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A version of the 3800 never made, why not?

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Old 07-27-2007, 04:59 PM
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Default A version of the 3800 never made, why not?

I was replacing the radiator in my wifes Mitsubishi Montero last night. I love that truck almost as much as my bonnevile. So much thought has gone into the engineering in her truck. it has a 3.5L dohc V6 makes as much power and torque as a L36. I was just thinking how much more power you could get from a L36 if it was made into a 24 valve dohc design. Is it even possible to do that to a 3800? has anyone thought of it or done it yet? makes me wish I had a spare engine and a crap load of free time Well I am sure if there is a will, there is a way....
Old 07-27-2007, 05:11 PM
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Default Re: A version of the 3800 never made, why not?

Originally Posted by roadtech195
I was replacing the radiator in my wifes Mitsubishi Montero last night. I love that truck almost as much as my bonnevile. So much thought has gone into the engineering in her truck. it has a 3.5L dohc V6 makes as much power and torque as a L36. I was just thinking how much more power you could get from a L36 if it was made into a 24 valve dohc design. Is it even possible to do that to a 3800? has anyone thought of it or done it yet? makes me wish I had a spare engine and a crap load of free time Well I am sure if there is a will, there is a way....
Thing I liked about the GM 3800 ohv is the Power is right there from the begining. Most Dohc engines I have driven feel like they need to build up power first. I think the power they are getting out of todays V6s is amazing.

Btw I drove a 98 Montero with the 3.5 and it was not really that quick imo?
Old 07-27-2007, 06:06 PM
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I second the fact that DOHC needs to rev up to get its wind blowing.

My old mercury had the DOHC 2.5 v6 and it was an absolute dog under 4k, but once it revved past that it took off

I still prefer OHV over DOHC for that reason
Old 07-27-2007, 06:36 PM
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I agree, OHC engines do need to rev up higher to make their power, which is why I prefer OHV engines too. Here is a example of how the power is made -

http://www.youtube.com/watch?v=nuM04ntoBSo
Old 07-27-2007, 08:31 PM
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Default Re: A version of the 3800 never made, why not?

Originally Posted by roadtech195
Is it even possible to do that to a 3800? has anyone thought of it or done it yet?
Yes, it is possible, but like most things in this vein, it would be expensive as all get out to do. Short list of things that would have to be done: Custom heads, cams, cam drive, and valve train parts. Then you would need to plug the cam journals in the block along with the lifter bores. In short, it'* not worth doing just to pick up 4 valves per cylinder.

Airflow on a DOHC motor is usually much better then the exact same bore and stroke using a SOHC or OHV motor. What y'all are seeing in DOHC motors as being rev happy is also intentional..the designers are taking advantage of the high rev limit a DOHC motor has and push the power band up that way. (In other words, a DOHC motor can produce better numbers down low too, if the designer chooses to set it up that way.)
Old 07-27-2007, 11:26 PM
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doesn't seem worth it to me, i'll take an OHV engine any day over some OHC engine. Just not my cup 'o tea. Just don't feel as...THERE.
Old 07-28-2007, 12:50 AM
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OHC can be the same as OHV, but OHC engines can flow more into the cyl heads. OHC is used mostly these days to help make engines smaller.

Smaller engines are a little easier to balance, the rev a little easier, and the OHC system itself can handle high revs much better than a similar OHV setup. Peaky power from OHC engines is down to how it'* setup overall, the size, and powerband requirements of the cars.

A GM inline 6 in the trailblazer is OHC, but they have good down low power, etc...

My little 2.0T is OHC,and it'* turbocharged, but it hits peak torque well before a big, supercharged L67 does, (peak torque is from 1800-5000 RPM, not peaky at all)

Yes it can get caught out of the powerband momentarily if you're going along around 1500-2000 in a very high gear, but to keep up with traffic accelerating. I don't have to get it above 2000 rpm on city streets and rural highways.
Old 07-28-2007, 01:14 AM
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ANd keep in mind how much more efficient an OHV is than an OHC in terms of packaging. Hanging those one or two cams on top of the valves will make for a larger engine.
Just looking at what GM is doing with OHV engines now (The LS7 can go head to head with any normally aspirated engine in the world) the benefits of OHC'* seem so much less evident.
Old 07-28-2007, 01:59 AM
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The reference to the LS series of V8 engines is dead on. Why didn't they make a OHC 3800? If they can make supercar power using one cam in the block of a Vette, I think they can get by with one cam in a (relative) grocery getter like the H-bodies.

In my opinion, much of the hoopla over OHC engines is hype and customer opinions. More valves is better, right? Well, not necessarily, but the guy shopping for a new car seem to think so. Thus, auto makers cave and make these more complicated OHC engines.

For packaging, simplicity, weight, and reliability, you can't beat a cam-in-block engine, at least in the V configuration. For inlines, an overhead cam does make more sense.

Personally, I'm really glad that GM is still pushing the old OHC design to it'* limits, and going faster than cars that cost twice as much in the process.
Old 07-28-2007, 02:46 PM
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In my opinion, much of the hoopla over OHC engines is hype and customer opinions. More valves is better, right? Well, not necessarily, but the guy shopping for a new car seem to think so. Thus, auto makers cave and make these more complicated OHC engines.

That seems like a very logical answer. It has been good to hear many opinions on this topic. I for one am very happy with my L36 the way it is. These engines are little torque monsters, its nice to be able to pass people while going uphill.


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