Because this is a continuation of the overheating issues we've been experiencing, (tome, volume 1, outlined here: https://www.triumphexp.com/forum/tr4-and-tr4a-forum.7/composite-or-copper-head-gasket.1858156/ ) I thought I'd break this out from that topic because its more push rod tube leak related than head re-work and head gasket related.
While the head was at the machine shop to be inspected, they tanked the head and, as has happened before, dissolved the aluminum push rod tubes resulting in their replacement.
Once we got the head back from the machine shop and cleaned up, we proceeded with installing it on a fresh head gasket (Lucas CE330 HD) going through the proper sequence of torquing, valve adjustment, manifold installation, carb installation and tuning.
Got things cranked back up and tuned only to find that we had developed an oil leak somewhere that had left a considerable puddle of oil trailing down the back of the block and off of the clutch slave cylinder on to the ground.
Tracing the leak back up, we found the culprit was in the head with three of the eight push rod tubes seeming to be most contributory to the puddle. (I'm beginning to feel like I need to stock up on head and manifold gaskets with this car like I do with carb mounting gaskets or thermostat gaskets. Keep a few of each handy at all times just for good measure.)
Off comes the head,again.
The newly replaced push rod tubes were found to be seated and sealed on inspection, just as they had looked when we got it back from the machine shop but there was still a gap in the top and bottom ends that looked like it could ship oil out of the head despite having an obvious amount of sealer in the fitment.
Add to this the realization that the commonly available replacement push rod tubes are not the correct OD dimension for the head and often have to be turned prior to being installed. For example, I came across this bit of info while searching this topic in another forum and the machine shop confirmed the cited measurements were pretty close to accurate: "...the new ones sold by Moss and others are +22 thou oversize on diameter. In consequence they are too big to fit into the head, unless of course the the head is machined to suit at extra expense" (or the tubes are turned down on a lathe and then inserted in to the head).
In my digging, I realized that the tubes could probably use a bit of a swage at the ends to stop the flow of oil and reached out to the machine shop to see if I could bring it by and have them do this for me. They said I could but it might be a week or two before I could get the head back. I decided to see what others had done for this and give it a go.
I found somewhere that the optimal angle for a finish swage on the tubes was about 60 degrees. I went in search of a tool to do this, hoping it might be cheap, and found out it was not going to be for the number of uses I was going to get out of it.
I pondered using the peening face of a ball peen hammer and setting the peen on to the tube and gently striking its flat face with another hammer to see if this would swage the fitting but just before I struck the peening hammer, my brain said, "What if you knock this tube out of its seat and make this problem worse?" I often ignore that little voice but opted not to this time.
Staring at a picture of the swaging tool, at first I thought the ball inside a ball valve would be a good possible swaging face. It already has a hole in the middle of it so I could use all-thread as a clamping force with some nuts and washers but it ended up feeling like it was going to be a better idea on paper. As I was standing, pondering my next move in the plumbing aisle, I spotted a series of flare nuts for about $2.50/ea in an adjacent rack. EUREKA! I bought two of each in two different sizes and a short length of all-thread, two washers and some nuts.
Back in the workshop, I found the 3/8" flare nut was just about the perfect fit in the push rod tube. It has an angle of ~60 degrees and with the 3/8" all-thread, there was very little play in the fit. I cleaned the head and push rod tube with brake parts cleaner, swaged the #1 tube on the head and then cracked the nut back off to see if I had ruined a push rod tube. Nope! It had a nice flare and I got a good clean squish of cured sealant "squeeze out" that the machine shop used. I took a fine tip Xacto blade and laid it flat on the head and shaved the fillet of sealant flush with the head.
I proceeded with a thorough cleaning using brake parts cleaner and a heat gun (not both at the same time) to flush out any residual oil and made my way through the rest of the tubes, focusing first on the bottom of the head. In doing this, I found that not every tube produced that little squeeze out when swaged but the fit of the tubes looked tighter and more clean once they had been swaged. Happiness all for the low, low price of about $10 in hardware bin parts and two flared nuts. (There's a joke in there somewhere but I have to resist the urge...)
In my research on this, I found several posters reported using penetrating (green) loctite as reinforcement in this process so I squeezed a watery bead of this around the tube opening and let it sit for 24 hours. While I had the head facing bottom side up, I went ahead and cleaned the flange area around the tube where it goes in to the upper flange of the head and squeezed a bead of the green loctite in to that void to close any possible leaks there. After letting it sit overnight, I found 4 very small trickles down the push rod tubes where green locktite had made its way through the flange of the head and down the tube.
I then flipped the head over and did the top side of the tubes and the fit joint where the tube goes in to the bottom flange of the head, leaving a healthy and fat fillet of green loctite to cure for another 24 hours.
Once cured, everything looked nice and smooth and the loctite had settled down in to the joints with a hardened feel to it.
I cleaned off any loctite residue and a few runs, repainted the head in POR15 engine paint since the solvents had removed much of the paint and put it all back together. It seems to be holding. I wasn't enthused about trying to trickle loctite in to and around a connection that appears to be full of a sealant already but with the amount of solvent I've pushed in to and through those fittings to clean out any residual oil, it seems to have been clean enough to hold things together and keep the oil in. Only time will tell.
--Jake
Edited 1 time(s). Last edit at 2022-04-02 02:27 PM by 7873jake.
