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post #1 of 7 (permalink) Old 05-22-2008, 11:43 PM Thread Starter
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2.7L Design Modifications

I know, I know... another 2.7L thread.

What if you were given the password to the computer that designed the 2.7L? What would your modifications be to the 2.7 and why? Please don't say "well i'd just scrap the whole thing... blah blah blah". I firmly believe that if a few modifications were made to the internal design, then the 2.7 would be a bullet-proof, powerful, fuel efficient, smooth, refined engine. I mean heck, my 2.7L trep gets better gas mileage than my corolla sometimes (yea, it happens). The only problems I run into are raised production costs. But if it were possible to get this good of gas mileage out of a much more reliable engine then I would have no problem justifying a few extra hundred on the MSRP for the changes.

My Changes:

Externalize the water pump. -- This is a god awful design flaw IMO. It just wreaks of "coolant in the crankcase".

Make the 2.7L a dry sump design. -- That way there's better internal lubrication, plus since there's more oil in the system... it stays cooler. And since there is better internal lubrication it would extend the life of the average timing chain/tensioners. Also, since there is no oil pan, the engine can be mounted lower... more to the car's center of gravity.

Better Quality Rod & Main Bearings. -- A couple of dollars more on the MSRP wouldn't hurt anyone. Although, with the above mentioned dry sump design, there would be dramatically fewer bearing failures anyway, with the current bearings.

Last edited by XGX; 05-22-2008 at 11:46 PM.
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post #2 of 7 (permalink) Old 05-23-2008, 12:07 AM
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also:
stronger rods

better sensors/electronics.

The redesinged colent beleeder valve houseing/ bypass tube should have been standard

the plenum should have a threaded metal insert for the PCV valve to reduce cracking.

not sure if it would involve too much modification to be viable but makeing it a non-interface design so that no severe damage would be done in the event of a timeing chain failure would have been nice
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post #3 of 7 (permalink) Old 05-23-2008, 07:26 AM
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External water pump, and better oil drainback from the heads, and a real oil cooler. Forged crank and rods.

Jim Snover

Quote:
Originally Posted by XGX View Post
I know, I know... another 2.7L thread.

What if you were given the password to the computer that designed the 2.7L? What would your modifications be to the 2.7 and why? Please don't say "well i'd just scrap the whole thing... blah blah blah". I firmly believe that if a few modifications were made to the internal design, then the 2.7 would be a bullet-proof, powerful, fuel efficient, smooth, refined engine. I mean heck, my 2.7L trep gets better gas mileage than my corolla sometimes (yea, it happens). The only problems I run into are raised production costs. But if it were possible to get this good of gas mileage out of a much more reliable engine then I would have no problem justifying a few extra hundred on the MSRP for the changes.

My Changes:

Externalize the water pump. -- This is a god awful design flaw IMO. It just wreaks of "coolant in the crankcase".

Make the 2.7L a dry sump design. -- That way there's better internal lubrication, plus since there's more oil in the system... it stays cooler. And since there is better internal lubrication it would extend the life of the average timing chain/tensioners. Also, since there is no oil pan, the engine can be mounted lower... more to the car's center of gravity.

Better Quality Rod & Main Bearings. -- A couple of dollars more on the MSRP wouldn't hurt anyone. Although, with the above mentioned dry sump design, there would be dramatically fewer bearing failures anyway, with the current bearings.
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post #4 of 7 (permalink) Old 05-23-2008, 10:56 AM Thread Starter
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Quote:
Originally Posted by James88 View Post
External water pump, and better oil drainback from the heads, and a real oil cooler. Forged crank and rods.

Jim Snover
If I'm not mistaken the 2.7 has a forged crankshaft, just not rods or anything. I remember reading that the crankshaft was like 27% stiffer than the 3.3L.

EDIT: allpar says its on only 26% stiffer...lol
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post #5 of 7 (permalink) Old 05-23-2008, 06:45 PM
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Agreed on all.

External water pump.
Possibly belt drive for the DOHCs instead of chain drives - or - a more reliable chain tensioner system.
Oil Cooler
Increased oil capacity
crank and rods - I see no problem with the existing parts. I do see a problem with the bearing life for the con rods. The tri-metal bearings don't seem to have the longevity of other designs.
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post #6 of 7 (permalink) Old 05-23-2008, 11:03 PM
 
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The water pump design would not be an issue had they stayed with a belt instead of going to a timing chain on the 2.7. They did go with the chain for strength, only to find it created another weakness in the process, the aforementioned water pump. The internal water pump design running off the timing is not new, been like that many motors now, its just they need a better safety in place with a timing chain system in the event of failure.

Both the coolant bleeder and metal pcv valve are scary designs. I mean a threaded metal insert pressed into a plastic housing. And not only that but its got 100K mile/5 year anti-freeze in the system. So we are talking a LONG time for that bleeder to be unopened. Yes it is possible to open them after they've been closed for a long time without breaking it, I know because I did my antifreeze last year before I traded it in. but as many have found out, you cannot strong arm those things because they will not take much.

The pcv valve did get a redesign and new part number. I did get my hands on one last year. So far at that time the only place I could find it was dealer only. It has a bigger opening whereas the old one has three slots. Also unlike the original design that had a metal body, the newer one is plastic. Not only plastic, but to me it felt like the kind of plastic that will break easy. That is important since we would rather the valve snap than the plenum. With a metal valve, you know what is going to happen to the plenum if you overtighten it.

One thing I did not see mentioned I found issue with my 2.7 was valve cover baffling. The valve covers are not baffled very well and allow a decent amount of oil to escape from both the pcv side and the breather side. And I know many of you have noticed oil in the pcv hose along with that hard crumbly crap that builds up. Then others who have actually ventured far enough to remove the air tube elbow off the throttle body and found oily residue there as well. Not to say the pcv system is totally fool proof, but the valve cover baffling on Dodges leaves a lot to be desired.

On a side note about pcv systems, the Ecotec motors in the Ions do not have a pcv valve, its done internally. there is one external breather hose running off the valve cover to the intake duct, but no valve. Matter of fact, if you open the oil cap with the engine running you will hear the sucking sound of the vacuum, and I actually set a lean code by doing this. I've seen older Audi's that also used internal ventilation like this. I can't tell you exactly how it works because I've never taken one apart, but I imagine there is a fixed orfice in the head that feeds directly into either the intake manifold or into the intake ports themselves.
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post #7 of 7 (permalink) Old 05-23-2008, 11:25 PM
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I stand corrected, thanks.

The other mod I would like to see is a 5.4-litre, DOHC, 4-valve, 60-degree V-12 put into production. If they actually had the guts to do it, I would buy from Chrysler/Dodge again despite all my misgivings. I'd even buy the current Charger, if that was the only vehicle I could get it in, though I would really rather get it in a third-generation Intrepid.

That would have been the engine to brag about. Was it you who showed me that link to it on AllPar? I know it was somebody on the board who told me about it.

Jim Snover

Quote:
Originally Posted by XGX View Post
If I'm not mistaken the 2.7 has a forged crankshaft, just not rods or anything. I remember reading that the crankshaft was like 27% stiffer than the 3.3L.

EDIT: allpar says its on only 26% stiffer...lol
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