CR3171 Finally going back together!

[Aussie Mike]

Originally Posted by DaveW

Hi Mike, what's the plug(sensor) next to the oil pressure sensor on the block below the steam vent tube?

That's the Cam angle sensor. LS1 motors had it on the top/rear of the block where the later motors have it on the cam cover at the front.

The LS1 also has the knock sensors in the valley and they run through the valley plate. Later motors have them in the sides of the block.

Cheers

[deano59]

hi mike this is the torque angle gauge I use and been a snap on reasonably priced as well .
ive had this one for a little while but to be honest I haven't had to use it a great deal yet been semi retired I only pick and choose the jobs I want to do nowdays .
cheers dean


TA360, Torque Angle Gauge, 1/2" Square Drive

[Aussie Mike]

With the clutch bolted up it was time to check the clutch clearance. This was something I hadn't really understood when I first assembled the clutch and gearbox. I took for granted that the guys from SPEC who sold me the clutch would have the clearance pre-set.

So what I've found since messing with these a gearboxes is that there is often insufficient clearance between the slave cylinder when fully compressed and the fingers of the clutch. When the clutch wears the fingers steadily move further away from the flywheel face. This brings them closer to the release bearing/slave cylinder. If the release bearing can't go back any further the result is the pressure plate being slightly disengaged and the clutch starting to slip.

We don't think about it with a conventional clutch fork as there is usually plenty of external adjustment and travel. The Hydraulic throw-out bearing has no adjustment so needs adequate clearance set before assembling the whole thing.

To check you need to put a straight edge across the bellhousing and measure the distance to the fingers. in this case it's 53.57mm



Next we check the throwout bearing. Remove the spring and fully compress the hydraulic throwout. Measure from the bearing face to the front of the gearbox (where it bolts to the bellhousing). In this case it's 54.34mm



Subtract the available space between bellhousing and clutch fingers from the space used between gearbox face and throwout 53.57mm - 54.34mm = -0.77mm. That means my setup is running with the pressure plate fingers compressed by 0.77mm before I've even pressed the clutch pedal.

To rectify this I'll have to machine about 6mm off the mounting face where the slave cylinder meets the front of the gearbox. Fortunately I've made a fixture to make this an easy job on the milling machine.

If I'd put it back together as it was it wouldnt have been long before the clutch was slipping and stuffed.



Cheers

[Aussie Mike]

The gearbox is in a million bits while I freshen up the internals. My own box was the first one I built and I'd done a fair bit of development since then. It was time to roll that back into the original one.



A mod I've been doing to a lot of the T56 boxes is changing out the pressed steel synchronizer keys for much stronger billet steel ones. When I first built mine aftermarket retaining springs weren't available for them and I had to use the originals. The spring has a hook on the end of it that's designed to engage in the hollow back of one of the pressed steel keys. This stops it rotating and potentially popping one of the keys loose. The issue with that is there is no hollow in the back of the billet keys, they are solid. The spring hooks over the side of the key instead and there is a chance the spring could rotate and one of the keys pop loose. I set them up so the rotation of the gear would keep the hook snug against the side of the key but it still worried me. The aftermarket springs have hooks on both ends so they can't pop loose (Green one on the right).



Another upgrade I figured I'd do is to change the stock plastic pads on the selector forks for some bronze ones. The plastic ones can distort under hard shifting. I had one older gearbox come in where the 1-2 and 3-4 pads were stuffed and I replace them all. The bronze ones should be a lot tougher and provide a more positive shift feel.



A fun job I finished off today was the engine cross member. A few hours on the mill and I whittled away a lot of material out of it. I removed a lot of weight and improved the aesthetic while keeping it's strength.



Looks pretty cool bolted in place.



Cheers

[1 TUF AC]

I love watching this work of art getting put together. It will be one hell of a car when it's finished. I would love to see it when it's finished and this car only lives 15 min away from me. keep up the good work.

[Cobrakiller]

Mike do you have other mods that necessitates the machining of the T56? What about OEM clutch, does that still require machining.

[Aussie Mike]

The OEM clutch and flywheel should be OK but it's always a good idea to check to be sure.

A lot of guys have been using the LS7 clutch and flywheel. This clutch is designed for the Corvette drive train. It uses a torque tube from the bell housing back to the trans axle in the rear. The dimensions can be a little different to the conventional setup.

There's some machining involved in the way I do the mid shift conversion. I do the reverse lockout a bit differently to others. I use the solenoid location from the old CAGS system for the lockout. This boss for the CAGS solenoid in often blank and not machined on later boxes. I like this way of doing it because it makes a lockout that you cant force past and also makes for a seamless 5-6 shift (You cant feel the reverse gate as you go past.

Cheers

[Aussie Mike]

Today's job was to get the steering rack back together. I can't progress any further with the gearbox as I'm waiting on some parts. I expected them during the week but they didn't turn up. There's plenty of other jobs to do in the mean time.

I bought a reconditioned rack but stuffed up when machining the input shaft. I was going to swap the input shaft from a spare rack but whoever had recoed the rack had mangled the roll pin that retains the shaft so I couldn't get it apart. I had a good spare one I picked up at a swap meet so decided to use it instead.

I stripped the rack down and checked it out internally. It seems to be OK. I bead blasted the housing and repainted the valve assembly. A few new O rings some fresh grease and a bit of adjustment to the pinion and it was good as gold.



I picked up a nice stainless steel Universal joint that is designed for 3/4" double D shaft which is what I had the old manual rack set up for. Splined shafts are not to bad to machine up but double D is dead easy so I went that way.



That's one more job marked off the whiteboard list.

Cheers

[750hp]

Looking great as always Mike. Had there been any previous issues that lead you to fit a cooler to the power steering system?

[Aussie Mike]

Never had power steering on it to know. Excess heat has been known to be an issue with Commodore power steering. I've seen a few with yellowed and distorted plastic power steering reservoirs. Reading the forums and a few have fitted coolers of some type. I had a cooler sitting on the shelf so figured I'd plumb it in now rather than having to add one later if it's a problem.

Cheers

[750hp]

Interesting stuff - thanks mate.

[Tenrocca]

I found the cooler and a good synthetic fluid made a lot of difference. The P\S pump used to whine after a lap session before that.

Beautiful work as always Mike.

Cheers

[Aussie Mike]

I was having a think about this last night. I think part of the heat problem with the Commodore setup is the PS pump is bolted directly to the front of the cylinder head. There must be a fair bit of heat soak from the engine directly into the PS pump and then the fluid.

Cheers

[Gav]

That it does Mike, however synthetic power steer fluid (not trans fluid) fixes it lickety split.

[deano59]

used to have he power steering fluid boil in our race car holden pump bolted to holden head . I just put a small trans cooler on the return line and problem fixed has not done it since .

[Gav]

That's what I have on mine now.
I also run a remote finned powersteer resovoir and have no issues.

[Towmaster]

Originally Posted by Gav

That's what I have on mine now.
I also run a remote finned powersteer resovoir and have no issues.

A lot also fit a larger pulley, slows the pump down, doesn't get so hot. I had to run ducted air to the cooler to keep it from boiling on the Supercar. Also a good hydraulic fluid helped...

[Aussie Mike]

That's some good feedback, thanks guys. Looks like I'm going in the right direction.

The pump setup is a bit of a hybrid. It's from a BA falcon I believe but I think it's pretty much the same as the holden one. I machined a pulley in the stock size but I'm running a 25% underdrive crank pulley so that should slow it down a fair bit.

I spent the day in the garden and I'm a bit tired and burnt. I'm waiting on gearbox parts so it's small jobs for a while. I felt like doing a bit of machining to unwind and it's fun to do. Creating a part out of a lump of metal is very satisfying.

I started with a piece of 20mm stainless bar stock. Stainless can be fun to machine but it can be a beast too. The swarf it makes doesn't break into small chips and you end up with long pieces of razor sharp swarf coming off the part. You have to be careful especially working close to the chuck as the jaws can grab it and whip it around. It's also hard on tooling and if your tooling is blunt it'll work harden the stainless and turn into a real pain.

Flood coolant helps keep the tooling in good shape and keeps the part cool.



The milling machine and a rotary table are great for putting a hex on the end of a part. I need to use a spanner on this piece so it gets a 15mm hex on the end.



Machining the other end and the part is taking shape. I use mainly ISO standard tungsten carbide tooling.They use replaceable tips that have several cutting edges to choose from. The advantage is you have a super durable cutting edge and if it goes dull you just flip to the next edge. You don't need to remove the tool from the lathe and your setup dimensions should be the same. A lot quicker than regrinding a tool steel cutter too.

There is still an need for tool steel cutters though. If you need an odd shape cut like a radius or an O ring groove you can grind a cutter to the right shape. Here I've cut a groove near the tip for an O ring and a groove behind it for roll pin to retain the part.



Here's the finished part on the right with the O ring installed on the end. The original part that I'd cobbled together is on the left. It's a fitting for the clutch slave cylinder that lets me connect a braided line to it. The original was welded together from a piece of the original slave cylinder fitting, a machined tube and an AN fitting welded on the end. Part of the issue with it was that during the welding process the plating on the part that went into the slave cylinder peeled off and the dimensions were slightly small. Over the years since I made the original I've gotten better at using the lathe so figured I'd make a nice one piece stainless one.



Here it is installed. It's retained into the housing with a roll pin so it can rotate. The end with the hex on it is drilled and tapped with a 1/8" NPT thread so I can screw an AN#4 adapter into it. The hex lets me tighten the AN fitting down and leaves the braided line completely outside the bell housing. A lot of setups I've seen have the line running inside the bell housing to the slave cylinder. I'm not a fan of that. If you damage the line it means pulling the motor to replace it



Cheers

[Dimis]

Mike,

I marvel at your ingenuity and "can do" attitude.

It's quite inspiring for a back yard hack joker like myself to see.
It encourages me to - man up and give something a go...
(Well, that and boxhead's sign off about professionals building the titanic and novices the ark).

It's a real shame that many of the painstaking details that are going into your car, will not even be see by the masses who cast eyes on your beast.

Well done and many thanks for sharing.

[Modena]

Have you got that T-56 back together yet Mike?