Intake manifold questions

[cooper]

I finally had a chance to swap the 2bbl intake off my 81 na 3.8 for a 4.1 intake.

On the 3.8 intake, there is a temp sending unit to the right of the thermostat housing, on the top. (for the idiot light)

On the 4.1 intake I see what looks like 2 sending units, one directly below the t-stat housing on the front, and one to the left of that one, still on the front.

My questions are: Do I really know what I'm looking at, or am I out in left field? What are the two connections for?

Thanks for the help, and thanks for the past help, too. It was much cheaper to get a 4.1 intake and Q-jet than to buy aftermarket.

 

[Ttype83]

Originally posted by cooper
1.On the 3.8 intake, there is a temp sending unit to the right of the thermostat housing, on the top. (for the idiot light)

2.On the 4.1 intake I see what looks like 2 sending units, one directly below the t-stat housing on the front, and one to the left of that one, still on the front.

3.My questions are: Do I really know what I'm looking at, or am I out in left field? What are the two connections for?

I'll asnwer 3 first, Yes you know what you are looking at.

The new connection is a temp sending unit to the ECM, it should be a round connection unless it's been changed. Then it's should be more square.

 

[cooper]

Thanks for the quick answer.

 

[Freddie's Buick]

What's up Cooper!

Long time no see.......Freddie's Buick in the house with an '81 N/A also. Drivers side is the coolant sensor for the ECM. Passengers side is the idiot light sending unit.

On the 4.1 intake you'll probably have an additional opening next to the coolant sensor which holds a temp controlled manifold vaccum port, (it is not used on our 3.8's).

I removed it and installed a temperature gauge sending unit for a temperature gauge. I highly recommend it. Now I have the added advantage of a working idiot light and a temperature gauge.

 

[cooper]

Been busy with kids, work, kids, work....it never seems to change.

I like the idea of putting a mech gauge in there. I've always been a little wary of idiot lights.

When you swapped intakes, did you have any problems with the air pump pipe? The 3.8 goes into the top of the manifold, and the 4.1 goes in the back. The original pipe wouldn't fit, and I found out it doesn't bend (it breaks). I found an AC Delco part number for a 4.1 pipe. $14.00 or so. Problem is, it's a special order, so I have to wait a couple days.

Thanks for the help.

C-ya

 

[Freddie's Buick]

Yep,

Had that problem too! I believe I went out to my local bone yard and ripped one out from a later, ('84 and up), 3.8.

It was either that or another 4.1. I paid $3.00 for it. But man was it hard to rip out. I don't remember the wrench size but I used a 2X4 for leverage. Once you get one.....be careful putting it in. You could strip the threads on the intake, (it's aluminum). I did mine prior to installing the 4.1 intake. (Easier and safer that way....).

 

[cooper]

Thanks for the heads up!!