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allante 9 engine swap to a y engine

6305 Views 10 Replies 5 Participants Last post by  chp350
first time posting, but i have been getting good infromation from this site since 2006.thanks to Ranger,AJxtcman,tateos,Submariner409 and 97Eldo guys are great!!!! heres the question. my friend has 1993 allante with a blown engine other friend has two complete y engines...the one in the wrecked 1994 eldorado has just had the heads redone with block studs, good trans axle also..the other y engine is engine only...he is not looking to make this car orginal he just wants me to install one of the y engines or y engine and trans axle into this allante...can i get some feed back on this from you guys on which way u feel i should go and any advice from you would be appreciated..I trust your knowledge and opinions on this..thanks
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anybody got any ideas if this swap will work? will i have to have anything reprogrammed ,would the higher gear ratio effect much or should i use the stock transaxel in the allante..i'm new to posting did i post it wrong? 68 people reviewed but nobody has responded..
Allante is a bit out of my realm, BUT, if the overall Northstar swap advice holds true here, you should go with a same/close year engine with the transmission and PCM/ECM for that engine to avoid connector, programming, and transmission-speedo-shift problems. The two FWD Northstars, 9 and Y, are set up for their respective final drive ratios, and that's the way they'll deliver their best performance.
Can you get the PCM from the eldo also? If you can, that's the way to go.

If you can't get the PCM with the engine/tranny your best bet would be to buy just the engine and swap the heads so you keep the old ones. Everyone would recommend doing the headgaskets on a secondhand engine anyway. So why not just convert the new Y engine to a 9 by using the old heads?
thanks for the replys..the allante engine and heads are toast..while trying to determine the valve train noise the engine locked up from lack of oil and ruint the cams and lifters ...the 1994 eldo y engine just had head gaskets redone with head studs app 1,500 miles ago 46 days ago..he has the whole car with all wiring harness and computers (tree fell on car)..IF i use the engine transaxle from the eldo what will i have to do so that i'm not limited to top speed of 112mph or would it be better to swap out the engines and use the existing computer trans axle in the allante? thanks again.. if i need to have the computer reprogramed who can do that on this board?
It would be better to swap the whole powertrain and computer. If you put a vin Y engine with a vin 9 pcm, it will never run right. The only way you can do the procedure and have no speed limiter is to get the vin Y PCM reprogrammed with a Tech I or Tech II scan tool.

The eldorado I'm driving right now is a vin Y, however I pulled the vin 9 engine/tranny/PCM out of a rear ended STS and put them in my eldo. It runs great. I definitely wouldn't mix and match with these cars though. There are too many electronically controlled systems on them and no easy way to tune them to work together.
AJxtcman or Wester's Garage will remove a speed limiter, using your PCM, for about $300.
Keep in mind this is a 1993 model we're talking about. I think AJ's tuning work is on the OBDII cars- anything 95 and older can be chipped, if I remember correctly. I'm the mechanical guy. AJ is the guy to talk to- he knows his stuff.
Bolt JUST the VIN Y engine into the car with nothing else and you will be 100% happy.

This is a S/D fuel setup and it really won't know the difference. Use the Allante everything from the intake to all the sensors. Use the Allante` trans and torque converter. Take a good look at the Exh manifolds to see if the newer set look better. I have been told the oldest ones were the worst flowing.

Now for the Kicker. If you want to know if the engine is worth installing pull the rear valve cover and look at all the lifters for a round circle. If you find this the cams and lifters are failing. On the other hand 75% or more of all 93 to 99 Northstar's are that way driving on the road. If you don't want to know don't look.
AJ is there any other place to get replacement cams, then from GM? They list for I think over $800 each. Is there any better priced source for cams? I can machine the lifters, but with bad lobes it does NO good.
AJxtcman,thanks for the advice on just using the Y engine and leaving everything else a lone..worked out perfect..In fact to reason I say that is because this was my friends car that I did this swap for.. I also have an allante with the 9 engine and now that he has the one with the Y engine he gets better gas mileage and can out run mine..Dont understand why being that i have the 25 more hp but its ..thanks again T
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