The Guy in MY 99TA

I purchased a Eagle 383 crank(for a 350 block 3.75 stroke 5.7 rod---hence part number 35037505700). I also bought a set of SRP forged flat top pistons for a 4.040 bore, 3.750 stroke, 5.7 rod. I baught a set of Scat ICR I beam 5.7 rods.

I started putting the engine together I noticed that the crankshaft touched the bottom of the pistons. Well I kind of quit there and called a couple of known machine shops around and some old hot rodders and they all told me to take a die grinder and just notch the area on the piston a little. Well I did I came to find out that it didn't change much that some of them were still hitting. I called back around and asked again and they told me to remove enough to where it would clear b/c they have seen it happen before. I did and it worked so I put all the pistons in and put the cam in(small base circle comp solid roller) and time it and turn the short block over and WHAM the number 6 rod hits the camshaft. This just plain bumfuzzles me and I call an old freind and reminds me to check the casting numbers on the crankshaft I looked and well low and behold the numbers DON'T match the numbers that were on the BOX! The numbers on the crank were 350375060000 which notes that the crank is for a 6 inch rod engine. I called the place up and they said ok we'll get you one here and you can just bring the other one in. I did and I go the next week to pick it up and ask if they could help me out on the balancing($$$) and he said well I can't but what I CAN do is call Eagle and get them to balance a crank for me. I didn't like the idea but I went along. They forgot to get the weight on the pistons and rods to balance it with and the sales guy couldn't remember my name to be able to call me and the machine shop guy couldn't either. So I went back last week and they told me the delima and I gave him my name and he called the machine shop and got the weights(the guy had them on record) and called eagle with them and got it on the way). He calls me this morning and informs me that the crank is in and I can pick it up.

This evening I go and pick the crank up and everything is dandy the numbers match etc. I went to my shop just a little while ago and started to put the engine BACK together and discover that NOW the crankshaft is hitting the area that supports the wrist pin on #3 cylinder!!!!!!!!!!! and I mean hitting it GOOD.

I checked to see if the piston is going all the way to top dead center and 1-2 and 3 look fine( noting that the rods lengths should be right.. and they have 5.7 stamped on them). The pistons don't have an actual number on them besides SRP 40F on the bottom side. I imagine 40 means .040 over but could the F mean something different?????


Guys I hated making this SOOO long but this is my first actual high performance build(well other than your regular 400hp 350 with of the shelf parts) and I really don't know what else could be wrong. HELP ME PLEASE!!!!!

TIA!!

Josh S.

J-Rod

We just did an Eagle 3.8x stroke crank, and I have done a few 383s. I haven't had those issues. I'll see if any of the guys I know have had issues. We have done everything from 400 crank short rod (5.56) motors to 6 inch rod motors. I haven't had those issues. About the only thing i have run into is a bit of block clearancing every once in a while, or trimming the tops of the rod bolts to clear the cam. A 383 is usually really easy... Something sounds really off... Also with all the grinding oin the pistons, are they all close to the same weight. I'd never do grinding like that on a piston. It sounds like your pin height may be off... Hoew do they sit in the motor, down in the hole or right on...

The Guy in MY 99TA

What do you mean by that?

I haven't heard of that either.

Could there be something wrong with the block somehow? Wrong main webs or wrong deck height? I haven't heard of a taller or shorter deck height small block but this motor did come out of a truck.

distortion_69

iTrader: (20)

Are your pistons in backwards? Some "performance shop" put some guys pistons in backwards.. so it is possible. Hehehe.. Just kidding..

I just wanted to add that sometimes you will have to clearance the rods for larger cams.

Good Luck,

J-Rod

Installing pistons backwards won't cause the skirts to hit the counterweights.

The reason I ask how the pistons sits is that if the pin height ont he piston is wrong, the piston could sit down too far and contact the counterweight. At TDC is the piston right at the top of the cylinder, or is it down in the bore a bit.

There are no tall deck SBCs except for some of the aftermarket stuff.

ChrisB

I'm a bit confused as to what is going on here?

The machine shop said they couldn't balance the crank and that you needed to send it back to eagle? Ane you sent it back and they balanced it without the rods or pistons? Did you actually weight each rod/piston and give them the weights, or did you match all the weights? How accurate was the scale you used?

The Guy in MY 99TA

ohh sorry chris. Eagle couldn't balance the crank without the weight of the rods and pistons( they had to be gotten from the machine shop). The place where I baught the stuff wouldn't help me pay to have the shortblock rebalanced so they left it up to Eagle.

I'm taking the WHOLE engine to the place where I baught the stuff tomorrow and I'm gunna get some **** straight!

Josh S.

J-Rod

I talked with a buddy of mine on this and we came to the conclusion that you must have gotten a set of 5.7 pistons (pistons for stock rod length), and put them on your 6.0 rods. That is te only way the skirt would hit. If you ground on the pistons, I'd expect you to have a very expensive set of paperweights now. The right pistons will clear the coutnerweights with no problems.

masterdill

iTrader: (2)

my guess is you have pistons for 6 inch rods

Taspeed

iTrader: (1)

ummm...yes....wrong pistons.

Datankid069

iTrader: (15)

Hate to hi-jack, but i figured we got some pretty knowledgeable 383 guys so i better ask a few questions myself. Is a 383 worth the extra money on a budget build over a 347? I just purchased Diamond 3.905 piston and wanna do a 383 ls1 build. With a 4.000" crank:
What size rods will I need?
What clearance issue will need to be addressed with the ls1 block/heads?
If I take my time and have the right tools will I be ok doing it myself? (Helicopter mech, with some car experience first time motor build)
What else besides the rods, pistons/rings, crank, hardware, gaskets, and gridle will i need to complete my shortblock.

KCS

iTrader: (20)

Don't worry about the hijack, no one has posted on this thread in almost 7 years so I don't think anyone will mind.

If you already bought pistons for a 347, they won't work for a 383. Most pistons for a 3.622" stroke crank will have a compression height of about 1.3xx", while pistons for a 4" stroke crank are more like 1.1xx". Compression height is the distance from the center of the pin to the top of the piston. If you were to use those pistons meant for a 347 with a 4" stroke crank, you may end up with the piston sitting about .200" above the deck.

Datankid069

iTrader: (15)

Man... That helps out so much! Comp height is 1.315, looks like I'm doing a 347 build!

Arc00TA

iTrader: (17)

I lol'd.