Mysterious holes and Knock Sensor Placement

[SpoolinGSX]

I have two questions:

1) What are these two holes for that I have circled?

2) I am doing a 6 Bolt swap into my 2g. The block was originally a NA block that I have machined for oil squirters. The previous owner had the block prepared to accept a knock sensor.

I have a 2g knock sensor. I tried to screw it onto the block but the boss that it is suposed to screw into appears to have been grinded down too far. The 2g style knock sensor is wider than the 1g and when I screw it down it hits the buldge on the block from the oil drain from the head. I have my AC removed and I relocated it, as seen in the picture to the boss from the AC bracket. Is this going to work? The thickness between the knock sensor and the cylinders is not the same. The block is already in the car and I can't take it back out.

Here are the possibilities as I see them if the sensor will not work where I have put it:
1) Try to shave down the sides of the sensor - not sure this would be the best idea because I have no idea what the internal construction of the senor is.
2) Fabricate some kind of nut that is thick enough to bring the sensor out far enough to enable it to not hit the drain buldge. I would have to figure out some way of securing the nut, maybe JB Weld.
3) Buy a 1g knock sensor - I may run into the same problem of it hitting the buldge. I am not sure if this would trigger a DTC or if they are even compatible.

Anyone have some insight?

 

[SpoolinGSX]

<img src="http://img.photobucket.com/albums/v462/SpoolinGSX/128_2836.jpg">
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<img src="http://img.photobucket.com/albums/v462/SpoolinGSX/128_2832.jpg">

 

[xcelr8n]

thats for the bracket behind the manifold.
2 bolt holes in the manifold, and one further down and in between the two top holes.
this forms a triangle, and is suppossed to hold the manifold tighter to the head maybe?
I'm not 100% sure why its there, and I know lots of people who dont have them.
this shouldnt be of immediate concern to you...
good luck

 

[dsm10sec]

I don't have my intake mani bolted down... Waste of time if ya ask me.

 

[sweet97]

DSM10sec I cannot make out the green printing. I have a 6-bolt engine in my garage. Can you just type the descriptions that are in green and just refer to their location in your pics? Thanks, Mark

 

[Morphius]

There should be two vacuum lines that port into the intake there. The one on the left goes to the BOV. The one on the right goes a solonoid on the dash (1g).

The second one simply referances the boost for the fpr. You could delete it.

 

[sweet97]

Morpheus could you identify the green words for me? It seems the first pic is referring to the rear of the block. How does the knock sensor come into play with this as I don't see what I think is the hole for the knock sensor?
The second pic has the ground down area which does not appear to be anything on my intake??!! I can't make out the green writing on my screen. Thanks, Mark

 

[Morphius]

The first pic writing (l to R) says original location, and starter.

The second I can't read all of the second pic, it says XXXXXX and ignition coil.

He's has a NT block set up for a turbo application. I thought the boss NT to Turbo was the same with the excpetion they tapped the turbo block. I thought both were drilled. At least the NT block I used was drilled. I simply tapped it and used it.

Anyone have a camera handy and can get a shot of a turbo block and the knock sensor boss?

 

[sweet97]

Thanks for decoding the green words for me! I don't have a camera. However the boss is just left of center when looking at the block. There is a freeze plug just to the left of the boss. This is on a 6-bolt from a '91 AWD. Mark
PS: The hole marked "original location" is the location of the sensor "boss" except tere is no boss in the pic, just the hole. Again the location is correct.

 

[SpoolinGSX]

Sorry for the late reply. The picture of the manifold is taken from the front looking down where the fuel rail is. It is not the back of manifold like people have been saying. The bottom of the picture is a blue towel over the valve cover. The green writing on the left says MDP Sensor Bung, this is for the EGR system. I was just trying to show that the picture is taken on the front of the manifold.

As far as the knock sensor thing goes I guess my question wasn't clear enough. The question was, since I can't use the original bung for the knock sensor, is it ok to use the bung for the AC bracket. Or will that not be ok? My plan is to JB Weld a nut with the correct thread pitch onto the original location so that I have enough clearance to be able to screw it down without hitting the oil return from the head.

I will bypass this project if having screwed into the AC bracket bung is alright. My thinking is that if the knock sensor is screwed tight against the block near the cylinders that it would be receiving similar pressure differences to if it was screwed into its original location.

 

[peregrine]

heres a bump. i want an answer for this for my 2.4.

 

[sweet97]

The first pic is the back of the blockand the hole is for the knock sensor. How abou this. Find out the threading on the knock sensor and get some threaded rod with the same threading. Find a nut with the same threading and use the threaded rod to "position" the nut for welding so it will have the threading line up and continue uninterupted from the nut into the block? You can't have very much interference do you? You mentioned an oil line or passage so I may have suggested something that would not work, just a thought. Mark

 

[SpoolinGSX]

The oil passage I am speaking of are the two vertical tube looking things directly to the right of the original hole.

Another problem is that the block is already in the engine bay with no way of getting it back out. There is not enough room to get welding equipment in there.

My thoughts as of now are to use the threaded rod idea but to JB Weld the nut on there. The sensor doesn't have to be on that tight so there is not much risk of twisting the nut. I would have to grind this nut so fit over the buldge of the oil return.

The problems I am thinking about are as follows: The nut is not going to be cast iron so the harmonics of the sensor mounting surface will be different. Ideally I would like to get a cast iron nut or some sort of iron.

Here are some ideas I have so far: use the threaded rod to line up an initial nut which is ground to fit over the buldge. Then take extra nuts and weld them to the original nut to give enough clearance for the sensor to not hit the oil passage.

Or fabricate some sort of iron peg with male threads on one end and female on the other. I could screw this into the block and then screw the sensor in the other side (sort of like a stud with female threads on one side).

 

[sweet97]

The iron peg idea would work great however it could be costly and time consuming to fabricate as it would in my opinion be a fab shop job and too small for a 1 off to worth their while. Thanks for the explaination of the oil return galleys. i got it now. Iam tearing down a 6-bolt fr a possible rebuild and am seeing some of these items for the first time.
You might find something in a plumping section of a specialty store or a big chain store where I have seen iron tubing(piping) theaded, say 4" sections. You might be able to make the peg yourself. Get the smallest diameter you can. One where you could tap the inside for the sensor anyways. Then youwould have to cut to length and machine and thread the other end to the correct block threading which is of course the same as the sensor again. I see this as a pssibility! It is 6 A.M. and I just woke but still ths could work with minimal machining. You could tap the end for the sensor and cut to length. If you were careful and the pipe you got.....could a peg that was hollow work or do you think it would need tobe solid? Mark

 

[houstonECLIPSE]

i'm using a nonturbo 4g63 6 bolt block in my 98 gst. there was already a place to put a 2g knock sensor. i didnt have to drill or tap anything. its in about the same spot that it was on the 7 bolt 4g63.

lupe

 

[jérôme]

Hey nathan, i have a spare 1g knock sensor i can give you. let me know if you want it?
jerome