ARP Head bolt question, real time - How Long?

[Azca]

I cut precisely 1/4" off the front of the opel kit (209-4702) but the once torqued down, after the first pass, the fronts, as well as the rest, look long to me.

The front studs protrude .624" (16.2mm) above the stock toyota washer
The max height of the remaining studs protrude a maximum of .920 (23.3mm)

I have read many posts on this topic but have never seen this information, what do you guys think?

 

[Dave 2000]

I do not see it as a problem, but wait for someone with more experience before buttoning it up.

regards

Dave

 

[Azca]

I cut precisely 1/4" off the front of the opel kit (209-4702) but the once torqued down, after the first pass, the fronts, as well as the rest, look long to me.

The front studs protrude .624" (16.2mm) above the stock toyota washer
The max height of the remaining studs protrude a maximum of .920 (23.3mm)

I have read many posts on this topic but have never seen this information, what do you guys think?

View attachment 1140406
View attachment 1140407

Also, Toyota head bolt length is 97.7mm to shoulder of bolt
ARP Stud length = 126.7mm overall, approximately 76.5mm of shank with 25.5mm of threads at the top and 22.5mm at the bottom.

 

[sbman]

There are plenty of threads left over, and you should have enough clearance, but you should check it for your specific installation. I used a machinists ruler to measure the distance from the camshaft bearing surface to the stud and see how much clearance I had. Then I measured the distance from the bearing surface to the edge of the gear on the camshaft to see how much clearance I'd have. I think I ended up with more than .125", if anything moves an 1/8" then I've got big problems in the engine.

This is what mine looked like after I clearanced it:

 

[Azca]

Thanks guys! Sbman, what did the others look like?

 

[sbman]

I think they were the same as yours.

 

[NLXTACY]

I used the same kit and no modifications were needed.

 

[sbman]

I used the same kit and no modifications were needed.

If I remember correctly I measured 0.010" clearance at the gear(s) with no modification and it's probably plenty. I wanted a bit more...

 

[Azca]

It looks like I could have gotten away with no mod as well, tough to see in the photo but plenty of clearance with the .25" cut off.

 

[baldilocks]

Why not just use the 1FZ kit from paradiseracing?

 

[sbman]

The 1FZ kit from paradise doesn't have studs long enough in my opinion. You have to 'float' the stud away from the bottom of the hole in order to get full engagement at the nut end. ARP says to bottom the studs, paradise says you don't have to. I wanted to follow ARPs instructions so ended up ordering the opel kit and did not use the paradise kit.

 

[baldilocks]

The 1FZ kit from paradise doesn't have studs long enough in my opinion. You have to 'float' the stud away from the bottom of the hole in order to get full engagement at the nut end. ARP says to bottom the studs, paradise says you don't have to. I wanted to follow ARPs instructions so ended up ordering the opel kit and did not use the paradise kit.

I spoke to ARP and they told me there is no need to bottom the stud. What is critical is having enough thread engagement. I read elsewhere that most of the stress on a bolt or stud is on the bottom ten threads, or so. The bolts don't bottom out. I brought this up for future readers to know that ARP gives differing info. I used the 1FZ kit a couple thousand miles ago and no issues yet.

 

[NLXTACY]

I'm at 42k now since my rebuild almost three years ago using the Opel kit.