: 2000+ NorthStar modified to fit 1994 = success



olaf_sc
02-24-04, 02:16 PM
Hello Folks,


Wanted to report a success in using a 2000 (and above) short block in a 1994 Deville Concours. The whole thing started out with me buying a 1999 engine, planned to just use the shortblock and mount my old heads from my 1994 engine. The problem was that even if it was a 1999 engine it was made late 99 hence for a 2000 Cadillac. The 2000 (+) NorthStar is very different from a 99 and earlier. It uses a totally different crank sensor wheel, crank sensors and cam sensor/wheel in order to be able to ignite each cylinder individually.

The new crank sensor wheel is therefore incompatible with the older sensor wheel in terms of the amount of teethes and their layout, to make matters even worse its slightly smaller in diameter. Since its smaller the crank sensor position has moved closer together (not read the 2000+ manual but it still looks (me calculating) like it also uses 27 crank degrees between the sensors) .

The above means that even if you fit a old crank (pre 2000) in the new bottom end it will still not work. For once the sensors are too long well kind of since the narrower distance of the holes for the sensors makes them come closer to the wheel, actually scraping the wheel it self. Secondly since they are around 6mm to close there will be no spark. The coil pack simply can't figure out what the heck is going on and refuses to fire of a spark.

Sure should have read more of the posts and taken a closer look at the date stamp but I didn't so I was sitting there with an engine that didnt work :(. Since I on a tight budget for this car you simply dont want to spend to much since the car is not worth to much in the first place. Hence a new block was out of the question so what to do I needed a new short block? What about mounting the old crank in the new block after all there is no other diff than the sensor location and the sensor wheel.

Done, out with the engine again and mounted the old pre 2000 crank in the 2000 block. Back with the engine - from top since my garage is too small to handle the whole cradle. Now test that it works stop isn't the pos of the sensors wrong? Well the NorthStar is designed to be able to work with just one crank sensor (or to be precise two out of three sensors) so I pulled the plug from one of the crank sensors and spark we got. The engine is now drivable even if we are in a limp home mode so to say. (NOTE: You will need to have a spacer on the sensor other wise it will scrape the sensor wheel which isnt a good thing).

Okay but we don't want to run the engine in limp home mode (its not working to well trust me :). Nope we will need to fix the sensor position this can be done in two ways. Either you modify the holes by relocating them 3mm up (and down) i.e. 6 mm more apart, or you modify the sensors. I did the latter one. The recipe is to stick in the sensor in the hole and make a mark on it now grind 3mm of the plastic between the mark and the base on the sensor. You will need to grind of the 3mm on the lower side on the lower sensor and the 3mm on upper side for the upper sensor. Dont grind the whole sensor since the sensor it self is at the very end (tip) of the sensor so to say and don't grind to much or you will end up with a sensor not working. Mount the modified sensor pressing them up/down as much as you can when securing them. Note you will not need a spacer now since the distance to the wheel is right. Ah, you will need some silicon gasket otherwise it will leak oil.

Now plug just one senor and test for spark if you have spark your mod of the sensor was okay. Go a head test the next sensor if you have spark then you can plug in both sensor at the same time and test for spark. If you have spark your modification was successful and you can now drive your very odd engine :).

Some notes; Only change the crank leave everything else from the 2000+ engine (there is a few modifications to small things e.g. the old harmonic balancer will not work). Also when changing heads (pre 95) be sure to order one head gasket set for the 2000+ engine and one set for the 94 engine. Use the longer bolts (from the 2000 set) for the lower row of head bolts and the short (94) bolts for the upper row. If not you will most likely stripp the threads. BTW: Changed several heads and never used timeserts! I don't get all the buzz about you need timeserts etc..

Ah, still have some issues (hesitation) with the engine although not related to my modifications since they where present before I swaped engine. But more of that in another post. Anyways hoped you will find some info useful.

Cheers Olaf

zonie77
02-24-04, 03:34 PM
Thanks for the update and congratulations on getting your car running!

olaf_sc
02-24-04, 04:57 PM
Thanks,

Determination to make things work definitly helped me in this case. It's now over to chasing down the hesitation (or what ever you should call it) problem. Need to restore my 66 Eldorado first although. Did the engine rebuild this weekend and just put the engine assembly back yesterday evening. Given it two weeks of restoration work (120h or so) and then I can steer my focus back on track with the hesitation problem of the NorthStar.

Cheers Olaf

PS: Those 120h is naturally not just the engine but every little thing that needs attension.

Fiero STS
02-25-04, 10:52 AM
Very cool, I was working on the same problem, getting 2000+ engine to work with 95 ecm. Found cam gear is different, no big deal, just swap gear and sensor with an older version. Also need to make sleeve as older sensor is not as big around as new sensor. The crank sensors, for 94-99 are of a smaller diameter. I thought of enlarging holes in the block and making eccentric bushings to get the sensors in the right position then just change crankshafts to one from 94-97. Anyone see any problems with my solutions? One question how much plastic can be removed from the sender? Maybe I could just turn down the sensors in a lathe and make eccentric bushings. That would eliminate making the mounting holes in the block a different size. If this would work the only big part of the job is swapping crankshafts.

olaf_sc
02-25-04, 12:17 PM
Hello


You can remove around 3mm from the sensor this is just enough to make it work. I suggest you use a bench grinder not a lathe - you simply have more control of the process (if you are a good mechanic).

Now don't even think about touching the end of the sensor. Mount the pre 2000 sensor in the block, from the bottom you will see it sticking out on the inside of the block. Make a mark on the sensor just where it enters the block. You can now grind of 3mm between the base of the sensor and the mark (go 1mm or so over the mark so you are sure to have clearance).

When you grind of the 3mm you will naturally need to grind the sides too (although not as much) otherwise it will just be flat and not fit the hole in the block.

While grinding you will come down to a layer where there is a speparation in form of a yellow plasitic film (in my case). Don't grind beyond that layer since my guess is that the cables connecting to the tip of the sensor is running underneath it. Whould be nice to see a construction drawing of the sensor then we whould know for sure.

I covered the grinded part of the sensor in a very thin flim of sensor safe silicone to make sure that oil didn't enter the sensor when it's inside the block later on.

Cheers Olaf

zort
10-16-05, 06:33 PM
I am trying this same thing.

i am confused on a few points.
1. Do you have to swap heads for this to work?
2. What are timeserts?
3. If you are swapping the 94 crank into the new block, what do you do if your 94 Crank is what is defective? do you replace it? machine it with oversize bearings?
4. What else needs to be changed around besides the Crank sensors, cam drive and sensors, and harmonic balancer?
5. did anyone take pictures of the procedures they did that we could look at?

thanks again for sharing your success with everyone.