over heating issues during break in

[j.rigby15r]

So here is were I am at. I just rebuilt a sbc 350 in my 64 c10. It has a small rv cam, edelbrock intake and carb, clutch fan, no shroud, and the stock 3 core 25"x17" radiator. My buddy and I were starting to break in my cam and motor and had to shut it down because the radiator cap started spewing coolant, ( I forgot to put the new one on). It was about 230-240 in temp after about 10 min of run time. it was about 65-70 degrees outside. we let it cool for about an hour and got a better temp gauge. After letting it cool we started it up again and after about 5 min it was back up to aprox 240 so we shut it back down. It dieseled a bit after killing it. I am trying to find a fan shroud, most of which I can find are $150 plus. Any recommendations on a fan? I've been looking at these

http://www.summitracing.com/parts/opg-ch26693/overview/

http://www.classicindustries.com/pro...ts/z40020.html

Any thoughts on fan shrouds or on heating issues, as well as breaking in issues.

[siggyfreud]

Well when breaking it in you're running at road speed rpm without the airflow associated with actually moving. Use some space fans to push air through the radiator.

A shroud would definitely help too. Make sure your timing is right as that can lead to overheating if it's too lean.

You might also have air pockets in the cooling system as well. Might consider keeping the cap off to displace air during the start of the break in process.

[65c10restomod]

check your thermostat

[j.rigby15r]

Thermostat was working. Using a laser temp gauge we could tell it was opening.

[65c10restomod]

when you say you could tell it was opening was it because you had same temp on the incoming hose and the outgoing hose?

[j.rigby15r]

Yes.

[65c10restomod]

has the engine been bored over?

[j.rigby15r]

.060

[65c10restomod]

try an electric fan or a spacer to get the clutch fan closer to the radiator

[j.rigby15r]

That's one of the things I'm thinking. I first want to get a fan shroud but don't want to pay a lot of money.

[65c10restomod]

make a simple test fan shroud out some thin sheet metal from a hardware store

[pimpston65]

Originally Posted by j.rigby15r

That's one of the things I'm thinking. I first want to get a fan shroud but don't want to pay a lot of money.

if your going original looking i have a V-8 style fan shroud that you can have free, its got a crack at the bottom, but can be repaired with fiberglass. pay for shipping. if non oem look run electric fans, also u may wanna ck into a 180degree thremostat it opens sooner to aid in cooling faster, also ck for air pockets in the cooling system as another member stated!!! oh and try a clutch fan...

[pimpston65]

Originally Posted by 65c10restomod

make a simple test fan shroud out some thin sheet metal from a hardware store

i've seen engine builders use cardboard as a temp shroud, works great and cheap!!!

[66Gilbert]

Is this the same radiator that was in the truck before you rebuilt the engine? It is good practice to have it rodded out, re-cored or replaced when installing a rebuilt or new engine. It is to expensive to rebuild or replace an engine with new to take a chance on a radiator that has not had something done to it. Bored .060 over and most everything new with tighter tolerances it is going to run hotter than before and need extra cooling capacity or a radiator working at 100% cooling capacity. A shroud would help but what siggyfreud said place some fans or even a portable swap cooler in front of the radiator during break in will help significantly.

[j.rigby15r]

Yes it is the same radiator but different motor. It had a 305. I'll have to try the cardboard shroud with a fan and it's cold here so hopefully next time I'll be okay.

[63burban]

Make sure you don't have an air pocket in the cooling system. Then set a box fan on high on a chair in front of the radiator.

[brokenspoke]

Its a timing issue....

[j.rigby15r]

Originally Posted by brokenspoke

Its a timing issue....

Why do you say that. The distributor was dropped in at aprox 12 before tdc and my chain is lined up.

[65 C20]

Originally Posted by pimpston65

if your going original looking i have a V-8 style fan shroud that you can have free, its got a crack at the bottom, but can be repaired with fiberglass. pay for shipping. if non oem look run electric fans, also u may wanna ck into a 180degree thremostat it opens sooner to aid in cooling faster, also ck for air pockets in the cooling system as another member stated!!! oh and try a clutch fan...

That is a very nice jesture.
He is low on dollars and you stepped up and offered it for free.
He may have other issues but will still need the shroud.
Cal.

[PGSigns]

Well if you have not put a timing light on it you can only assume what the timing is. I am making the assumption you are breaking in the lifters and seating the rings. Motor needs to run at 1800 or so for about a half an hour. Before doing it again put a new 160 degree thermostat in it and fill it back up with water. Start it up with out the cap on the radiator and see if the level drops and top it off. Put the cap back on and set the timing. Run up the rpm and let it sit. Put a good fan in front of it. watch the temp.
Jimmy

[61K10]

I always fill the block up then put the t/stat in then fill the rad. so no air pockets

[pimpston65]

Originally Posted by 65 C20

That is a very nice jesture.
He is low on dollars and you stepped up and offered it for free.
He may have other issues but will still need the shroud.
Cal.

i figure i have a crap load of parts that are nice and wont be using, so why not give it up. this forum is worth more then a part and the networking has paid me in spades...

[j.rigby15r]

Originally Posted by pimpston65

i figure i have a crap load of parts that are nice and wont be using, so why not give it up. this forum is worth more then a part and the networking has paid me in spades...

Message me with some pictures please, as well as contact info. And a price. That is very nice of you. Also if you have more stuff you want to get rid of let me know.

[TJ's Chevy]

A newly rebuilt engine will run hotter then normal...that is why it is recommended to do the break in at a cooler time of day, outdoors, and with plenty of cooling supplies...not only the radiator and fan, but also shop fans placed around the engine to aid in cooling. Its alot on a new engine to run at 2000 rom for 20 minutes...and be careful at how many times you turn the engine on and off during break in because your cam could go flat.

[Heater63]

^^^ All good info up there. TJ and PGsigns are right, as your rings are sealing the first hour it will be hot. Retarded timing will make it run hot. During breakin, 240 degrees is nothing to be afraid of. But check your timing immediately, use a big fan for lots of air, and if your using flat lifters make sure you have a break in ZnPh additive in the oil. After 30 minutes at 2000 rpm you should be good and temps should be normal on later run periods IF timing, mixture, etc are correct and cooling system is at full correct operation.