Destroking a CB engine

[Mario_Boost]

Has anyone ever de-stroked a common block engine? Say a 2.2 to a 2.0 or a 1.9?

[Reaper1]

I've stroked a 2.2...does that count? I took the stroke up to 3.75". I haven't been able to run it yet though(engine is still in boxes!). I do know of another person who built a VERY similar engine as the one I am building(same stroke and rod length if I remember)...he said it ran like a scalded dog! BTW, rod length is 6" in my combo....

[mo' parts]

im curious on this topic also. chrysler used a 2.0 version in the imsa gtu series, that produced 403 hp and was very reliable.

not sure how they did it, maybe welding up the crank and grinding it in an offset.
sounds interesting........hmmmmm..

[macncheese]

go to thedodgegarage.com and check out the salt flats lebaron. it's been done....
tony

[mo' parts]

that is the motor they used in the imsa series in 1987. in 1992 they pulled it off the shelf and put it in that lebaron to set speed records at the salt flats. it was not altered or rebuilt. just proves how reliable they really are.

from what i understand, these motors work best at 2.0 litres, although i believe it is very expensive to accomplish.

definitley would like to find out more, anyone else have any info/ experience to add?

[Ben Paquin]

A problem with destroking a 2.2 is our heads don't flow well enough to utilize the shorter stroke and higher rpm band.

But I would definately see a destroked 2.0 running a ported 16V and a big cam kicking some ass.

[macncheese]

wow *drools*
if you're going to go through all the trouble of destroking a motor, may as well put forth the extra effort and go 16v ala brian slowe.
tony

[igotaneed4speed]

that could be a fun winter project...

[shelbyluvinfool]

Quote:

Originally Posted by igotaneed4speed that could be a fun winter project...

or 3 winters...ask the 16v guys!

[Koreth]

if your going to destroke a 2.2 to to 2.0 and slap a neon head on it, wouldn't simple be less time and trouble to simply slap a neon powertrain into your TD?

[OmniSRT4]

Quote:

Originally Posted by Koreth if your going to destroke a 2.2 to to 2.0 and slap a neon head on it, wouldn't simple be less time and trouble to simply slap a neon powertrain into your TD?

The Neon 2.0 is a weak motor with a short deck and a not so ideal rod ratio.

Actually you would be best off installing a 2.4 with a 2.0 crank and custom length rods/pistons.

Howver, the fact is, destroking your motor is pointless. You dotn hve have acces to variable valve timing so you are limited toa single cam profile. If you put a cam in big enough to work with the 2.0's RPM range, it will not idle and will run like crap at anything other than flat out. If you use a stock or a mild cam, then you will be wasting the extra thousand rpm's worth of power. You would be better off with a properly built 2.2 with a 16v head and aftermarket cams. The stock 2.2's stroke has no problem running 7k rpm with the right setup which is the limit of any streetable cam profile anyhow.

In my opinion, since we do not have variable valve timing to work with, we need to stroke the motor to a level in which it runs out of breathe at the same time a as single cam profile, thereby maximizing its power output with the current bore size.

[russ jerome]

A 2.2 block with a 2.4/16v head spins happily past 7k even with wrong 2.4 cams and shallow cam/base timing.

[OmniSRT4]

Quote:

Originally Posted by russ jerome A 2.2 block with a 2.4/16v head spins happily past 7k even with wrong 2.4 cams and shallow cam/base timing.

That is my whole point. Destroking serves no purpose but to lower specific output. You would need to run the 2.0 into the 8k range to utilize its full potential, and i'd like to see you find a streetable cam with a range of 8k....

An example of this would be the S2000 which features a 2.0 in the old one, and a 2.2 in the new one. (stroked version of old motor) Both of which have very similar bore and stroke (suprisingly close) to ours.

The 2.0 version makes max power at 8500 and the 2.2 makes max power at 7500. Even 7500 is too high for a streetable cam profile (but would make an awesome race engine). This is one reason why I went 2.4 for a street car.

The entire point was that the 2.2 already has the ability to rev higher than than the effciency of a single cam profile allows for, so why destroke?