Blueprint 105 - Main Bearing Oil Clearances

In this episode we measure the bores for the crankshaft and calculate the oil clearances based off of information gathered in the previous video. If you subtract the diameter of the crankshaft from the bore diameter, you end up with your oil clearances.

If this were an assembly with new parts, I would have also paid close attention to bearing measurements 45° off-centerline just to make sure the bearings aren't pinched. I would also have double-checked the clearances using Plastigage. But what I'm doing here is just getting baselines prior to machining.

If you're doing a dry assembly like this, DO NOT ROTATE THE CRANKSHAFT. Without oil, there is nothing preventing it from being damaged.

Category:

Autos & Vehicles

Tags:

• Jafro
• Jafromobile
• 4g63
• 4g64
• turbo
• 6bolt
• 7bolt
• 6-bolt
• 7-bolt
• assemble
• disassemble
• inspect
• short
• block
• shortblock
• rod
• cap
• bearing
• oil
• clearance
• gap
• measure
• journal
• bore
• test
• do
• it
• yourself
• diy
• VFAQ
• calculate
• crank
• shaft
• crankshaft
• stand
• dial
• gauge
• high-mileage
• high
• mile
• Engine
• Internal Combustion Engine
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[tonkpils707]

do those bolts stretch after torque?

[Jafromobile]

@tonkpils707 They sure do! Factory bolts all stretch. So do ARP's but they're more resilient than factory bolts. I'm not using these again, I'm replacing them with ARP studs... so I don't care what their spec is... but you should measure them all to ensure they're in-spec if you're trying to re-use them. I can't find a spec in the Haynes manual, so I'd measure them against one another and look for a long one to replace.

[watchforfinger]

jaf what are those things at 8:20 sec in the bores that look like injectors of some sort ?

[Jafromobile]

@watchforfinger Great question! Factory turbo 4g63 engines (6&7 bolt) all have oil squirters drilled into the main galleries. Their purpose is to deliver extra oil, aside from what the rod cavities provide to the wrist pins of the skirts & pistons... they just hose everything down from the back side.

The theory is the turbo engines achieve much higher final compression, and therefore, heat. Supposedly they cool things down and prevent oil from coking on the pistons.

I like 'em. Some don't.

[watchforfinger]

@Jafromobile thanks for the explanationisisisisiss

[Jafromobile]

@watchforfinger LOL!

[bradikus7]

I have watched all of your videos Jafro, and I love them. I just hate waiting a week for the next installment lol. I've been pretty concerned with spending the $3,000+ on parts to build my engine and assembling it myself. Your videos make me a bit more confident though. Keep it up man, we all appreciate your videos!

[Jafromobile]

@iconone5 She's serviced far more cars than I've owned, that's for sure!

[bsivoljr]

Dude your build vids are sick. High Def. Articulate. Awesome tools. All your missing is a nice beverage :) Preferably Vodka. Haha. On a side note "Axixisisisis" :D lolo

[rcfirdy]

Just a little tip when setting up your dial bore guage in the micrometer.Do not place your fingers on the anvil or the spindle.The body heat that is conducted into these components of the micrometer cause them to grow,reducing the measurement.That also applies to the frame of the micrometer.High quality micrometers will have a insulating pad from which the instrument should be held.Happy Blueprinting. :-)

[mazzmari]

Great videos, fantastic series.

[wwjoshdew]

you amaze me... you simply amaze me. While I didn't watch the whole 10 minutes (because I was so lost) I still enjoyed the video!

[380gb]

Great video. i love this series. Ive already learned a-lot