OK, I will do a "before and after" test. I have a number of 250-400-600-750-1000W loads that I can stack up on the motor til it starts smoking, and a Kill A Watt to measure each and see what the total draw is. I will then port the head and run the same test again to see what the difference is. Again, maybe it's just my particular "direct injection" head that sucks, but there is a freakin 1" vertical wall right there in the bowl area that is a major restriction. I am LAUGHING at any suggestion there is no gain to be had here.
Fuel efficiency shouldn't be greatly affected, as long as the thing has enough air to start with, putting more in a diesel won't help much.
Under a partial load, it isn't about "putting more air in the engine." It's about reducing pumping losses by removing restrictions.
Power yes if you turn the wick up or if the thing was starving for air in the first place but that's the thing.
Yeah that's the thing...it IS starving for air. What do you suppose the volumetric efficiency is on one of these old iron lungs? I guarantee you it isn't over 75%, and is probably much lower. Less restriction = more airflow = better fuel efficiency = more air available at HIGH LOAD = less smoking and more peak continuous power.
If' it's getting enough air now, giving it more won't help unless you give it more fuel to make power but that's not the same as getting more work from the same amount of fuel .
If the motor is smoking under maximum load, then what effect does more air have in that situation? Less smoke, more power!
I was going to suggest taking some sort of measurement of the engine power before and after the work but then I remembered you had a problem with the engine so you probably aren't inclined to put it back together just to run a test then pull it again. I wouldn't be. That said, if you do have any tangible loads you have driven that you can make a comparison with, I'm always happy to be proven wrong on things like this.
As I don't have any power source available other than this engine, it is definitely going to complicate the work a little. I will have to charge up the compressor, shut it all down, pull the head, port it some, clean up and reinstall, run and recharge the tank, shut it down, etc. I figure it will probably take 10-12 tanks worth to get it all done so it's definitely going to be a pain, but at least the head only takes like 1 minute to remove if all the tools are in place.
the shape of the port even though somewhat odd can and does have an effect over how the cylinder is scavenged... so unless you really understand what is needed there, porting can result in a much dirtier running engine.
Yes, I do really understand what is needed. I can take one look at the port and identify several areas in need of major help, and that's just the intake port. When you have ported dozens of cylinder heads then it becomes immediately obvious where the restrictions are on any given head.
far more heads on any engine have been ruined and/or performance degraded by porting than have been improved by guys in a home shop.
That may be true in a general sense, but I am an airflow
expert. I appreciate your concern, but I am not some clueless redneck with a die grinder. Every head I've ported and put on an engine has made more power, often considerably so. This one
will be no exception.
I was looking at the exhaust the other day wondering if a long straight exhaust might have some scavenging effect on the cylinder. Given the pulsing nature of the engine, I am sure it would but finding the right length and diameter pipe would be a fun exercise... Not.
Actually it is really simple. The exact number can be calculated based on the speed of sound and runner length. Someone mentioned 14 ft which sounds about right. Even if you are an inch or two off you will still get noticeable gains as the effect lasts as long as the intake/exhaust valve is open. Check this out:
http://speedtalk.com/forum/viewtopic.php?f=1&t=29113&sid=d0fca2fee0eb80970bf4374f3137902bThe trick really with one of these engines is not power as much as torque. We can get more power just resetting the governor and spinning the thing up faster, what we really want is more torque at the same RPM.
Yep...and anything which reduces pumping losses (increased volumetric efficiency) will give you that extra torque!
I have to admit, since seeing it on the Utterpower site I have been keeping an eye out for a cheap turbo to put on the roid. May not work very well but it sure would look cool! Grin
I'm a big believer in turbos especially on Diesels. I have had 2 same models vehicles, one NA and one with a conservative Turbo boost and the difference is night and day. My 75 yo father has a Subaru Forrester turbo and that thing is just ridiculously fast for what it is and again, the difference over the NA models in incomparable.
I imagine a lister could handle a fair bit of boost as well and the power gains could be highly significant.
I have experience with building turbo engines and a turbo kit is definitely on the agenda, for this winter or next summer. I can say for certain just by looking at it, that this beast of an engine can swallow MASSIVE boost and survive it just fine. I still have research to do on the fuel system as I am a bit rusty on diesels in general and Listers in particular, but as long as I can get a pump/injector on this thing that can supply enough fuel, 10kW continuous (reliable) power output should be well within the realm of possibility. 20+ PSI is a piece of cake and 30-40+ should be achievable with correct turbo sizing.
