Possible to swap an 8.1L into a GMT900 truck?
05-02-2017, 08:15 PM
#21
TECH Enthusiast
05-02-2017, 08:18 PM
#22
TECH Enthusiast
OP, did you ever get the details figured out? It sounds like you have a good set up, the real issue is when you try to run the gen IV ECM in the Gen III trucks, ending up having weird set ups. I was under the impression you could almost use a tune off an LQ4 for an L18. I have an 01 RCSB Sierra and find used 8.1L's all the time for 4-500 and always wonder how much fun it'd be to build it, stuff it under the hood mated to a 4l80e and call it a day(or year). Looks like Ray Eng has done it a couple times before...
Another thing to look into would be the later model motorhomes. It is possible they ran an 8.1 E38 PCM. Some newer school buses also have a PSI 8.8 that is based off the 8.1. They may have updated the reluctor and PCM in those being they are making them brand new in 2017.
08-17-2017, 01:08 PM
#23
TECH Apprentice
Some one on the facebook 8.1 classifieds page is saying they are using the below kit to swap a 8.1 into there gmt900 suburban with a 6l90e
Big-Block Crank Trigger Ignition Conversion Kit: GM Performance Motor
Big-Block Crank Trigger Ignition Conversion Kit: GM Performance Motor
08-18-2017, 08:52 AM
#24
TECH Enthusiast
Another thing to look into would be the later model motorhomes. It is possible they ran an 8.1 E38 PCM. Some newer school buses also have a PSI 8.8 that is based off the 8.1. They may have updated the reluctor and PCM in those being they are making them brand new in 2017.
Richard
08-23-2017, 07:41 PM
#25
TECH Apprentice
Some one on the facebook 8.1 classifieds page is saying they are using the below kit to swap a 8.1 into there gmt900 suburban with a 6l90e
Big-Block Crank Trigger Ignition Conversion Kit: GM Performance Motor
Big-Block Crank Trigger Ignition Conversion Kit: GM Performance Motor
"The other big (little) differences between gen III and IV LS engines is that the sensors went from traditional pipe thread to metric straight thread and with his help we discovered that the L18 and LY6 coolant/oil sensors are electrically perform the same. So in this instance, running adapters is more expensive and complicated than re-pinning a simple metri pack 150 series connector.
the L18 uses the coolant sensors on the passenger side head however on the driver side there is a plug in the siamese spot, easy fix then without having to do any crazy wiring and de-looming.
Knowledge is progress and progress is good! (or at least a solid re-assurance) I think the biggest hurdle is going to be the engine mounts since the 8.1 and duramax share the same mounting position/mounts/frames, I am led to believe that the HD gasser frames have a slightly different engine mount frame section but custom engines mounts is a pretty easy task in comparison to other engine swaps.
GM offers a kit for the cam/crank signal and sensors
MAP and IAT is the same between the two
using the LY6 throttlebody/maf/intake since it bolts onto the L18 intake manifold"
09-14-2017, 09:52 AM
#26
I'm the one actually doing the swap the trigger kit works pretty well and should work fine. You only need to cut the connector off of the CKP/CMP and re-wire it to a new plug and it should adapt.
the issue I just discovered is that I cannot bolt the 6l90E tq converter to the BB flexplate. The housing of the tq converter interfears with the flexplate itself.
the 4l80/4l85E tq converter won't work on the 6l90E trans and right now im investigating a custom flexplate or tq converter which is not fun.
this was an unanticipated problem
also, I forgot I had this login on this forum - I used to buy LS1 intake manifolds and re-sell them on ebay for 3x as much haha
the issue I just discovered is that I cannot bolt the 6l90E tq converter to the BB flexplate. The housing of the tq converter interfears with the flexplate itself.
the 4l80/4l85E tq converter won't work on the 6l90E trans and right now im investigating a custom flexplate or tq converter which is not fun.
this was an unanticipated problem
also, I forgot I had this login on this forum - I used to buy LS1 intake manifolds and re-sell them on ebay for 3x as much haha
09-14-2017, 07:38 PM
#28
They didn't do anything opted for an easier method
Here is the woodruff key I made that would make it flush with the reluctor wheel installed on the crank gear. I then glued this piece to the wheel so I could secure its location while I drilled the hole to lineup/spot my rollpin hole on the gear itself.
to help locate the wheel correctly on the gear using a 1/8 roll pin
The gear was deep enough that I didn’t need to drill all the way through but a standard size hardware store roll pin would work fine:
Here is it completed, all that’s left is to re-install the cover and install the crank pulley and oil pan.
Here is the woodruff key I made that would make it flush with the reluctor wheel installed on the crank gear. I then glued this piece to the wheel so I could secure its location while I drilled the hole to lineup/spot my rollpin hole on the gear itself.
to help locate the wheel correctly on the gear using a 1/8 roll pin
The gear was deep enough that I didn’t need to drill all the way through but a standard size hardware store roll pin would work fine:
Here is it completed, all that’s left is to re-install the cover and install the crank pulley and oil pan.
The following users liked this post:
Jrgunn5150 (09-22-2017)
10-09-2017, 02:15 PM
#29
TECH Apprentice
They didn't do anything opted for an easier method
Here is the woodruff key I made that would make it flush with the reluctor wheel installed on the crank gear. I then glued this piece to the wheel so I could secure its location while I drilled the hole to lineup/spot my rollpin hole on the gear itself.
to help locate the wheel correctly on the gear using a 1/8 roll pin
The gear was deep enough that I didn’t need to drill all the way through but a standard size hardware store roll pin would work fine:
Here is it completed, all that’s left is to re-install the cover and install the crank pulley and oil pan.
Here is the woodruff key I made that would make it flush with the reluctor wheel installed on the crank gear. I then glued this piece to the wheel so I could secure its location while I drilled the hole to lineup/spot my rollpin hole on the gear itself.
to help locate the wheel correctly on the gear using a 1/8 roll pin
The gear was deep enough that I didn’t need to drill all the way through but a standard size hardware store roll pin would work fine:
Here is it completed, all that’s left is to re-install the cover and install the crank pulley and oil pan.
Was wondering how much progress youve made on this.
10-10-2017, 09:12 PM
#30
Yeah, might have it started by the weekend. missing a few items.
I got a build thread on CK5.
https://ck5.com/forums/threads/2008-....331355/page-2
I got a build thread on CK5.
https://ck5.com/forums/threads/2008-....331355/page-2