Mopar Follies (was: easiest engine)

In article >,
51_racing > wrote:

> > Hate to break it to you but the Chrysler 8.75 "pumpkin" is
> > serviced the exact same way, as was a version of Oldsmobile rear
> > axle used in the late 50s early 60s. The Chrysler advantage is
> > that the pinion stem is 3/8"-1/2" bigger in diameter which also
> > gets you bigger bearings. Ford 9 inch rear axles make me laugh
> > the same as Muncie and Borg Warner transmissions make me laugh
> > when I compare them to a Chrysler unit.
>
> How about gear selection?

You mean in .05 increments?
I know that above certain ratios, I have to do a lot of hugging
of metal from the pig on Ford 9" to get clearance for the ring
gear.

> I can put any rear end in the car that I race that I choose. It has a
> 9". I can change gears in my floating rear in less than 30 minutes at
> the track.

If my 8.75 had full floating axles, I'm sure I could meet that
time.

> I will agree that axles in the Ford aren't the greatest, and
> aftermarket parts help that, but stock parts are plenty strong for 500+
> H.P. how is that weak?

Not weak, weaker.

In article >,
51_racing > wrote:

> Daniel J. Stern wrote:
>
> > On Wed, 16 Nov 2005, 51_racing wrote:
> >
> >> How about gear selection?
> >
> >
> > How about it? 2.76, 2.94, 3.23, 3.55, 3.91, 4.10, 4.56, 5.13 and several
> > others I'm leaving out. Not enough choice for ya?
> >
>
> No as a matter of fact, not nearly enough. And not nearly steep enough,
> how about starting in the mid 5's and go up from there, the most common
> types used in racing.

If Chrysler 8.75" rear axles were dime a dozen, Richmond and the
like would make the ratios available.
It's not because it can't be done, it's because of what is
commonly used. What is commonly used is as I mentioned earlier,
perceived to be easier to service by a small margin.

aarcuda69062 wrote:


>
> If Chrysler 8.75" rear axles were dime a dozen, Richmond and the
> like would make the ratios available.
> It's not because it can't be done, it's because of what is
> commonly used. What is commonly used is as I mentioned earlier,
> perceived to be easier to service by a small margin.

Granted, it's partially a supply/demand situation but not all housings
can handle these types of gear sets. GM for instance in the 7.5"
carriers had to use two, the 2 series and the 3 series. Can the Chrysler
physically fit those gears?

Bret Ludwig wrote:


>
> Yeah, the reluctor, actually it's the feeler gauge that's brass.
> Sorry. It has the TO case transistor on the little box with the five
> pin connector with the screw through it. You can usually fix them
> yourself by changing the power transistor and the diodes and caps out,
> if you can get it depotted.

Why would you want to, when a brand new one is under $20? And here, I'll
surprise you: GM's HEI is a bit better ignition than Mopar's electronic,
at least from a performance standpoint. Capacitive-discharge allows a
hotter spark without added power draw.

a
> GM alternators are the best. Period. They are reliable and more to the
> point, can be had in high current versions cheaply.
>

GM alternators range from very good to utter crap (CS series anyone?)
Mopar alternators range from reliable but low output through superb with
high output. Sadly, Mopar doesn't build alternators and hasn't since
1988 or so- but at least they mostly buy Nippondensos, which are for the
most part far better than Delco.

> The Chrysler is reliable enough. But it's what, 60 amps? And that's
> the BIG version.

That's the biggest finned-case version. The biggest is the 100A
exposed-fan version that can deliver a constant 100+ amps at 14.8 volts
for as long as you want it to without failing. Its one of the few
automotive alternators (not counting big truck units like Leece-Neville)
that actually is rated at its *sustainable* output.

51_racing wrote:

> How about gear selection?
> I can put any rear end in the car that I race that I choose. It has a
> 9". I can change gears in my floating rear in less than 30 minutes at
> the track. I will agree that axles in the Ford aren't the greatest, and
> aftermarket parts help that, but stock parts are plenty strong for 500+
> H.P. how is that weak?

Gear availability for the 8.75 is beginning to be an issue since it
hasn't been built since 73. On the other hand, you can still get:

2.76, 2.93, 3.23, 3.55, 4.10, 4.80, and (IIRC) 5.30 ratios for a Mopar
8.75. Not bad for a 30 year out-of-production piece!

That said, I also like the Ford 9" fine. Its smaller pinion shaft is
offset by having bearings on both sides of the pinion gear, but that
also makes setup quite a bit harder.

51_racing wrote:

> aarcuda69062 wrote:
>
>
>>
>> If Chrysler 8.75" rear axles were dime a dozen, Richmond and the like
>> would make the ratios available.
>> It's not because it can't be done, it's because of what is commonly
>> used. What is commonly used is as I mentioned earlier, perceived to
>> be easier to service by a small margin.
>
>
> Granted, it's partially a supply/demand situation but not all housings
> can handle these types of gear sets. GM for instance in the 7.5"
> carriers had to use two, the 2 series and the 3 series. Can the Chrysler
> physically fit those gears?

To the best of my memory, the "742" and "489" housings can physically
fit all the gears (and probably the 741 and earlier housings too, just
less experience with those). At some point in there as you go through
the ratios, you have to change to a different ring-gear carrier in order
to allow the pinion adjustment range to stay centered as the ring gear
gets thicker. I don't remember the break-point though.

On Wed, 16 Nov 2005, Steve wrote:

>> The Chrysler is reliable enough. But it's what, 60 amps? And that's
>> the BIG version.
>
> That's the biggest finned-case version.

Nope. The highest-output small (finned) case Chrysler alternator is 80A.

> The biggest is the 100A exposed-fan
> version

Physically biggest, yes. There is the '88-up Chrysler-built 120A unit,
which has a smaller case than the exposed-fan unit you're talking about.

On Wed, 16 Nov 2005, 51_racing wrote:

>> How about it? 2.76, 2.94, 3.23, 3.55, 3.91, 4.10, 4.56, 5.13 and several
>> others I'm leaving out. Not enough choice for ya?

> No as a matter of fact, not nearly enough.

Sorry, no sale. You'd have to do a great deal of very persuasive talking
to convince me that a 186% spread split up into steps of 5% and 10% is
"not nearly enough" for any real-world purpose.

Daniel J. Stern wrote:
> On Tue, 15 Nov 2005, wrote:
>
> > At least some 1975 or 1976 Slant 6 cars with the single barrel Holly
> > stalled so badly that the federal government forced a recall for the
> > problem.

> True. And? Find me *any* automaker's product that didn't have *at least*
> one significant driveability-related TSB or recall in the mid-1970s.

Actual federally mandated recall and not just a TSB or voluntary recall?

aarcuda69062 wrote:
> In article
> .com>,
> wrote:
>
> > At least some 1975 or 1976 Slant 6 cars with the single barrel Holly
> > stalled so badly that the federal government forced a recall for the
> > problem.

> The off idle stumble/stall fix was;
> 1) Adjust the power valve piston
> 2) Bypass the OSAC valve
> 3) Tweak the hot air intake sensor in the air cleaner so the air
> door stayed closed until 110 degrees.
>
> And it took about as long to do as it took me to type this...

This particular 1975 came with the OSAC already removed, but the
wonderful dealer was clueless and probably tried everything but the
things you listed. They even wanted to charge for the federal recall.

How did you tweak the hot air intake sensor? Wasn't it just a fixed
bimetal valve?