81 Malibu "Uncaged" Performance Therapy project thread

[deuce4935]

Now thats what I call getting hooked up!

[NOT A TA]

Originally Posted by deuce4935

Now thats what I call getting hooked up!

Oh ya! I would have just kept driving the Malibu with the stock 6 cylinder drivetrain if it wasn't for the contest and the machine shop.

Had to take a couple months off this project to get other non car stuff done, but I'm back on it! Scrounged around the machine shop and put together a set of Manley valves from miscellaneous leftovers. They are 2.02 intakes and 1.60 exhaust and are the correct length. Some new and some used so I cleaned up the used ones and polished the stems. Then "cut" the valves. Since the 1.6's are bigger than stock the heads will be cut later for new seats.

Cutting valves involves grinding the correct angle on the face that contacts the seat and then chamfering the top the stem and cutting the tip flat. For this engine 44.5 degrees is the angle of the face where it contacts the seat. Here's a pic of the machine we use. It's an older machine and we rotate the valve by hand to do the seat angle and the bevel on the tip. In the pic the valve is set for making the bevel on the tip which is done dry. The 44.5 angle on the head is made with the grinding stone on the other side of the machine and is done with lube that flows onto it while grinding. Forgot to get a pic of grinding the angle on the valve heads.

[NOT A TA]

With a set of valves ready now, it's time to check the valve guides. Shop technique for this is to put a valve through a guide and wiggle it to feel how much play there is. Then put a finger over one end of the guide, insert a valve stem till it hits the finger, then pull the valve out quickly to listen for a pop caused by the suction. After checking all of the ones in my heads we decided the valve guides wouldn't need to be replaced but needed a bit of work to tighten them up a bit. This is done with a "sipraler".

A spiraler cuts a groove into the inside of the guide without removing any metal. By deforming the metal it causes the inside diameter of the guide to be reduced and also allows path for lubrication. After the spiraler is run through the guide a ream which is the correct diameter for the valve being used is then run through the guide. Both tools are run down from the top and drop out the bottom so the head needs to be up on stands.

Pic below is a spiraler bit and a drill with a gear deduction so the work can be done at slow bit speeds. No pressure is used just the weight of the tool is enough. A couple drops of cutting lube are used during spiraling.



In the pic below you can see the grooves cut into the inside the valve guides by the spiraler and the ream being used to make the inside of the guide straight and the correct diameter. No more lube needs to be put in before reaming, whatever's left from spiraling can stay and is fine.

[NOT A TA]

The head I found to replace the cracked one already had stock size exhaust seats installed in it at some point so they needed to be removed before cutting both heads for the bigger exhaust seats that will be installed. Seat removal is done with a cutting bit on the drill press. The head is mounted and leveled then the old seat is cut till just a very small amount of it is left which then spins freely and can be removed.

Here's a couple pics showing the cutting bit that gets lined up on the bit guide which is inserted into the valve guide and then the old seat after cutting and removal.

[NOT A TA]

Since we were out of the correct size for the new exhaust seats (and it was a holiday weekend) I jumped over to working on the block a little. I had scored a set of breather tubes for the lifter galley out of an engine I was stripping for scrap at the shop a few weeks ago. Someone had blown up something and swapped all their good parts over to a new shortblock and left the old one with the tubes in it. They're not the fancy looking aluminum ones but will do the same job so they're perfect for my no budget build.

The block needs to be threaded in order to insert the tubes and plugs so while I was at it I threaded the end holes for plugs also. To thread the holes first a tapered reamer is used on a drill to chamfer the top of the hole so its easier to get the tap started. Then cut threads with the tap. Because these are tapered pipe thread the depth is checked on the first hole and then the tap is marked and the rest are tapped to the same depth.

Here's a pic of the reamer and tap . And then a pic of the vent tube and a plug. Bottom pic is the end of the block where plugs get installed.

[NOT A TA]

Since I was pressing wrist pins out of connecting rods at the shop I figured I'd get mine apart so they'd be ready for some work I want to do to them. The block had been bored to work with a slightly used set of .040 over forged pistons my buddy Mike at Mikes Automotive Machine in CT hooked me up with long before I moved south. It's been so long and with all the miscellaneous parts I've had and moves I made etc we figured we should double check the cylinder bores and pistons to be sure everything was going to work out cool. No sense taking the piston/rod assemblies apart if they wouldn't work. So here's a couple pics measuring things.



The cylinders came in at 4.041 and the pistons were around 4.0398+ so we'll be right in the ballpark of the recommended .0015+ gap recommended by TRW after the cylinders are honed. For the experienced/knowledgable guys I'm aware that these pistons were prone to cracking in the skirt curves when run too loose loose back in the day before they switched to the shorter skirts and I checked these. They were a gift so although they are an older design they're waaaay better than what I would have otherwise! Thanks Mike!

[NOT A TA]

For those that have never seen it done, this is how we remove stock style wrist pins from piston/connecting rod assemblies. (Later on in the thread I'll show how they're installed)

The pin is fitted with an interference fit in the top of the connecting rod and it takes a lot of force to push them out so a press is used. A support is placed under the side of the piston (different supports for different pistons) with a hollow base support below that to provide enough height to push the pin down. Then a tool that fits inside of the wrist pin with a shoulder that will push the pin is inserted. The tool is smaller in diameter than the pin so it will fit through the hole in the side of the piston. In the bottom pic the wrist pin is still stuck in one side of the piston but can be pulled out by hand. The "tight" fit is in the top of the connecting rod.