I am finding pressure buildup in radiator . Burps past radiator cap . Sounds
ugly . Flushed out cooling system, replaced head gaskets, intake gskts . Put a
new rebuilt water pump on . Used a cooling system pressure pump and pressureized the radiator overnight . Next day with spark plugs removed spun
engine over and nothing out plug holes but did loose all pressure . No external
water leaks noticed with pressure pump . A fello told me that 360s can crack
internally and the oil pressure can work into the cooling system . This is my
second engine that did this . Never lost coolant and doesnt overheat . Always
checked prestone before cold weather set in . This is a 360 with 390 crank,
rods and pistons . This also happened on my first 360 that was all origional
except for intake manifold switch .
ANYONE else suffer this headach ???

 

Yes, I am willing to bet that your FE has a mirror image 105 on the drivers side front of the engine. You can fix this by sleeving the galley with a pushrod from another engine but I can't remember which it is. Someone else should know.

 

Ford 300CI six. Unless you have engine oil in the coolant I'd look elsewhere for the leak. Try taking the intake manifold heater hose off, stick it in the top of the radiator and cycle the thermostat. This should remove all the air in the block. Engine running at id;le, normal operating temp, look in the radiator for bubbles (head gasket).

 

I am sure now its engine oil . I ran the truck 40 miles so there is no air left in system.

 

Cracked oil gallery is a fairly uncommon problem. Are there any parts this engine shared with the previous engine with a similiar problem? The block and bore for 360 and 390 are virtually identical. The crack develops in the long oil gallery that feeds the heads. The cure is to overbore the block gallery and insert a sleeve made from a 300CI pushrod. Some machine shops do this mod as a precautionary repair on all FE blocks. Ogain, unless you clearly have oil in the coolant, I'd look elsewhere for the leak. IMHO!

 

Nope . The two engines never saw parts from each other . Have a high
pressure oil pump in the one causing trouble besides so that adds to more
oil in cooling system . I am going to check with a machine shop to see
how much $$$ they charge for this repair .
I wish i had done this oil gallery sleeve thing a while back . It should be
done anytime work is done with the block . Will save you a headach down the
road later !
WHAT the heck causes this in the first place ???

 

Yah I had the problem with oil going into the coolant. WHAT A MESS!!!
The place that fixed it had a sheet from somewhere that showed that they drilled this hole to deep on some FE engines causing a weak spot at the bottom of the oil gallery and it will crack over time.

 

I am thinking of a engine swap now,,, to a 400. Maybe .

 

I'd stick with FE motors, you already own all the parts. Get another block and do the oil mods and sleeve the block to head gallery and move your parts. Set of gaskets, bearings and rings should be about all you need, These blocks are a dime a dozen around here and who knows you might get lucky and find a good 390 crank and rods you could sell to help defray the costs!

 

I asked a machinist about sleeving oil galleries . He now does sleeving if it needs it
or not , both sides I believe. $ 80.00 for the oil galleries alone, plus cooking the block
plus new cam bearings plus honing cylinder walls for new rings ,,,, humm these pluses
are adding up .
I already had installed a crank and rods from a 390 junker . problem was with 390
pistons gave more compression and it pinged while towing so I compensated with
timing adjustment .

 

use pistons from a mercury 410 to drop cr to about 8.5:1.

 

Those pistons sound rare ,,,Iwill have to look to see if i can locate a set ,,,, maybe
from one of the vendors on this web page ??? Dont remember seeing 410s much .
Thanks .

 

what about 360 pistons ?? do they lower the compression yet more ???
anyone know what the compression ratio is for 360 pistons vs. 410s ??

 

You might call summit they have a set of pistons labeled "truck only" These are probly low compression pistons.

 

Silvolite 1130's work well in a truck 390.