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| | | Forums66 Topics128,021 Posts1,055,346 Members48,420 | | Most Online14,466
Apr 26th, 2026 | | AD Chevy Trucks  Over 6,000 pictures Brad Allen has an awesome collection of Chevrolet factory pictures that he has set up from film strips. Check them out!
Lots of work on Brad's part ... pure enjoyment (and references) for you!
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For helping keep this great
old truck web site
on the Internet for over 30 years! and not clogged down
with Ads!  Again, thanks!
| | | | Joined: Oct 2019 Posts: 449 'Bolter | | 'Bolter Joined: Oct 2019 Posts: 449 | 52Carl your "tractor engine" reference makes me like 'em even more!
Kevin
1965 Chevy C10 Longbed Fleetside
| | | | | Joined: Feb 2004 Posts: 29,746 Kettle Custodian (pot stirrer) | | Kettle Custodian (pot stirrer) Joined: Feb 2004 Posts: 29,746 | I'm waiting for someone to come up with a SEFI system that uses individual injectors for each cylinder; one that sprays the fuel at the back of the intake valve tulip just before the valve opens. Throttle body injection is just half a carburetor, with all the drawbacks of poor fuel distribution that a carburetor has, and the added complexity of a computer and a bunch of sensors to meter the fuel spray from the injection nozzles. It's a fun project for somebody with lots of time and money to waste, but is it practical?
Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!
| | | | | Joined: Mar 2010 Posts: 1,660 Curmudgeon | | Curmudgeon Joined: Mar 2010 Posts: 1,660 | GM Brazil bought the rights to produce I6 engines. They redesigned the 250 (4.1L). Of note is that the head has 12 ports and port fuel injection with fuel rail. Along with a different camshaft, GM Brazil changed the low RPM high torque "tractor" engine into a modern engine but this was only for 4 years '95-'98. Apparently the engine design improvement was not enough to compete in a modern market. So, I hope they sold enough of them to pay back for the R&D and the manufacturing costs.
(Valvoline) On the issue with direct injection (the wording sounds marketing-ish):
"Designers found that GDI (Gasoline Direct Injection) engines don't have the fuel molecules touching the intake valves on their way to incineration in the combustion chamber. Intake valves have seals on them that keep oil lubrication, where they meet the camshaft or rocker arms that press the valves open, from running down their stem and dripping into the intake port. However, no matter how good they may be, a tiny bit of oil still makes its way past and runs onto those intake valve stems. Without gasoline washing them clean, that oil can bake onto the valve and accumulate into carbon buildup."
+++This is an excellent example of a technology improvement that generates an unforeseen problem (too much carbon build-up).
I like logical improvements, with known good payback results, that don't require a major redesign.
"Adding CFM to a truck will only help at engine speeds you don't want to use."
"I found there was nothing to gain beyond 400 CFM."
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