2.0 liter build on a non common block what rods?

[going4speed]

I just picked up a imsa 2.0 crank. Have done searching for two days but cant seem to find a link to anyone having a built motor.

Any ideas on what length rods would be needed to use the imsa crank with stock type persons?

[Vigo]

Why would you use a stock-type piston? If you are trying to build a high-rpm motor and have to buy custom rods anyway you might as well use a lighter piston design as well.

[going4speed]

By stock type I meant an off the shelf forged piston and not a custom length piston.

[Vigo]

I am suggesting using a shorter/lighter piston design than the stock-style 2.2 piston (forged or not) and getting your custom rods sized to accommodate that piston.

[4 l-bodies]

Before you even attempt to build something like this, you need to do your own homework. Stan Weiss's website has an easy to use formula for figuring out compression ratios. You need to feed in basic info like stroke, bore, headgasket thickness and diameter, dish of piston, how much piston is in or out of the hole, and cylinder head volume. When you have all these measurements then you can determine what piston might do the job, or what length rods you need. BTW- Custom length rods will be more expensive than custom pistons, so why do you seem so adverse to using a custom piston?
I'll do some of the math for you. Assuming your 2.0 crank is 3.246" stroke, a custom piston with 1.784" compression height will get the job done using stock length rods. That gives you a rod ratio of 1.83:1 Using custom rod length, you would need a rod length of about 6.135" to use a standard 1.594" pin height piston. This gives you rod ratio of 1.89:1. Both of these figures leaves the piston down the hole about .010 (which is stock). Now you need to do some more math using these figures to determine what compression ratio this gives you using various pistons, and head (chamber volume).
Good luck!
Todd

[glhs727]

sounds like then ideally use the BC 2.2/2.5 hbeam rods that are 5.945" and you can buy off the shelf here at FWD, and get custom pistons made. They say 1.80 is the perfect rod ratio and having owned a long rod 2.2 motor, I have to agree. Thanks to Todd for enlightening all of us with his math skills. I know I appreciate the info!

[ShelGame]

To use something like an off-the-shelf Neon 2.0 piston (same bore), the CH is 31.1mm. Which means you would need a ~6.5" long rod to make it work. That's really long. Nothing off-the-shelf is that long. Not even for a Big-Block V8. You can find surplus NASCAR rods in 6.4" length...

[going4speed]

I sounds like custom length pistons and stock tII rods might be the way to go. Yes not an ideal rod ratio but I dont want to spend money on rods and pistons.

[Vigo]

Well, that's your prerogative. But really, knowing more or less what you paid for the crank, i think the low price kinda set you up for a fall. The only way that crank is useful is if you modify the entire rest of the motor to make power and be reliable at an rpm that makes the stock 2.2 reciprocating assembly untenable. $$$. Trying to do a 'budget' build with a 2.0 crank, stock rods, and heavier than stock pistons is just going to get you a novelty with no real upside vs a stock 2.2. Depending on the weight gain of your larger pistons it may not even be able to safely rev any higher, although unless you are doing a 16v top end conversion or dumping pro-level work into an 8v top end, you won't make power high enough for durability to become an issue anyway.

If you are ok building a 2.0 purely for novelty factor to tell people you have one rare part in your car, then cool. But if you are expecting to see any tangible benefit from the 2.0 crank, then your statements do not really add up.

[going4speed]

So I have a $300 boat anchor...totally awesome!

[Vigo]

I would just sit on it until you plan to do a whole motor up around it with custom rods and pistons and a high-rpm capable top end. Or you could probably flip it for what you got in it. But if you WANT to build a 2.0 with stock rods and longer pistons then don't let me stop you!!

[going4speed]

When I bought it I was not under the impression it would take this much money to get going. I really need to get out of turbo dodges.

[glhs727]

Frank, I think the 2.0 is a good idea even if it takes a couple of years to gather all the needed parts. If you want the higher reving 2.0 can provide, you will likely want better than t2 rods anyways, and custom pistons aren't any more money than forged 2.2/2.5 pistons.

[Vigo]

When I bought it I was not under the impression it would take this much money to get going. I really need to get out of turbo dodges.

Trying to build a de-stroked high-rpm version of anything will be fairly expensive. I dont think that's a knock against turbo dodges in particular. If you want to go fast for cheap there are tons of people here who are willing to help you on that! If you relist your 2.0 crank someone will probably buy it and you can put that money towards other mods. Or, just sit on it and save some money and keep researching and build an awesome 2.0 motor down the road!

[Ondonti]

If you thought there was easy power to be had by decreasing displacement you were tricked by people here obsessing about 2.0 or destroke cranks. Those people never talk about the supporting mods because they almost always will never spend the money to buy them. I don't think any known private parties ever have.
I would be more worried about surviving high rpms and the cylinder head/valve train and you don't even want to pay for some pistons. I don't like spending money so I try to keep from complete custom setups.