Hey guys, I just installed my 327. I'm trying to figure out what to do about the knock sensor. The guys that prepped the block put allen head plugs in the block drain plug holes / knock sensor locations with what I THOUGHT was teflon paste. It must have been some kind of locking compound. After I put the engine in, I went under the car to remove the passenger side drain plug & guess what - it wouldn't come out. I even completely rounded off the allen head plug I was trying to get out. (I was even using the correct wrench.) I did get the car started but it wanted more timing. I had stabbed the distributor & set it to what I thought was zero based on the crank & damper (engine not running). It wouldn't start & was backfiring, so I advanced the timing bit by bit till it would start. Maybe the computer was pulling timing since there was no knock sensor installed? So the question is WHAT NOW? I had a couple thoughts. I could try to remove the driver side drain plug, extend the harness & install the sensor there - but I bet it's just as tight. Maybe there is some other hole on the block with the same threads. I'd rather not disable the knock sensor, but if I had to I could connect it to the harness but not the engine. Or I've heard it's got 100 ohm resistance, so maybe I could wire a resistor and omit the sensor. I'd like to retain the sensor. But not bad enough to pull the engine. HELP. Thanks.

By the way I will be doing custom tuning but I don't have the stuff for it yet.

The engine is a 327 +.060 (336), with patriot vortecs 2.02/1.60 valves, GMPP vortec TBI intake, lunati 60103 cam & 9.8 compression.

Currently it has open hooker shorty headers and the stock tbi. But it will have headers w/ full exhaust and the holley 670 tbi. The chip is stock 305 tbi for right now.

Currently the knock sensor (this thread) and oil pressure switch (a different thread) are lacking and the harness is left disconnected at those sensors.

Thanks again.

If you were using the right size allen you shouldnt have stripped it. it's possible they put some sort of locking compound, cant you ask them? you might try heating it up first to make the compound melt and then taking it out. You can try welding a bolt to it and then using a ratchet loosen the bolt and that might take it out. toher than that i dont know what to tell you

Once you go for it, it's a 'no going back' route, but.... You could drill through it, then use a square easy-out (you pound them in, then the flutes jam into the sides).

The bigger the hole the better (without killing the threads!), and obviously don't go too deep! Just through, then stop.

And as said above.... heat.... after you've drilled the hole, put a torch on the block around the plug. Don't heat the plug. It'll swell and get tighter.

You can drill/tap a hole in the fuel pump blockoff plate and mount your knock there

There is another factory hole in the rear chinawall near the dist you can mount the oil pressure sender. Get a 90* bend and it will tuck even nicer

I use channel locks to remove old knocks as I dont reuse them

Thanks for the responses, guys. FYI, it was the correct size allen wrench - 1/4" was a perfect, tight fit. And I had an enormous amount of force on it before it stripped - I was using a cheater and everything. I do think he used some kind of locking compound. I can ask the guy. But, he did the block prep a few months ago - we will see if he remembers. The stuff he put on the threads was white, so I thought it was teflon-based. Apparently not.

Those were some good ideas about removing the bolt. BUT since I don't want to pull the engine, I may try drilling and tapping the fuel pump block off plate since I do have an extra one. (I'm not comfortable using a torch, laying on my back under the car.) If that works, I would just wait to use one of the above plug removal methods until some future occasion when the engine is out.

I guess my only concern about using the fuel pump block off plate is that the sensor may "hear" different things right next to the timing chain than next to the bores. It is still probably better than not having a knock sensor at all.

Thanks again for the ideas!

'327

I went through the same problem on 350 retrofit. Drain plugs tend to rust-in and backing them out is next to impossible. In my case both shared off (about 2/3 came out), end up drilling through and re-tapping hole. Same goes for oil galley plugs which use weak 1/4 square drive. You have another drain plug on the opposite side of the block. You may try it there, but the chances are is that it is going to be no go there as well.

Drilling a pilot hole and right sized easy-out is really the only option.

Do not use alternative locations or adapters - KS is a tuned frequency microphone.

//RF

I had the same problem with the 400 I swapped into my car. Not that I was ever going to find the right sensor for that motor, but figured something was better than nothing. I started with some PB Blaster, nothing. Ended up getting a little propane torch on it and heating the thing near cherry-red. Came out there. I know you said you stripped the head plug, may be worth drilling out, heating up the piece, and using the easy out as previously recommened. Desperate times call for desperate measures .

do you have enough room so you will be able to drill in at a clean 90 degrees? and if they used lock tight you can put a torch to it for a minute or two and it will allow you to break it free. i would still us an easyout after drilling a pilot hole, better than damaging the block when you dont have to.

I could get close to a straight shot at it with a drill.

Keeping in mind this is an allen-head plug in the block (where the knock sensor will go), isn't it possible that the right size ez out could just fit into the stripped allen head area, no drilling required?

Drilling into something that is going to spill coolant at me & the drill doesn't sound so fun.


Thanks and keep the ideas coming. Especially if any involve not having to remove these plugs! (other places to install)

The back end of the that plug is rusted into the block threads. In my two attempts to remove these plugs only 2/3 came out! The last 1/3 was sheared off and stayed put!. Drilling into the remaining metal and easy-out was the solution for me.

Initially I tried to use regular socket and breaker bar - did not work, just rounded off the plug. Followed by BF Wise-locks that stayed put while I applied gorilla sized force, but that sheared drain plug off! Either way, it was one messy affair that they do not show on Hot Rod TV episodes!

Use 90deg drill adapter or air driven drill to avoid unpleasant combination of coolant and electrical drill.

//RF

The block was just completed. I doubt the plugs are rusted in.

You have a 88 camaro sport! i had one of those, with a 305 in it. Until someone ran a red light and T boned me...Not a good car to have a crash in. Totaled it... R.I.P Camaro I have a 95 firebird formula 6 speed now with an lt1, but sometimes i still miss the old '88 camaro