3.8L V6 SII Upper Intake L36 to L26 Conversion

[cazanowick]

Hello Grand Prix Owners,

I am planning an engine and transmission rebuild on my 2000 Grand Prix SE with the 3800 Series II NA engine. My intentions are to make modifications to eliminate problematic plastic parts which should have never come in contact with the engine in the first place. I managed to acquire a used Series III L26 UIM.

Does anyone out there have photographs of the appropriate modifications I need to make in order to have the L26 UIM perform exactly like the L36 UIM? My goal is just to replace substandard material, plastic, with the more appropriate metal material. There are a couple of YouTube videos out there, but they lack details and don't address the throttle body on the L36 engine. Also, a number of articles do not accurately and clearly describe the modifications. I am familiar with need for the adapter, and that is a no-brainer.

Thanks for any help you can offer,
C.A. Zanowick

[indygrandprix]

It's a lot easier to just plug off the coolant ports to the throttle body and use the plastic manifold. Not that i don't agree with you the plastic intake wasn't designed the greatest but It's really not worth the money time and effort unless you where going turbo... and even then some turbo cars use the plastic UIM

Youll need a TB adapter which cost like 100 bucks from zzp unless you can get one used for like 60 prbly. Then you also have to do something with the evap. someone will post a link to the page on how to do it eventually. I don't have it bookmarked at the moment.

[cazanowick]

IndyGrandPrix,

Thanks for the input. Yes, I am familiar with ZZPerformance's TB adapter and briefly mentioned that in the bottom of the post. That is straight forward and the easiest modification in the project.

As I mentioned, effort to move to more durable material is good insurance against losing the whole engine to coolant leaking into all the wrong places. That happened to me before in another GM engine well known for bad intake gasket design/material (2.8L V6 S10 Blazer). So, this post is more directed to the people who have successfully completed full conversion. The responders of other post on this website addressing the same subject included links to photographs documenting what they have done. Unfortunately, those links no longer work. I was very curious as to how they did it. As of yesterday, I managed to get a bit more information on what needs to happen to the PCV inlet.

I have time before pulling the trigger on the rebuild. So, I do plan to thoroughly document what I have done for the benefit of those who want to get the most out of their engines. All the parts which will require modifications will be acquired as an extra part ahead of time to allow the machinist to work on them off the engine.