To stroke or not to stroke - NJFBOA - Home of New Jersey's Camaros and Firebirds

B4C · 10-15-2018, 10:21 AM

So I got completely screwed on the "machine shop fresh" motor that I purchased and have decided not to use it. I'll be using an ls6 that I was saving to swap my wife's 86 trans am. The motor I have needs the crank polished, new bearings and I'm going to have new rings and a fresh hone done too. Wonder if it's worth it to stroke to a 383 or just install forged rods and pistons and reuse the stock crank?

Blackbirdws6 · 10-15-2018, 10:45 AM

I think it just depends on your power goals. The stock cranks seem pretty strong so if the crank can be cleaned up and re-used, save the money and put it towards the machine work/new pistons/new rods. If you are going for big X,XXX rwhp, then a new crank probably isn't a bad idea.

B4C · 10-15-2018, 11:08 AM

Would like to see upper 400, 500 would be nice. Since my stock ls6 short block needs work just wondering it's it's even worth replacing the rods or just installing arp rod bolts and doing pistons. Will be setting the car up to handle with a watts link and strano/afco coilovers. Have afr 205 heads, and ported fast 90 with the end opened up to 92mm. If I stay stock displacent I was planning on running this cam and 11.5:1 compression
https://www.corvetteforum.com/forums...-500-rwhp.html

wretched73 · 10-15-2018, 11:44 AM

I stayed stock stroke with my LS build for most durability on the street. The longer stroke will force the piston further out of the bottom of the cylinder than a lot of people like and could reduce longevity. The longer stroke also pushes the wrist pin into the oil ring land.

A happy medium is a 3.9" stroke crank. 4+" stroke cranks have the issues above. 3.9" is the biggest without the oil ring issue.

Stock LS6 will handle up to 700 hp without issue. If you're looking for over 600 that's when you should really invest in forged parts.

B4C · 10-15-2018, 11:55 AM

Quote:

Originally Posted by wretched73

I stayed stock stroke with my LS build for most durability on the street. The longer stroke will force the piston further out of the bottom of the cylinder than a lot of people like and could reduce longevity. The longer stroke also pushes the wrist pin into the oil ring land.

A happy medium is a 3.9" stroke crank. 4+" stroke cranks have the issues above. 3.9" is the biggest without the oil ring issue.

Stock LS6 will handle up to 700 hp without issue. If you're looking for over 600 that's when you should really invest in forged parts.

Well if they hone it to .005 won't I need new pistons anyway? Guess if that's the case then I'll just reuse the stock stuff unless I need to replace the pistons then ill go forged. The car will never see nitrous or forced induction, staying n/a.

MyFirstZ · 10-15-2018, 12:10 PM

What wretched said is the reason I ended up resleeving my LS2, then I ended up big bore with a 4" stroke. 440ci.

I can't remember if you need over sized pistons for .005" I think you would just need to install new rings. But if there is damage .005 might not be enough to fix the damage. May want to take it out more buy new pistons and rods, just remember they will need to be balanced

B4C · 10-15-2018, 12:27 PM

Quote:

Originally Posted by MyFirstZ

What wretched said is the reason I ended up resleeving my LS2, then I ended up big bore with a 4" stroke. 440ci.

I can't remember if you need over sized pistons for .005" I think you would just need to install new rings. But if there is damage .005 might not be enough to fix the damage. May want to take it out more buy new pistons and rods, just remember they will need to be balanced

It's a fairly low mileage short block and I didn't see any damage to the cylinders. I'll let the machine shop decide what's up with it and the determine what I'm going to do. Looks like I'll just be reusing all the stock parts in it and adding arp rod bolts at this point.

wretched73 · 10-15-2018, 12:58 PM

Quote:

Originally Posted by B4C

Well if they hone it to .005 won't I need new pistons anyway? Guess if that's the case then I'll just reuse the stock stuff unless I need to replace the pistons then ill go forged. The car will never see nitrous or forced induction, staying n/a.

Quote:

Originally Posted by MyFirstZ

What wretched said is the reason I ended up resleeving my LS2, then I ended up big bore with a 4" stroke. 440ci.

I can't remember if you need over sized pistons for .005" I think you would just need to install new rings. But if there is damage .005 might not be enough to fix the damage. May want to take it out more buy new pistons and rods, just remember they will need to be balanced

WS6 store on LS1tech sells .005" overbore pistons, they're hypereutectic like stock but "better". Not sure how they are better but that's what the vendor claims. They'd still be plenty good for NA

MyFirstZ · 10-15-2018, 02:19 PM

If you had to get new ones I wouldn't stay with hypereutectic.
Only way i can see them being labeled as better is if they have a valve relief

unstable bob gable · 10-15-2018, 02:35 PM

If you have the time and the coin, there is no replacement for displacement.

wretched73 · 10-15-2018, 04:12 PM

Quote:

Originally Posted by MyFirstZ

If you had to get new ones I wouldn't stay with hypereutectic.
Only way i can see them being labeled as better is if they have a valve relief

Why not stay hypereutectic? He has no plans on boost or spray or monster HP. They're ~1/2 - 1/3 the cost of forged pistons.

MyFirstZ · 10-15-2018, 04:30 PM

seen plenty of stock pistons blow ringlands

V · 10-15-2018, 05:32 PM

For comparison, my stock heads ls6 made 425rwhp with cam and bolt-ons. So it was like 500 at flywheel. Only upgrade to bottom end was arp rod bolts.

B4C · 10-15-2018, 07:42 PM

Quote:

Originally Posted by V

For comparison, my stock heads ls6 made 425rwhp with cam and bolt-ons. So it was like 500 at flywheel. Only upgrade to bottom end was arp rod bolts.

I'm hoping for around 500 wheel

sweetbmxrider · 10-15-2018, 07:55 PM

For whatever reason, 370s do better than 383s in ls land.....

B4C · 10-16-2018, 05:20 AM

Is it worth getting the stock pistons fly cut? Or to just go aftermarket?

wretched73 · 10-16-2018, 07:44 AM

Quote:

Originally Posted by sweetbmxrider

For whatever reason, 370s do better than 383s in ls land.....

What do you mean? 383 certainly isn't popular, it doesn't cost any more to go 400ci. Cranks cost the same and no additional machining is required.

Quote:

Originally Posted by B4C

Is it worth getting the stock pistons fly cut? Or to just go aftermarket?

I'd assemble and check PTV first, then decide if you even need them fly cut.

B4C · 10-16-2018, 08:35 AM

Based on my research on the heads I have and cam I want to run it's going to be close. Plus I'll be milling the heads to have about 60cc Chambers.

MyFirstZ · 10-16-2018, 12:04 PM

While its apart better safe than sorry, or at least check it. Super easy process.

sweetbmxrider · 10-16-2018, 08:59 PM

Quote:

Originally Posted by wretched73

What do you mean? 383 certainly isn't popular, it doesn't cost any more to go 400ci. Cranks cost the same and no additional machining is required.

I'd assemble and check PTV first, then decide if you even need them fly cut.

Sell ls6, buy lq9, same boat as before but with moar fubared cubes!

B4C · 10-17-2018, 05:12 AM

Quote:

Originally Posted by sweetbmxrider

Sell ls6, buy lq9, same boat as before but with moar fubared cubes!

Would like to keep the weight of the iron block off the front end since the cars going to be setup for handling. Will save roughly 100 lbs off the front end. And no I don't want to go ls2, weary of buying anything used anymore and don't have the coin to buy a new ls2 block and rotating assembly. I'll stick with the ls6 that I have.

unstable bob gable · 10-17-2018, 03:29 PM

If ya gots 'em smoke 'em and build 'em.