Category: 66Mustang

Last week I temporarily installed the camshaft, and after a bit of a learning curve got it degreed. I could have saved the effort; the cam reads within half a degree or so of the specs on the cam card. It’s well within my confidence of the measurement process, parallax errors when reading the degree wheel, etc. So, it’s getting installed straight up. The cam is a Summit Racing K3600, which has substantially more lift than the stock cam but not enough to require screw-in studs and the resulting head machine work. Once the cam was checked, I slathered it with the supplied assembly moly lube and re-installed it along with the timing gear and double roller timing chain.

With that done, I went to work on the heads. The stock ’66 289 heads aren’t bad for compression at about 9.3:1. They are not, however, renowned for their excellent flow characteristics to say the least. While this engine was not thermactor equipped, there were large lumps cast into the exhaust ports for air injection. I say there “were“, because they’re gone now. I’d never used a die grinder before, never modified a cylinder head, any of that… but the heads have the thermactor lumps ground out, exhaust ports smoothed as much as I could manage, and I even took the time to gasket-match the ports. I’ll do the same to the exhaust manifolds before re-installing them. I probably removed a pound of cast iron from those heads; what a mess.

Sunday the 5th I got all 8 pistons back in the block, just not torqued yet. And why is that? Because there’s one block, eight pistons, eight connecting rods, eight rod bearings, eight rod caps, and fifteen nuts to secure the rod caps. Where is nut #16? I do not know. My best guess would be, “Somewhere on the garage floor”… although “buried on the workbench” would not be an unreasonable guess either. Sigh. The hunt continues.

As the re-assembly moves on, I’m giving some thought to painting the engine once it’s all back together. One issue is the extreme grime on the oil pan, along with a few other bits. I believe I’m going to gather up the external bits — oil pan, heads, valve covers, timing cover, maybe the exhaust manifolds — and take them to a car wash with a can or two of oven cleaner. I don’t have access to a parts washer or hot tank (which would destroy the timing cover anyway). The valve covers won’t need much since they’re chrome… I’m debating whether to leave them alone or paint them to match. I’ll probably leave them chromed.

Last night I was back in the garage. I decided to check the main bearing clearance. The journals are smooth and measured exactly where they should be. I had never used Plastigauge before, but the concept is pretty basic. Sure enough, the Plastigauge shows about .00125 to just under .002 main bearing clearance.

I applied a generous amount of Lucas assembly lube, which is a thick green lube that looks like it would be pretty good around Halloween. I had to drive the pin out of the rear main bearing to accommodate the new rear main seal. I cleaned up the area with brake cleaner, then plugged the hole with a little silicone gasket compound. I installed the rear main seal and the main bearing caps, tightening them all down to 65 ft-lb.

The Moore rebuilding book says to use silicone on the mating faces of the block and rear main bearing cap. I’m generally not in favor of using silicone sealant anywhere in an engine or fuel system. I have some Permatex Aviation Form-A-Gasket that I considered using, but in the end I used the silicone gasket maker that I had bought for this project. I figured that the amount needed between the cap and block would be so small that it really didn’t matter much what I used, so I wiped on a thin film and tightened the bolts down. I’ll probably re-torque them tonight just to be on the safe side.

I ground the lumps out of the other head; in fact, it’s better than the first one so I’ll have to do a little more on that one. The carbide grinding burrs I bought do an outstanding job of removing iron from castings. I’ll clean them up with a flap wheel later on, but I’m not going to go for a complete polished exhaust port. This is a street engine, and just removing those big lumps of cast iron will do a lot for air flow.

Has it really been two months since I touched this thing? Sheesh. Well, in the mean time I completed the annual condition inspection on the plane, solved a very pesky problem with the Mercedes (turned out to be gummed up fuel injectors, of all things), took a vacation in northern MN, and… umm… whatever.

I gotta get something going with this thing. It’s been taking up way too much space for way too long. I was supposed to have this car done and sold six months ago. But it’s awfully easy to put off things I’ve never done.

Tonight, spurred on by the bravery of a good stout Manhattan, I attacked the heads. It all started innocently enough. I had bought a new dial indicator with a magnetic base to check the valve guides for excessive wear. It was still in the case, so I tried it out. Can you believe I made it to 50-nevermindhowmany years old, grew up the son of a professional mechanical engineer who designed semitrailer tank trucks, and have never used a dial indicator? The valve guides are fine, thank goodness… the worst one I found had .005 wobble at the tip of the valve stem, in any direction. That works out to around .0015 clearance, according to Mr. Monroe’s book. I decided to lap the valves, as long as I was out there.

I got all 16 of the new valves lapped; the seats all look quite good now. While I was at it, I decided to finally try out the carbide burrs I bought a couple months back. One cylinder head now has all four of the big lumps removed from the exhaust ports… THAT was easier than I thought it would be. I’d never used a die grinder as a grinder before, either. I’ve used a cutoff wheel… anyway, I’ll finish the cleanup and polishing (to some degree at least) once the other head is done. I figure even if left rough it will be better than having the big restriction in the port… but I’ll clean and polish them up as best I can. I’m pretty happy with the results.

I was on a roll. I heard a tiny voice taunting me. Took me a while to track it down, but it was the Flex-Hone calling me all kinds of names I won’t repeat here. I swear that’s why I pulled it out of the box of stuff from Summit Racing and doused it with oil. I figured shoving it into a cylinder bore would shut it up. The taunting continued until I had beaten it into submission with a Ryobi drill and a number of passes through the cylinder. By the time I was done the cylinder wall looked so nice, I went ahead and did the other seven. No more taunting from that tool, I tell ya! And those cylinder walls look good now, too. 45 degree cross hatch, and a light coating of WD40 to keep them safe for a few days until they get something better. Like another Jet A cleaning, a light coat of oil, and pistons installed.

While I was out there, I pulled the main bearing caps off and dropped them into the can of degreaser, after removing the old bearings. I used some solvent and a brush to clean up the mating and bearing surfaces in the block, then dropped the new bearing halves into the block and set the crankshaft in place. Figured that was enough for one night, so I went in and spent almost as much time trying to scrub all the grease and iron powder off my hands as I did working on the engine.

Tomorrow I’ll pull those main caps out and try out Plastigauge for the first time, too. I measured the bearing journals with a micrometer early on (I HAVE used those before!), so everything should be OK… but Plastigauge is cheap. If I’m not careful, I may actually have this thing back together before the end of summer. Really, the biggest challenge looks like it will be getting the block and heads cleaned up enough to repaint.

Heads are off, valve train completely out, everything more or less cleaned up. I sourced all new valves and rockers. The original springs are OK, the free height on all of them measures within spec and within a few thousandths from spring to spring. The cam I’m going to use isn’t too aggressive for the pressed-in factory studs or springs, I don’t think. Once I have the heads cleaned up a little more and check the valve guides with a dial indicator, I’ll start lapping and re-assembling the heads.

The block is ready for honing… but I’m holding off a bit until I figure out exactly what I want to do to clean up the water passages. I’d hate to have to replace the cam bearings, so hot tanking or electrolysis is probably not a good option. I may try some Evapo-Rust or CLR and see how well that works.