[AMC-list] so that's why I did this!!!

[tom jennings <tomj@xxxxxxx>]

I feel a little bad posting this, what with Dave's recent bummer.

I think I'm over the hump on scary problems with my new motor... (knock on
old cast iron) Still breaking it in of course, basically low-ish RPMs,
varying speeds, and moderate loads. I've slowly been increasing the shift
point speed, 2500 for the few 50 miles, but now once in a while shifting at
3000, 3500. It's been very happy with this, and though it doesn't idle nice
yet (correct idle jet arrives tomorrow) mid range and high end are good
enough for now. Slight flat spot when the secondary opens.

Today, I did a 4000 rpm 2-3 shift, and it was VERY HAPPY at 4000, pulling
hard. 10 minutes later (careful paranoid listening after that space-age
RPM...) I pulled it hard to 4300 second-to-third, and it was VERY HAPPY,
smooth, vibration free, and still pulling like mad. I've got a shorty
exhaust, 2", with a Summit turbo muffler, the whole thing about 80" long,
and it SOUNDED KICK A**! I ain't never heerd a Rambler make that sound! 4000
doesn't sound like much if you have a "modern" motor, but it's a big deal
for this old hulk.

These were just upshift speeds, not sustained; peak then throttle up and
shift. Funny, the thing that limits high upshift speeds in a practical sense
is the T-96, the synchros basically suck. They are more like "suggestions"
that the gears mesh, please.

The "old" engine (same one before work-over) ran to 3000 OK, but it wasn't
that happy doing so. Same ignition for now (Pertronix and epoxy coil) but
good carb and much improved exhaust, but I think the new valve springs are
the reason it didn't break up and grumble.

I don't plan on running this thing at 4500, or even 4000, but it sure is
nice to know it can do it! With overkill oiling and correct head cooling, I
have no doubt I will be able to run this thing at 4000 if I want to once
it's broken in.

First oil change in the morning.

I don't know what would limit practical maximum RPM for this motor. The TSM
specs it as 138hp@4500, so we've been calling that "maximum". Valve float?
The springs are pretty weak! Would valve float let a pushrod drop out?
They're like foot long soda straws. Weird torsional vibration? Would
anything like that happen to any modern-ish six below 6000+?

I plan on not finding any of these things out, just thinking out loud. My
budget isn't big enough to ask such questions. I am curious though.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://list.amc-list.com/pipermail/amc-list-amc-list.com/attachments/20100516/c3dd06d7/attachment.htm>
_______________________________________________
AMC-list mailing list
AMC-list@xxxxxxxxxxxx
http://list.amc-list.com/listinfo.cgi/amc-list-amc-list.com