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These are various house, car, and bike projects i've done. And more!

New: TR6 work log, a running tally of work on the car, and the future todo list.

Engine plumbing and startup

Posted on June 22, 2021

With the engine finally mounted in the car, it's just a matter of making all of the connections needed to do the initial startup and break-in. 

One of the changes i've made in the new engine build is removing the original fan and adding an electric fan instead. It's a fairly common modification - the stock cooling system is usually plenty to keep the engine cool while driving without any fan (so removing the fan removes a bit of unneeded drag), and an electric fan gives the option for full air flow when sitting at an extended idle (when the car would tend to heat up).

I found a fairly cheap fan option at American Volt, complete with thermostat and relay for $70, which is cheaper than the common Spal fan by itself. It's a good fit on the radiator and seems to have good flow with a low amp draw.

fan fit on radiator

To mount the fan, i made some mounts similar to what Ed did on his TR6 and tacked them to the edges of the frame.

radiator fan mounts

This worked great, but i should have test fit this in place before painting the frame, as later, when installed the radiator i realized the radiator protection shield on the chassis sticks up a bit higher than the bottom edge of the rad. I ended up moving the mounts up by 7/8", but it still fits just fine along the top edge.

rad mounts moved

Now it fits fine, and all wired in. I followed the standard wiring and added a manual override switch as a backup. The thermostat sensor is in a new downpipe that has a bung welded in. 

Another update was to add adjustable jets to the original Stromberg carbs. These '69 carbs don't have the adjustable needle that the 72 and later carbs had, and this will allow me to tweak the fuel mix if needed with the new cam. Here are the old jet and plug parts and the adjustable version that replaces it.

old and new jets

Here's a view with one kit installed, to show the difference. Ignore the wire nut on the old vacuum switch, that whole switch got replaced with a new one (though i may just cap off that vacuum and eliminate it entirely).

one new jet installed

The bottom screw is what adjusts the jet height in the carb body, they're set to 0.10" below the surface to start, and i'll leave them alone until i get a few miles on the new engine and get the other parameters in tune.

The remaining connections seemed to go fine, though i found a literal bug in the works when i went to add the distributor cap and plug wires. Apparently a june bug crawled into one of the spark plug boots as its final resting place.

plug wire june bug

Then, with coolant added through the thermostat mount and oil added to both gearbox and engine i felt ready for an initial startup. You want this to go well, because this is when all of the new components are wearing together for the first time, and you want good mating but also good lubrication so nothing overheats or wears abnormally. Ideally, it's just like a cold start where it needs a bit of choke but fires quickly, and you run the engine for 20 minutes at around 2000-2500 rpms to break in the new cam and lifters. 

I had packed the oil pump with vaseline, so decided to just spin the engine with the starter and the plugs out to get oil pressure, rather than make a shaft to spin the oil pump separately. This worked fine, and i had pressure within 10 seconds or so. I figured with the copious amounts of assembly lube the risk was pretty low, plus i added all of the oil by pouring it over the cam, so the most vulnerable parts had a fresh coat of oil.

With the plugs in and a friend over to provide extra hands, i turned the key and ... nothing. Rechecking everything, i'd left the fuel line valve off, maybe that was it? Again, nothing. It didn't seem to fire at all, not even a burp. With hands over the carbs it felt more like pushing than sucking. We tested compression and go nothing, which was really weird. Finally, i walked through each step of the compression cycle and realized the valves weren't in sync with the cranks, i had gotten the cam timing wrong.

As noted in the previous entry, like an idiot, i had initially timed the cam ATDC instead of BTDC. I took the radiator and cross brace out, removed the timing cover (wrecking the gasket), and re-set the timing correctly. I had to wait 3 days for my new gasket to arrive, so i rechecked my work multiple times to make sure it was right, and felt pretty good by the time i could reassemble everything.

But then again it wouldn't fire. I rechecked the valve movement and the cam timing was right. I went through the same cycle with the distributor cap off and realized the rotor was not pointing where the #1 plug wire was. I hadn't touched the spark plug wires since removing them, so it seems that the previous engine build had everything off by 1 place. 

Third time was the charm, apparently, and with the plug wires reset it caught almost immediately and ran strong for the 20-minute break in.

Oil pressure was good, starting at 75-80 psi and settling in around 50 psi when everything was hot. The radiator fan kicked on when the temp got above about 1/2 on the gauge, and the manual override also worked great. I dropped the idle back down to a reasonable range before shutting it down and letting it cool off.

After a couple of minutes into the cooldown i heard a little crack, which seemed odd, then noticed drips under the front of the car. One of the radiator tubes had cracked in the heat cycle and was leaking pretty quickly. I brought it in to a shop the next day and they were able to fix it quickly and cheap, $35. I was happy to not have to pay for a recore after everything else, and it's stayed solid so far.

The only other glitch has been the clutch. It's smooth and engages fine (if a little too high), but doesn't seem to disengage fully. It's hard to get into gear, especially from a stop. I know the mechanicals are solid, with a new pin and extra reinforcement pin installed, but i bled the hydraulics and the fluid looked pretty hazy. I'm ordering replacements and will tackle the slop in the clutch pedal, hoping that fixes it.

I have about 30 miles on the car so far post-rebuild, and it feels good. It's noticeably stronger, pulling especially well around 3000-4000 rpms, and maybe higher but i'm trying to keep it capped at 4k for a little while yet. I can't wait to get the clutch sorted and get some miles in, but so far it feels like a really good upgrade.