kayakertom

Good luck, they are fun cars.

Recycled 11 car batteries; received $5 each for regular car batteries at Battery X-Change in Beaverton and received $91.44 for 8 T-105 6V batteries or ~$11.43 per battery at Far West Recycling in Tualitan.

Those two wires on the driver's side near the strut tower get connected when doing the timing and then disconnected for driving. RPM fluctuations often mean vacuum leaks. Double check your spark plug wires. Clean up the multiple ground connections.

After some Al-Cu brazing practice, the old brass pipes are now attached to the new aluminum heater core. Had to redo the brass pipes to the copper elbows because the melting temperature of the AL-Cu brazing sticks is higher than the plumbing solder used for the brass pipes to the other end of the copper elbows. The brass pipes are made of thin brass, so that necessitated using brazed elbows rather than the shark-bite type. Next step is to slightly modify the plastic bosses that anchor the pipes to the heater box.

Some slow progress: Cleaned and renewed the foam on the flaps; cleaned the debris out of the fan squirrel cage. Switched to 1/2" - 90 degree copper connectors to connect the old brass heater pipes to the new aluminum heater core. The reason for this is that the brass pipe is thinner than regular plumbing pipe and where it needs to be cut is not very round due to the factory bends - to solder, the brass needs to be a tight fit to the copper, so it takes a little effort with a proper sized socket to reshape the brass. Photos: Foam tape used for the heater flaps. Foam tape on flaps. Old heater pipes marked for lining up with plastic supports prior to cutting. Squirrel cage before cleaning. 1/2" copper 90 degree joints soldered to old cut brass pipes. New aluminum heater core set up to braze to the copper connected old pipes. This is the brazing rod I am trying to use: https://parts.rheem.com/product/RPD-SW-ALCU5-5 First attempt not successful (rod not flowing)! Am trying to figure out what I'm doing wrong - any hvac people out there???

That's a nice, bright and heated shop! No thumb photo?

If your fuel filter is partially clogged, you'll notice it initially at higher rpm. Another possibility is at least one of the 4 fuel injectors acting up and one possibility is a corroded electrical contact on an injector:

If your fuel filter hasn't been changed in a long time, it might help to change it.

OK, I found a replacement heater core that fits in the plastic heater box: https://www.carparts.com/Heater-Core/Replacement/REPM503005 I'm looking into using Sharkbite 1/2" 90 degree elbows to reuse portions of the old piping: https://www.amazon.com/SharkBite-Connect-Plumbing-Fitting-UR248A/dp/B0C4QWMXST/ref=asc_df_B0C4QWMXST

Probably lots of old vacuum hoses and even a small leak can make your idle rough. "To detect vacuum leaks in a carb car, the most common method is to use a carb cleaner or a similar spray around suspected leak areas while the engine is running; if the engine RPM changes noticeably when the spray is applied, it indicates a vacuum leak at that point."

AI is getting results closer to something that could be used: https://www.napaonline.com/en/p/NRCNH9010200 Cut off a bit of the pipes, re-flare and add hose.. https://www.carparts.com/details/Nissan/Sentra/Replacement/2000-2006/REPN503001.html

Here's what AI says, shows promise: Finding a heater core with exact dimensions of 7" x 9" x 1.25" inches is challenging. However, the APDI 9010503 HVAC Heater Core is a close match, measuring approximately 7.75" x 9" x 1.25" inches. Amazon This heater core is constructed from aluminum and is compatible with various vehicle models. If precise dimensions are critical for your application, consider reaching out to specialized manufacturers like The Brassworks, which offers custom fabrication and restoration services for heater cores. The Brassworks They can create a heater core tailored to your specific size requirements. Before making a purchase, ensure compatibility with your vehicle or system by consulting with a professional mechanic or contacting the manufacturer directly.

Have paused the repair and am still looking for either a lower cost recore or finding a ready made unit that could be substituted. Hart Radiator in Kelso, WA says ~ $350 for a recore. Have asked auto parts stores if they can search by core dimensions = 7" x 9" x 1.25" but that doesn't seem to be possible. Will see if an AI search will help.

This Fall, I put on a Cardone front driveshaft from Rockauto on my '88 GL and it works fine. Have ordered many parts from them and only a small percentage were junk.

Can still buy them through Rockauto: https://www.rockauto.com/en/catalog/subaru,1987,xt,1.8l+h4+turbocharged,1270640,drivetrain,cv+axle,2288