November 21, 2012 at 7:05 am #7529jensenracing77Participant
After having the transmission rebuilt earlier this year for the Jetfire i have had some issues trying to get it adjusted. I did it by the book to the exact detail. it would shift good but at a real slow pace it would not act right. My transmission guy told me another way to adjust it and it now works VERY GOOD! He said that you can’t go by the book completely because of to many wear points that have tolerances that all “stack up” and springs that may not have perfect tolerances. Not to mention the internals of the transmission on the rebuild may have changed a slight amount from where GM had them when new.
he had me shorten the TV rod going to the transmission a little at a time till i had the sensation that the transmission would not want to shift till i slightly let off the throttle. Then i had to lengthen it to where that was gone and would shift completely on it’s own. The next part, i still have to do. He said i need to hook up a tachometer and go wide open throttle starting in first and make sure it shifts close to the redline RPM. (I am not sure where that should be on the Jetfire) he said if it wants to go to high in the RPMs before a shift i will need to lengthen the TV rod just a little more but won’t take much at that point.
From where i had it adjusted by the book and where it is now is 2 1/2 turns shorter. It works great at this point but i have to check the high RPM shift still.
Anyone know what the Redline of these engines are? I have no intentions of racing it but like to know it is not over revved on a WOT shift.November 21, 2012 at 9:45 pm #7530
I’ve never seen factory published data but my factory tach (Cutlass, not Jetfire) shows redline between 5400 to 5600 RPM. I have an old Hot Rod Magazine article on the 215 from a special magazine in their “Technical Library” called HOT RODDING The COMPACTS. They did some tuning and some easy bolt-on component replacements to see what kind of power they could get from the stock engine. They experienced valve float at just over 5000 RPM with the stock valve springs. The factory specs. for the Jetfire engine are peak horsepower of 215 at 4600 RPM and peak torque of 300 ft lbs at 3200 RPM. Later today I’ll try to post the Hot Rod article. It’s very interesting. There’s also an article on the Jetfire & Corvair turbo engines that I’ll try to post as well.November 21, 2012 at 10:38 pm #7531
Here are the Hot Rod articles.November 21, 2012 at 11:55 pm #7532
Sorry, pdf files wouldn’t upload. Hopefully these jpg files upload o.k. I may need to split these up because these don’t seem to be uploading either.November 21, 2012 at 11:57 pm #7533November 22, 2012 at 12:00 am #7534November 22, 2012 at 12:01 am #7535November 22, 2012 at 12:02 am #7536November 22, 2012 at 12:06 am #7537November 22, 2012 at 2:52 am #7538jensenracing77Participant
thanks for posting that. That is a great read. It is interesting to see that todays Turbo cars are much closer to the direction Oldsmobile went than the way Chevy went. I need to find a correct muffler for my car. I am sure mine is holding the car back.
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