Valve seats??
08-26-2012, 09:51 PM
#16
CF Veteran
Join Date: May 2008
Posts: 3,018
Likes: 0
Received 17 Likes
on
17 Posts
Year: 1988
Model: Cherokee
Engine: AMC242
Interesting...and thanks. Filled in some gaps in info that I had wondered about. I should clarify the Chrysler comments were not directed at you, but to the subject of the thread itself, that Chrysler "chose not to use hardened seats". That was not the case.
If I'm not mistaken, the "0331" head problem wasn't so much the redesign itself as the fact that (I believe) they finally replaced the old head tooling and casting fixtures along with the redesign, and had issues with the new setup.
If I'm not mistaken, the "0331" head problem wasn't so much the redesign itself as the fact that (I believe) they finally replaced the old head tooling and casting fixtures along with the redesign, and had issues with the new setup.
I'm just bummed that they stopped making the 6-242. After all, the Chevvy SB350 has been in continuous production (with updates) since 1955 or so, right? The 6-242 was only around 1987-2006.
And, while Dr. Z said that the inline six design was "dated and unsafe," it should be noted that:
- GM has been bringing their I6 back in VORTEC trim (oddly, one of them has a nominal displacement of 4.0L as well.)
- BMW has been using them continuously - since about the founding of the company.
- I believe Mercedes-Benz has been using them continuously as well (Yes, as in Daimler-Benz - and, for a while, DaimlerChrysler...)
- The Cummins I6 engines (Diesel, I know) are some of the best general-use engines around (Historical note - Rudolf Diesel devised the Diesel engine while working for Daimler-Benz...)
And I'm sure there are other factors not in mind at the moment as well.
The inline six occupies an excellent middle ground between fuel economy and usable power, generates more useful torque at low RPM than most V8 engines, and runs smoother than most other engine configurations out there (it's balanced as a pair of inline three-cylinder engines, and has no second- or third-order harmonic forces. How many I4 and V6 engines use balance shafts? I don't think any V8s do, but there's an awful lot of unbalanced forces at work.)
Honestly, the only engines that balance better are horizontally-opposed engines, and only Subaru is still using those.
08-26-2012, 11:16 PM
#17
CF Veteran
Join Date: Apr 2012
Location: Wisconsin
Posts: 5,302
Likes: 0
Received 20 Likes
on
17 Posts
Model: Cherokee
4.0 was an excellent engine, most of the AMC design I6's were pretty stout.
To add to your list- Ford's 300 I6 has been in continuous production since 1965 and is still being built for commercial use. Generators, pumps, that sort of thing. The non-diesel UPS trucks still run them, lol.
As I understand it the biggest problems with the 4.0 were that the long stroke made it difficult to hit changing emissions numbers, Chrysler wanted to shutter Kenosha Engine, and the tooling was on the verge of wearing out ..again. Heck they only churned out 5 million of them or so, lol.
To add to your list- Ford's 300 I6 has been in continuous production since 1965 and is still being built for commercial use. Generators, pumps, that sort of thing. The non-diesel UPS trucks still run them, lol.
As I understand it the biggest problems with the 4.0 were that the long stroke made it difficult to hit changing emissions numbers, Chrysler wanted to shutter Kenosha Engine, and the tooling was on the verge of wearing out ..again. Heck they only churned out 5 million of them or so, lol.
Thread
Thread Starter
Forum
Replies
Last Post
Karmageddon
Stock Grand Cherokee Tech. All ZJ/WJ/WK Non-modified/stock questions go here!
5
10-05-2015 08:29 PM
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)