My 2.4/2.6 hybrid build

[clutchdust]

Granted this is a little old now but it's never too late to show off.

So here are some pics from my build of my 2.4 block with 2.6 rotating assembly. My original 2.4 block was still in really good shape. #1 cylinder was right on the edge of needing to be bored but stayed inside limits even with a hone to clean up the wear. The rest of the cylinders were beautiful. I was given a 2.6 engine by a guy who builds and races Zs. That block was too worn and would need to be bored. So naturally, it just made sense to pull the rotating assembly from the 2.6 and marry it to the 2.4. Fresh bearings, rings, chain, tensioner, guides, oil pump and gaskets. Pretty much everything else is just reused.

I had the cylinders honed, the crank turned just enough to polish the journals and .005 taken off the head, but otherwise very little done to the assembly. As usual, #1 cylinder (#2 was close behind it) had the most wear just due to the cooler water hitting it from the water pump. If this was supposed to be a long term engine rebuild or something, I might have bored it or at least sleeved the cylinder. But this engine will probably not hit 20000 miles in the next decade, and then will probably be rebuilt or replaced so I'm not real worried about the future wear. The car will just be a little weekend get-around-town toy for a while.

Machine work, Pertronix, headers, intake and Holley, I think I'm still well under a grand. I'm pretty happy with the way it runs. I would like to bump the cam a bit but it's still strong even with the factory cam.

So here goes.

Just a basic 2.4 block. This is fresh out of the machine shop before I started any assembly. I primed and painted the block a "cast iron" engine enamel. You can pick it up in some of the later photos but it's close enough in color that it's hard to detect.

I coated all the oiling surfaces of both the block and head with Glyptol. I've used this a couple times before and it works really well. It's a thick enamel that fills in pours in the metal and dries with a smoother finish than bare metal. I also knocked casting flash off the block that might slow down or capture oil in the return to the pan. You can also see the main caps installed.

Dropping the pistons. I didn't upload a pic of the crank installed first just for bandwidth reasons, but it's already in there. So you can see I have the top ring in the empty cylinders. I squared them in the cylinders by dropping the piston inverted to the oil ring land and then measured the gap to make sure the gap was good. #1 was right on the outer limit which was no surprise but still good, but they got progressively tighter up to #3 and then maintained a pretty consistent gap well within tolerances. Notice using the correct tools to install both the rings and pistons. Piston #1 is already sunk. You might also be able to tell I polished the snot out of the piston tops. The idea is just to reduce the grooves and valleys that allow carbon build up to accumulate.

Here's the crank installed with the rods being sunk. I plastigaged both the main and rod caps as I went. Everything was within specs but as you might expect, a little loose.

Here's the head assembled. New valve seals but even the valves and guides were still well within tolerances. Like the piston tops, I polished the snot out of the chambers. Not only does it reduce the surface area for carbon build up but it also reduces the amount of heat transferred into the head. You can also see I did a mild port and polish on the intake and exhaust ports. Not really a true port and polish but more a clean up of casting imperfections and smoothing. I wanted to remove a lot of the imperfections on the intake side and smooth the exhaust. I also did a basic port match.

New chain, tensioner and guides installed. Don't sweat the head and pan installed. The pan is just loosely bolted at this point as I stored the engine upside down when I wasn't working on it.

Here everything is all put together and the engine is installed. That's an MSA 3-2 header and Arizona Z intake with a Holley 4bbl carb. I really hate that neither company offers both parts, because they don't fit together without modification. I had to dimple the #2 exhaust pipe and grind #3 intake port to get the clearance needed. It was not fun to take a hammer and/or grinder to brand new parts. Another thing about the intake, I like it and all and think it's a better (at least cheaper) solution than the triple carb set up, but it has a couple issues. First is the aforementioned fitment issues with the header. But the other is that the carb base isn't thick enough on the flange. When I first mounted the carb I had a good 1/8" gap on one side of the carb where the flanges didn't meet at all. There was NO sealing. I "solved" this problem by putting a 1/2" phenolic spacer between them, but that cut down on my cleaner clearance, hence the Edelbrock triangle filter. Not my first choice but better than nothing.

Finally, here it is all installed and running. I thought the linkage would be a little more "trick" this way than simply running a simple cable to the throttle. Works great. I have about 600-800 miles on the engine so far and no problems with it. Can't explain why the audio doesn't match the video but this is also just running through a simple Cherry Bomb. I have since put a Dynomax on there too to quite it down some.

I have also had the radiator refurbished and replaced the fuel pump you see in the video. I would like to put a little bit bigger cam in it but otherwise I think the engine is done.

Thanks for looking.