[DeTomaso] head drilling for air release
Asa Jay Laughton
asajay at asajay.com
Wed Sep 2 22:02:12 EDT 2009
Tony,
All good questions, see responses in-line:
Tony DiGiovanna wrote:
> Asa,
> Here's some more crazy things to check (been to all of them):
> Is the thermostat right-side up?
>
Yes most definitely.
> Is the thermostat opening? I usually run without one anyway. That's not a
> bad place to start.
>
This is the point most agree needs to be checked. I'll boil it when I
get it out.
> Is there an un-supported length of hose on the inlet side of the water pump
> that is sucking closed?
>
Nope, it's all Green Stripe, extremely short lengths.
> I once had a hose where the inner half separated from the outer half and the
> inner half collapsed shut even though there was one of those helical spring
> supports in it. It looked and felt fine from the outside (cost me an engine
> it did.)
> You gotta watch new water pumps: There's a crapload of potential mfg errors
> that can affect you, e.g. impellers designed for the opposite rotation. I
> once bought two waterpumps of the same mfr and PN. The impeller design was
> a bit different between them, enough so that one overheated at idle and the
> other did not.
>
I thought about this on the way home. I'll compare the impeller photo
on my Flow Kooler to the photo John Taphorn sent me.
> Try disconnecting the water pipes at the front of the cockpit and use a
> garden hose to flow water backwards thru the radiator. Sometimes you can
> expel crap that gets caught in the tube entrances. Once, at a track event,
> I reversed the lines to reverse the flow in the radiator. Overheating went
> away. I didn't even miss a session.
>
A decent idea, but I know all the lines are brand new with no crap and
the radiator was flushed prior to putting it back in. I have a TEFBA
filter on the outlet side of the engine, hoping to catch the crap as it
exits and before it makes its way to any other parts. I checked it last
night and it was clean as a whistle.
> Not sure why, but when I fill my coolant system, I always have some air that
> bleeds out of the petcocks in the back of my heads. Not sure if it really
> is an issue, but it is there.
I don't doubt this due to the engine orientation. You would probably
get some out the front as well, since the coolant has to go -down- back
into the block before it can exit. I honestly don't think an excess of
air was my problem. Flow was the problem.
I appreciate you sharing, they are all very good points to check. Thank
you,
Asa Jay
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