[DeTomaso] CHI 4V heads question

Sun May 17 20:04:28 EDT 2020

Larry,

I tried using donut gaskets. They were hopeless. 

The GTS header pipe diameter is large enough that the GTS swaybar whangs it regularly, making a swaybar-shaped dent in each pipe. 

That whanging takes its toll on the donut gaskets and eventually they blow apart, leading to the mother of all exhaust leaks. I had to change one at the track at the Fun Rally one year. I suffered several failures. 

I knew that the system wasn’t designed for donut gaskets but because of the same misalignment you have (except more) I thought it was a superior solution. Eventually I hit on the notion of doubling up on Remflex flat collector gaskets (which are considerably thicker than conventional collector gaskets) and that has worked perfectly for me for many years now. 

You could always try using sintered aluminum donut gaskets, which would have much better resistance to the type of insult they receive than the conventional fiber donut gaskets, but honestly I wouldn’t bother. The header and pipe aren’t configured to work with donut gaskets so exhaust leaks might be ever-present. 

Mike

Sent from my iPad

> On May 17, 2020, at 16:23, Larry Finch via DeTomaso <detomaso at server.detomasolist.com> wrote:
> 
>    Thanks Julian,
> 
>   As usual you introduce valid considerations.
> 
>   The rubber isolators are used and were selected from my collection of
>   about eight and are dimensionally comparable to what I removed.
> 
>   The pedestals are new, but I just checked and they are the same height
>   as the older ones. I've never heard of two different heights but one
>   never knows.
>   There is Line-X bedliner underneath the pedestals with a measured
>   thickness of about .125 inch.  My gut feeling has been this is too
>   small an amount to have such a notable effect, but????,
> 
>   2511 was on a frame alignment machine during repairs but while I am
>   unsure how much attention was paid to the rear of the chassis, I would
>   assume dimensional checks were made and nothing I have observed in the
>   last year points to any chassis deformation. I have not yet had the car
>   in for tire alignment.
> 
>   My second engine builder (don't ask, there was also builder #3)  and I
>   had the opportunity to compare the iron heads to the new aluminum
>   heads. Not knowing the milling history of the iron heads made precise
>   comparison measurements difficult but we both had the impression that
>   the header bolt holes might have been raised a small amount.
> 
>   I did encounter a definite issue when using those heads with the blue
>   thunder Pantera-specific intake, and I know of another owner who used
>   these heads (intake unknown) and encountered the same need for spacers
>   on both the engine block china walls --
> 
>   image1.jpeg
> 
>   So that experience and the gut feeling from the comparison has prompted
>   this query on the CHI heads.
> 
>   I just finished talking with the previously mentioned owner and found
>   his header collector flange to exhaust pipe gasket is the round, fiber
>   donut style. The mechanic who did the wrenching on his installation
>   made no mention of alignment problems similar to what I am finding.
> 
>   So now I am wondering if perhaps there is much more adjustment range
>   with the donut style gaskets? I have no personal experience and would
>   love to hear others' thoughts on this ---
> 
>   Could changing over to the donut style of gasket come with a greater
>   alignment flexibility and overcome and solve my current misalignment
>   issue?
> 
>   Larry
> 
>   Sent from me using a magic, handheld electronic gizmo.
>   On May 17, 2020, at 3:27 PM, Julian Kift <[1]julian_kift at hotmail.com>
>   wrote:
> 
>   Larry,
> 
>   I am almost certain the CHI 4V heads are a standard exhaust port and
>   bolt location. Could anything else have changed during your rebuild
>   e.g. new engine mounts rubbers, thicker head gasket, painted engine bay
>   (below motor mounts) etc.?
> 
>   It may be a dumb question, but assume it was on a chassis alignment
>   rack during collision repairs, perhaps it wasn't straight to start
>   with?
> 
>   I have CHI 4V, C302B and A3 heads here, but no stock iron heads to
>   compare to if I were to measure exhaust header bolt location.
> 
>   Julian
>     __________________________________________________________________
> 
>   From: DeTomaso <[2]detomaso-bounces at server.detomasolist.com> on behalf
>   of Larry Finch via DeTomaso <[3]detomaso at server.detomasolist.com>
>   Sent: Sunday, May 17, 2020 2:51 PM
>   To: Email List Address For Posting
>   <[4]detomaso at server.detomasolist.com>
>   Subject: Re: [DeTomaso] CHI 4V heads question
> 
>   Mike,
>   So your experience with the same heads showed no major header flange to
>   exhaust flange gap, but you apparently chose the Remflex gaskets
>   because they could overcome a ....small.... gap you encountered?
>   I have used their gaskets at both ends of my headers for some years now
>   and this gap is beyond their sealing capabilities.
>   If only this issue ...could... be solved so easily ......
>   Thanks,
>   Larry
>   Sent from me using a magic, handheld electronic gizmo.
>> On May 17, 2020, at 2:00 PM, Mike Drew <[5]MikeLDrew at aol.com> wrote:
>> 
>> Larry,
>> 
>> I wound up using a pair of Remflex gaskets on each side (collector
>   gaskets) for that reason. I think it came about when switched from iron
>   to CHI 4V heads.
>> 
>> That solution worked fine for me.  They have a lot of `crush'
>   capability and can be useful for alleviating such concerns. I also use
>   their header gaskets exclusively.
>> 
>> Mike
>> 
>> Sent from my iPad
>> 
>>> On May 17, 2020, at 13:54, Larry Finch via DeTomaso
>   <[6]detomaso at server.detomasolist.com> wrote:
>>> 
>>> All,
>>> 
>>> This is a question for any owner that has installed the CHI 4V
>   aluminum cylinder heads on a Cleveland in their pantera.
>>> 
>>> During collision repairs I had a 404 ci stroker Cleveland built for
>   2511 and used the CHI 4V heads.
>>> 
>>> I did not change the GTS exhaust pipes/mufflers nor the GTS headers
>   supplied by Dennis.
>>> 
>>> But something has changed and the exhaust pipe will no longer
>   correctly mate with the header flanges. With the mufflers as close to
>   the body as possible, there is a gap at the top of the header flanges
>   of about 3 sixteenths of an inch. Even removing the ZF side mounts and
>   letting the transaxle rest on the rear crossmember, there is still a
>   header flange gap.
>>> 
>>> I'm thinking the exhaust ports on these heads may have a raised
>   header bolt pattern and this is the source of the misalignment.
>>> 
>>> Has anyone else found similar misalignment problems after installing
>   these heads?
>>> 
>>> Thanks,
>>> 
>>> Larry
>>> 
>>> Sent from me using a magic, handheld electronic gizmo.
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> References
> 
>   1. mailto:julian_kift at hotmail.com
>   2. mailto:detomaso-bounces at server.detomasolist.com
>   3. mailto:detomaso at server.detomasolist.com
>   4. mailto:detomaso at server.detomasolist.com
>   5. mailto:MikeLDrew at aol.com
>   6. mailto:detomaso at server.detomasolist.com
>   7. mailto:DeTomaso at server.detomasolist.com
>   8. http://server.detomasolist.com/mailman/listinfo/detomaso
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