Aftermarket Pre-Combustion Chamber Inserts

[JMattJ]

Does anybody have any experience with these aftermarket pre-cups? It looks like they're made in El Salvador. I emailed the guy and he only wants $4.50 for each!
It sounds too good to be true, so I figured I'd run it by you guys before I placed an order.

Here is the link:
http://www.hbaron.com/precombustion_chambers.htm

[bluescout]

I would be tempted to go for it. You'll have to pound them in good and tight, then have the head decked to make sure they're flat. For that price, get them and see if you like them.

[Jim]

At that price it would seem worth it to give them a try. Did you find out how to fix the issue that came up when you removed your old ones?

BTW, how do you check the chambers? Is it from the lower side or do you have to shine a light from the top? If a machine shop did my valves and a pressure test, does that mean they would have noticed any issues with these chambers? I rebuilt the top end and did some piston/liner work many years ago and now Im questioning the integrity of the head since I have always had a hard starting engine with a lack of power. I never instpected the head, I just dropped it in after picking it up from the shop.

[vegestar]

Nice find Matt! I wouldn't hesitate to give them a try. The only issue I see is they don't mention the turbo engine and the pre-chambers ARE different. The difference being the shape and size of the opening or "flame channel". If you look at the specs in the pdf one would notice the part # specified for the SD23 and SD25 engines has a larger opening. I would be inclined to use these instead of the part listed for SD22 and 33. I'll order up a couple sets to experiment with. Also note that when installed they should NOT be completely flat with the surface of the cylinder head, rather they should sit proud about .003-.005 like they specify on the website and Nissan factory manuals.