1992 964 Engine rebuild - reasonable approach?

[Sboxin]

Originally Posted by J Richard

Roy, looking forward to seeing it full throttle at chuckwalla!
What was the ultimate difference from the first pull to the last? Wondering what the improvement was. Yea that blip looks familiar, I've always wondered if the opening could be adjusted or what the curve would look like if the flap was just held open.

Nice!

We started at 258/234 -- but the A/F was up and down during the runs.
Once Sergio got the throttle cable adjusted Steve went to work to stabilize the A/F across
all RPMs - this is tedious but he is very patient.

I know we talked before about holding that flap open all the time but forgot to mention it
when we were doing the dyno tuning. I need to write more things down on paper...oh well,
there will always be a next time...

The final answer will be Brian's "butt dyno" along with lap times and Traqmate data.

Take care,

[Sboxin]

Added video for Cold Start Idle with Steve Wong chip on modified
1992 Porsche 964 engine with light weight Patrick flywheel and no
front damper, race headers with single out exhaust...


VID 20121125 00004 - YouTube

Regards,

[Sboxin]

Well.........latest report on engine after running hard at weekend track event

Two things:

1) When the valve rocker arms were removed for oil leak sealing pitting was found;
they need to be reconditioned
Note: this was about the only part not refreshed or replaced

2) We need more cooling (as several had mentioned earlier- we were just waiting
to see how much more we needed) as temps went to 250F when engine was pressed
to 7K RPM during race conditions - it would cool back to 210F when shifting at 6200.
Two front fender coolers will be added to the 26" front center cooler.

My son is happy with the new engine and the increase in power...


Regards,

[CaptainCalf]

Nice work & enjoy!

[kandhmfg]

Hey, wait a minute. What's that white car in the picture trying to keep up! Great photo actually of the UPS car at Chuckwalla.

Good to see you the other night. Can't wait to see what the car will REALLY do when Brian opens it up.

Happy Holidays to you and the family.

Erik

[J Richard]

That is a cool pic of you guys. I had a weird nightmare of showing up at the track and you were in a 79 oldsmobile and Brian swapped the UPS car for a Buick leSaber...must of been something I ate!

Happy holidays!

[kandhmfg]

Something like this...

[Sboxin]

Auuugh -- no more Lemons -- I'm blinded!!!

Erik -- that was the only time you were behind the UPS - congrats on the Sunday race!
The car will be ready to race again in January at Firebird...
Happy Holidays and see you all at Rock Bottom Brewery in the New Year!

[Sboxin]

An update on our 964 engine rebuild:

-- pitting was found on rocker arm surfaces during shaft sealing process --
valve rocker arms were reconditioned by Webcams with new rocker arm shafts
installed and sealed by shop Don Jackson Enterprises, Phoenix (we should have
done this earlier when the engine was apart - but the rockers were all smooth
except one that was replaced with new ). Maybe others will benefit from our
experience.

-- Oil coolers added - one in each fender plus new/replaced front custom built
cooler -The side coolers are from Pelican (not OEM) - Steve W advised to watch oil temps
and we took his advice -- big thanks to Steve.

Big thanks to Roland at Jackson's for the oil cooler installation and rocker shaft sealing.

Results:
There are now no leaks from rocker shafts and engine runs at 210F while setting
new best track lap time by 3.5 seconds over our 3.2L engine at Firebird Raceway
East Track (1.3 mile). At our previous tack event engine oil temp was up to 250F.
Driver/son Brian also set the new TT3 class record and collected 2 Hoosier comp tires. (Father bragging )

Left Side:



Right side:



Center:



Until next time . . .

Regards,

[Sboxin]

Well . . .

When you put a more powerful engine into your Porsche with a 915 gearbox
the next thing you need to do is rebuild the gearbox - - we broke a pinion gear
tooth and wedged it into the 5/R gear change lever - - that's better than catching
in a gear set. So we dropped the engine/trans and took the trans to CMS in Lake
Havasu, AZ for a really good rebuild with many new parts - it has been 3 years
since the last rebuild - it was due - they did an excellent job. We also added a trans
cooler with pump and filter (work done by Kent Porter shop in Gilbert, AZ). Also, pics
of the inside the car with the cooler located behind the driver seat on the shelf, NACA duct and hose in the quarter window.











Steve Weiner Rennsport Systems was absolutely right about adding more engine cooling
-- the added 2 Carrera fender
oil coolers needed more air flow in our warm May and June temps. So, we opened
the headlight buckets, expanded the turn signal openings and added aluminum
panels to act as air ducts through the oil coolers (copied idea from others on the
forums -- air flow is really important)
Thanks to the Don Jackson shop in Phoenix and Roland for mounting and plumbing the coolers - -
we also changed the front center cooler to a Setrab oil cooler from Elephant Racing.
The 911 headlight rock guards make for a nice touch too.





The results are that the trans now works perfect and the engine used in race
conditions and 100F air temp runs at 210F. I am hoping this is the "end of the story".

Thanks to all who post on this and other Porsche forums for valuable
information and experiences.

Regards,

[ShakinJoe]

Any updates Roy?

[Sboxin]

Originally Posted by ShakinJoe

Any updates Roy?

August NASA race at Fontana, CA --- the big oval + infield
The engine and transmission ran strong - no issues or problems
Brian was shifting at 6500-6800 RPM and engine pulled very strong.
Engine and transmission cooling is very effective.
We learned a thing or two about the banked ovals and tires . . . more pressure in right rear tire . . .

We are using Amsoil 15-50 race oil -- was very good in the 3.2L and lab tests showed
no degradation in 6 track weekends

Thanks again to our engine builder Don Jackson Enterprise in Phoenix, AZ
- - - and CMS for the transmission rebuild/upgrade

Regards,



This is the engine drop photo by Son and father for the trans rebuild

[ShakinJoe]

Are you guys using oil tank and filter system from factory?

[Sboxin]

Originally Posted by ShakinJoe

Are you guys using oil tank and filter system from factory?

Yes, but with the 3 oil coolers and extra lines we are using about 15 quarts of oil in the system.
We run the tank level at 1/2" above the low mark on the oil stick. The breather
hose is a closed system with no catch tank or outside vent.

Our events are mostly 30 minute sprint races and some Time Trial sessions that
are also very short.

Regards,

[ShakinJoe]

Thanks. Just building my system and I stock fender cooler plus one in front. Not sure if I'll need another fender cooler or if two will cut it. I will have a stroked 3.6 to 3.7L using 50 PMO's so it should put out 350+ at crank.

[Sboxin]

Originally Posted by ShakinJoe

Thanks. Just building my system and I stock fender cooler plus one in front. Not sure if I'll need another fender cooler or if two will cut it. I will have a stroked 3.6 to 3.7L using 50 PMO's so it should put out 350+ at crank.

ShakinJoe,
All the best on your build !
I've been looking for photos of your build, but not found any yet?

The engine cooling process was a trial and error method for us.
Our center cooler is a Setrab 172 and the front body section is rounded downward
for the air to pass through the center cooler and then under the car. This worked
really well for our 3.2L engine and hardly saw temps over 180F. But, this stock spec engine also
had the engine oil cooler along with our front center cooler.

The 3.8L with 12.5 CR JE pistons and Webcams 20/21 cams running 100 octane fuel and
timed by Steve W does not have an integral oil cooler. When we added the 2 Carrera
fender coolers I decided overkill wouldn't hurt because we sometimes track in 100+
temps.

Regards,