Does anyone have a procedure to replace the head gasket on an 1990 esprit SE 2.2 turbo. I got a head gasket kit from JAE and ARP bolts.
I a little late to the party... sorry, but I don't hang out here a lot.
You got ARP bolts or studs?
There are popular ARP bolts for bolting the two cam carriers to the top of the head. They have nothing to do with the torque spec required for securing the head to the block and sealing the head gasket. When you install them, torque them to 14-16 lbs-ft... working from the center outward.
Then there are long ARP studs that screw into the top of the block. The gasket and head slide on over them, then are secured with washers and nuts. The torque for the head/ gasket applies to those nuts on the studs.
The torque varies according to the stud type, so use the torque that's appropriate for the studs that are currently installed in the block. In all cases, the threads and nut/washer faces are oiled first.
1) The original studs were pretty common stuff, and are identified by a flat upper end. Use a torque wrench and torque them to 75 lbs-ft for the three pairs in the middle, and 70 Lbs-ft for the two end pairs (two front nuts / two rear nuts). Don't tighten them to 70-75 all at once, but use three or four small steps, such as 20 lb-ft, 45 lb-ft, 60 lb-ft, and finally 70 or 75 lb-ft. For each increment, work from the center out to the ends in a criss-cross pattern, as shown in the manual.
2) In Jan 1993, Lotus upgraded the OEM studs to stronger steel, and they are identified by a depressed dimple in the upper end. For them, use a torque wrench to apply an initial, light torque. All that does is take up the slack to provide a solid starting point. Then, use a Torque Angle Meter (glorified protractor) to turn the nuts so many degrees, as follows:
a) 15 lbs-ft, torque wrench, initial setting.
b) +75 Degrees, torque angle meter.
c) +40 Degrees, torque angle meter.
d) Wait 5+ minutes (more is better).
e) +20 Degrees, torque angle meter.
The net result of Lotus’ new torque angle spec is a higher final torque/ clamping force than was produced by Lotus’ original 70-75 lb-ft torque spec. Do NOT consider the old spec and new spec as simply different ways of expressing the same thing. They are different, the produce very different clamp loads, and they are NOT interchangeable.
3) The ARP studs are an further strength upgrade, have fine pitch threads instead of coarse (like the Lotus OEM studs), and require yet another unique torque spec. Each stud/ nut is to be tightened with oiled threads, and ARP specifies that you use their proprietary thread lubricant. The tricky part is that they have revised their lubricant a few times, and their torque spec changed with each new version of the lube.
If you didn't receive a torque spec with your parts, then dig around and find the little squeeze-pouch of ARP lube in order to get the name exactly right. Then call JAE, tell Jay exactly which lube you have, and ask for the appropriate torque spec to use with that lube.
If you didn't receive any ARP lube (oops), then order some and ask for the appropriate torque spec to use with that particular ARP lube. The info I have at my finger tips is:
90 Lb-Ft with "ARP Ultra-Torque Fastener Assembly Lubricant".
If the wording on your ARP lube pouch varies from that description even a little, then inquire about the correct torque spec to use with yours. I wish ARP would settle on one lube & spec in order to reduce confusion, but apparently that's the price of progress.
:-(
Don't use the following, but my faulty memory has an echo of 100 lbs-ft with the previous ARP lube, and 120 lbs-ft with motor oil (mineral or synthetic ?? I dunno). Again, don't use those values, I'm just illustrating the impact that the lube can have on torque.
*~*~*
Using a torque wrench to apply a specified torque is a method full of opportunity for inaccuracy. It only controls the applied torque, but friction between the threads and hex head/ washer eat up 1/2 to 3/4+ of the applied torque. How much actually goes toward producing a clamping force is a crap shoot.
A Torque Angle Meter measures how many degrees the hex head is rotated. The thread is an inclined ramp of so many degrees wrapped around a cylinder. It's geometry. For so many degrees of rotation, you can trig how far the fastener will advance. You know how much clamp you're putting on the joint. It's far more accurate, and I was pleased when Lotus issued a Torque Angle spec for their new studs and gasket. Why the heck ARP is still stuck in the past with 'torque' specs is beyond me. But they are. Jeff at JAE talked with them about a Torque Angle spec, but got no where.
*~*~*
What Calvin and I talked about over breakfast was something I've wanted to do for some time... come up with an equivalent Torque Angle spec for ARP's torque spec(s). It would be relatively easy to do, given the opportunity. But fortunately, I've not blown any head gaskets lately, so I've been a little short on opportunity.
The last time Dave C blew a head gasket was a few years ago. When we were re-installing the head, we wrote down a few numbers, but we really hadn't planned ahead for it and didn't have a good set-up. We were intrigued by the correlation, and we agreed that next time we should do a better set-up and take real readings. Well, I guess Calvin is the next time. He has his Esprit's head off at the moment (actually, it's in my garage... I'm replacing cam seals and shimming the valves), so here's the opportunity. Maybe we'll have something to report later.
Regards,
Tim Engel