How to measure head bolts?

[rc51kid]

I was told there is a way to see if the head bolts are withing spec. I found a spec listed in the FSM but it just list a max and min measurement. I am not sure what surface i am measuring. There are two smooth areas on the bolt and then also the threaded area. I am kind of thinking i measure the diameter of the threaded area. Is that correct?

 

[scottryana]

Nope if any part of the smooth area measures under spec the bolts are over stretched and no good.

 

[rc51kid]

There is a thicker part right under the head of the bolt. Then a longer thinner area. It looks tome like you would want to measure the thinner area. If that is right then mine all look out of spec. I just ordered new ones from beno, ouch those arnt cheap. So much for DIY head gasket being cheap. I guess it is still WAY cheaper doing it myself and i know i will do it right. All new Toyota gaskets, new valve seals, new valve guides, new head bolts, new exhaust studs and nuts. The "while you are in there" list is getting trimmed a little. I was going to do motor mounts and power steering lines but i will hold off on those. I will still do new alternator brushes, hoses, belts, injectors sent to witch hunter and so on. Not to mention the machine work of going through the head.

Sounds like i am complaining, but actually it has been a rewarding project and i am enjoying it. It is just easy to let it get out of control. I am actually excited about seeing it come together, no complaining at all.

 

[thatcabledude]

Should have got ARP head studs.

 

[ajax1]

Nothing wrong with the Toyota head bolts, look for stretch in the threads, just make sure you torque like fsm says

 

[blkprj80]

FSM shows to measure it on the threads at a distance 25 to 30mm from the tip end. 10.6mm minimum, or 0.417in.
This will be the part of the bolt that is threaded, but wasn't into the block threads.
This area may be slightly smaller in size (OD) than the rest of the threads. Take a few measurement with good 6" calipers and use the smallest measurement as your deciding factor.

 

[slow95z]

why not spend a little extra and get arp studs. not exactly the part of a 1FZ i would skimp on.

 

[rc51kid]

FSM shows to measure it on the threads at a distance 25 to 30mm from the tip end. 10.6mm minimum, or 0.417in.
This will be the part of the bolt that is threaded, but wasn't into the block threads.
This area may be slightly smaller in size (OD) than the rest of the threads. Take a few measurement with good 6" calipers and use the smallest measurement as your deciding factor.

Thanks. I found the specs just didnt see a diagram of what to measure.

 

[Dave 2000]

I think your decision to buy new despite the additional cost was the right one. Not worth faffing around, I would also run a bottoming tap down the block holes.

regards

Dave

 

[120mm]

I grew up with two principles being pounded in my head by my dad vis-a-vis heads: First, always use new head bolts, unless you have studs. Second, always run a bottoming tap to ensure a correct bolt torque.

BTW, x1000 replacing the bolts with studs. Studs yield a more reliable torque value and can be reused. Only time studs aren't superior to bolts is when you have clearance issues.

 

[baldilocks]

Even with beno's discount, I believe the studs were cheaper when I did mine about a year ago.
I chased the threads in th block out with the appropriate sized chaser by running it in and out three times with my shopvac sucking out what it could. Despite my efforts to clean the bolt holes, some of the studs would not thread into the block without the use of a hex key while others threaded in by hand easily. This tells me that obtaining even clamping force on the head with the use of bolts would have been impossible.