lobe center and timing with a degree wheel and dial
indicator when installed. Each lobe should be checked. I
have seen a couple of cases where a single lobe was not
correct - this is not likely with todays computer-ground
cams. They are sometimes off a few degrees regardless of
manufacturer. If it is off a degree or two, it can be
corrected easily with a multi-keyed crank sprocket or offset
cam key. Otherwise, get the cam replaced with a good cam.
One of the biggest problems with cams is lack of proper
breakin to prevent the lobes "going flat". This must be
done correctly the very first time the engine is fired after
a rebuild with new cam and lifters. There must be proper
breakin lube on the cam and lifters and, the engine must be
fired and run between 1500-2000 rpm with the speed varying
for at least the first 20 minutes or so of engine operation.
This is the time period where most cam failures begin even
though the failure may not become apparent for a few
thousand miles afterward. You must start it with a proper
viscosity oil that would normally be recommended for the
engine/climate/operating conditions. The reason for the
breakin procedure is that the cam lobes are lubed by
throwoff from the crank bearings - you need this RPM to
maximize oil throwoff to the cam area. Many camshafts fail
or go flat very quickly if this is not done. If you are
concerned about starting the engine above idle because of
dry crank bearings, get a long 1/4" drive extension with a
5/16" socket. Tape them together and put it in your 3/8 or
1/2 drill turning the same way the distributor would and
prelube/prime the sucker thru the distributor hole. You
should do this on any dry rebuilt engine anyway. If you
want to go first class on the tool, buy the priming adapter
from Summitt or Jeg's. Years ago, I fought with my 351C for
a long time before I gave in the the idea that the cam had
gone flat like a new Volvo boat engine had done before that.
Both engines came back to life after replacing the cam and
lifters and breaking in properly with no more overheating
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