I'm curious, the torque spec for the crank pulley bolt on the Honda J35 changed. It used to be 181 foot pounds, now it's 47 foot pounds + 60 degrees. Any idea what the improvement is?
Torque spec question
- Thread starter Dave Sherman
- Start date
I don't know the real answer, I know the text book answer (it provides more accurate thread tension) but I can tell you this, if you get the SOB to 181 ft.lb it is not coming out on its own. Torque plus angle is usually reserved to TTY (Torque To Yeild) bolts which AFAIK the Honda crank bolt is not.
I was going to echo the book answer: more precise clamping pressure.
Torque is a proxy for desired bolt stretch. An angle gives a precise bolt stretch. More precise than torque. The stretch is a function of thread pitch and angle. Pure geometry.
Torque is a proxy for desired bolt stretch. An angle gives a precise bolt stretch. More precise than torque. The stretch is a function of thread pitch and angle. Pure geometry.
Angle torque does not signify torque to yield bolts, it's just more acurate. Variations in threads, tight, loose, lubrication of threads, under bolt heads, operator technique etc. Angle torque is the same every time. That's why it's used.
I said usually used on TTY bolts that does not mean it is exclusive on them.
Its great to be that accurate but many DIY do not own an angle TW so I would guess anything between 150 and 180 would be fine in the real world. Before the pissers get on me for this I do not advocate going against specs but they did spec 181 for this bolt not too long ago so it is not beyond the materials limits.
I suspect more than a few have been tightened with an impact by someone didnt have the holding tool.
Question, did you use a new bolt with clean threads or is this reading using the original bolt? It would be interesting to see if there was any difference.
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Interesting, thanks for the info.
Old bolt with clean threads. I applied engine oil in the specified sections.
As a pro mechanic giving advice, I am quite surprised you are implying you are advocating re-using any TTY bolt with your question. Almost all other sources on this topic that I've seen state that bolt yielding is a one-time affair and re-use often results in long-term fracture of the fastener or tearing of the threads, both of which cause uneven tightening or total loss of clamp force.
I don't think he was advocating re-use of TTY bolts. He talked about TTY commonly requiring angle tightening, and he talked about the practical aspect of using the old spec (pure torque) even though Honda updated this bolt (which isn't TTY) to an angle spec.
Astro explained it but I will add to that that not all TTY bolts have to be replaced. Read this especially post #17
Reusing TTY head bolts
I've got a 2000 Chrysler 3.2 with a bad valve. I've got pretty much everything I need to replace it and have started disassembly. I know the rule of thumb is to replace the TTY head bolts, but have heard a few people saying that it is OK to reuse them once. Any thoughts? I would rather not...
bobistheoilguy.com
Just for your info if a length spec is given then they sure can be reused without issue, I have tested these bolts and they were good for 3x before getting near the do not use spec. One example.
Yes, on MB for instance some bolts are single use only, some you measure the length, and some they don't care about.
when I rebuilt toyota 1zz-fe, 2zz-ge, 2az-fe, the OEM Toyota manual which you can buy from Toyota online for $30ish…said to re-use head bolts as long as they will hold the torque, I applied motor oil and reused them without any failure ever…
I also used an impact on the crank pulley bolt because I didn’t have the holding tool, again never had any issues…
I also used an impact on the crank pulley bolt because I didn’t have the holding tool, again never had any issues…
If you follow the FSM on some German cars they want you to replace every nut bolt and screw. I have done many clutches on VW cars in particular that would cost over $150 in new bolts alone if you were to follow the FSM.
I do replace the rear and front trans seal, new flywheel with all new flywheel and clutch cover bolts with a quality throw out bearing as that is the correct way to do the job but bell housing, starter, slave cyl, shift rod, battery tray, etc all of which are not TTY bolts is ludicrous. They are pushing bolt replacement for additional profit IMO.
I will say if the bolt(s) that are not TTY that needed a smoke wrench or were otherwise difficult to remove, has corrosion or is damaged in any way it goes in the bin. In the salt belt anything on the brakes or suspension I feel better replacing them.
I do replace the rear and front trans seal, new flywheel with all new flywheel and clutch cover bolts with a quality throw out bearing as that is the correct way to do the job but bell housing, starter, slave cyl, shift rod, battery tray, etc all of which are not TTY bolts is ludicrous. They are pushing bolt replacement for additional profit IMO.
I will say if the bolt(s) that are not TTY that needed a smoke wrench or were otherwise difficult to remove, has corrosion or is damaged in any way it goes in the bin. In the salt belt anything on the brakes or suspension I feel better replacing them.
It may be that the use of angle torque wrenches is now more common but I’ll bet plenty of mechanics are still give it 3 Ugga Duggas.
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Just noticed Canadian Tire has them, but three at 3 times the cost of a click torque wrench. $270 CAN ( $220 ). As a shade tree mechanic I wouldn’t bother, but it’s still a pretty cool toy. Maximum is Canadian Tire’s upper tier store brand.
It depends on the application. Toyota's TTY head bolts are reusable if the stretch is within spec. The service instructions list a procedure for doing measurements to determine if the bolts are suitable for reuse.
Reuseable TTY bolts - I've learned something new.
You don't need an angle TW for 60 degrees... It's 1 flat on the head of the bolt. IMO, this is why they pick values like 60 degrees.
just my $0.02
