When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Engine build - Knock sensor hole too big, how to reduce diameter?
Here’s an odd one - Building up my replacement blueprint engine and found one of the knock sensor holes is too big. I called the manufacturer and they told me to go to a local hardware store and get an insert which will fit the OEM knock sensor thread size.
Thoughts on this? I really don’t like the suggestion, but I’m kinda against a wall as I’d really like to avoid sending the motor back (already swapped a new cam/valvetrain, etc).
wondering if anyone has experience with this type of repair on a block and what type of insert to look for?
The sensor needs to pick up vibrations. Steel would be probably be better than brass. Brass has a dampening quality. At the same time might be desirable on a modded engine; it would reduce sensitivity.
From: Las Vegas - Just stop perpetuating myths please.
Originally Posted by 9T3VETTE
This is what I’ve been able to find locally and I believe what your are referencing. Would it work given the hex end and brass construction?
My concern is the sensor not penetrating far enough into the block, but I have not measured yet.
Congratulations, I didn't think there were 3/8" to 1/4" pipe bushings. That seems awfully tight but I'm not at the hardware store right now. But I will assume that if you found one then a hardware store with more/greater assortment of pluming piping should have a 3/8" to 1/4" bushing (if Home Depot doesn't) - if it's physically possible. I used cast iron pipe bushings all the time at work so if it's possible then there should be one. But I still think 3/8" to 1/4" is awfully tight for a bushing.
I found this flush bushing on eBay, so they do exist. Question is if the flush bushing is a better option than the hex pipe bushing?
With a flush bushing how do I ensure it does not thread too far into the block and potentially fall in? The hex option obviously has a stop point when the hex contacts the block.
I say use the brass fitting you have. It's not long enough to have an effect on the vibration transfer. What casting number is on that block out of curiosity?
From: Las Vegas - Just stop perpetuating myths please.
NPT (pipe thread) is tapered so the flush bushing will only twist in so far. But I don't see any difference in the results either will produce. And my choice would be cast iron pipe bushing. Don't forget to use some pipe dope.
Thanks for the help everyone. Luckily I ended up finding a face bushing at another store and used that. The hex bushing didn’t work so well as it would not penetrate into the block far enough, leaving the knock sensor hanging out. Didn’t feel right to me. Hopefully it seals well, here’s a picture.
Regarding the block number where is it located? I’ll snap a pic. It would be interesting to know what it decodes.
They are just NPT pipe threads , wrap with teflon tape and tighten, pipe threads are tapered. It will seal, and if it doesn't.. give it another half turn. Using brass may have the benefits of filtering out roller rocker noise.
Originally Posted by 9T3VETTE
Thanks for the help everyone. Luckily I ended up finding a face bushing at another store and used that. The hex bushing didn’t work so well as it would not penetrate into the block far enough, leaving the knock sensor hanging out. Didn’t feel right to me. Hopefully it seals well, here’s a picture.
Regarding the block number where is it located? I’ll snap a pic. It would be interesting to know what it decodes.
Designer Imagines A Corvette That Looks More Like a Corvette Than the Corvette
Slideshow: A Jaguar designer's personal project imagines what a modern front-engined Corvette might look like if Chevrolet revisited the golden age of the Stingray.
Engine build - Knock sensor hole too big, how to reduce diameter?
