Toyspeed.org.nz Message Board

by **strx7** » Thu Jun 30, 2011 12:23 pm

aren't those race 'forged' crank pics that have been posted actually BILLET steel cranks that have been turned down from one big chunk of steel? which is why they look totally different to factory forged steel cranks?

by **Mr Revhead** » Thu Jun 30, 2011 12:29 pm

I don't know.
I think it would be pretty hard to tell a fully machined forged crank from a billet one. Machining removes all the pointers I know to look for. So as far as I know on those ons they can look the same.

by **MAGN1T** » Thu Jun 30, 2011 3:28 pm

A TRD crank has TRD pressed into it as part of the manufacturing process which is done with hydraulic presses.
Billet cranks have the ID either engraved or etched into them.
All of those pics I posted of "steel " cranks have the letters "cast" into them.

Steve

by **nzae86** » Thu Jun 30, 2011 7:08 pm

MAGN1T wrote:A TRD crank has TRD pressed into it as part of the manufacturing process which is done with hydraulic presses.
Billet cranks have the ID either engraved or etched into them.
All of those pics I posted of "steel " cranks have the letters "cast" into them.

Steve

Wrong, I actually own the crank in this picture it is not just a photo I found on the net , the TRD emblem is etched into the crank not pressed! , the box from the factory states that it is forged .

Speaking from a wee bit of experience . Check the part numbers if you like. Or is this not a TRD crank??

by **fivebob** » Thu Jun 30, 2011 7:54 pm

I think you may find that the TRD crank is machinined from a solid billet of steel, probably 4340, that has been hammer forged.

This isn't the same as a forged crankshaft that attains its final shape from the forging process.

by **Flannelman** » Thu Jun 30, 2011 8:55 pm

To add some more spin to the forged debate.

All would agree that a cast crank - no matter what material is used - will have a rough, textured surface on the counterweights. This pattern is from the casting sand.

If a forged item uses a press to squeeze the material into shape, then wouldnt the counterweights be smooth because the press is smooth?

by **4agtepwr** » Thu Jun 30, 2011 9:14 pm

I agree with fivebob on that one, I'm pretty sure you will find that that TRD crank is machined from a solid billet and then heat treated and normalized and then finish ground, its very hard to forge something as intricate as a five journal main four cylinder crank let alone a straight six or bigger, there's a fairly big difference between forged and billet although it seems to be a common mistake, but If i were a betting man and you chopped that crank up and xrayed it the grain structure would all run straight along the axis of the crank instead of following the shape.

by **MAGN1T** » Thu Jun 30, 2011 9:16 pm

You guys make it hard on yourselves.

All you need to do is download a factory manual or two. It actually tells you.

http://www.toyota4wd.dk/Teknik/J70/Toyo ... %202Lt.pdf

There's my Toyota manual.
The counterweights are cast into the crank.
Don't know how they'd manage that if it's forged.

If you're machining a crank on a lathe (Billet) then the counterweights tend to come out round rather than flat sides of the TRD which would require more work.
There's lots of pics of billet cranks on the net (V8 strokers)

Steve

by **Mr Revhead** » Thu Jun 30, 2011 9:27 pm

It uses the word "cast" in the 4age manual too. And they most definitely are forged.

You need to follow your own advice and relearn.

Why would you have to use a lathe to make a billet crank?

by **4agtepwr** » Thu Jun 30, 2011 9:30 pm

4age cranks are cast steel mate

by **Mr Revhead** » Thu Jun 30, 2011 9:31 pm

In that case hell is freezing over because soooo many people are wrong about them then.

by **Malcolm** » Thu Jun 30, 2011 9:35 pm

MAGN1T wrote:If you're machining a crank on a lathe (Billet) then the counterweights tend to come out round rather than flat sides of the TRD which would require more work.

Oh noes, having to perform an extra (incredibly simple) machining operation on a part which already requires a significant amount of machining and different operations! It can't be done!

by **nzae86** » Thu Jun 30, 2011 9:40 pm

4agtepwr wrote:I agree with fivebob on that one, I'm pretty sure you will find that that TRD crank is machined from a solid billet and then heat treated and normalized and then finish ground, its very hard to forge something as intricate as a five journal main four cylinder crank let alone a straight six or bigger, there's a fairly big difference between forged and billet although it seems to be a common mistake, but If i were a betting man and you chopped that crank up and xrayed it the grain structure would all run straight along the axis of the crank instead of following the shape.

Anyone want to buy my crank and try this??

by **4agtepwr** » Thu Jun 30, 2011 9:45 pm

I couldn't bring my self to do it haha, What does it weigh out of interest?

by **nzae86** » Thu Jun 30, 2011 9:50 pm

4agtepwr wrote:I couldn't bring my self to do it haha, What does it weigh out of interest?

About 2 pound more than a standard cast -forged-hammered-chiseled-ground-sanded-and polished steel-iron-muck metal crank .

by **Mr Revhead** » Thu Jun 30, 2011 9:50 pm

4age crank:

Note forging marks and texture of the surface.

From here: http://www.club4ag.com/faq_and_tech_pag ... lysis.html

by **spencer** » Thu Jun 30, 2011 10:55 pm

I hate to say it but revhead is correct

the 4ag crank is forged, shit just look at it

by **4agtepwr** » Thu Jun 30, 2011 11:07 pm

I may have to admit defeat here.... I always just thought the marks were casting marks and thought it would be uneconomical to make a forged crank in that sort of volume, haha you learn something everyday, some pretty cool vids on youtube of some v8 cranks being made by a forge/robot
http://www.youtube.com/watch?v=p4amaa6MpVY

by **RomanV** » Fri Jul 01, 2011 12:16 am

4agtepwr wrote:http://www.youtube.com/watch?v=p4amaa6MpVY

Could imagine that robot saying

"Hot stuff coming through!"

http://www.youtube.com/watch?v=icIwKaci3MI#t=0m14s

:lol:

by **Mr Revhead** » Fri Jul 01, 2011 8:46 am

OEM forged cranks are not that rare. Hell my 1963 Imp has a stock forged crank!

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any one in NZ make billet cranks for 3sgte /ge

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