Knock Sensor Locations?

[TheSilverBuick]

I still want to install a knock sensor on my car (it does ping at low elev if I don't back the timing off) and determined a while back that the standard GM knock sensor does not fit the coolant drain plugs in the Buick 455. So I was thinking of alternative locations that may work and be relevant.

My first thought was to maybe drill a hole and tap it on an accessory bracket, but I'm thinking that wouldn't be a very good location (if it is tell me! )

But while furthing thinking about it, the LS engines have put the sensors in the lifter valley (through a cover plate), and was thinking "what if" I drilled an tapped a spot on the rear of my intake? I won't take a drill to the block for fear of permanent damage. But an aluminum intake... If I swap cam's I'll be pulling the intake and could drill and tap it then, and if something goes wrong get it welded back up. And that then also begs the question would the knock sensor still work as intended?

Proposed location above the A, it's dead space under there.



My last thought is while looking up the LS setup, I noticed the LS knock sensors had a finer thread on them than the older '80's-'90's GM's. Any one build/pull an LS engine recently and have an un-usued knock sensor that I could have?

Thoughts?

[squirrel]

Re: Knock Sensor Locations?

look at a buick V6, you'll find a hole on the top of the bellhousing area, right?



hard to tell but it's the hole between the two upper trans bolts, slightly towards the left of center, in this random interweb photo.

Now...how do you put that hole in your block?

[TheSilverBuick]

Re: Knock Sensor Locations?

Now that's think'in Jim! People drill holes in their Buick's right there to run an oil pressure line for either measuring oil pressure or to plumb extra pressure there from the pump.

So a follow question, if I drill that hole with out pulling the engine/trans, what possible problems could there be if some metal shavings happen to fall into the clutch area? Now that's worse case scenerio as I should not have to drill completely through that to tap it for the sensor.

[TheSilverBuick]

Re: Knock Sensor Locations?

Hmm, it looks like the 455 has a larger dip than the V6, not that it's a huge issue, but not as simple.

[TheSilverBuick]

Re: Knock Sensor Locations?

Hmm, I went out and looked under the hood. I don't see an issue drilling the hole (particularly if I have the intake off, but could either way), but I'm not sure if I'd be able to tap it. Hmm.

The V6 picture you posted has me looking at the front part of the valley, like right under the bypass water hose.




My previous concern with drilling the block really was about drilling the side of it and risk tagging a cylinder, but those two places have a very low "ruined" the block out comes.

[SpiderGearsMan]

Re: Knock Sensor Locations?

just hook a choke cable to the distributor and listen close .....save you from the code 42

[CTX-SLPR]

Re: Knock Sensor Locations?

I'd worry about timing chain noise in the front getting picked up.
Two options; hit a coolant drain point on each side for a knock by drilling them oversized for the sensor or run it in the valley webbing on top of the bellhousing.
For the rear webbing, put 1 dead in the center and drill straight through. You're going to have to worry about clutch noise though. There is also that sound does funny things going around corners, I'd rather mount the sensor either verticlally in the bellhousing webbing or a pair into the waterjackets. Will your headers clear the sensors if put holes between 4/6 and 3/5?

[TheSilverBuick]

Re: Knock Sensor Locations?

I kind of wondered about the timing chain noise. I can't imagine clutch noise being an issue except while shifting, and when the clutch pedal is pushed the engine isn't as loaded up to ping.

I did kind of think about the rear webbing, when the intake is removed, cover the lifters valley and drill through then tap from the outside and thread the sensor in from the outside. That may be my best bet.

I don't want to mess with anything around the water jackets on the side of the block. I thought about taking a 1/2" drill to the coolant drain plug and then re-tapping it... but it makes me nervous to do so. Not that I'd expect widening a hole with a drill to be tough. There is room under the headers.

[IRONHEAD]

Re: Knock Sensor Locations?

isn't there any oil gallery plugs on this engine you can tap into..
you can also get iron threaded bushings.. to bring your coolant thread down to the sensor thread..
these sensors don't like loose forged pistons..
your valvetrain may set it off too..
what was the sensor used for(what app)
what herz is it set for

[CTX-SLPR]

Re: Knock Sensor Locations?

I kind of wondered about the timing chain noise. I can't imagine clutch noise being an issue except while shifting, and when the clutch pedal is pushed the engine isn't as loaded up to ping.

I did kind of think about the rear webbing, when the intake is removed, cover the lifters valley and drill through then tap from the outside and thread the sensor in from the outside. That may be my best bet.

I'd put it vertically in the bellhousing webbing, not into the valley. From my experience with ultrasonic testing, it looks like a cleaner path into that webbing than the valley wall.

I don't want to mess with anything around the water jackets on the side of the block. I thought about taking a 1/2" drill to the coolant drain plug and then re-tapping it... but it makes me nervous to do so. Not that I'd expect widening a hole with a drill to be tough. There is room under the headers.

I'd put a pair of new holes in the cooling jackets. Get/make a magnetic drill guide, use the proper drill size , and an NPT tap. I'd use 3800 sensors, most of the tuning for frequency rejection seems to be in the ECM as the LT4 had an add on module that was different than the regular LT1 for it's roller rockers.

http://www.korit.com/tapndrill.htm

[TheSilverBuick]

Re: Knock Sensor Locations?

Ok CTX-SLPR, you have me sold on the Bellhousing webbing or maybe the coolant one. Thanks.

The one I grabbed was off a late 80's Chevy truck. Sensor and knock sensor module. I figured that one would be calibrated for a lower rpm, lugging the engine, conditions.

My cam isn't wild so I shouldn't have excess valvetrain noise.

[fabricatordave]

Re: Knock Sensor Locations?

what size are the block drains????

[CTX-SLPR]

Re: Knock Sensor Locations?

Ok CTX-SLPR, you have me sold on the Bellhousing webbing or maybe the coolant one. Thanks.

The one I grabbed was off a late 80's Chevy truck. Sensor and knock sensor module. I figured that one would be calibrated for a lower rpm, lugging the engine, conditions.

My cam isn't wild so I shouldn't have excess valvetrain noise.

That module is really what is going to control the output to the ECM for KR (Knock Retard), probably a decent choice, I'll let DG weigh in on what might be a better one. If it is audibly pinging and the sensor isn't pulling timing, tighten it into the block more to see if you have a sensitivity issue as this will increase your coupling. If it's overly sensitive, back off the torque or put some thread sealer in (be very careful on how much though, don't want to overdamp the interface).

[TheSilverBuick]

Re: Knock Sensor Locations?

what size are the block drains????

Significantly smaller than the knock sensor needs, 1/2"?

[IRONHEAD]

Re: Knock Sensor Locations?

what size are the block drains????

Significantly smaller than the knock sensor needs, 1/2"?

drill and tap