avrfan

One other quick question:

I'm swapping an s5 na motor block with all s4 components
(OMP, Intake, Emissions controls, harness etc).

Do I need to change the front counterweight if I change
the front cover and OMP?

Also, regarding the harnesses, can I use the 1986 NA Engine Harness
in an 1988 chassis? and if so, do I have to switch to low impedance
injectors or use high impedance injectors.

Thanks,
Dave

fstrnyou

i believe 86 and some 87's used low impedence injectors. if you want to use the injector resistor block, then you need low impedence. if you don't use it, then keep using your high impedence injectors. all you have to figure out is how to bypass the resistor block and take it out. i don't know what one looks like, so i can't help you there.

Icemark

counter weights are based on rotor weight... so if you are using S5 rotors, then you use S5 counter weights.

avrfan

Got it! Thanks! So its all gravy as far as my weights go, I'm just going to leave them the way they are.

avrfan

I think the resistor block is located under the factory stock airbox. But I have not seen one in so long that I'm not sure.

I'm just wondering, if I go with 86 engine harness injectors and resistor block and ecu complete, it should work all together fine with the 88 Dash Harness and other electrical right?

Does anyone know if the 86 engine harness, injectors, resistor box, and ecu are compatible on an 88 chassis?

Basically, I don't want to use the 86 engine harness etc if I have to change the dash harness and a bunch of other stuff. I can manage with just the engine harness thats a snap.

Thanks,
Dave

Dave

avrfan

One more comment on the engine harness:
The reason I'm not using the original 88 engine harness etc is it was butchered by some previous guy and I only have an 86 right now.

Thanks,
Dave

Digi7ech

iTrader: (1)

OK your statement confused me a bit but here is the info.

86 and 88 harnesses are the same except some 87.5 and up engines had high impedance square style injectors.

Now High impedance injectors have an offset notch.
The low impedance ones are centered notched.

Series 4 injectors and plugs are square.
Series 5 are oval plugged.

I am going to assume your using the S4 harness on the S5 block since the S5 OMP won't work.
You will need the S4 BAC as well since that is oval or sqaure plug as well.

Pretty much just take everything off your S4 engine and put it on your S5 block. Keep the manifolds though since they are better.

avrfan

Yeah you figured it out. I should make it clear what I'm trying to do. I have an S5 Block. I want to put that into an S4(1988) Chassis using S4(1986) Harness and sensor/emissions components.

So the S5 Intake is better? How does the VDI system Actuate with the S4 Harness? Is any of its operation dependent the S5 harness/ecu/vacuum lines etc?

I was thinking of using S4 vaccuum spider and hoses and intake and harness and all sensors and front cover/OMP etc completely on the S5 block to make it as close to smog legal as possible. I heard that the only difference between the S4 and S5 blocks is that the S4 has provision for EGR Valve and S5 Does Not. And also, another difference is either s4 or s5 has a "Port Air" hole where the intake bolts to the block. Kevin Landers at Rotary Resurrection said you have to plug the port air holes with Epoxy when doing a s4/s5 conversion or you'll have some kind of leak but he wasn't clear about what model has the hole.

Thanks for the pointers on the harness, I really appreciate it!

inflatablepets

Kevin Landers has a pretty good writeup on that swap. Rotary Resurection.com I believe.

avrfan

Actually I have been all over that site, read every word of every how-to. I've personally talked with him via email. He knows alot of stuff however I don't believe the swap how-to addresses all the issues I am asking here. Also, he's a busy business guy so I don't think he had time to address my questions in detail. The site is a really good starting ground but its not exactly a newbie tutorial. There's a few typos also which make it confusing. Other than that its been a great starting point for learning and good marketing for his business. If he gets the time to brush up the details a bit on there it would be great.

Dave