[Fot] Intake / Exhaust manifold mating surfaces to head---THANKS

[John Styduhar]

The latest model of  bare TR2-4 cylinder heads with casting 11695 and 1 1/2
intake ports at the face (cleaned and manafluxed) are available from Team
Triumph in Warren, OH.  Give Scott Harper a call at 303-392-7176.

On Thu, Oct 9, 2014 at 3:57 PM, Tony Drews <tony at tonydrews.com> wrote:

> A little more on port matching - what Jack found working on the flow bench
> is that if you open up the intake runner ID too quickly you kill the flow
> through the manifold.  The air delaminates from the surface and becomes
> turbulent.  You need to keep the change in ID to under 7 degrees of taper.
> Also, look at the port in the head - some of them had a ball mill shoved in
> for a short distance and the inner port diameter is much smaller.  In that
> case you may be better off adding epoxy to the port in the head to make it
> more of a straight shot.
>
> He also found that a step from smaller diameter to larger diameter in the
> direction of flow wasn't very harmful to overall flow.
> http://www.tonydrews.com/uncle_jacks_engine_building_tips.htm#Head
>
> Tony Drews
>
>
> At 04:06 PM 10/8/2014, John Styduhar wrote:
>
>> You should read what Kas has to say in his prep manual..  He recommends
>> port matching.
>>
>> On Wed, Oct 8, 2014 at 3:57 PM, Dan Cronin <adcronin at mi.rr.com> wrote:
>>
>> > 10/8
>> > Thanks to all who took the time to read my query and respond.  Very
>> > interesting variety of thought on wether or not matching the ports is a
>> big
>> > deal --- or not (as long as the gas / exhaust flows from smaller to
>> larger
>> > bores).
>> > Dan
>> >
>> > On Oct 7, 2014, at 3:46 PM, Dan <adcronin at gmail.com> wrote:
>> >
>> > I am preparing my TR4a head to accept the intake and exhaust manifolds
>> and
>> > there seems to be a rather significant difference in the diameters
>> between
>> > the
>> > intake ports of the head (1-1/2" dia.) and the intake manifold (1-3/8 to
>> > 1-7/16" dia.). In addition, the two mating gaskets I measured come in
>> with
>> > a
>> > dia. of 1-23/32nd, just under 1-3/4".  The literature I have consulted
>> > recommends that the intake ports of the head and the manifold match up
>> > perfectly including the dia. of the mating gaskets.  Not so critical on
>> the
>> > exhaust  as a "notch" to the upside on the exhaust port apparently aids
>> in
>> > extracting gases.  What have you all found in your engine building
>> > experiences?  I could carefully enlarge the intake ports to match the
>> head,
>> > but the remaining intake  (TR4a long runner) shell would need to be a
>> > opened
>> > up around 7/32nds thereby perhaps weakening the runners?  Thoughts?