JackDidley

I switched to a Miniram 2 weeks ago. I also modded the governor in the 700 R4 to shift at 6000 RPM. Went to test & tune Friday night and made 3 passes. Saturday, I ran some errands got back and parked it. 2 hours later I started it and the bearings in the alternator (25 K miles on it) locked up instantly. I took it back, got anther rebuilt one and a belt. All fine. Later on I made a beer run, stood on it one time, up to 6000 RPM, went in, got beer. Came out and the battery light came on at start up. No charge. The question is, did 6 grand kill 2 alternators, or is it just one of those things ??

mseven

I haven't eaten one due to 6k, I think it's probably a poor re-build, cheap bearings etc.

STL94LT1

My car has seen 6000+ rpms on a regular basis for years, without an alt failure.

JackDidley

I went and got a new one at the Zone. Not a rebuild this time. It has a lot more meat to the case and hopefully some good guts. I will take the rebuild back to Advanced and let them warranty it again and put it on the shelf for back up.

MarkBychowski

Rev past 6K quite often and never had a problem. I'm sure it accelerates the alt's demise, though.

hippy

Obviously the faster you spin crap the faster it dies but that Alt was on its way out regardless of the 6000 spins. I've run a MR for almost 2 years and my Alt is still fine. I do know that someday soon it'll die as they are pretty crappy alternators.

JackDidley

Thanks guys. My Nova sees 7k in the water box on occasion. Not intentionally, I just blink and its there. Never a problem, but it has an old style big alternator and I know they are not as fragile as the one in my 87. I guess the new rebuilt one was just weak. I will probably find out about the new, new one in the next week.

JackDidley

I agree. Just mostly wanted somebody else to say it too .

Fatt Vette

There is an internal plastic fan at the back of the alternator that has exploded several times on high RPM passes on my '86. I replaced it with an LT1 alternator and have had no more problems.

JackDidley

I did not know the LT1 alt was different/better. Is it a direct fit??

ol,RJ

I've blown 2 or 3 but it always happened in first gear and there was extra load on the charging system (laptop/datalogging or headlights/radio at night). that plus I had a high (numerical) first gear that rev'd out very quickly.

I can't rule out the alternators just being cheap to start with. but a underdrive crank pulley seems to have solved my problem.

REDC4CORVETTE

Make sure the brace is on the back of the alt,I have cracked many cases.
I have taken out a few at 7500 rpm's,the plastic fan inside blew apart .
I had the rebuilder install a metal fan inside the alt and last week I had him install a clutch to disengauge the alt at 5k ,works great but I don't think you would like to spend 200 bucks for a clutch for an alt.
I guess Ford and VW came out with the clutch type alt pullys a few years back .Ford has them on the Diesel vhls and VW has them on some of the porshes.
Good luck with those auto parts stores.
I have also broken the Idler pully bracket and have a 1/2 piece of aluminum welded to keep that together.

cv67

Hmm, never heard about the plastic/metal fan bit.

88BlackZ-51

How did the MR perform compared to the old intake?

JackDidley

The Mini rocks. Already ran = ETs and better MPH at the 1/8 mile track, running the TPI tune. Working on getting the tune this week. I will post a report on the Mini when I get the chip.

JackDidley

I have an underdrive on the crank and an OD on the alternator. It should = stock all together.

Fatt Vette

Much better, it is bigger but does fit. The top mounting lug on the alternator must be modified.

https://www.corvetteforum.com/techti...=254&TopicID=2

https://www.corvetteforum.com/techti...=189&TopicID=2

JackDidley

Looks like the 2nd link applies to my 87. I favorited it. It could be my next step if the problem continues.

88BlackZ-51

What did it run?

JackDidley

I could tell you, then I'd have to kill you.

J/k, When, the chip is tuned, I will post the results.