thebeebe5 Posted May 6, 2020 Report Posted May 6, 2020 Soon after completing the rebuild of my ‘37’s 201 (Time for an Overhaul thread) I noticed some rust forming on the top of the head between No.s 4&5 cylinders. It turned out to be about a 1.5” crack. Annoying.... Now, I don’t know if it came about after the rebuild, or if (while magnafluxing the head during the rebuild) I’d simply missed it. Could certainly have been the latter. Anyway, being a non pressure cooling system it wasn’t much more than an eyesore. Last weekend I finally pulled the head to have it repaired and here is how it turned out. I assumed the shop would braze the crack as they had the large crack under the water neck, but this time they used the Lock n Stitch product to produce a repair that was effective (pressure tested!) as well as nearly invisible! I’ll be looking forward to reinstalling the head some time today, Friday or Saturday, depending on time availability. 4 Quote
Loren Posted May 6, 2020 Report Posted May 6, 2020 If you go to their website you can see how its done. One of the biggest advantages of Lock-n-stitch is that you don't have to disassemble the engine. A crack on the top of a flathead could be fixed without removing the engine either. In the pre-world war one days the savvy mechanics used brass rods they threaded themselves. Now days they use plugs made of steel. Keep in mind the repair is all mechanical. There is no welding, bonding or anything like that. If the section is thick enough (such as old car engines were) you can use their patented plugs which have a thread which pulls the metal together instead of pushing it apart like a standard thread would. In one video they repair a Chevy boat engine which had frost damage to the water jacket. A large chunk of the block was missing as well. The technician ground the hole out to a shape he could duplicate in mild steel plate, then "stitched" the piece in. It was about 4 inches around. Again, they didn't disassemble the engine. Some things are really good candidates for Lock-n-stitch but sadly some are not. Quote
thebeebe5 Posted May 7, 2020 Author Report Posted May 7, 2020 I pulled the head because I incorrectly assumed the other shop would braze it again. Turns out Brian has the Lock n Stitch at the shop and we could’ve done it ourselves, but neither of us thought of it… ah well... Quote
DonaldSmith Posted May 7, 2020 Report Posted May 7, 2020 They used Lock n Stitch to repair the Capitol dome. I wondered how that would work. If i put a conventional threaded rod in a cracked hole, the rod doesn't hold anything together, The Lock n Stitch has threads that are like the branches of a fir tree. The downward angle keeps the sides of the hole from separating. So I guess it works. I wonder if "Capitol dome" sets off any 'politics" alerts to the moderators. Republican... Democrat... (Just teasing, guys. No political onion expressed.) 1 Quote
Sniper Posted May 7, 2020 Report Posted May 7, 2020 Using a threaded rod to fix a crack has been a round for a very long time, lock n stitch just seems to have improved on the stiching pin part of it. Back in the day we'd drill a hole at each end of the crack then start drilling, tapping and using a regular old bolt to fix the crack, some would use loctite green or teflon paste on the threads, cut the head off, grind flat and move to the next hole overlapping the bolts into each other so they don't back out.https://www.hotrod.com/articles/mopp-1203-cast-iron-cylinder-head-crack-repair/ Quote
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.