Datsun Roadster Forum-311s.org

I put a set of these "Datsun Roadster Smog Plug Inserts - Set of 4" from Datsunparts.com part number 2208.

They come with 4 plugs and instructions. They are for eliminating the chirping noise that you sometimes get from putting in other short plugs. My old ones made the roadster sound like an old Volkswagen.

The instructions that come with it are very good.

I had issues getting my old plugs out that someone put in with the plumber pipe style 3/8 inch square top plugs. These were short and created the chirping sound. And are hard to remove.

I got 2 of them out but the center two were in further and they have the 3/8 inch square top not a hex top so I had to use an upsidedown socket that was for 3/8 inch and then used a allen wrench that attached to a 24 inch breaker bar. But it felt like it was going to strip and it strippped the head a little so I had to find a better 3/8 socked that was more flat on top so it got a better bite lower on the square plug. I found one for a impact wrench that looked good and worked to get those last two off after squirting lots of Kroil and trying and more kroil and waiting a day and trying and more kroil and trying and continued doing that for a week and they finally came out. I did not want to force it as i was affraid of stripping them off.

Then I bought a new bolt to clean the old threads out but bought too short of one and the head hit the block by the valve cover before cleaning all the bottom threads out so make sure you get a bolt longer than you think you need so it clears.

The new plugs went in fine. Very tight fit so using a new wide screwdriver is important. I picked up a new one at Ace for $11 that had a flat shank I could use a wrench on for extra leverage.

After getting them in with some anti sieze as directed, they seemed to work very well and cut out about 90% of the chirping noise I was hearing.

I attached some before and after pictures.

I see that you are rocking the Tygon tubing too!

I had the brass plugs before I went with the inserts. I de-smoged before the inserts were available. If someone really wants to go cheap and use the plumbing bits, I'd suggest cutting a groove across the top so you can use a screwdriver to get them in/out.
Better yet, heed svwilbur's advice.

Another option is the allen plugs - they take an allen wrench to install/remove. That beats cutting a slot into the other ones. You still should fill the void below. Oh, get a heat shield!

Wow, what a demonstration of patience!

Note of warning on that Tygon tubing - it will melt in the high head environment near the exhaust manifold. It is fuel safe but not made for heat.

James

I have never had any melt, and it has been in some high temp locations. The stuff I have bought has indicated that it is heat resistant. Where have you seen a failure James?

I did a little digging. Typical Tygon fuel tubing as specified for small engines is Tygon Fuel and Lubricant Tubing F-4040-A. According to a supplier - US Plastics - the tubing is rated to 165 degrees. With a heat shield in place, that should be just fine. Here is a link to their site:

http://www.usplastic.com/catalog/item.aspx?itemid=23487" onclick="window.open(this.href);return false;

165F is easily achievable with heat soak. It is not running conditions to be concerned with, it is the drive-thru lane at Burger King where the under hood temps are the worst.
use "heat dots", available from several sources, they send you a 150/250/350 batch, and you can learn a ton.
(we used them when specifying / recommending composite drive shafts for street cars. 250 turns color, you had better re-route the exhaust)

I have not noticed any heat issues yet but do not have many miles on the tygon either.

spl310, I do have the stock heatshield in place but it is not visible in the pictures but they are there.. The carb return springs are hooked to it I think. The shield is behind and below the carbs

You can see part of the heatshield in this old picture. It is the rustly plate on the left http://www.311s.org/phpBB3/download/fil ... &mode=view" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;

That was before cleaning and replacing the fuel lines. These stock ones were leaking on the mt diablo run. I was wondering what the occasional gas smell was. Lucky it did not light up on me. The one closest the firewall was cracked and leaked badly if choked.