here's the scoop, wasn't getting too much responce in lt1 tech section

97 lt1 le1 head/cam package, fully built top end.
threw a rod last weekend.
i need to do something with the bottom end so it doesn't break again,
what can i do? i don't want to put -new- stock parts in it, do i need forged parts?
i was under the impression that you could put a 383 stroker crank/rods/pistons in a stock lt1 block, w/o boring it, am i wrong?
thats what i'd like to do, if not what are my other options?
basically i'm in need of a crank/rods/pistons, forged, but i don't have the $$ to bore my block..can i get forged parts w/o boring my block?
thanks a ton for any help..
-Jason

 

First thing to determine is why it threw a rod. AS long as the block is undamaged and the bore is good, then yes you can just hone it and toss in a new bottom end. Plus it saves you an overbore for the future. If you are going forged, then there is a good chance that you can rerun the standard bore, since forged pistons run a little more clearance than the stock hypercraptic pistons did.

 

Problems I see:

1. Is the lack of pistons for a stock bore, at least good quality ones.
2. Not a new surface finish for the rings so the piston to wall clearance could be loose if you stayed around 4.000"
3. Not being able to set the piston to wall clearance.
4. 4.010 or 4.020 only costs a little bit to do and it's done right the first time, you have to put new cam bearings in the motor anyways so the added money for the boring to get the cylinder correct is well worth it.
5. Not doing it right the first time costs more money in the long run.
6. A LE1 package is not designed for a 383 so you will be down on power and RPM with a 383, so basically you wasted your cash on the wrong heads. I hate to see you get bad results and think that because it's a stroker it should make more power. If you wanted to do a 383, do it right send the heads back to Lloyd for him to make them work better with a 383 and get a cam for the 383 with those heads. If you need a new LT1 crank they are cheap, I have a buddy with 3 of them and it wouldn't be to hard to polish that up and send it to you.
7. Forged parts are not the place to spend the money. A set of Scat or Eagle I beam rods (which are forged) a stock LT1 crank that you have the journals polished on, and a set of good 4.010-4.020" pistons. By some decent rings and some bearings and have the machine work done right.
8. If you were the guy with the pictures of the broken rod, it's because you ran out of oil on that rod and spun the bearing. You didn't have too much power, probably just something in the motor or in the oil that caused that to go boom.
9. Good block work and assembly is worth more than Forged parts in keeping your motor together. If the machine work is junk and the forged parts are good you just spent a lot of money to break the forged parts because the tolerances are off and clearances are incorrect.


Good article for you to read about just throwing a bigger crank in the motor because it needs to be rebuilt......

http://www.rehermorrison.com/techTalk/15.htm

Good Luck,

Bret

 

Scat is also another great alternative for a crank. really cant beat their 9000 cranks for $189


damn strong too. rumors say stronger than GM's forged crank but who knows

 

ok, thanks for the help
i will not stroke it, so could i just polish my stock crank and re-use it? buy new rods and pistons? i don't now that 4.0 and 4.01 measurment stuff, the first time we rebuilt the lower end, we re-used the stock crank/rods/pistons and just put new rod bearings/main bearings/and piston rings on, we also honed the cylinders.
my dad took the oil pan off last night and said the block wasn't damaged...so i can re-use my stock crank, just get new rods/pistons and hone the cylinders?
thanks
-Jason

 

Might be able to polish the crank, depends on how much the spun bearing did to it.

You've rebuilt this motor once before?

Bret

 

Please dont take this the wrong way.I wouldnt for the life of me put a Scat crank in my engine if it was given to me for free.Now before anyone jumps all over me, especially the people who own these cranks and will tell me they know so and so pushing x amount of HP for x amount of time.Scat at this very time is being sued in a multi million dollar class action suit.Seems their 4340 steel is not even close to being what they advertize it as,and they have been found out.And an inside source has told me their standard weight 4340 steel cranks go out the door costing under $150 to machine and forge.So any knowlageable person who know the cost of quality steel and machining cost can attest that the chinese made Scat cranks are junk, and cannot be 4340 steel. Spend the extra dollars and get a Callies,Cola or Lunati crank, just isnt worth it to take the chance. This is one place where buying american pays off.

 

Ive always read as a general rule of thumb, "if you can feel a groove in the crank journal with your fingernail, its trashed".

 

ya we rebuilt the engine about 10 k miles ago, everything was fine until this happened, went through the lower end, new rings/bearings.
my dad looked at it and he doesn't think lack of oil was the problem, he said the crank wasn't too torn up, we'll see what happens. i guess i'll put just a regular lt1 eagle crank/rods/pistons in it ?
thanks
-Jason
i'm also going to be steping up my cam, it won't be a daily driver anymore so i'm going alot bigger..

 

Interesting...have some proof to share? Links, etc. What court is the lawsuit filed in?

 

As SS MPSTR said, please come forward with specifics. I'm a knowledgeable person on materials and manufacturing of metal parts, and I cannot conclude that your statements are true.

FWIW:

It's easy to determine the chemical composition of a piece of metal. The Chrome, Molybdenum, Nickel and Carbon percentages, the main alloying elements in 4340, can be determined by a lab.

Nearly 40% of the steel produced in the world is produced in China. It is very difficult to buy 4340 originally melted in the USA. I'm not saying all Chinese steel is good or bad, nor that they are 40% of the 4340 source, but their output is prolific.

There is 4340 and also Aircraft Quality (AQ) 4340 (as well as other alloys). AQ steel is most often double vacuum melted, x-rayed or other ways tested for inclusions, laps, seams, etc. that "commercial" quality steel doesn't see. I believe that lower priced 4340 parts are probably not made from AQ steel. Very high end producers will advertise the fact that they use AQ steel, but you will pay well for their products. AQ steel isn't inherently stronger, it's just "purer" in composition, cleanliness and consistency.

I'm not defending Scat, but the stuff we have seen from them has been everything they claim it to be. The 9000 cast cranks (completely produced in China from the markings) that we have measured have been spot on. Other forged parts that were machined domestically have also been fine.

It is entirely possible that a lot of steel is falsely certified by the steel dealer. There are unscrupulous folks in every industry. There have been cases where flight-critical aircraft parts were falsely certified, which is scary to me. This could have happened in the case you mentioned. It has certainly happened to other producers/sellers of aftermarket parts.

There is no assurance that stuff produced in any specific country (USA or otherwise) has guaranteed good quality. Today at lunch a guy was showing us some T-handle rocker arm cover hold downs sold by a well known domestic manufacturer that he had just purchased. "Made in the USA" was stickered on the blister pack. The external turning was pretty, as was the anodizing. When I handed the parts to one of my CNC lathe operators, she was shocked to find the tapped end had countersinks which varied almost 1/8 inch from part to part. She works in thousandths (.001) and "tenths" (.0001) daily, and thought the parts were "junk machined". These were $4 each retail, and Made in the USA. Functional, sure, but high quality? Not IMO.

My highly opinionated $.02

 

I cannot give detailed specifics.But the story was first heard on the thirdgen site. I have spoken with the said individuel who is involved in the suit.He should be posting this in the next few weeks. Seems Scat is being sued to the tune of 130 million dollars, (I think) for misrepresenting its parts as "Made in the USA" which they are not,they are just machined here in the USA. Thing is the individuel had the equipment and technology to examine the said broken parts and found the metal to be substandard steel. Not even close to 4340 specs. Trust me you will all hear about this in the upcomming weeks.This is all I know at this time.

 

There is a significant difference between the representation that something is "Made in the USA" and whether the products they sell are materially what they represent them to be. At first blush, a $130mil complaint seems pretty hefty for a broken crank/rods (I don't know specifics) - how many engines could you replace with 1% of that amount?

As OldSStroker said, I too have used the 4340 Scat stuff in both stroker engines I've built, and both were everything Scat said they were, and well within spec to boot. I'll reserve judgement until I see the complaint filed with the court.

 

ok, well i called about having my block bored, and its in the budget, so i've decided to go w/ a 383 stroker kit, to maintain a lil more drivability over the 396. now where can i get a good 383 rotating assembly? what are things to look out for, i was looking into the eagle 383 lt1 kit, some people rave about it, some people bash it, i guess i'll find that w/ every kit huh?
-Jason
some one also recomended crower, i can't find a complete -lt1 383- kit by crower online??

 

Now this is only my opinion first off. If I was in your position, I would be looking at the top 4 for cranks. Callies, Cola, Lunati, and Crower. All high quality made parts, and more than likley you will not hear any bad things about their quality. My builder, when I went to his shop told me the Eagle stuff is ok, but all the time when he gets the rods(SIRs) and the cranks from Eagle , always,always , their is at least 3 or more out of round big ends on the rods and the crank journals are off,so he has to clean them up, which adds to the cost. If your builder doesnt know to check this you may be in for some problems. If you are looking at rods,and you like the price of the Hbeams, just remember that most are manufactured in China,even the expensive H beam from Manley. Depending on your budget, Lunati, Crower sportsman, or the more expensive Oliver may be the ticket.You didnt specify NA or Blown. I think at this point, to forgo further problems look into high quality machine work as the best parts in the world wont survive shoddy machining and assembly.It might be a little more expensive up front but will pay for it self in the long run in reliability. There are many builders who can supply a short block already machined and assembled, just add your own stuff to finish. This might be another route.I am not familer with the LT1s at all. But Im sure alot of knowlagable people here can chime in and steer you in the right direction, as I assume their are more than a few here running 383s. Just remember, you might save $$ on the crank, but the savings will negate it self if you spend $200+ in mallory to get it to balance. I just got a Cola crank spent $650 for it, but since the price in Steel is going up the price has jumped 45 dollars since I purchased it. Same thing with my Oliver rods, I paid $699 for the forged units, they are now $825. I think a Callies crank goes for $795. To put in comparison, the Eagle forged is around $600 and sometimes it hit or miss on the journals,plus if you spend $200+ in Mallory balancing it+ if the journals are off, you are already around the price of the others. Samething with the Cast steel from Eagle, sure its cheap, at around $200, but if it cost you $400 to balance it is it still a deal? More than likley your best bet would be a balanced and matched rotating assembly, from either Callies or Lunati.. Hope this helps.