Engine Bearings out of Spec

4agtehatch
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Engine Bearings out of Spec

Postby 4agtehatch » Mon Aug 17, 2015 11:33 pm

Long story short I plasti gauged my new ACL main engine bearings and its out of spec. It came out to .051mm the Haynes book says .012mm to .039mm that's for 4ag engines years 86 and 87. 1985 says .012mm to .049mm I'm using a crank out of a 3 rib 4ag so 1985 crank in my GZE block. Stander bearings so does that mean I should go with the 1985 specs of .012 to .049? Is the Haynes book even accurate and would I be okay with these specs of .051mm or do I need different bearings or crank? This is my first engine build and I've spent a lot of cash on pretty foraged parts I don't want to blow it up right away.
I need some help on what I should do.

4agtehatch
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Re: Engine Bearings out of Spec

Postby 4agtehatch » Mon Aug 17, 2015 11:49 pm

Also just to add the Haynes book said 43Ft pounds for the main bearings. I'm not sure how accurate that book is. I've see online people saying its 47Ft Pounds. Just added a little more info that might help.

d3nso
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Re: Engine Bearings out of Spec

Postby d3nso » Tue Aug 18, 2015 7:21 am

According to the Toyota repair manual mainbearings are torqued to 40-47ft pounds

Maximum mainbearing clearance is 0. 10mm.

Standart should be 0.025-0.060mm

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oldeskewltoy
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Re: Engine Bearings out of Spec

Postby oldeskewltoy » Tue Aug 18, 2015 8:03 am

from the AE92 factory service manual

Image



from the AE86 FSM...

Image


In both cases maximum is .1mm, your .051 is a bit loose, but should be ok. Keep an eye on idle oil pressure.
OST Cyl head porting, - viewtopic.php?f=22&t=300

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4agtehatch
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Re: Engine Bearings out of Spec

Postby 4agtehatch » Tue Aug 18, 2015 8:40 am

Do you think if I tried 47 foot pounds it would put me more into spec? Like I said before I only did 43 Ft pounds. Thanks for the help makes me feel better knowing I don't have a lemon.

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oldeskewltoy
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Re: Engine Bearings out of Spec

Postby oldeskewltoy » Tue Aug 18, 2015 2:19 pm

4agtehatch wrote:Do you think if I tried 47 foot pounds it would put me more into spec? Like I said before I only did 43 Ft pounds. Thanks for the help makes me feel better knowing I don't have a lemon.

if you can get the mains to torque spec... do it. Not likely to make your clearances tighter... but getting the mains to torque spec is a good idea
OST Cyl head porting, - viewtopic.php?f=22&t=300

Building a great engine takes knowing the end... before you begin :ugeek:

Enjoy Life... its the only one you get!