[DeTomaso] Head Gasket Holes

Thomas Tornblom Thomas.Tornblom at hax.se
Thu Jun 17 01:51:30 EDT 2010


It's been asked before, but I've seen no answer to it: are you sure you 
installed the head gaskets in the right direction? They are marked which 
way should be at the front, and the difference is that the water holes 
are sized to provide equal flow between block and head both at the front 
and at the back. If you install the gaskets backwards you will not get 
enough flow in the back of the engine and it will overheat.

Have you verified timing, not just at the balancer if it is a stock 
balancer?

Thomas


2010-06-17 05:19, Tony DiGiovanna skrev:
> 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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-- 
Real life:   Thomas Törnblom             Email:  Thomas.Tornblom at Hax.SE
Snail mail:  Banvallsvägen 14            Phone:    +46 18 32 31 18
              S - 754 40 Uppsala, Sweden  Cellular: +46 70 261 1372




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