Shelby Motor

[colsteege]

hey everyone I have a few questions for the aurora braniacs, I have the lucky to have found a supposed shelby L47 my question to everyone is how to tell if this is an actual shelby series motor, the motor comes with a bulid sheet that has the Shelby logo on it but idk how true that is. So idk if there are distinguishing marks or changes in the design to look for and how well do these motors work in a stock classic, ik a few members have done the swap my question is how well does the shelby motor swap in?

[Marc]

Shelbyracing has done that swap. Ask him.

[scottyaurorav8]

I'll tell you one thing. It working in your car is more of a possibility than ever, now that Madtuner can tune the cars now. I believe in order to tell if the engine is Shelby is on the intake side. The cams should be marked. As Marc stated shelbyracing can clarify this. Great find if its a true Shelby engine.

[sall]

VIN 9 cams in your Aurora equals same thing as the 'Shelby motor'.

[shelbyracing]

Sall is correct. However some of the Shelby Motor's were blueprinted and had more exotic tuning and were stated to be 370HP I believe it was. There is controversy about if that was the true number or not with those motors. Any motor that was finished I assume was test and tune and probably nobody knows what they did with it.

They are pretty much brand new however. And if you want to know if it has been cam swapped pull the valve cover. It is a very easy task to do. Check for these #


You will be shifting when you reach peak horsepower with the factory computer, and a tune would liven it up tremendously. It would stay in it's powerband. You would want 3.71 gears also. A stall converter would be killer as well. ;D

The only trouble I ran into was:
the pilot bearing whoops lol. Got 1 bolt in and no matter how much I rocked the motor and trans it just wouldn't line up all the way. So I took my only bolt out and was relieved lol.

Also the sensor located on the back head just above where the motor meets the trans was different. I thought it was a cam sensor but honestly idk what it is lol. I took the one off my old block.

[scottyaurorav8]

I'm surprised with a lot of the guys on here that are so mechanically inclined, swapping to VIN 9 cams in our motors isn't more prevelant, then just getting a tune from Madtuner. That's definately on my "to-do" list as soon as I finish dealing with some of the other ******* I need to pay for.
Shelbyracing- I also thought the intake manifold was different on the shelby motor as well? and the EGR was deleted too.....

[shelbyracing]

The intake is supposed to be different but I have never inspected it. (The 'intake' you see on a Series 1 pic is a really nice valve cover, and intake plumbing). Yes the EGR was blocked off with a plate, but I replaced it for better fuel mileage. Doesn't make a difference at WOT.

Here is a pic

[RCA1186]

Man that really does just look like a stock northstar haha its mind boggling

[colsteege]

Ok thanks for all the advice guys, im really leaning towards purchasing this motor, its a no miles crate motor and I think with madtuner available im gonna pull my old motor and swap this shelby motor in i plan on doing the brake and suspension upgrade as well Ill hopefully have a write up for all the members to see, does anyone have any recommendations of what else to do while the engine is out and the engine bay is pretty much open lol I want to do a freer flowing exhaust maybe try a true dual or just cleaning up the stock pipes and welding a different muffler in im open to everyones idea

[colsteege]

Anybody have any idea as to what this motor is worth? New still in a crate.

[Marc]

There's one for $3500 in the ad noted below. I think that it might have been sold some time ago.


www.racingjunk.com/Engines-Components/182042492/Shelby-Series-1-Crate-Engine-GM-L47-4.0L-320H.html

[sall]

IMO it is not worth it. Not sure what the the allure is other than the name. I would personally rather stud,reseal etc a 4.6L variation and drop it in versus using a VIN 9 cammed 4.0L. Then get it tuned. That would be less expensive and more fun .

Some other things to do while you are in there though is re-building the torque-axis motor mount and replacing all other motor/trans mounts. As well as drive belt idler pulley and belt tensioner.

[tigger]

Dec 20, 2013 21:59:56 GMT -6 sall said:

IMO it is not worth it. Not sure what the the allure is other than the name. I would personally rather stud,reseal etc a 4.6L variation and drop it in versus using a VIN 9 cammed 4.0L. Then get it tuned.

Exactamundo.

[shelbyracing]

There must be a reason McLaren didn't find it necessary to have larger displacement than 4.0 (3.8). Also the LMP (Proudly badged Northstar) isn't sporting an original 4.6 either.

It is obvious larger displacement has more torque. However it is also obvious a 4.0 has a thicker head seal. Once you start studding that probably becomes less relevant. I would also think that smaller pistons would have less drag and friction at higher rpms. Also a 4.0 that is tuned for high rpm power should get better fuel economy when you are cruising.

Moral of this story is personal preference is exactly what what it sounds like, personal. Some of us are infatuated with the Series 1. I know I am, has been a favorite for years. I think it is amazing I have a motor that was mounted or destined to be mounted in one of those amazing cars.

[colsteege]

Well everyone I have some good news, I was able to purchase my new motor today, I was able to get it for $2500 and I am proud to say that it is a shelby motor with a build sheet matching the engine code!!!! ;D ;D ;D ;D Let the rebuild begin! Ill post pictures as soon as my camera agrees with me lol

[colsteege]

Note the EGR block off






Brand new

[shelbyracing]

Change your fuel rail to prevent a potential fire. The evap solenoids should be different, and if you have oil cooler outlets you can buy factory hoses from GM for an Aurora. You could also change exhaust cams with most mild from CHRFAB too, a thought I have pondered for a while. Increase your fuel pressure also, it will cause a little studder on a cold motor during take offs, but when it warms up it will run better and not lean out in WOT like mine was.

[colsteege]

The motor is stamped December of 99 I thought the fuel rail problem was only on the early versions of the 4.0 I mean the motor I have now has the same fuel rail and I called gm and had them run my vin and they said it didnt apply to mine amd my radiator does have the hook ups so I will run those cooler lines, amd for raising the fuel pressure are u just talking about changing the pressure regulator or just having it uped when it gets tuned?

[shelbyracing]

Before you get it tuned you can adjust it with a tamper-proof torx. Mine had those lines too, I trust SS more. Should be on a JY Aurora.

[colsteege]

oh ok ill have to adjust it and figure which ways up and down, hopefully my service manuals can help with that and ok im just wondering cause I was hoping to leave this motor alone and just drop it in but what ever is best for my aurora ill do haha

[Marc]

IIRC, the fuel rails on the 1995 - 97 were nylon. If it's a 1999, it should have the SS fuel rails.

[sall]

98-99 have nylon rails that were not recalled.

[Marc]

Dec 22, 2013 10:16:01 GMT -6 sall said:

98-99 have nylon rails that were not recalled.

I never knew that. I thought it was only the 1995 - 97s that had the nylon rails.

[shelbyracing]

My motor said 99 and also had nylon. Apparently the recall was only for those years. Yet still, I don't trust that much nylon and that many crimps. I put the SS rail from my old motor on, it is much more simple design as well.

[auroradriver98]

I know this tread is old, but I'm curious about Shelby's L47! Did GM only install L37 intake cams! To get 320 hp?! The LD8 and L47 share the same intake cams (L37, LD8, L47 all have same Exhaust cams)! But i've noticed that all have the same exhaust valve diameter, but the 4.6l has larger intake valve diameter! Did the Shelby L47 also have larger  intake valve diameter?  320 hp naturally aspirated Shelby L47,  supercharged 600+ hp! On stock L47 heads, or were they modified?  Wouldn't compression have to be dropped? And who studded the block GM or Shelby? Curious i wanna build one!!!!