: LT5 Vs Early Northstar



CadiJeff
05-19-05, 02:16 AM
Just curious, other than displacement and orientation, whats the difference?

Randy_W
05-19-05, 08:21 AM
Everything!!!!!

CTX-SLPR
05-19-05, 10:21 AM
Northstars don't have secondary runner control do they? The biggest differences I can think of is the fact that the LT5 is a conventional deepskirt block with maincaps and an oilpan vs the the casehalf and oilpan design of the Northstar, 16 injectors including one in each runner with the secondaries controled by butterfly valves that kept the air from flowing into the second set of intake valves, and the design to be used with manual transmissions. Northstars don't fair well long term wise with sticks because of the all aluminum main bearing surfaces and only 180 thrust bearings on each side of the thrust saddle.

BeelzeBob
05-22-05, 12:35 AM
There is absolutely no similarity between the LT5 and the Northstar. They are about as different as two engines can be. About the only thing common between them is that they are both V8's....

Pjs
05-22-05, 10:43 AM
Northstars don't fair well long term wise with sticks because of the all aluminum main bearing surfaces and only 180 thrust bearings on each side of the thrust saddle.

I'll have to disagree with you on this one. I had the bottom end of my 95 apart last year with 137K on it. The main bearings were still in excellent condition. I had to replace the rod bearing only because they can't be reused but the original mains are still in there...engine has almost 146K on it now.

You can check out this thread complete w/ pictures...

http://www.cadillacforums.com/forums/showthread.php?t=24550

CTX-SLPR
05-22-05, 11:16 AM
BBob,
I can think of lots of ways that they are simular, ie both are V8's correct however both are DOHC motors with AL blocks and AL heads. I think you are over analysing the architecture between the two saying they are as different as two engines can be

Pjs,
If you are reffering to your motor out of you 95 SLS, you have the benifet of a torque converter to absorb the thrust loads of the transmission. A stick on the other hand has inherent axial motion with the clutch engagement/disengagement cycle. Since the clutch is 2 different halfs with one half on the transmission and the other on the crank when you disengage the clutch, especially fast, you essentually shove the crank forward in the block making it contact the thrust surfaces. Since the Northstar has only a 180 thrust surface, there is not a very large area to distrute the load.

Aurora40
05-24-05, 06:49 PM
Another similarity is they both set production endurance records in the early 1990's.

97BlueDeville
05-25-05, 05:26 PM
BBob,
I can think of lots of ways that they are simular, ie both are V8's correct however both are DOHC motors with AL blocks and AL heads. I think you are over analysing the architecture between the two saying they are as different as two engines can be


CTX Those are very obvoius claims. Internaly they are very different even if they are both V8's, Lotus and GM made the LT5, and it is very different. Aluminum Blocks and DOHC, :bonkers: ummmm k. You and I are both Humans, we have arms, legs, etc.. but we are very different.... ;)

BeelzeBob
05-26-05, 12:29 AM
BBob,
I can think of lots of ways that they are simular, ie both are V8's correct however both are DOHC motors with AL blocks and AL heads. I think you are over analysing the architecture between the two saying they are as different as two engines can be

Pjs,
If you are reffering to your motor out of you 95 SLS, you have the benifet of a torque converter to absorb the thrust loads of the transmission. A stick on the other hand has inherent axial motion with the clutch engagement/disengagement cycle. Since the clutch is 2 different halfs with one half on the transmission and the other on the crank when you disengage the clutch, especially fast, you essentually shove the crank forward in the block making it contact the thrust surfaces. Since the Northstar has only a 180 thrust surface, there is not a very large area to distrute the load.



Trust me, if you laid out the parts of a Northstar and the LT5 dissassembled side by side on tables you would agree that there are very very few similarities. About none. Yes, the obvious, they are both V8's, both DOHC, both 4 valves, both have a lot of aluminum in them, uh.... that is about it.

I am not stretching anything regarding the architecture of the two engines. The blocks are completely different designs, materials, everything. As an example....the Northstar has cast in place iron cylinder liners....the LT5 has loose fit, wet, aluminum cylinder liners that are nikasiled....think a 4.1/4.5/4.9 style of wet liner but one made of aluminum instead. The LT5 has a deep skirt block with separate main caps...the Northstar has the two piece block that is split at the crank centerline...totally different. Look at the timing drives on the engines....COMPLETELY different setups. The LT5 has the PCV oil separator in the valley....the Northstar has the starter in the valley. Etc...etc...

The LT5 and the Northstar are very very different engines with little or nothing in common.



Even though the Northstar has only a 180 thrust bearing it will work fine behind a manual transmission. There have been a number of experimental installations with manuals and the thrust bearing is perfectly adequate for the task of dealing with a pressure plate and throwout bearing. Shelby installed 4.0 Aurora's in the Series II cars with a manual and they worked fine. We set 2 world land speed records running with a manual transmission behind a 4.0 Aurora....and the records required running flat out , round the clock for 10 days....the thrust bearing looked fine. Lots of aftermarket applications with manuals out there and they work fine. The sand car guys run manuals behind them all the time and they work fine for them, too.

Don't forget that a torque converter "ballons" when hot and under high load which can put a lot of stress on the flex plate and into the crank/thrust bearing. The oil pressure in the torque converter is acting on the area of the torque converter snout always trying to push the torque converter out of the trans. That force is considerable at times and is absorded by the thrust bearing on the crank...so just because an engine has an automatic does not mean it doesn't work the thrust bearing heavily at times.

97BlueDeville
05-26-05, 02:05 AM
:hide: This Guy above me has a world of knowledge...

dkozloski
05-26-05, 03:31 AM
What are the relationships between the Chevy Ilmore, the Indy Aurora, and the current Indy Chevy that morphed from the Indy Aurora? Also wasn't there a Mercedes/Chevy deal in there somewhere?

eldorado1
05-26-05, 12:48 PM
nikasiled

Thanks. You just turned me off to the LT5 vette. :leaving:

Aurora40
05-27-05, 05:15 PM
the Northstar has the starter in the valley. Etc...etc...


Just a very small note, but the LT5 also has the starter in the valley. It's right under the coil packs under the plenum. :)

I love both my GM DOHC V8's. They both sound awesome, and are both fun to run to the redline!

http://members.aol.com/aurora402002/misc/twov8s.jpg

Aurora40
05-27-05, 05:20 PM
What are the relationships between the Chevy Ilmore, the Indy Aurora, and the current Indy Chevy that morphed from the Indy Aurora? Also wasn't there a Mercedes/Chevy deal in there somewhere?

I'm not sure about the old Chevy Ilmore, but I doubt they had much in common. That was a turbo motor. The Aurora IRL V8 was originally a 4.0L n/a motor. I believe the Chevy IRL V8 was just a new name on the same program when Olds was killed. They made some improvements, but would have done the same thing if it was still an Aurora-branded motor.

However, the current Chevy motor has nothing in common with any of them. After two years of getting kicked around, Chevy contracted Cosworth to design and manufacture the Chevy IRL V8.

CadiJeff
05-31-05, 03:38 AM
What engine is that on the postor behind the vette?

Spyder
05-31-05, 01:52 PM
Yea, I was wondering the same, sure looks interesting... ... ...

Aurora40
05-31-05, 03:53 PM
What engine is that on the postor behind the vette?

The Aurora IRL V8. :) The poster to the right of that, the one you can only see a corner of, is a cutaway poster of the same engine. I need to get some more Corvette posters!