1FZ Pre-Build Questions (1 Viewer)

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Alternator shopping. Can anyone point me to whatever specs there are on the crank pulley--like the diameter where the belt runs? Not seeing anything like that in the FSM...
 
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@landtank may have some input

Here's a previous thread discussing pulley sizes: (Edit: misread the original post, thought you wanted alternator pulley sizes, I need new glasses).

 
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@landtank may have some input

Here's a previous thread discussing pulley sizes:

Interesting thread, thanks! But no dims for the FZ crank. Same for another thread titled '1FZ crank pulley dimensions.' And so it goes...
 
Yeah. Aftermarket alt maker looking for a diameter to work up a power curve, but I don't have a tool that'll measure it...
 
Got a sketch of what they need to know?
Is it just the outer diameter?
Outer and the grooves where the belts run, which is the actual working diameter. Calipers or careful measurement with string or wire, if someone happens to have a de-belted pulley handy…
 
Outer and the grooves where the belts run, which is the actual working diameter. Calipers or careful measurement with string or wire, if someone happens to have a de-belted pulley handy…

I'll measure this tomorrow for you. I have an engine sitting with no belts on it


If I remember :oops:
Hit me up if I don't
 
Screenshot_20230401-203423.png

OD is 176.5mm

Pitch diameter is 176.5mm minus whatever is needed for the belt. I'm not 100% clear on how to measure that.

PXL_20230401_091502799.jpg


Shít photo. I'm sure you know which belt goes where.

AC, the belt sits deeper in the groove.

Alternator/water pump belts run flush with the outer diameter.
Inner edge of the pulley is a few millimetres larger diameter, by has no bearing on pitch diameter

PXL_20230401_091444106.jpg
 
Great, thanks! Just to triple-check: alternator pulley figures.

I don't suppose you have a belt (even a busted one) you can hang on that for a PD measurement...?

IF the belt bottoms out in use, then measuring the belt depth in free space on an installed engine will give us the number to subtract…

As to measuring the diameter at the bottom of the V directly, all I can think of are pincer calipers (the ones that look like ice tongs) or a string or wire pressed into place with fingers or pencil eraser etc., overlap point marked, then string/wire removed and measured to mark when straight...

Thanks again!
 
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Forgot about this, Rockauto sells a crank pulley that is identical to the original


Pulled from that website:

DAYCO PB1413N Specifications
Bolt Hole Quantity2
Counterweight BalanceNeutral, no counterweight
Crank Bore1.497 in.
Crank Bore38.01 mm
Crank Trigger/Exciter PlateNo
Hardware IncludedNo
Installation Instructions IncludedNo
Nose Outside Diameter2.052 In.
Nose Outside Diameter52.10 mm
Number of Integrated Pulleys3
Outer Ring MaterialGrey Iron
Overall Outside Diameter6.930 in.
Overall Outside Diameter176.00 mm
Overall Width3.111 in.
Overall Width79.00 MM
Pulley 1 Number of Grooves1 mm
Pulley 1 Outside Diameter6.930 in.
Pulley 1 Outside Diameter176.000 mm
Pulley 1 TypeV-Belt
Pulley 2 Number of Grooves1 mm
Pulley 2 Outside Diameter6.930 in.
Pulley 2 Outside Diameter176.000 mm
Pulley 2 TypeV-Belt
Ring Width2.441 in.
Ring Width61.98 MM
Timing MarksYes
Woodruff Key IncludedNo
 
Forgot about this, Rockauto sells a crank pulley that is identical to the original


Pulled from that website:

DAYCO PB1413N Specifications
Bolt Hole Quantity2
Counterweight BalanceNeutral, no counterweight
Crank Bore1.497 in.
Crank Bore38.01 mm
Crank Trigger/Exciter PlateNo
Hardware IncludedNo
Installation Instructions IncludedNo
Nose Outside Diameter2.052 In.
Nose Outside Diameter52.10 mm
Number of Integrated Pulleys3
Outer Ring MaterialGrey Iron
Overall Outside Diameter6.930 in.
Overall Outside Diameter176.00 mm
Overall Width3.111 in.
Overall Width79.00 MM
Pulley 1 Number of Grooves1 mm
Pulley 1 Outside Diameter6.930 in.
Pulley 1 Outside Diameter176.000 mm
Pulley 1 TypeV-Belt
Pulley 2 Number of Grooves1 mm
Pulley 2 Outside Diameter6.930 in.
Pulley 2 Outside Diameter176.000 mm
Pulley 2 TypeV-Belt
Ring Width2.441 in.
Ring Width61.98 MM
Timing MarksYes
Woodruff Key IncludedNo
Thanks! Confirms @mudgudgeon's work above. Interesting that it says three pulley and only specs the two we need. Still don't have the PD measurement pointed out by @mudgudgeon: diameter of belt on pulley. Can anyone measure that--or an actual belt from 'top' to 'bottom?' Anyone have a new belt set sitting around...? @NLXTACY, perhaps? We could get an approximation of the the pulley's inner diameter if we had an accurate measurement of an alternator belt, and the space between the belt top and the pulley's outer edge (assuming the belt bottoms out at the pulley's deepest point).
 
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IF the belt bottoms out in use, then measuring the belt depth in free space on an installed engine will give us the number to subtract…

The belts sit flush with the outer edge of the groove, they definitely should not bottom out in the groove.

There's a polished wear mark that shows the belt contacts the first 5/16 of the groove. (Darker line in the pic above).

I'm unsure if the pitch diameter is measure at the outer edge of the belt as it sits in the groove? Or centreline of belt etc

I would think at the outer edge of the belt, as it's the circumference of the belt.
That would make the pitch diameter same as OD in this case.
 
The belts sit flush with the outer edge of the groove, they definitely should not bottom out in the groove.

There's a polished wear mark that shows the belt contacts the first 5/16 of the groove. (Darker line in the pic above).

I'm unsure if the pitch diameter is measure at the outer edge of the belt as it sits in the groove? Or centreline of belt etc

I would think at the outer edge of the belt, as it's the circumference of the belt.
That would make the pitch diameter same as OD in this case.
Mmmmyeah. Apparently it's not as simple as I thought. I keep seeing illustrations like these. Lemme ask the guy if he even needs this spec; maybe this is a rabbit hole we don't need to go down...

Pulley Pitch Diameter.png

Pulley Pitch Pic.jpg
 
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What does it do to displacement if you bore out .5?
 

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