SiCkRs

iTrader: (6)

I am rebuilding an engine and they told me to use plastigage and i got some the red and blue one i wanted to know if i don't check with the plastigage it would affect on the rebuild i am doing.

AlkyIROC

Plastigage confirms machining tolerances. A crankshaft main may be machined .010" under but the block may have inconsistencies which won't be seen without using plastigage. The same goes for the rods.

The thickness of the plastigage, color, depends on the crush specification you're checking. Checking the crank mains, green is the common thickness.

If the crush specifications call for .0025" and the plastigage says you have .0015", you'll need to get undersized bearings. Of course you can only check the crush specifications with a set of bearings.

SiCkRs

iTrader: (6)

I ordered stock bearings so i don't know if those would work and the plastigage goes on the connecting rods to the crank or on the main caps of the engine

AlkyIROC

Without knowing the specifications, checking them tells you nothing.

Start with the mains. Install the bearings into the block then place the crank onto the bearings. One main at a time, install a strip of plastigage onto each main and torque the main cap down. Remove the main caps and measure the crush thickness.

If the crank mains check out, do the same thing to each rod bearing.

Anybody can assemble an engine but it takes skill and knowledge to build one properly. My best suggestion is for you to have the bottom end put together by a proper machine or engine building shop. If you screw something up and spin a bearing, it will cost you more than what a shop will charge to put the bottom end together. Then again you may luck out and everything will be close enough to specs.

SiCkRs

iTrader: (6)

How much do they charge also the engine is all stock you think it will be ok or should it go to the shop

84Z28406

Is plastiguage the prefered method or is a mic set acceptable if you have access to them?

jkris53406

iTrader: (5)

The very first thing you should do is verify you have standard size bearings on both the rods and mains. Remove the bearings and on the back it will say .010 or whatever the oversize may be. If they are stock, there should be nothing.
You may want to head down to your local parts store and pick up a book on small block chevys as well

Sonix

iTrader: (1)

mics are preferred. Plastiguage is very susceptible to user error. I'd pick up a mic if I had it...

84Z28406

Ok, I'll use my mics then. Need to pic up the one that measures inside the circle though, I've only got the outside ones right now.

AlkyIROC

That means you have to install the bearings in the block. Then without the crank in the block, torque down a main cap, with the other half of the bearing in the cap, then measure the distance.

Measure the mains on the crank which should be smaller by the specification tolerances.

Do you know how much clearance you're allowed on the mains and rods yet?

SiCkRs

iTrader: (6)

So the plastigage goes on the main bearings and on the connecting rod does it really effect the engine this is my first rebuild that i am doing

84Z28406

I know how to measure the clearances using the mics, but it's good to have it confirmed. As for actual clearances, my Haynes techbook for Chevy V8s says in general it should be 0.001 - 0.002 inch for rods and mains, but that sounds a little tight, so I'm open to suggestions.

AlkyIROC

Plastigage is a thin strip of modeling clay. Once crushed to take the measurement, you wipe it off the crank surface.

SiCkRs

iTrader: (6)

Would it affect it if i put the wrong bearings i am probably going to rebuild it again like in a year to do 383

AlkyIROC

If clearance is excessive on the mains you'll have very low or no oil pressure. Excessive on the rods and you'll get a rod knock.

If clearance is too little, you get no oil lubrication to the bearings and you burn up a crank/rod/block.

SiCkRs

iTrader: (6)

I will take it to shop instead what cam is good for the tpi i would like a nice rumble to my iroc but wouldn't like to spend alot on only the cam.

BASSETT IROC 85

iTrader: (2)

.0025 for me

allred

the best thing you can do is educate yourself. read everything you can, and maybe take some classes. otherwise you may end up spending a lot of money on a blown engine.
you need to get the block thorougly cleaned.(dont forget to remove cam bearings. magnafluxing is highly reccomended. bore it, torque plate honing recomended. you definetly wanna get your mains line honed. and check the decks for warpage.you may need to shave them. and any parts you are reusing will need to be inspected and may need maching or replacing
clean the block some more. get some pipe cleaners and go through all the holes and oil gallies.(ps use standard oil pump not high volume)
keep it as clean as possible.
make sure to get all the specs you can from the machine shop(amounts of material taken off) for ordering your new parts.
if you want to assymble it yourself get quality measuring tools. measure everything!!!!
oil clearences, endplays, the clearances between the rotating assymbly and the block cam, oil pan, ect ect. deck clearance, piston to valve.
degree your cam!! bending a valve cause your 1 tooth off or cause its the wrong cam isnt fun.
and get a good torque wrench! properly torque every bolt, and use the proper assymbly lubes. and break in oil for flat tabs.
prime your oil pump!
check and check and check timing. detonation is bad.
and do a proper engine break in.
i believe that is everything except the kitchen sink.
if i forgot anything holla

SiCkRs

iTrader: (6)

A mechanic is helping me now he has over 10 years building small blocks so i think it will come out okay how much do they charge to bore .030

allred

i belive last time i checked it was less than $100 bucks. id call several local machine shops and get quotes.

AlkyIROC

Boring is roughly $10 per hole. To do it properly, they should have the pistons that are going into the engine so they can hone the walls to the proper size. They will also want to know what type of rings will be on the pistons to know what kind of finish to leave on the cylinder walls.

I said it way back near the top. Building an engine properly isn't just assembling a bunch of parts together.

It's amazing how many people don't realize that if you take an engine into a shop to be built properly that you can usually expect it back in about 3 months.

SiCkRs

iTrader: (6)

WOuld i need to buy new connecting rods too

AlkyIROC

Not unless the old ones are damaged. New rod bolts would be an investment.

SiCkRs

iTrader: (6)

Around how much would it be for a 0.030 bore and new pistons

the zander

Stephen mentioned above that it'll cost you $10/hole for the machine work. As far as the cost of pistons is concerned it depends on what you want, they can cost as little as $10 each and as much as $200 each. For your application stock replacements like the ones below would be adequate.

http://store.summitracing.com/partde...0&autoview=sku

-Z

SiCkRs

iTrader: (6)

Do they come with the pins in them and that would give me less mpg cause this is my daily driver