351c overheating

[Castiron355]

Hey People,
I have just built a 351c. I usually dabble with chev and holden and the clevos are new to me.
While I was running the cam in it started to get pretty hot. No thermostat for the run in and a new radiator.
My question is and while I paid particular attention to it. Can the head gaskets only fit one way. Or can you reverse them and unblock a water gallery or something?
I have also plugged the heater hose outlets at the water pump and block. Should these have been bridged instead.
Cheers


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[Gregaust]

The head gaskets can go backwards . You can see with the heads on though if they are right. If you look at a gaskets the front corners of the gasket are more squared off than the rear , so you can see the gasket protruding at the front corner if it is correct.

Plugging those heater outlets really won't cause overheating.

[GOLIATH]

From memory the gaskets are one way, foolproof.


Stock cooling is way more than adequate on most applications.
You only need 2 things.
1. water flow = lift the cap and see or feel different areas.
2. More importantly you need *AIRFLOW*.

Most times anyone says new radiator and still overheating! = Its a 'missing or poor shroud' (it is the most overlooked).

Any good Electric or mechanical fan should MOVE some serious big air - not just go round and round. Shroud that sucker so it's sucks like a black hole.
Engine warm and running, then much hot air should be blasting out the back of the fan.
Fan should be hiding into shroud 2/3rds deep with under an inch clearance to blade tip.

No shroud = no cooling.


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[Castiron355]

Okay no worries. It’s in a Ftruck. No shroud and the steel 4 blade fan.
Only reason I didn’t shroud etc is it always ran this way in the past.
I’ll get a temp gauge on it, thermostat and reassess when I drive it.
Thanks guys. I just thought I heard something about head gaskets. Maybe it’s the 400M or something.


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[46Crab]

Okay no worries. It’s in a Ftruck. No shroud and the steel 4 blade fan.
Only reason I didn’t shroud etc is it always ran this way in the past.
I’ll get a temp gauge on it, thermostat and reassess when I drive it.
Thanks guys. I just thought I heard something about head gaskets. Maybe it’s the 400M or something.


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Thin Clevo bores?
Timing ok?

[Castiron355]

Thin Clevo bores?
Timing ok?

Sill standard bore. Timing was 30 at 2200 during run in.


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[hq308]

I'm not big on Clevos either but I vaguely remember there is something about them needing to run a thermostat. If I remember correctly the thermostat blocks the bypass when open and without it too much coolant bypasses the radiator. I believe there is a Cleveland specific thermostat for the job as a regular thermostat won't work unless you block the bypass?

[46Crab]

Sill standard bore. Timing was 30 at 2200 during run in.


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Roger. Maybe it really needs the thermostat even for that run in period. I’m sure you have checked the many variables etc but I’d throw the thermostat in and go again.
Radiator Hoses aren’t sucking in flat?

[Castiron355]

Roger. Maybe it really needs the thermostat even for that run in period. I’m sure you have checked the many variables etc but I’d throw the thermostat in and go again.
Radiator Hoses aren’t sucking in flat?

No hoses are fine. Yeah I’m thinking thermostat to slow the flow a bit. Give the radiator a chance to do it’s job.


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[46Crab]

No hoses are fine. Yeah I’m thinking thermostat to slow the flow a bit. Give the radiator a chance to do it’s job.


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[LXCHEV]

Just another item to consider is the water pump itself (flowing efficiently and not cavitating water). Even brand new water pumps can have issues if the clearance from the body to the impellor is not correct. I wouldn't think this would be super common, but if you exhaust all other options and get desperate - it's something to look at. Apparently this was quite common on Holden pumps and I know my engine builder/dyno tuner was always in the habit of checking clearances for SBC pumps too.

[GtoGeoff]

If it has new pistons, rings rebore etc, you would expect it run a little hot from the extra friction of new parts getting to know each other....

[GOLIATH]

If not shrouded it will overheat - unless moving.

An unshrouded fan does NOTHING! it's just a decoration & complete waste of energy.

Let us know when you get it sorted.

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[Castiron355]

Problem found. Cracked head. Yay...


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