A 3.4 DOHC Build then... F40 Turbo (Page 26/57)
Fierobsessed JUL 28, 08:42 PM
It's been a little while, it's time for an update!

I've been in a bit of a holding pattern for a while mainly due to the clutch. But finally I have a moderate clamp force pressure plate. However story doesn't end there...
I ordered a medium pressure 2,400 Lb 9-1/8" pressure plate from Spec. This is a 50% increase in applying pressure.


Immediately I got right down to inspecting my purchase. I have to give Spec their due credit. This is one pretty pressure plate. Manufacturing defects? Zero.
But what is it? What did they do to increase the applying force?
I noticed that it seemed like the pressure plates surface is awfully low in relation to the mounting surface. So I broke out the caliper and a straight edge to take a measurement.


So, .271"

Ok so... The next obvious thing to do was to measure my Clutch Net disc.


That means that...


Oh, that's not so good.

I sent an e-mail to Spec inquiring about the intended clutch thickness for this model pressure plate, their answer was .350" to .360". Which is really helpful. Or in my case, bad news. Although I could just install it, and I could drive with it, It would have a minimal life, and will never have full holding capacity.

I happened to have a pressure plate from when I originally put the 3.4 DOHC in my car already, it is a Valeo brand stock replacement. Turns out it is exactly the same donor pressure plate. This gave me a unique opportunity if you know what I mean...


Ok here's the difference

They drill out the three rivets on the straps that secure the friction surface, and they re-machine the fulcrum point inward, which does cause the friction surface to lose some clamping distance, which can be made up for with a slightly thicker clutch disc. Intern, there is a dramatic increase in holding pressure. With that bit of machining done, they put the friction surface back, replacing the rivets with new ones. It would work great but only if I have the correct thickness disc for their pressure plate.

I have some thinking to do. This problem is not yet resolved. But in the meantime I've been very busy. I loaded the engine back in the car for another fit check. And it was nearly perfect. Only the dipstick tube needs an adjustment. The air filter the silicone elbow and stainless joint all fit, and it looks like the oil separator has it's home too.



I'm back on hold on this project. Getting married! So needless to say the next week or so I'll be a bit preoccupied!
Joseph Upson JUL 29, 01:13 AM
Married, arrested, same thing, congratulations.

I've mentioned it before but, given how many times I've read about problems with the Spec combos on first go around, you may want to visit your local clutch builder if you have one. My pressure plate started out as a stock HD unit that was modified the same day to 2300 lbs clamping pressure. At this point given how well it has held I wouldn't consider buying a plate, or disc from any company unless the local builder couldn't supply it.
Squeaky AUG 07, 11:42 PM
Have you ever considered building kits of your turbo set-up?

[This message has been edited by Squeaky (edited 08-07-2013).]

Fierobsessed AUG 13, 07:25 AM
Nah, it's just too much work, and not financially viable. I'll save the details of why for the conclusion post I will do once this project is more or less done.

Onward!

I am pleased to say, that now that I am married, that I still have my Fiero's and I'm still working on this project. Well, at least just getting back into the groove now.

So I finally decided to grab the bull by the horns and make a custom higher strength pressure plate. This was a really fun project, and one I only wish I knew then, what I know now, so let me share.

The fun starts with a standard aftermarket Getrag pressure plate. This one is a Valeo PN AMC44, Sold under the brand name Dynapak.


First things first, drill the rivets from the pressure plate face side, I started with a 5/32" drill, then only drilled a little bit down with a 7/16"


Once the rivet head was just starting to show break through, I removed the remains with a pair of pliers, the idea is to not damage the strap in any way, so drilling had to be done very carefully.


Head removed


I very carefully pried the straps off of the rivets with a flat head screw driver, they popped off rather easily.


Oh, I almost forgot, label! Is orientation important? I don't know, but It can't hurt. And I know my 1 is backwards, I wrote it while it was upside down and I suck at it.


I tapped one of the straps out of the way so I could remove the pressure plate.


With that one strap out of the way, it wasn't difficult at all to free the pressure plate


Remove some rivet remains


Now for the fun stuff, and another reason I love my 12" lathe


All I have to do is move the pivot point closer to the fulcrum, So it started out like this:


And after a little reworking, it's now like this:


Measuring from the face to the pivot point, it was .770" stock


I cut it down at the same outer face angle to .720"
This pressure plate lost some throw, but gained some leverage.

For assembly I needed to make some rivets. No problem. Another easy task for the lathe.



I put the plate back in place and tapped the one moved strap back into place and slipped the rivets into place


Today's custom tool... A rivet thingamabob. Some 1/4" steel hastily welded to a vice grip. But oh, what a wonderful tool it is.


And what does this tool do? It clamps the rivet into place for pressing, without interfering with the pressing process.



I also made up a small shaft of steel to do my rivet pressing, then mounted it all up and pressed away.


Final result:


IT'S DONE! I finally have my clutch all sorted out. I've been on this problem since February, and I spent all kinds of money on pressure plates that didn't work out. Reworking a stock plate was more fun then I thought it would be. I'm just so relieved that it's done. Now I can start to really wrap things up and get this car going in the near future.

I've also settled on the rear suspension links for the toe and trailing links. They're on order. I'm getting excited about this project again, and that's just what I need right now.
Steven Snyder AUG 13, 03:42 PM
Nice work on the pressure plate. It's cool how black box items can become so simple and easy to modify if you just take the time to measure and investigate.
Fierobsessed AUG 24, 05:45 AM
Todays task was to build some brackets to mount the intercooler. These brackets slip in between where the 88's front suspension anchors to the frame, and the frame itself.



After painting and mounting them, you can see it hovering right in front of the condenser


Then it was just a matter of slipping the intercooler in and bolting it up!


And here's its final resting place. Just enough clearance to make me happy!


I still have to make up a radiator cap setup from what I cut off of the intercooler so I can fill it, I'll "T" the overflow line in with the coolant system's overflow. It's just convenient that way.

I also received some parts for my rear suspension links. I sort of ordered the wrong ones, paid a little extra for a feature I had to remove...


No big deal to remove the studs,


The rod ends I got are from QA1, they are Chromalloy Steel on Steel, 3 piece, and equipped with a zerk fitting. They really are the best thing I could find for the application. Along with those, I also got aluminum hex style adjusters, 9" and 10", and I got seals for the rod ends. I'm hoping my choice in a moderately high end grease able rod end will result in excellent performance and lifespan. We'll see. I still have to make up some spacers, but it looks like if I drill out 1/2" nuts, they will fit perfectly.


And on another side note, I picked up a new toy. I absolutely love this truck. I've wanted one for years, and now I finally have one! So hopefully before the end of the year, I will be driving two vehicles with 400 or more horsepower I'm just glad I don't have to work at it with the Trailblazer SS.
Dr.CGT AUG 24, 03:38 PM
Looks good son. After years of lurking this is my first post
Dr.CGT AUG 24, 03:46 PM
Looks good son. Cant wait to take a ride.
Fierobsessed AUG 25, 03:57 AM
Wow, after 5 and a half years of not knowing my dad even registered, he finally posts!
Fierobsessed AUG 26, 01:12 PM
Did a bit more work on the front mount heat exchanger today.
Originally, the FMHE had a radiator cap on the top on one end. But, there is no way that the intercooler would have fit between the frame rails with that overhanging the end tank.


So... I used my trusty sawsall to cut it off.


Still needing a fill port, I decided to make the coolant fill a remote mount. I welded in a 1/2" NPT bung.


I put a 1/2" 90 degree barb fitting into it. This way I can JUST sneak a hose between the frame rail and the condenser, then up to the remote fill.


The next big task, was to make the remote fill. I figured why not use the part I cut off the intercooler, and some aluminum stock to make the filler.



Ready to be mounted


Here seems like a good spot.


I still have to mount the pump, and run some lines, but the hard stuff with the FMHE is done.
That's all for now!