I have heard many different opinions on using the stock crank and rods with boost. Is it truly safe to run intercooled 10-12lbs of boost on them? of course supporting mods/tune/pistons wil be upgraded. Will two bolt mains hold up as well?

 

why bother? to save a couple hundred dollars? i would say if your going to run a stock engine till it blows then build something go ahead.. that is what i am doing.. if your building up cheap engine for boosted application why waste your money.. do it right and it may last..

also you can make 500fwhp easily with heads and cam.. if thats your goal then dont waste money on forced induction.. if you have a bigger goals then 500hp then the stock crap will be short lived.

 

I'm looking for 500rwhp. i have heads/cam, bolt on etc. I read on a sticky above that one member recomends reusing the crank and rods, thats why i'm asking.

 

you can get a eagle forged rotating asy for 1200$ with pistons.. how much are you saving?? once you resize your rods get better rod bolts, turn your crank?? to me it doesnt seem worth it..

 

im not really worried about saving a couple hundred bucks(not like im rich). if i dont have to change the crank and rods and still have a reliable motor than thats what ill do, if not, i'll get a rotating assembly.

 

my point is if your going to pay 100$ for new rod bolts then pay 100$ to get the rods resized why not pay 210$for new rods? or pay 375$ for h beams that are good to 800-1000hp

same goes for the rest of the components..

will the stock componets work to 500hp? probably.. just i wouldnt bother.. the savings will be minimal at best and if it blows up you will kick your self in the *** for saving 500$ on a 2500$ scrap engine.

once you add up all the machine work to build a new engine then all the gaskets and bearings and bolts the rotating assy becomes a smaller portion then you think..

 

I'm in the same situation, but if the stock ones will work, why not, I just want to know how much will they take too.

 

THe stock crank is much stronger than the rods. If budget is a concern run a stock crank.
On the list of the fastest LT1's there is some guy with a h+c 355, He hits a 300 shot on top of it. I have also read about many guys with a FI setup pushing 800 flywheel hp, so I would go ahead with some h beams, a very good piston(diamond,JE, ROSS) and just have the stock crank polished/checked.

You said that you already have heads and cam. Are they aftermarket castings? If they are i would consider stroking the motor too. You need bigger heads for a bigger motor, especially when you running boost.
So if you have a set of AFR's or TFS heads look into spending a few more hundred, it will pay out on the dyno and track. Stroking a LT motor makes a big difference, much more than an LS motor.

 

I started out the same way you are thinking. "all i want is 500" and I was planning on using my stock PM rods and crank. since that first thought I said F-it and went forged everything and im in the process of putting together the engine and fuel system to support 800+... Now if I was still back at not going over 500hp then I would absolutely reuse the stock PM rods and crank. Has anyone EVER seen a stock crank fail!? I havent. As for the rods the PM rods are just as good as the cheap I beams from Scat and Eagle. If you do upgrade the rods only upgrade to the H-beams.

Just remember if you ever want to push more boost your going to wish you built the engine now to support it.

 

i have e.b. ported lt1 heads. i have a 503 cam as of now but will be changing it with a turbo to something like 221/221 or 224/224. should i stroke it out? the heads flow just like le3's.

 

I'm running stock crank/rods with ARP bolts and was making 510 at the flywheel. Soon to be +600. A couple of things to consider:

*Stock crank/rods will be less tolerant to detonation.

*Stock crank/rods (especially rods) will be less tolerant to higher RPM and heavier pistons (ie. inertial loads due to tension.....not compressive loads due to increased power)

*In my assessment, typical rod failure occurs in tension (force as a function of RPM and Mass ONLY)

*The above means a well thought out combination and safe tune.

*As stated, 500 will not satisfy most people for very long so consider doing it right the first time. However, there are a handful of people that I have seen successfully running 500-600 at the crank with stock LT1 C/R.

*Peace of mind goes a long way when your hammering on your ride and cringe thinking about the forces at work inside you engine. Again, tensile forces are more significant. On the power stroke you are actually helping to balance the tensile force which wants to send the piston/rod assm. through your cylinder heads. The highest tensile force on the rod cross section occurs on the exhaust stroke when there is not much counter-action. Notice how you see alot of motors come apart through the traps when you lift your foot and are getting TWO very high tensile loads per cycle at high rpm (Free revving your engine un-loaded is BAD).

*Moral: At least get the best rod/main hardware in there. Consider what the stock crank/rods were designed to do and loads they were designed to endure. 275hp at 5700rpm with stock weight pistons. If you increase piston weight and/or shift point, then you reduce number of cycles components will take (life span). So, maybe a better idea to use stock rods with 10,000 miles on them rather than a set with 150,000 miles.

Please search the Advanced section here and over at LS1Tech.com for some good information on rod loading. It may ease your mind.

Regards,
Scott.

 

Use the stock crank and rods IF they are in good shape.

Rich

 

I'm going for 500RWhp, or about 625hp at the crank. it seems it was misunderstood that i was going for 500hp at the crank.

 

if your heads flow le3 range you have enough airflow to support stroking the motor. Buy some cheap rods, have the stock crank checked out and you should be good till 600rwhp.
Make sure to use arp head bolts, splay the mains or go 4 bolt. Just make sure you get a great piston= JE, Ross, Diamond. Aim for 9.5.1-9.1.1 compression.

 

I don't think going with a 4 bolt conversion is necessary. If you are going to stay under 6500 rpms and make ~600hp, 2 bolt studs will work. I personally think people over build motors. Can someone show me stock crank or rod failure due to too much power and not improper use?