hello everyone. i recently built a 383 stroker.. my friend and i noticed it seemed hard to turn but didnt really know how hard a new engine would be to spin over. we connected the starter it wouldnt budge it but a few inches if that... we then realized we had mixed up the caps and put the wrong cap on the connecting rods.. we got new bearings and replaced them all... then put the correct cap on the correct rod... it is STILL a little too hard to turn. easier than it was but the starter still wont turn it but just a little.. how can you tell when the main caps are in the correct order? i know they have arrows that point to the front of the engine.. but how can u tell what order they go in? this is our first time building an engine and so far its been a pain.. but we've DEFINATLY learned from our mistakes.. lol. thanks for any help..

Usually they are numbered but if not they should be stamped with a number before they are disassembled so you can be sure to get them back in the proper location.

If you have the proper main bearings with the proper clearances installed it sounds to me like you need to disassemble the engine, take it to a machine shop and have it align bored.

What pistons and rings are you using? I had a similar problem with my 383. The oil ring expanders were pressing the rails way too tight in the bores. It took nearly 90 ft lbs to crank it over!

If your main bearing and rod bearing caps are not numbered...always number them with a stamping tool before you dissassemble. I always use plasti-guage when I build a engine to verify that my clearances are right.

Doc here,

ALSO be sure the rod big end AND bearing cap is facing in the correct direction..

Doc

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Aftermarket Solutions
Electronic & Electrical
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Certainly don't want to rub salt in the wound, and as you said - you are learning from your mistakes, but this is one of the textbook examples of the old adage: "Build a little - test a little - then build some more".

ALWAYS rotate the bare crank a couple of turns after you install each main cap and after torquing. ALWAYS rotate the crank a couple of turns after you install each rod cap and after torquing.

We have ALL installed something up-side-down, backyards or inside-out at one time or another (some of us more than once).

I would either have it aline bored (preferred) as centerline suggested or go all the way back to the bare crank and keep "swappin' and tryin'" (not preferred) until I got a best fit.

If my senior memory serves me; there is a thread on the Bulletin Board somewhere about how much torque should be required to rotate a SBC at various stages of assembly. This won't solve your immediate problem, but should help you identify when you've hit the problem spot.

I, for one, feel your pain! Been there, Done that, Got the tee shirt!

the pistons dont really seem too tight in the bores.. i can slide them up and down in the bores with a little effort (by pushing/pulling the rod) i know all of the caps are on the correct rod now, i just have to figure out the sequence of the mains.. if i can get that then i hope itll turn over correct. ya live and u learn.. next engine build should go ALOT faster.

Are you cranking the engine over WITH or WITHOUT the spark plugs in? Got the cam in correctly!!! Did you end gap the rings? got the rings in correctly?

I would suggest that you find a 'good buddy' that has rebuilt an engine or two to go over your engine with you and give you a better understanding of what you should be looking for. good luck.

the plugs are in but only finger tight.. the heads are stock heads that were just cleaned up and bigger valves installed.. pistons are keith black hypers' flat top.. dont think they had really high compression..

IMO you need to take the thing back apart and make sure the main caps are in the correct place... If they are not numbered and you have a understanding machinest he can get them in the right place for you, but it might cost you 1 or 2 hours worth of labor...

As someone else pointed out you really need to be sure the caps are on the correct rods and also in the correct direction..

I would also take the time right now to learn how to measure bearing clearance... we can help you through it and you really should know how to if you plan on building any more engines...

most short blocks, crank rods,pistons, no cam chain etc... with normal clearances and normal ring packages take 20/25 ft/lbs to rotate....much more then that something is wrong


Keith

Keith

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K-Star Automotive
Performance Engines
It's better to have a gun and not need it, then need a gun and not have it.

ok thanks k-star. i know how to read calipers etc... just not sure about checking the clearance of the bearings.. but i am like 99.8% sure the rod caps are correct... they are eagle rods and the cap and rod have part #'s that match for each rod... so i believe now its just down to the mains... also is it possible to over torque the rod caps and that make it too tight?? thanks for all the help guys. oh btw that is with my timing chain on also...

Yes you can over tighten the rods but if you did them with a torque wrench your probably not close to the stretch.....

All you need to do to measure clearance is bolt the rod up with the bearings in them, stretch the bolts to the correct value. and then measure the bore at 90 degrees to the parting line. measure the crank size and do the math...

Same goes for the mains.... If your are into some learning you can find the right location for the caps your self..If it's a 4 bolt you only need to do the center 3... You can just torque the cap and check the bore diameter. keep switching caps untill you get the one with the correct size, and register fit...


Keith

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K-Star Automotive
Performance Engines
It's better to have a gun and not need it, then need a gun and not have it.

383's use chamfer bearings.

Did you get the "new" bearings chamfered?

no.. i didnt get them chamfered... what does that mean... and also why does it need to be done if the crank journals are the same as a reg 350?

I would imagine that what he is referring to is that you have a '400' cu. in. crank in there instead of a regular 350 crank. Which are NOT the same.

I know that you don't want to, BUT you will have to take the engine apart anyways. You may think that it is just the mains, or rods, or? or ? All your really doing is playing tag with your own tail. Thinking that some guru is going to give you the magic potion and your engine is going to run like the wind. If your thinking that someone is pissing down your leg. There is an exact procedure that you follow to putting an engine together and tests that go in along the way. As I said before get a hands on buddy to go over the engine with you and tag all the bases along the way, otherwise your just pissing in the wind and wasting your time. Good luck.