|
Update
I finally got a chance to put the "Big Mouth" prechambers in and I am very pleased with the results.
I should note one of the mods that I did to the burn tube was to taper the ID which had been done by another member over at STD, so these are a collaborative result lol.
When I first started the engine up with them installed it ran like crap, missing now and then at idle, ruff and smokey cold start up, and noisy.. I was not thrilled at that time. Keeping in mind that there was still air in the injector lines and the other member did state that after tapering the Burn Tube he had to advance the timing, I advanced mine as much as it had left which put it at 26*. After doing that, all the problems went away, nice idle, no smoke, and it even got quieter and had a nice light rattle like a real diesel lol..
I wanted to advance the timing more but would have to pull and re-index the pump, so I had to wait till I had time to do anything more. Thanksgiving gave me the time to take the car to a friends heated shop and I advanced the camshaft 10* before I went crazy with the injection timing. I drove it with 26* and the camshaft 10* ahead for a week so I could keep track of which mod did what.
Then I pulled the pump, modified the governor, and reinstalled it at 28*. I am very please with the result of all the mods. When I get a chance I want to bump the timing up to 29* and see how it does.
You can see in the pics why I call these the Big Mouth prechambers lol.. In addition to cutting our the three burn holes in the front and tapering the burn tube ID, I also opened up the ID of the injector heat shield seat to 14mm and instead of sinking the seat down, I back cut an angle bellow the seat to allow for better swirl a the injector. Doing that in addition to tapering the burn tube increased the volume inside the prechamber. I also installed the balls so the flats are on a slight angle instead of perpendicular to the burn tube.
I would call this set up a hybrid between a DI and IDI engine.
In addition to advancing the injection timing to 29* or 30* the next step is a bigger turbo and 10MM pump.
|