Field Expedient Engineering: JB Weld Porsche Cylinder Head Repair

Murilee Martin
by Murilee Martin

When your 1980 Porsche 924 craps out minutes after the start of its first race and you’re in rural Texas, parts might be a little hard to find. You won’t get far with a blown head gasket and big ol’ notches burned in the head itself. But, damn, the clock keeps ticking! The Moose Knuckles team called every junkyard within 500 miles, but nobody had any 924 (or Audi 100) cylinder heads. In fact, nobody had ever heard of them furrin thangs.

The Moose Knuckles were able to find a head gasket a few hours’ drive away, but they came up with exactly bupkis on the head. But then one of the guys remembered the fine print on the JB Weld package: Repairs Engine Blocks. Block, head, what’s the difference?

Picking up some JB Weld and JB Kwik, the Moose Knucks got right to work. Sure, combustion-chamber temperatures get higher than the JB Weld-rated 500 degrees F, but we’ve seen such repairs work in the past… on cast-iron heads. What will happen with an aluminum head?

Fill in the holes with that magical gray stuff, sand it down, and slap the head back on the engine. Take the car on the track. Return behind the tow truck. Repeat. Endlessly.

Because the track exit at MSR comes before the transponder loop, and the Moose Knuckles’ Porsche never managed a full lap under its own power, all those laps that ended on the hook didn’t count. Official race results counted the car as a DNS. On the bright side, the Moose Knuckles took home the I Got Screwed award.

Just so you don’t think JB Weld repairs always fail at LeMons races, here’s a JB-patched E30 oil pan from the same race. The car wiped out, bottoming the pan and cracking the hell out of it. Thanks to a generous application of metal-filled epoxy, the car finished the race.





Murilee Martin
Murilee Martin

Murilee Martin is the pen name of Phil Greden, a writer who has lived in Minnesota, California, Georgia and (now) Colorado. He has toiled at copywriting, technical writing, junkmail writing, fiction writing and now automotive writing. He has owned many terrible vehicles and some good ones. He spends a great deal of time in self-service junkyards. These days, he writes for publications including Autoweek, Autoblog, Hagerty, The Truth About Cars and Capital One.

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  • Panzerfaust Panzerfaust on Apr 29, 2011

    I've seen J-B weld used to repair VW vanagon crank case. Heat really wasn't an issue-except when the owner would use his Coleman catalytic heater to warm the engine up in the winter so it would start.

  • John Horner John Horner on Apr 30, 2011

    JB Weld to patch up an oil pan? Sure. JB Weld to fix a head .... never had a chance. JB Weld can't take the mechanical stresses or temperature. Didn't anyone at the track have a TIG welding set up? That could have worked.

    • Panzerfaust Panzerfaust on May 01, 2011

      Probably because a good portable TIG welder costs 3 times as much as any of the cars do. As I posted above, welding an aluminum head in the field is an iffy proposition. First it has to be of an alloy that can be welded, second the contamination from years of fuel, oil, coolant and other grime creates such porosity that you can't get much of a bead at all, or you have a weld fails almost immediately. But it would certainly be worth a try if the head was scrap anyway.

  • Bkojote Allright, actual person who knows trucks here, the article gets it a bit wrong.First off, the Maverick is not at all comparable to a Tacoma just because they're both Hybrids. Or lemme be blunt, the butch-est non-hybrid Maverick Tremor is suitable for 2/10 difficulty trails, a Trailhunter is for about 5/10 or maybe 6/10, just about the upper end of any stock vehicle you're buying from the factory. Aside from a Sasquatch Bronco or Rubicon Jeep Wrangler you're looking at something you're towing back if you want more capability (or perhaps something you /wish/ you were towing back.)Now, where the real world difference should play out is on the trail, where a lot of low speed crawling usually saps efficiency, especially when loaded to the gills. Real world MPG from a 4Runner is about 12-13mpg, So if this loaded-with-overlander-catalog Trailhunter is still pulling in the 20's - or even 18-19, that's a massive improvement.
  • Lou_BC "That’s expensive for a midsize pickup" All of the "offroad" midsize trucks fall in that 65k USD range. The ZR2 is probably the cheapest ( without Bison option).
  • Lou_BC There are a few in my town. They come out on sunny days. I'd rather spend $29k on a square body Chevy
  • Lou_BC I had a 2010 Ford F150 and 2010 Toyota Sienna. The F150 went through 3 sets of brakes and Sienna 2 sets. Similar mileage and 10 year span.4 sets tires on F150. Truck needed a set of rear shocks and front axle seals. The solenoid in the T-case was replaced under warranty. I replaced a "blend door motor" on heater. Sienna needed a water pump and heater blower both on warranty. One TSB then recall on spare tire cable. Has a limp mode due to an engine sensor failure. At 11 years old I had to replace clutch pack in rear diff F150. My ZR2 diesel at 55,000 km. Needs new tires. Duratrac's worn and chewed up. Needed front end alignment (1st time ever on any truck I've owned).Rear brakes worn out. Left pads were to metal. Chevy rear brakes don't like offroad. Weird "inside out" dents in a few spots rear fenders. Typically GM can't really build an offroad truck issue. They won't warranty. Has fender-well liners. Tore off one rear shock protector. Was cheaper to order from GM warehouse through parts supplier than through Chevy dealer. Lots of squeaks and rattles. Infotainment has crashed a few times. Seat heater modual was on recall. One of those post sale retrofit.Local dealer is horrific. If my son can't service or repair it, I'll drive 120 km to the next town. 1st and last Chevy. Love the drivetrain and suspension. Fit and finish mediocre. Dealer sucks.
  • MaintenanceCosts You expect everything on Amazon and eBay to be fake, but it's a shame to see fake stuff on Summit Racing. Glad they pulled it.
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