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-   -   2.2T to High compression 2.4T (http://forums.pelicanparts.com/911-engine-rebuilding-forum/130811-2-2t-high-compression-2-4t.html)

red-beard 10-08-2003 07:57 PM

2.2T to High compression 2.4T
 
I know if I change the crank on the 2.2 to a 2.4 I get both an increase in CR and in displacement.

For a T with T P&Cs and T cams, will there be valve/piston interfernce?

James

Scott Clarke 10-08-2003 08:07 PM

James-
Since you have T pistons and T cams, there should be no clearance problems. The added stroke occurs at the bottom of the cylinder, not the top. The relationship of the piston and valves will be the same with either stroke (at TDC). Since the added stroke will mean that the piston is moving faster, there should be slightly more clearance on either side of TDC with the 2.4. 2.4 (non-CIS)and 2.2 T cams are the same.
-Scott

red-beard 10-08-2003 08:12 PM

Thanks!

HawgRyder 10-08-2003 09:02 PM

Beg to differ with you Scott....if the stroke is increased...say by 2mm
then the piston travels upwards an extra 1mm and downwards an extra 1mm.
So the compression will be increased and the clearance of piston to valve will be decreased.
This is why stroker pistons have the pin location moved upwards (to keep the piston from hitting the valves).
Bob

Scott Clarke 10-09-2003 06:58 AM

Bob-
That's why 2.4s and 2.7s have shorter rods! The deck height is exactly the same on all motors from 2.0 to, I think, 3.6. So, a 2.4, with a 70.4mm stroke, has rods that are 2.2mm shorter than a 2.2 motor with its 66mm stroke. the piston pin height is excatly the same on motors from 2.0 to 2.7. I'm not sure about the larger motors.
-Scott

HawgRyder 10-09-2003 06:14 PM

OK Scott...thanks for the info....I stand (sit actually) corrected.
I have been thinking about doing some work to my 2.0 when I rebuild it.
Was thinking that a set of 2.7 P&C's would spark it up some...but with the MFI I would need MFI type jugs from the 2.7...right?
Bob

red-beard 10-09-2003 06:38 PM

Which cam are you running? The 2.0 case can be used for up to 2.7 (I just did this). If you're running s cams, you need the RS pistons in them.

Your other option is find a used set of P&Cs and then buy JE pistons to go with the cylinders. They can be setup for any combination of compression and cam.

James

Wayne 962 10-09-2003 08:03 PM

Yes, you can think of the 2.2 pistons as high compression "trick" pistons when used in conjunction with the 2.4 crank. I haven't personally built this engine combo, but I would suspect it would work, and if not, then you would have to machine the tops of the pistons a bit, or simply use 'S' pistons instead.

-Wayne

HawgRyder 10-10-2003 06:31 AM

I am running stock S cams....the engine has never been apart.
So what I am looking for is an RS setup with pistons and cylinders...probably as rare as hens teeth!!
Thanks
Bob

Scott Clarke 10-10-2003 07:05 AM

Bob-
You are talking about doing wht I'm in the middle of doing. The cheapest way is to use JE pistons intended for twin plug 2.7 motors. In a 2.7, these are 10.5:1 CR. With your 66mm crank, these will be around 9.75:1. Perfect for pump gas. I found a set of used cylinders for fairly cheap. These are plentiful, as there are many blown up 2.7 CIS motors around. I have sent them to EBS. They will recondition the cylinder walls for $750. So, for a total of $1745, you can have a set of really nice pistons and cylinders. You would, however, need to install piston suirters in your case in addition to other modifications.
-Scott

Scott Clarke 10-10-2003 11:20 AM

James-
Bob is talking about using his 2.0 crank. The RS pistons would produce too low of a compression ratio with the 66mm crank, hence the reason for the JEs.

HawgRyder 10-10-2003 03:03 PM

I don't know if I could swing the expense at this time.
What I will probably do is use Total Seal rings on my stock pistons...and put the turbo oil pump in (I already have one)...do the oil bypass mod...and maybe do time serts or something like that.
I have decided to use Raceware rod bolts as well...so that they are reusable.
I figure I can do a rebuild this way for the minimum amount of $$.
Bob


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