ANTI VENOM

I built a LT1 383 bottom end. I checked all the clearances myself before assembling, for what that's worth. Crank spun free. It got progressively harder to turn as I added pistons of course. I really noticed that it was hard to turn when I went to degree the cam. It had sat for a couple weeks and I had a difficult tiime getting it to start to spin. Once I get it "broke loose" it seems to spin fine. Let it sit for awhile and its very difficult to get to spin again. It's difficult to say how much torque it requires to get it to spin coz I can tip it over on the engine stand. (3 legged) It all lubed of course, no rust, etc....
Ideas????

aussie_g

Could be a whole list of reasons.
did you use feeler guage on the rod/main bearings to check the sizing.
was the block bored & honed? with a good cross hatching?
Did you check & size the ring end gap?
did you use plenty of lube during assembly?

I have built a bunch of engines & its fairly common with a fresh bore & new rings for there to be quite a bit of friction.
Did you have any trouble putting the pistons in the bore?

ANTI VENOM

NO. I used different methods including micrometer, telescoping guages, inside mic, digital caliper, and lastly plastiguage. I tripled checked everything. I don't build engines often so I was very careful, but I could have overlooked something

Block was bored and honed with a good cross hatch by a professional enginge shop. I double checked bore dimension before ordering pistons.

Yes, I checked and file fit the rings per manufacturer specs. I did use feeler guages here.

Yes, I used Lucas assembly on bearings, and engine oil on rings and cylinders.

I also checked the ring land clearances. First rings were too tight.

I did have some trouble putting the pistons in the bore but that was not because they were to tight. I had some difficulty getting the small oil control ring to stop popping out. I bought a bore specific tapered piston installation tool that helped.

cohocarl

How about rod orientation on crank? (bevel towards counterweights, flat side towards other rod) If I remember right, a general rule of thumb is about 30-45 ft/lbs to rotate a short block.

Tom400CFI

Vizard said 50 lb ft on a freshly assembled motor. I'd think a little less for a modern one w/roller valve train, so the above seems right. If that were MY motor, and it would tip over the engine stand trying to turn it...I think I'd start taking things back apart to have another look. Can you pull the timing chain and try it? Then you're eliminating the valve train, distributor, oil pump in one move...

ANTI VENOM

I can guarantee the rod orientation is correct.

It's just the reciprocating assembly and cam, nothing else. It spins easy once you move it, but I would say its well over 100lbs before it will start to move the first time after it has set for awhile. That's what's confusing, If I get it to move, then I can stop and it will spin easy, let it sit and then its a struggle to get it to move again. The cylinders are oiled and look perfect to me.

Who is Vizard? JK LOL

C409

..... If you used a forged steel crank the fillet radius' are larger than factory stuff and REQUIRE chamfered bearings on rods and mains ... in Clevite it would have an H in the part number ... basically race bearings .......

lbzraptor

My machine shop always wanted me to get pistons first, They bored and then honed to match the pistons. Be careful if a piston is sticking. Could break a ring.

Churchkey

What C409 said.

What is your rod side clearance? I like .014 - .016 for performance street.
.020 for a track engine.

Piston to wall clearance?

Suggest adding a front cross bar to your 3 leg stand.

cv67

Valvesprings adjusted yes it can feel "sticky" woulndtworry about it

Red 91

I if it were mine look at the cyl. bores for any telltale signs. I would pull it down until I knew what the problem was. GOOD LUCK

charliet615

FWIW, It's a new engine, it will be a little tight, continue with your assembly. I would not worry as i have built quite a few engines and the are always tight at first...

powerpigz-51

This might be out there, but could the friction of the binding part generate enough heat to be picked up with a IR temp gun? Referring specifically to the fact it is easier to turn once it gets going........

383vett

No heat with a breaker bar

ghoastrider1

thrust bearing clearance?

ANTI VENOM

Thanks for all the great responses, when I have time to get to the shop I will address each of them.

I know the bearings are chamfered and the crank spun very nicely all by itself.

I recently sold an engine that was on the 4 legged stand. I will transfer it to that one as it is much nicer and more stable.

Apache 84

Does this engine have a 2 piece rear main,as sometimes these can be extremely tight after being fitted.I do all my checks before fitting seal.Best of luck

C409

..... Check the cylinder bores for any strange or different scratching on the walls ... it is possible that an oil ring expander is overlapped OR on narrow ring packages like Mahle , that the expander pushed past the rails ..... What kind of assembly lube did you use ? ........

ANTI VENOM

Single rear main seal.

Assembly lube was Lucas. I think it is synthetic. It's sticky and is ok for engines that won't be started soon after assembly.

trackbird

Just a quick note. If you pull the timing chain, you run a risk of piston to valve contact (depending on compression, piston valve relief depth, cam lift, etc). Be careful, it may spin and then hit something solid...that's likely a valve. DO NOT lean on it to keep it spinning if that happens (with the timing chain off). Otherwise, I'd back all the rocker arms off before taking the timing chain off of the engine and trying to turn it.