Observations on a GT4 engine pull.

The new buckets came in and we spent all day yesterday in the shop building the heads. We checked a few valve clearances with the new buckets and found them to be around .004" thicker than the originals (wear or different specs?). That required re-setting all the clearances. Every one of them were off by a few thousandths. Each bucket and shim was marked with a Sharpie with the cylinder they are fitted to, then placed in my custom parts indexing containers (paper egg cartons).

First we installed all of the stem seals, then we moved on to getting the valves, springs and retainers installed. We used the valve machine to depress the springs using a piece of schedule 70 PVC pipe with a window milled in the side to insert the keepers. A little shade-tree, but it worked. It's pretty hard to use a traditional spring compression tool without scoring the sides of the bucket bores, and as I mentioned before the tolerance is pretty tight. The PVC pipe is non-marring, cheap and effective. You can use this method in a drill press if you don't have a valve machine. Actually, you could also use a traditional valve spring compressor and a piece of PVC pipe of the jaws open up enough. Use a thin magnet and a thin screwdriver to pull the retainers out and position them back in.

Mike then performed a procedure I am forbidden to disclose, but hell, we're all friends here: He took a 1" thick plastic rod and a 3 lb sledge hammer and whacked each valve stem right on the top. This procedure is intended to insure each set of retainers are fully seated.

Mike used a tool that draws a vacuum on each of the ports to check for leaks, and none were encountered. Done. At least that part. I decided to install the heads with the cams off then put on the cams and the belts and recheck the valve clearances one more time. Still a lot more work before the engine is ready to go back into the car. (And the car is ready to receive the engine).

I checked with Mike if I should smear some assembly lube on the cylinder walls before I buttoned up the heads and he said "Just use some light oil like Singer Sewing Machine Oil.: Ha Ha - he refers to this engine as the "Italian Singer Sewing Machine Motor," but he did mention that the camshaft oiling and the slots to spray oil into the valve chambers and lubricate the buckets was very clever.
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Ok, OK... it's been 8 months, but I caught a bad case of "while I'm in there-itis"

Removed, refinished and reinstalled the fuel tanks.
Replaced every rubber hose in the car - vacuum hose, all coolant and fuel hoses.
Refurbed the starter and alternator.
Refurbed the coolant reservoir.
Dropped and ran the oil pan through the Roto-Jet Cabinet of Doom. Gasket was completely crushed, installed new one from Superperformance. The oil pan contained a considerable amount of the lubricants I squirted on the head studs when I was trying to get the heads off. I'm glad I decided to drop the pan and remove all that stuff.

My son came up to help, add his expertise (he loves "teaching" Dad) and install the heads on the engine. He is a licensed FAA A&P mechanic, and also holds an ASC Certification. This describes the procedure we worked out from his experience and sources from this site.

I had mentioned previously that I had installed a sacrificial anode in the block drain about 20 years ago, and only used distilled water in the coolant circuit. I attempted to remove the anode to inspect it. The bolt came out, but the anode was fused to the walls of the hole. Looking from the top with a borescope a small piece that remained protruded about 1/8" into the water passage. I was very concerned that it might break off and go someplace bad in the coolant circuit, so we used a shopvac, a machinist's pick and lots of water squirted in from the top to pick the soft metal (Zinc) out of the hole. That took half a day.

Before we installed the heads, we rinsed out the cylinders with WD40 - this does two things: rinses out any minute debris that may have accumulated in the cylinders; and frees up any stuck rings. Spray, rotate the engine and repeat until the puddle of WD40 in each cylinder is clear. Then we wiped down the cylinder walls with brake cleaner and smeared them with a thin coat of Redline assembly lube. Rotate to distribute.

The cylinder walls all looked absolutely pristine, no ridges so the bottom end looks ready to go. Applied a very thin coat of ceramic anti-sieze on the head studs (but not the threads!) and cleaned the block surface and stud threads with brake cleaner. Installed the new Elring head gaskets and dropped the cylinder heads on. New washers and old acorn head nuts.

The installation instructions that came with the head gaskets suggested lubricating the top of each washer before installing the nuts. This is so that that the torque readings are not effected by friction between the washer and the nut. Use a very thin coat and don't get any on the threads.

The new Elring gaskets look a lot different from the old ones so we decided to follow the instructions that came with the gaskets, rather than the shop manual. There is a stamp on the Elrings marked "Alto" (Top). Be sure to install them with that side up.

Then the specific torquing sequence (from the middle out): 60 Nm, wait a minute; 100 Nm, wait 15 minutes; 100 Nm once again. This "relaxation" time supposedly lets the head, head gasket and block surface get intimately acquainted. Kinda like foreplay. The third 100 Nm sequence resulted in an additional 30º to 90º turn before the wrench clicked (more pronounced on the inner nuts, which were torqued first), which proved the logic behind the instructions that came with the head gaskets vice the shop manual, which just said to torque them to 95 Nm (72 lb-ft).

We installed the heads without the cams installed. Our logic here was to let the head conform to the block unimpeded by any part of the valvetrain. The heads checked dead flat and didn't need any surfacing.

We decided to do a leak-down test at this point. The valves were all closed (no cams installed yet), might as well test it now instead of getting a big surprise later. We put 25 lbs of pressure in each cylinder and watched it for 60 seconds. No measurable leakage uniformly across all cylinders. We were happy with that.

On to the assembly of the valve train. Rotate the engine to PM (Primo Meridiamo as the Italians say, and so marked on the flywheel) better known as TDC (Top Dead Center) in Americano. I had previously set the flywheel pointer (under the window) to exact TDC with a dial indicator on Cylinder 1). Liberally lube up and insert the buckets and shims with assembly lube. Samo to the camshaft, oriented so the little scribe marks on the camshaft and the journal line up, and install the journal caps, new Belden washers and the old nuts.

At this point the cams and journal caps are sitting a little proud of being seated, because some of the cam lobes are in the position to depress their corresponding valves. Tighten the nuts on the journal caps 1/4 turn at a time to depress the valves and draw the cams into their correctly seated positions. Torque the nuts to 8.8 Nm (78 inch-lbs). Repeat for the next thee cams.

That is, until you realize that your parts supplier shipped you 3 of the correct oil seals for the cam ends, instead of 4; and 2 of the seals you only needed one of. We thought about using the best of one of the old ones, but decided that we're taking the time to do it right, why compromise now. So an online order to my supplier in England will go out after I install the water pump, crossover pipe and and oil filter housing and make sure I have all the correct gaskets and seals to complete the engine.

 

It's been three years since I last posted about this project. I had some serious health issues that took precedence, and prevented me from working on the Dino, and anything else for that matter. But my sons and I have been working on it for the last two years or so, whenever they got the chance to visit. We had first engine start exactly two years ago. Here's a quick video. Note the appropriate footwear on my knucklehead sons:

I can now report, after a couple of sessions with son #2 that the Dino has finally emerged from it's 7-year Desert Spa hibernation. Enjoy: https:/youtu.be/pAkFCOj-f6c