booogs

so crank spins perfect in the main caps. installed pistons and rods today and did 15ft pounds followed by the 85 degrees of torque angle and now the crank feels like it's almost seized. 85 degrees seems like it's way over torqued. any tips on what i should look out for? with the stock rod bolts, is there a set ft lbs that i can use instead of the 85 degrees?

some things to keep in mind:
- i've plastigauged everything and it's all to spec
- i've tried 55 degrees thinking i had the first version of the rod caps/bolts. still same issue but not as bad as 85 degrees
- crank spins a lot better after loosening up rod caps

07NBSChevy

iTrader: (1)

You are using stock rod bolts, and not ARP correct?

HappySalesman

iTrader: (3)

Also, (dumb question) you ensured all the rods are pointing the correct direction?

98znasty

What is the bearing clearance?

98znasty

Sure it's not the piston/ring

booogs

yes they are stock rod bolts and rods. they came out of an LM7.

they were installed/pressed by the machine shop, so i'm hoping they are, but i should probably double check. the flat edge of the rod cap is facing the front of the engine.

i believe 6 out of 8 were to spec perfectly when i plastigauged them but one of them wasn't squished. might redo them tomorow

a friend mentioned it might be that, but when the rod caps are loose and at 15ft torque with no degree torque, they spin perfectly with no resistance. rechecking that the pistons/rings aren't jammed up might be a last resort if i can't find anything else but if they seem to cycle fine when the caps are loose, it leads me to believe that it's either a bent rod or bearing out of spec/mispackaged.

truckdoug

iTrader: (25)

do you have a rod cap on backwards? bearing tangs misaligned?

thats always bummer when you have to tear it back down

booogs

nothing on backwards but i will be double checking that today. none of the tangs are out of place that's for sure but again, sometime i will end up double checking later too just in case one popped off during the installation process.

conan

iTrader: (5)

Dumb question, Are you trying to spin this over by hand or using a wrench on the crank bolt ?

DietCoke

iTrader: (18)

lolwut.

put your tools away and step away from the engine, and get it to someone who knows what they're doing. preferably someone who actually has the tools for the job

booogs

with just the crank shaft it spun smoothly by hand. with the pistons and rods in it needs a wrench on the crank bolt.

LLLosingit

iTrader: (4)

Hate to say it but I agree 100%, I encourage people to do their work when possible but at some point they either won't have the tools or skill to do it right. When I read "i believe 6 out of 8 were to spec perfectly when i plastigauged them but one of them wasn't squished" That tells me they are in over their head and chances are the outcome will be other posts with titles like.... What's this noise/No oil pressure/Metal in my oil/locked up? and so on.

KCS

iTrader: (20)

That's normal. Shouldn't be much more than 15ft-lbs to turn it over with the shortblock assembled.

The crank has a rolled fillet so it shouldn't really matter which way the rods or bearings are facing.

If it's really seizing up, then you may want to go back and make sure everything is clean and clearances are adequate. I clean everything with acetone on a paper towel before assembly. Any little dirt or debris behind the bearings can close up the clearances and cause it to seize.

A.R. Shale Targa

iTrader: (2)

Sounds to me like the big ends of those rods need to meet a sunnen hone machine I've seen rerorqued factory bolts distort the bore by as much as .001"
Pulled up GM spec with oil on threads and EPL under the bolt heads.
They needed a few honing strokes and were perfect in diameter specs and no need for the .002" over stuff.

HappySalesman

iTrader: (3)

The chamfered side of the big end of the rods should face to the outside. The crank may have a rolled fillet but never hurts to be sure.

one thing you might try is pop the pistons back out, then put them in one by one and see where the binding starts.

truckdoug

iTrader: (25)

after i dont know how may gen 3&4 motors I have yet to see one side of the rod chamfered more than the other.

5FOX3

Tear it all back apart and triple check everything, my L33 after assembly only took 12ft lbs to rotate it after assembly

RockinWs6

Personally I install one pair at a time and rotate, if anything feels wrong I know which ones ARE PISSIN ME OFF!

pantera_efi

iTrader: (1)

Hi, the best tech was from "Happysalesman" with the ONLY remark that the rods where installed with "flats" to Journal Fillet. (backwards)

NOW if the "flats" can be observed, there IS a difference !

What is the rod Side Clearance ?

My method is the observe the rod "touch" each journal "flat" with a easy slide in BOTH directions.
The rods "kiss" each other AND each Journal.

When one rod is found NOT to "slide", the above "tech" is well noted.

Lance

98cherrySS

iTrader: (2)

This is a serious problem... All rod and main bearings must have the correct clearance. Engine building 101. You will have problems on the first startup if this is not corrected.