balance shaft

[PowerRam348]

i'm rebuilding my 89 d50's 2.6 and am wondering what to do about the balance shaft. i've seen alot of mixed reviews about it, but the thing i have seen more of is not to mess with it unless i'm puting it on the track. anyway, i'm stepping up the bore to 92.5mm and using wiseco pistons with pauter 4340 x-beam rods... is there a shorter crank out there?? i was also wondering if i could use a turbo camshaft to achieve better top end on a non-turbo motor? one last thing, should i use a thicker head gasket if i shaved the head a little? if i don't, will it mess with the timing? looking forward to any feedback.

[pennyman1]

Not sure why you are using forged pistons and high end rods for an NA motor. If you plan on using a turbo, supercharger, or nitrous, then yes; but otherwise, it is a waste of good money. Are you aware that the stock rods are forged and will work in all but the most radical motors? This is a truck motor, and mitsu used the identical internals and block in all of their starquests 2.6 turbo motors; they added oil squirters to spray the bottom of the pistons as added insurance. I am building a conquest 2.6 turbo motor with hypereutetic pistons and reconned stock rods. They are good to at least 15psi boost all day and are not much more than stock pistons. Also, check your block and timing chain cover height before putting on the head; a minor difference here can cause a premature head gasket failure due to the head not sitting flat.

[PowerRam348]

basically what i'm doing is: balancing everything and i want be able to tow about a 4000 pound trailer better. it did a pretty good job before, but i want a little better. i've got the money to spend, so i'm gonna. she's getting tired, so i'm giving her some really good parts and a balance job. i was thinking of maybe turboing it later on, but for now no. thanks for the input... will probably need alot more.

[wrngwae]

well if your gonna tear her down and potentially turbo it buy a turbo block for it or put in the oil squirters. just in case you really do.

[capev86]

they are intended to cancel out vibration from having a long stroke crankshaft and it has some effect. Porsche reportedly used this same technology on some of its models. Chrysler borrowed the idea from Mitsubishi when they dropped the 2.6 from the K car lineup in favor of stroking their own 2.2 out to a 2.5. the big Mopar 4-banger had better fuel economy with about the same performance thanks to the efficiency of more stroke and smaller pistons than the 2.6. all n/a and turbo 2.5's (and some of the later turbo 2.2's) had balance shafts except on the Dakota as there was no room to fit that deep oil pan over the cross member. from personal experience i like the balance shafts as a 2.5 with shafts feels somewhat smoother than a 2.2 without them. eliminating the shafts on a 2.2/2.5 will give you an extra dozen horsepower at red line but that equates to only about 3 hp at 3,000rpm where the engine spends a lot more time. the shafts do put drag on the engine (like spinning an extra accessory) and that will slightly hamper it's ability to rev quickly. also on the 2.2/2.5, keeping the deeper pan after ditching the shafts gives you an extra quart's worth of oil capacity but the trade off is you still have less ground clearance than the standard oil pan (so lowering and back road driving demands some consideration). ditching the shafts requires cutting the chain that drives the shafts, pulling the shafts and tapping and plugging the oil feed hole. someone else can chime in on the pros and cons and what's involved on the Mitsubishi equivalent setup.

[camoit]

Me I like to have everything ballanced internaly. As for what Max said I don't know if this happens on thies engines. But I don't mind the viberations that is produced. As for what Wrngwae said about the oil squirters I know that an engine will produce more HP with out oil. This is why they dry sump engines. But that will run you around 3000 just for the parts. Thats why I'm not dry sumpping my build. But I would get around 50 HP more. Thats $60 per HP. That will be the next step if I decide to go that way. My truck is going to be hard enough to get the HP to the ground.

[4doorciv]

I agree that the balance shafts are there for a reason, but on my engine I'm eliminating it. To me, it's just another part that'll break but without the proper balancing it will wear on other parts as stated. My engine of course is the dsm 4g63 turbo motor, not the g63b that originally came in my truck if your wondering.