I am building a 355 right now I just got the heads on, and was trying to turn the crank so I could fix the timing, and put the rocker arms on, but could not get the crank to move more then about a quarter of a spin. So how can I get it to move so I can fix my timing?

It was able to turn till I put my heads on. The heads are all torqued down to spec. To turn the crank I was just using the crank bolt and my breaker bar

 

Take the heads off and see what's hitting what

 

I have not pulled the heads off yet, but I stopped by my garage one the way home from dropping a kids off at school to see if I could see were its getting caught at. When I turn the crank it looks like the number 7 piston is hitting the head and if I turn it the other way number 8 is hitting the head Could this mean This is an issue with heads or Block

 

Nope, pistons are supposed to hit the heads.... Here's your sign...

We need more info, what heads, what block, crank, rods, pistons and head gaskets?
Do you have plugs in the heads? Valves adjusted propperly?

 

Yes it could possibly mean that there's an issue. Yes could possibly be the heads or the block. Most likely not however, prolly something else.

Pop the heads off and see what's going on. Prepare yourself mentally for being about to go ALOT farther back into it.

 

did you put any rocker arms on yet?
if so, is the timing chain lined up properly- dot to dot is TDC on the compression stroke of cylinder #6.

 

Its a 355 vortec heads stock rods dish pistons bored 30 over... I am asume its the oem

 

Head gasket cause it came in my rebuld kit... Let be a little more descriptive on what happening

I thought my buddy had set running cause he was playing around with it... So I put my heads on it I did not notice till I went to adjust rocker arms that it was not set... So I loosened all the arms just so they stay on. After that I went to turn crank to line up dots and it would spin just enough for 7 to teach tdc then crank stops and bolt will now spin a again but crank stay in place... I then turned it other direction to see if it what was going on and did same thing... So I only got go movment between thoose spots.. is it possiblethat the threading is bad and there's just more tension on bolt when at top of cylinder so its just spinning

 

Did you tighten the main caps and the rod caps to spec?? i finished rebuilding my 355 and my crank was really hard to turn also but i was able to turn it. make sure your rods and main caps are torqued to spec and make sure to you assembly lube!

 

I have no idea what you are saying.

Are the dots on the timing gears lined up? If not, fix that ,before you do real damage.

 

Crank should not be hard to turn.

A bent crank can be.

 

Ouch, the pain, my heads going to explode..

 

well the whole block when its assembled was hard to turn thats what i meant

 

Take the heads off &look for something on the pistons- nuts, bolts, etc.
Find a known flat clean surface-- roll the pushrods across it watching for wobble & straightness.

 

Bolt spins but crank doesn't =
Stripping the threads??
Stop what you're doing-- take the heads off.
Take the crank damper bolt out & check the threads inside & check the bolt thread.

This is exactly why 1 person only should assemble a motor. That way, he // she knows what iz done // needs to be done.

 

does it turn if you use a screwdriver to turn the flexplate?

fyi: the crank bolt is not supposed to be used to turn the engine over.. it's purpose is to hold the damper and crank pulley in place, not to turn the engine over..

 

t-top that only works if the one knows what he's doing to begin with

 

Turns out it was the crank... Took it back to machine shop cause he gave me wrong one!!! Switched cranks and it spins fine now

 

glad to hear you got it figured out.
years ago i had a machine shop turn a crank, and they gave me a set of rod and main bearings with it when i picked it up. turns out they gave me the wrong size rod bearings.
gotta check everything twice.

 

Didn't you check your bearing clearances??? was it a stroker crank?? How did you get all the rod caps on without turning the motor over? (should be done with very newly installed main or rod cap).

 

My guess is that it was a 383 crank, which pushed the pistons too far out of the bore. Where they then contacted the head...

RBob.

 

When I checked stroke it was 3.75 I looked up its casting numbers and found nothing

 

Well stock 350 stroke is 3.48 so it sounds u were given a 383 crank. Wish I got that screw up. Lol

 

I would find another machine shop!

 

Yea... Part of me us regretting giving it back lol... I reassemble it to a short block but now I am thinking should have switched bearings again. What do you guys think

 

I would be doing a lot of checking with the proper tools. I hope you didnt get a 305 crank this time, they are balanced diff than a 350..
I hope you had it all balanced anyway..