| How to re-torque ARP studs after engine break-in to prevent Head gasket failure.
Description How to re-torque ARP studs after engine break-in
Author Leakie Tbar
Date Fri May 23, 2008 6:26 pm
Type Text How-To
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|How to re-torque ARP studs after engine break-in to prevent Head gasket failure.
How to re-torque ARP studs after engine break-in
|How to re-torque ARP studs after engine break-in
I've noticed over the years that MR2 enthusiasts do not take the time to re torque their ARP studs after engine break-in.
During the break-in period, the engine heat cycles, there are many vibrations that move things around, and other things that move the studs in the block. You have to re-torque the studs after this period, mainly to make sure the studs are seated in the block properly. If you do not, the head will eventually lift, and you'll get combustion gasses into the coolant system, overheating the car.
Here's what you do to keep this from happening:
1) Remove the valve cover.
2) Refer to the factory torque sequence (starting in the middle and working your way out in a criss-cross pattern just like you torque your wheels down), and work on one stud at a time. This torque sequence is shown below.
3) Break loose the first nut from the stud using a breaker bar.
4) Remove the nut completely. (A magnetic pick up tool works wonders!)
5) Use an Allen key socket (A handheld tool just doesn't cut it here.) to bottom out the stud in the block.
6) Make sure the nut is cleaned, and liberally apply ARP moly lube (not oil, not multi purpose grease, but ARP moly lube) to the nut.
7) Torque the nut down to 65 ft lbs. (Not 70, not 75, but 65ftlbs)
Move to the next stud/nut combo in the torque sequence.
9) Repeat steps 3-8 in the correct torque sequence until you have done them all.
10) Clean the valve cover gasket mating surface with carb cleaner or brake cleaner. Use a razor blade to remove old silicone from the mating surface.
11) Apply a dab of Toyota FIPG (the black stuff) at each corner (where the semi-circle meets the flat surface of the head) of the 2 cam caps on the timing belt side, and the distributor shaft tunnel on the flywheel side. This will be 6 dabs of silicone total. (I have no idea how many times I have seen the valve cover installed without these dabs of silicone.) This is shown in the picture below.
12) Secure the valve cover with bolts or Allen key bolts using the factory grommets and you're good. Just DON'T use the stupid Phillips head screws.
I hope this helps folks with rebuilt engines. If you do this properly, made sure your block and head were machined properly, and prevent detonation the best you can, you should not have a head gasket problem.
Originally posted by No Shoes
Recommended fitting tips with Arp's
Always follow ARP instruction's on torque specs and procedures.
Torque it down as normal in sequence to 60ft/lbs, then gradually loosen off in sequence of removal, then torque to 60ft/lbs again, repeating until your torque it for the 5th time.
This was discussed in length between ^Trickster^ and ARP this was the written reply from ARP.
Good question. Each time you torque any bolt or nut, up to about 5
times, the threads of the bolt or nut are seating in to the threads they
are going into. In a sense "polishing" each other. As this "polishing"
takes place the friction between the two pieces is reduced giving you
more torque applied to clamping load vs overcoming friction. After 4~5
times the effects are minimal. Once you do this it does not have to be
done again during assembly. If you disassemble the engine make sure to
keep the nuts with the studs, matched sets. Five times is a great way
to go but most don't want to spend the time. The reality is that it is
working for you. Don't change what you are doing!!!
Typically we recommend a head re torque after a period of time. This is
not due to stud stretch but normally to head gasket compression and
everything moving around a bit after running. That varies with the type
of gasket. Many times the head gasket manufacturer will tell you what
is needed in the instructions. Also torque wrenches and people make
mistakes so it is a good double check. What I recommend is that you
back the nuts off, one at a time, about 1/4~1/2 turn and then pull right
back to full torque. If you do one at a time that prevents the head or
gasket from shifting.
If you have any additional questions please contact me.
This post is only a guide if you carry out this procedure its done at your own risk YOU accept full liability.
Kev (Leakie Tbar)
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