[DeTomaso] Head Gasket Holes

Asa Jay Laughton asajay at asajay.com
Wed Jun 16 23:26:20 EDT 2010


What else is different about this engine build that prior builds?
- Any hard block poured in?
- Different compression ratio?
- Different Pistons?
- Manifold?
- Carb?
- Heads?

Asa Jay Laughton, MSgt, USAFR, Retired
&  Shelley Marie
Spokane, WA
******************************
http://www.racingagainstautism.com
http://www.teampanteraracing.com


On 6/16/2010 20:19, Tony DiGiovanna wrote:
> Thanks.  All good thinking.
> Yeah, I've been thru it all already.
> Checked the alignment of pump to plate to block.  It's a brand new timing
> cover from Summit, by the way.
> Edelbrock Victor Series Water Pump.
> The thermostat bypass hole is permanently plugged.
> Alluminum radiator.
> Dual pusher fans.
> And, all of this is the same as the 4 previous engines.
> Water flow is visually normal in the swirl tank, so I do not believe I have
> lower-than-normal water flow.
> The gauge temp is confirmed.
> Pure water with no cap boils at an indicated 210.
> Pressurized water boils at about 235 indicated.
> I am certain that it warms up a lot faster than previous engines too.
> I can run antifreeze and avoid boiling, but I still want the temp down.  It
> runs better at 190 than 230.  Everything points to the cooling system being
> ok.  This engine is just dumping more heat into the water.  I'm just looking
> to improve the situation for the summer, until I get my stroker finished and
> in.
> So...I am going to try to get more water flow.
>
> -----Original Message-----
> From: Charles Engles [mailto:cengles at cox.net]
> Sent: Wednesday, June 16, 2010 10:39 PM
> To: 'Tony DiGiovanna'
> Cc: detomaso at realbig.com
> Subject: RE: [DeTomaso] Head Gasket Holes
>
> Dear Tony,
>
>
>         One other place to look for a hidden restriction is the front engine
> plate.   I have a collection of, umm, six or seven plates.    Four or five
> are loose in the parts warehouse.  Someone smarter and more observant than
> me told me that there were *two* versions of the engine plate.   I looked at
> mine and he was right.  One of the plates had openings for the water pump
> that were bigger than the other plates.  Apparently, there were two
> stampings.  One stamping has a terrible mismatch for the size of the plate
> opening with the engine block and with the pump.  The other stamping has
> much more modest restrictions.  I was shown that if you then take a FelPro
> water pump gasket and add it's fitment to the block,plate and pump opening
> mismatches, then it can add further impedance to flow.
>
>        Consequently, as you are trying to rationally sort out your hot engine
> and you're not finding any obvious source, then you might consider the
> "heart" of the cooling system: the triad of the front of the block, the
> front engine plate and pump (and the gasket).  I would think that coolant
> flow is impeded in an average 351C and could be optimized with attention to
> these physical mismatches.  In particularly bad cases where everything is
> especially mismatched with others, then flow might be bad enough for a hot
> engine with no easy answer in the usual places.  I don't know that, but I
> think it is possible.
>
>         I will attach secret photos visible only to you (as the list strips
> attachments).  See what you think.
>
>
>               Your fellow engine builder,  Chuck Engles
>
>
>
>
>
> -----Original Message-----
> From: Tony DiGiovanna [mailto:tonydigi at optonline.net]
> Sent: Wednesday, June 16, 2010 8:38 PM
> To: wkooiman at earthlink.net; 'Tomas Gunnarsson'; detomaso at realbig.com;
> 'Charles Engles'
> Subject: RE: [DeTomaso] Head Gasket Holes
>
> Here is why I raise the question, and here is what I think:
> I have an engine that runs 230 deg F in my Pantera, when all of my previous
> engines ran 190.
> It ran hotter before I removed the perfectly functional thermostat.  It ran
> hotter before I had the radiator cleaned.  It ran hotter before I flushed
> the block out backwards.  This engine just runs hotter.  Everything else
> checks out OK.  If there is an issue, it is not an easy one to find/correct.
> I'd like to bring the temp down.
>
> Water always flows by pressure differential, so I think all the holes flow
> some from the block into the head.  I think the holes are sized to be the
> controlling orifice of the system; 1) to ensure positive delta-P along the
> entire head (like a pull-up resister for you EEs) so flow is ensured in one
> direction.  2) to ensure some fresh flow along the middle and front of the
> head.  Otherwise, the rear cylinders would always be colder and the front
> hotter.
>
> However, I think the sizing is based on factory engineering or experience
> with the stock 260HP engine and component.  I think the old additional
> "steam hole" revision was actually just an increase in water flow.  Not sure
> what steam has to do with it.  The system isn't in steam phase unless it's
> already boiling - too late.
>
> I'm thinking the flow thru entire engine could be increased by increasing
> all the holes by a fixed percentage of area and result in a decrease in my
> water temperature, maybe.
>
> I'm probably going to try it.  I'll post results.
>
> -----Original Message-----
> From: detomaso-bounces at realbig.com [mailto:detomaso-bounces at realbig.com] On
> Behalf Of wkooiman at earthlink.net
> Sent: Tuesday, June 15, 2010 9:13 PM
> To: Tomas Gunnarsson; detomaso at realbig.com
> Subject: Re: [DeTomaso] Head Gasket Holes
>
> Don't make the tiny holes bigger.  They are steam holes.
>
> The water enters both sides of the block by the water pump.  It travels to
> the back, and enters the heads.  It flows through the heads and back to the
> front.  It re-enters the block, then to the thermostat in the block, and to
> the water bottles.
>
> If you make the steam holes larger, too much water will flow from the middle
> of the block to the heads.  I don't know if it would happen, but I'd bet it
> would cause the head to run hot near the rear of the block.
>
> If you make the large hole near the front of the block larger, it should
> make the water flow faster - assuming the hole is a restriction.  My guess
> is the restriction is the thermostat housing, though, so if you make the the
> large holes larger, it shouldn't do anything.
>
> I wouldn't mess with any of the holes in the head gasket.  They are a
> specific size for a reason.
>
> -----Original Message-----
>    
>> From: Tomas Gunnarsson<guson at home.se>
>> Sent: Jun 15, 2010 3:32 PM
>> To: detomaso at realbig.com
>> Subject: Re: [DeTomaso] Head Gasket Holes
>>
>> Which holes are you talking about? All or only selected holes?
>>
>> Tomas
>>
>> -----Original Message-----
>> From: detomaso-bounces at realbig.com
>> [mailto:detomaso-bounces at realbig.com]On Behalf Of Tony DiGiovanna
>> Sent: den 14 juni 2010 23:59
>> To: detomaso at realbig.com
>> Subject: [DeTomaso] Head Gasket Holes
>>
>>
>> So..what happens if you make the water passage holes in the head
>> gaskets bigger?
>>
>>
>>
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