: It's Alive again



dloch
05-16-04, 11:52 AM
Lawrence, Bbob and all who have read any of the posts regarding the upgrading of a pre-96/97 to work in my 97 STS. I got it running again late Friday night after more fun..... The donor engine I had obviously had been setting for a number of years before I got it but everything looked new on it.

So on friday I am ready to fire it, leave to power connector off the coil pack and spin it for 30 sec's. Connect the power lead to the coil pack, turn the key on and off a half dozen times to make sure I have all the air purged out of the fuel system and start cranking........ nothing. So I figure here we go.... Now I start the checking procedure. Have power at the coil pack. Take a spark plug out of the bad motor and grab one of the spark plug wires and connect it to the plug and ground it.... good spark. Push the valve core in on the fuel rail to make sure I have fuel at the rail, connect a gauge up.. yep Houston we have fuel pressure... So I shoot some starting fluid into the intake and re-crank... the motor fires and dies. Now I'm getting someplace :rolleyes2 . I used the injector wiring harness from the donor engine and though with everything else I have found not quite right on that engine I'll try my harness. Crank the engine with my original harness.. the motor is trying to fire and run but only hitting on one or two holes so I add throttle and it does fire.... well maybe just a little... It is trying to run but is missing very badly. Now I'm thinking injectors.... then it dawns on me, when I removed the injectors from the other fuel rail which wouldn't work with my 97 it still have gas in it... you know the gas that has set for years... you know it by the smell. So I go about removing the connectors from each injector one at a time to see if it has any effect. Four had no effect the other four did. Shut it down and replace the look like new injectors with the old look like hell injectors from my leaker. Turn the key motor fires right up and idles like it's suppose to. Duh............:annoyed:

Then I go through checking all the fluids as it's running SOP. I changed my converter to a 3K Yank and replaced my internally exploded air conditioning compressor with a new one.

Got the hood back on yesterday with the help of the GF and took it for a ride. I can tell you it doesn't have any carbon build-up yet and I certainly exercised the rings :bighead: The converter helped get the car moving from a stop but not as much as I figured it would compared to the change it made in my Impala SS. It helped in the step on the gas to get around the person in front of you area though.. by a bunch. I also altered my cam timing some.... at 4000 RPM this thing acts like you just hit the nitrous button and pulls very hard until the upshift. If you do it in 1st and let the computer do the up shift it lights the tires up in 2nd gear. Didn't let it run out in 2nd until the 3rd gear shift yet to see how the car reacts yet.... but I will.

Thanks to all who have answered my questions. From this experience I can provide answers now.

Dennis

eldorado1
05-16-04, 01:11 PM
Very cool! Sounds like I need 3.73 gears rather than a higher stall converter then :) What engine you running? 275?


I also altered my cam timing some.... at 4000 RPM this thing acts like you just hit the nitrous button and pulls very hard until the upshift. If you do it in 1st and let the computer do the up shift it lights the tires up in 2nd gear. [ahem] specifics please? :lildevil:

BeelzeBob
05-16-04, 04:04 PM
If you retarded the cam timing to get the increased top end power you lost a bunch of low end. It would have felt REALLY sluggish without the higher stall speed converter. Since you changed two things at once it is hard to evaluate. I would suggest if you have the time put the timing sprockets back to stock and evaluate the converter...or...you should have gotten an even looser converter to work with the cam timing alteration.

I would recommend the higher stall converter much more than the altered cam timing/sprockets. If you do the sprockets, do not do them without the converter unless you really want the car to fall on its face off the line.

That is why the 300 HP motor always comes with a 160 K factor torque converter and the 275 HP motor comes with a 128 K factor converter. The looser 160 K factor converter covers up the lesser torque at low RPM's of the L37 engine/cams/camtiming.

eldorado1
05-16-04, 06:06 PM
That is why the 300 HP motor always comes with a 160 K factor torque converter and the 275 HP motor comes with a 128 K factor converter. The looser 160 K factor converter covers up the lesser torque at low RPM's of the L37 engine/cams/camtiming.
So they ARE different... Any idea on the approximate stall RPM on either of those? I have a line on a complete 300hp tranny, I can probably get the torque converter with it if it's worth it... a hundred rpm probably wouldn't be worth it though ;)

Lawrence
05-17-04, 12:40 AM
Excellent Dennis! Very glad to hear all is well, but I knew it would come together for you. Nice to know the model swap worked out too.

Since it seemed to be the injectors that were the problem, do you think either of the fuel injection harness' would have worked?

Sounds like it now has a bit a "powerband". Faster or not, they sure feel good like that. I remember a couple of old muscle cars I had that "hit" like that too. One, a 1968 442 had the strongest one I ever felt. Had the Rochester QJ on it and it would be tooling right along and feeling pretty strong, then out of nowhere it would hit so hard it would spin the tires (stock tires). Not from the shift but from the power coming on. I know it wallowed a bit then cleaned up. But that was the fastest "feeling" car I ever rode in. Later I had a 1974 Z28 that WAS fast. It also had that "powerband" effect. At 4000 it would hit and just rage to 7500, accerating faster and faster in it's quest for 7500. The meat of the powerband coincided nicely with the shift points of 7500 RPM's (auto I manually shifted) and when it would make the 2nd gear shift would lift the nose about 6"s and carry it for what seemed like forever, just dancing the front tires down the road. That first shift was ALWAYS good for an instant 2 car length's, against a fast opponent. But more important is that it kept and even improved upon that intial burst ALL through second gear, pushing the pace to unreal levels for anything on the streets. I can think of only a handfull of races that ever required third gear. I was never beaten in that car, and took all comers.

Sorry for getting off the subject here, but that word, "powerband" brings back fond memories. Fast or not, it sure FEELS GOOD!

Since you are already "excerising the rings", you need to get it out to the track and post some numbers. I would be curious to see them. What would be your estimated improvement?

dloch
05-17-04, 10:14 AM
If you retarded the cam timing to get the increased top end power you lost a bunch of low end. It would have felt REALLY sluggish without the higher stall speed converter. Since you changed two things at once it is hard to evaluate. I would suggest if you have the time put the timing sprockets back to stock and evaluate the converter...or...you should have gotten an even looser converter to work with the cam timing alteration.

I would recommend the higher stall converter much more than the altered cam timing/sprockets. If you do the sprockets, do not do them without the converter unless you really want the car to fall on its face off the line.

That is why the 300 HP motor always comes with a 160 K factor torque converter and the 275 HP motor comes with a 128 K factor converter. The looser 160 K factor converter covers up the lesser torque at low RPM's of the L37 engine/cams/camtiming.
I advanced the intake cam timing 10 degrees.

I agree it's hard to evaluate a change when you change two things at the same time. The other part is that I am comparing it with my uncalibrated butt dyno against what I have been driving for the past two weeks. It's a 94 S15 Jimmy with the high ouput V6 with 3:73 gears in it, which is fast of the line but tends to lay down at higher speeds and RPM, not to mention the weight issue.

After writting the intial post it dawned on me that when I changed the converter in the Impala I also changed the rear gears to 3:73 at the same time and rebuilt the trans for faster/harder shifts. The change in that car was dramatic. But again I changed more than one thing at the time.

When I get time I may switch the cam timing back ans see how it runs then. Another thing I have thought about was using the LD8 intake cam and advancing it.

The car felt better this morning, or at least my butt meter seemed to think the car felt better anyways. When I took the intial test drive the motor hadn't been running any longer than half hour at best and that was idling.

I need to drive it for awhile.

Bbob, with the intake cam advanced would that make the engine quiver a little more at idle? The quiver almost feels like a motor that has an larger cam in it.

dloch
05-17-04, 10:26 AM
Excellent Dennis! Very glad to hear all is well, but I knew it would come together for you. Nice to know the model swap worked out too.

Since it seemed to be the injectors that were the problem, do you think either of the fuel injection harness' would have worked?

Sounds like it now has a bit a "powerband". Faster or not, they sure feel good like that. I remember a couple of old muscle cars I had that "hit" like that too. One, a 1968 442 had the strongest one I ever felt. Had the Rochester QJ on it and it would be tooling right along and feeling pretty strong, then out of nowhere it would hit so hard it would spin the tires (stock tires). Not from the shift but from the power coming on. I know it wallowed a bit then cleaned up. But that was the fastest "feeling" car I ever rode in. Later I had a 1974 Z28 that WAS fast. It also had that "powerband" effect. At 4000 it would hit and just rage to 7500, accerating faster and faster in it's quest for 7500. The meat of the powerband coincided nicely with the shift points of 7500 RPM's (auto I manually shifted) and when it would make the 2nd gear shift would lift the nose about 6"s and carry it for what seemed like forever, just dancing the front tires down the road. That first shift was ALWAYS good for an instant 2 car length's, against a fast opponent. But more important is that it kept and even improved upon that intial burst ALL through second gear, pushing the pace to unreal levels for anything on the streets. I can think of only a handfull of races that ever required third gear. I was never beaten in that car, and took all comers.

Sorry for getting off the subject here, but that word, "powerband" brings back fond memories. Fast or not, it sure FEELS GOOD!

Since you are already "excerising the rings", you need to get it out to the track and post some numbers. I would be curious to see them. What would be your estimated improvement?
I'm sure the other harness was fine, it was the injectors that were plugged from the old gas I'm sure.

The big powerband increase at 4000 wasn't like that with the other engine I can tell you that. I've had a number of big block automatic cars that had the same feeling.... when this things bangs 2nd it brings back fond memories to me as well.

These were just intial observations, I need to track the good and the bad things of this combination. Like what RPM the motor likes to pull best at and in which gear, etc. Like any car you need to find out what it likes with a given combination.

eldorado1
05-17-04, 02:31 PM
I think it's time for you to forget the butt-dyno, and hop on the real one, get us some numbers! I'd be curious to see what a 10* advance would do on the northstar... My guess would be add ~15hp

BeelzeBob
05-18-04, 12:22 AM
I think the cam timing mods you made retarded the cam timing. Typically, retarding the cam timing increases the top end power at the expense of less low end. Advancing the cam timing will increase the low end and hurt the top end. I'm pretty sure you retarded the cam timing to get the higher HP output you describe.

eldorado1
05-18-04, 02:08 AM
You're right when you advance/retard all 4 cams, but he advanced just the intakes... which is the same (more or less) as retarding the exhausts... giving more overlap, and more power at higher rpm's. At least I think?? I'm not a cam expert :crying:

eldorado1
05-18-04, 03:16 PM
Nope you're right. My bad. Desktop dyno says the same thing. Did you really advance it Dennis?

BeelzeBob
05-18-04, 03:19 PM
Nope you're right. My bad. Desktop dyno says the same thing. Did you really advance it Dennis?

I would agree with the desktop dyno. The cam overlap or centerline is being advanced when you advance just the intake....so that would typically help the low end. Retarding it would help the top end.

dloch
05-18-04, 06:15 PM
Nope you're right. My bad. Desktop dyno says the same thing. Did you really advance it Dennis?
Yes I only advanced the intake cam 10 degrees, left the exhaust alone.

When I lined up the all the dots and new marks on the intake cam gear the intake cam pin was a little to the right of the centerline, the exhaust was straight up.

Eldorado, since you have desktop dyno what did that do to the lobe seperation?

This would open the intake valves earlier but more important it will close them earlier and by all rights it should have effected the to upper powerband range but it didn't.

The other thing I didn't add to the intial post was that I also changed valve springs as well. That shouldn't have anything to do with the upper powerband unless................ the valves were going into a not follow condition...