3.8 Interchange.

Topic: 3.8 Interchange. (Read 1239 times) previous topic - next topic

3.8 Interchange.

March 09, 2008, 10:51:05 PM

I just picked up an 88 Cougar with 3.8/AOD combo My question is i have an 86 cougar with 3.8/C5 combo.... the 86 cougar needs a fresher motor as it burns oil like crazy. can i
A. Swap the long blocks minus intake manifold
B. Swap entire harness/engine/trans

Reason i ask is because i know 88 3.8 had the internal balance shaft added to it... one year only... it is also the SEFI injection system so id know the wireing harness would have to be swapped. I would really appreciate any input.. v8 swap isnt an option right now (plus i enjoy being the fastest 6 gun on the board atm lol.
Eric

3.8 Interchange.

Reply #1 – March 09, 2008, 11:14:24 PM

88 was kind of a year for the 3.8. First year for MPFI, but it was batch fire, not SEFI. Because of this you MIGHT be able to use your existing CFI harness (though you might also have to repin the EEC-IV connector).

The 88 heads are different than 86 and older, so I don't know if the manifolds would swap (the top of the head is shaped differently, but I don't know if the ports are different)...

3.8 Interchange.

Reply #2 – March 10, 2008, 02:01:53 AM

here is some info that should help explain some things
http://www.babpen 15s.com/editorial/ar/ar90134.htm

3.8 Interchange.

Reply #3 – March 10, 2008, 02:19:30 AM

you can / could use your exising eec / harness but it would be much less painful to just swap in the entire harness / engine / transmission and adapt very little in the long run.

Now what you really have there is a nice option available to you.
Stuff in a 4.2L crank rods and pistons and you will have yourself a stroker 3.8. The 4.2L is nothing more than the short block of a 3.8 stroked.

The 4.2L short block parts are a direct swap. Get the cam as well because of things i discovered doing my 3.8 project a while back.

3.8 Interchange.

Reply #4 – March 10, 2008, 05:07:53 AM

well right now im lookin just something i can swap so i dont have an oil burning 3.8 lol

3.8 Interchange.

Reply #5 – March 11, 2008, 12:39:54 AM

well, just so you know,, you could use your existing harness and EEC since computers think there are two injectors. The CFI appilcation injectors are low resistance / impedance. Your six injector motor your calling "sefi" has a higher resistance injector three of which are in parrallel to pin 58 on the eec and the other three in parallel off pin 59. The three in parallel would come out to be about the resistance of a low impedance injector.

**check what the resistance is on one of the 88 injectors***

Once that hurdle is jumped, its very likely you can use your exisitng harness. The 88 v6 has a couple more sensors than the 87 setup but minor issues for now.

Required sensors to make the car run decent to great....
TPS
MAP
ACT
ECT

Issues i foresee
-transition of the 87 fuel line to the 88. this may be as simple as a disconnect and swap of the tubing where it changes to hard plastic.

-minor vac line which you can copy cat from the 88 setup to transition to the 87 car.

-throttle cable / tv cable engineering

-remembering to use the flywheel from the 88

ill probably think of something else. To gain more ground in the "fastest v6", you might wanna consider the combo i suggested. It should be pretty dirt cheap plus you get to open up the newer 3.8 and freshen things up.

3.8 Interchange.

Reply #6 – March 11, 2008, 02:04:09 AM

well right now my thoughts are to use the harness and complete motor from the 88 pending compression test and start up.
i do want to remove some of the emissions things and A/C but ill figure out belt routing later. ill keep ya posted

3.8 Interchange.

Reply #7 – March 11, 2008, 02:12:01 AM

yeah, it would be a good idea to short belt the fugger.

I suggest you study the tension pully and discover what makes it stop when you twist it CCW to remove said belt. You can cut off some of the aluminum housing and get more swing out of it so your belt size does not end up being an expensive odd ball lenght. Its really funny how a 6 rib belt being a half inch difference can mean the difference of 20 bux.

I short belted my 20th eliminating the ac and smog. Ill prob factor the AC back in when i get a vac pulled on it and define / locate leaks.

3.8 Interchange.

Reply #8 – March 11, 2008, 02:34:21 AM

ok cool... i left you a pm btw.

3.8 Interchange.

Reply #9 – March 11, 2008, 10:00:39 PM

It will likely be more work to use the '88 harness(I believe all the plugs are different) than to adapt the '85 harness to the '88 engine...

3.8 Interchange.

Reply #10 – March 12, 2008, 04:12:39 AM

yeah im thinkin of using the harness and ecu out of the 88.... it will eliminate overlookin anything and give me a chance to throuroughly check out the wiring harness to make sure nothing is chewed thru