- Location
- Torrance, CA
Okay kids... I'm considering stroking my "new" engine instead of straight rebuidling it and I've come up with a few questions.
First of all here are my primary goals:
1: I would like to save money where possible but not cut corners to do so.
2: The engine must remain CA Smog Check II legal; any modifications that will cause emissions failures must be easily swapped out (ie; throttle body, computer).
3: More power than stock (duh!). I'm more intersted in low end grunt than upper end horsepower.
Now, for the base here are the parts that I already have and will be going into it.
Stock Renix block.
Stock 2686 cylinder head (Renix).
Stock Renix injectors (I think).
Jet modified Renix ECU.
HO throttle body.
1" throttle body spacer / Renix TB to HO TB conversion plate.
Renix intake manifold.
Borla Renix header (has EGR bung).
Clifford 264 camshaft (0.474" with duration of 206° at .050 - Built for torque)
This is going into my '89 XJ. I will not ditch the Renix system nor will I be switching to a later style intake at this time (I may do it later on after I figure out a way to incorporate the EGR solenoid dish someplace). I will not switch to a 7120 casting head unless I find a killer deal on one.
Now for the questions...
The plan is to use a 258 crankshaft and rods, I am undecided about pistons at this time.
1. Do I have to grind out clearances for connecting rods at the bottom of the cylinders? The Mopar engines book (third revision) says this will be necessary to maintain safe clearances however I have not seen mention of this elsewhere.
2. About pistons. A guy on the strokers group mentioned running OEM 4.0 pistons. The pistons that are currently in that engine look beautiful (the may have been replaced recently) so if that option is valid those would be the set I'd run if the cylinders are straight enough not to need a bore (I'm 90% sure that they are good). What are the drawbacks?
3. If I do go with aftermarket pistons I'd rather use off the shelf pistons as I'm trying to save money here (If I spend too much on this I won't be able to afford gears and tires!); any suggestions for pistons that would work well either with a bore or not?
I don't mind having the cylinders bored if I can get pistons for that bore on the cheap.
4. Compression ratio. Is it worth it to deck the head to run a higher (+/- 9.5:1) compression ratio from a cost verses power standpoint. Take into consideration the extra wear and tear on the engine that comes with high compression.
5. Injector sizing. Can anybody tell me how much this really helps? I know it's a real popular thing to do but I don't want to waste money here. If I do go up in size I will probably do it at a later date. The engine will not run dangerously lean with 19 lb/hr injectors, right?
6. Fuel economy. This question is not a priority, I'm just curious. Those of you that have built strokers what change did you notice in fuel economy? I'm thinking more on a percentage change basis here not true numbers. This question is only valid if you did not make other major changes at the same time (gears, tires, lift, billboard mounted to the roof).
That's all I can think of at the moment, I'm sure I'll think of more though.
Thanks,
Sequoia
First of all here are my primary goals:
1: I would like to save money where possible but not cut corners to do so.
2: The engine must remain CA Smog Check II legal; any modifications that will cause emissions failures must be easily swapped out (ie; throttle body, computer).
3: More power than stock (duh!). I'm more intersted in low end grunt than upper end horsepower.
Now, for the base here are the parts that I already have and will be going into it.
Stock Renix block.
Stock 2686 cylinder head (Renix).
Stock Renix injectors (I think).
Jet modified Renix ECU.
HO throttle body.
1" throttle body spacer / Renix TB to HO TB conversion plate.
Renix intake manifold.
Borla Renix header (has EGR bung).
Clifford 264 camshaft (0.474" with duration of 206° at .050 - Built for torque)
This is going into my '89 XJ. I will not ditch the Renix system nor will I be switching to a later style intake at this time (I may do it later on after I figure out a way to incorporate the EGR solenoid dish someplace). I will not switch to a 7120 casting head unless I find a killer deal on one.
Now for the questions...
The plan is to use a 258 crankshaft and rods, I am undecided about pistons at this time.
1. Do I have to grind out clearances for connecting rods at the bottom of the cylinders? The Mopar engines book (third revision) says this will be necessary to maintain safe clearances however I have not seen mention of this elsewhere.
2. About pistons. A guy on the strokers group mentioned running OEM 4.0 pistons. The pistons that are currently in that engine look beautiful (the may have been replaced recently) so if that option is valid those would be the set I'd run if the cylinders are straight enough not to need a bore (I'm 90% sure that they are good). What are the drawbacks?
3. If I do go with aftermarket pistons I'd rather use off the shelf pistons as I'm trying to save money here (If I spend too much on this I won't be able to afford gears and tires!); any suggestions for pistons that would work well either with a bore or not?
I don't mind having the cylinders bored if I can get pistons for that bore on the cheap.
4. Compression ratio. Is it worth it to deck the head to run a higher (+/- 9.5:1) compression ratio from a cost verses power standpoint. Take into consideration the extra wear and tear on the engine that comes with high compression.
5. Injector sizing. Can anybody tell me how much this really helps? I know it's a real popular thing to do but I don't want to waste money here. If I do go up in size I will probably do it at a later date. The engine will not run dangerously lean with 19 lb/hr injectors, right?
6. Fuel economy. This question is not a priority, I'm just curious. Those of you that have built strokers what change did you notice in fuel economy? I'm thinking more on a percentage change basis here not true numbers. This question is only valid if you did not make other major changes at the same time (gears, tires, lift, billboard mounted to the roof).
That's all I can think of at the moment, I'm sure I'll think of more though.
Thanks,
Sequoia
