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LSA Drop in forged piston and Rods

2808 Views 13 Replies 6 Participants Last post by  Karch
Vehicle Car Hood Motor vehicle Automotive fuel system

Looking for a drop in forged piston and forged rod combo. Staying stock cubes and factory LSA crank. Perhaps a small bump in compression to 9:5:1

If there are some solid combos out there please let me know.

Any true drop in set ups out there? Perhaps without having to send the crankshaft to be machined? If so, Drop some links.

Had a lifter fail and the heads are off. Now I'm spiraling down the rabbit hole since I'm there馃槄

Bottom end is solid with no issue. I will also be replacing the main bearings as well while its taken apart.

Thanks and cheer馃嵒
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If you have the motor out and are doing all of this work, you might as well do it all. Cylinders on these engines are significantly out of round and need to be honed after a while. Also you at least need that because new rings will not break in properly on cylinder walls that aren't freshly honed. The crank will not need machine work most likely, just clean and polish but in order to confirm that you need to measure it.

In short there's no such thing as a drop in piston and rod. Main bearings need to be measured as well and sized. If you are going to touch the short block it is either all or none

Edit: I said all of this because you indicated you didn't want machine work, but if so any standard LS forged rod will work and there are plenty of 4.070 (10 thou overbore after honing) options posted on here that will get you what you want. But before you do that I would recommend getting the block cleaned and honed first because sometimes this reveals cracks (It did for me)
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Can supply a piston and rod combo for 9.5:1 but will need balancing with your stock crank
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I get that you weren't planning to do a rebuild but the lifter situation forced you this far. It would be nice to 'forge it up while in there' and we certainly will agree.
As Matt said, balancing will be needed and at the most basic level the crank should be polished and measured. There are lots of 4.070 piston choices and they all require a proper machine-honing operation for fit. It's not the old ball hone-on-a-drill maneuver that we used to do for the quickie iron block 'refresh', it has to be a machine process for these LSA blocks if you want it to seal and to last.
You don't have to go off the deep end like some of us crazies do, but you'll be way ahead if you put enough in to do the bottom right. You can do the top end and blower porting and all the fun stuff later and incrementally if needed, but it's a grand idea to do the bottom ONCE!
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Well looks like machine shop it is馃槀馃ぃ. thanks a bunch to those who have replied. Didnt know this page/forum is still active. Also For those of you who have done a forged lsa bottom end did you leave or delete/block off the oil squirters?
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Don鈥檛 be afraid of compression if it were me I鈥檇 be going 10.5:1 on pump gas at least.
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Don鈥檛 be afraid of compression if it were me I鈥檇 be going 10.5:1 on pump gas at least.
Ill be on e85
Ill be on e85
You can set compression based on how you plan to use it. 9.5:1 is a common street/strip setup for those running pump gas and E85. We have built them as high as 12:1 when running 1R full time.
You can set compression based on how you plan to use it. 9.5:1 is a common street/strip setup for those running pump gas and E85. We have built them as high as 12:1 when running 1R full time.
I plan to throw a set of twins later down the line. Dont want to bump compression too too ooooh high馃槄
I plan to throw a set of twins later down the line. Dont want to bump compression too too ooooh high
Just depends on fuel but 9.5:1 is certainly safe
post: 2584247 said:
said I need 50 posts. I will read more when I get home. 5 hour drive ;)
Make an intro post in the introductions thread.
I'm glad that you got a V today! Congrats!
This is a GREAT forum and one of the very few places where mods, racing etc are discussed and there are a LOT of smart folks and great advice and experience available.
It's great that you read at least part of the classifieds rules. Just be aware that the mods, here, take that stuff really seriously and your openly asking someone to help you work around the rules will likely get you thrown out before you have a chance to interact, here.
Skip that part, do some reading and research and enjoy the loads of help and information that abounds.
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Suspended for a bit. If he should try to circumvent the rules again it will be permanent.


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Oh well鈥.
I really tried
You did, like always.

I don鈥檛 get it, people just think they are above the rules, or they don鈥檛 pertain to them?

I have no emotion or get any satisfaction out of it, at all.

I apply the rules equally as best I can, and try to stay consistent.


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