where’s my f’in oil pressure! – NASA AI Javelin update

OK, that was an insane detour. So after completing the fender through clearancing I got the car back on the ground. I had a few little items I wanted to take care of before the October race. One of them was testing the alternator. I had a suspicion that it wasn’t charging. So i hooked a multimeter up to the battery and started the car. Meter read in the low 12 volt range so I was pretty sure that was confirmation that I wasn’t getting any charging from the alternator. That only took a couple of seconds.

No big deal I’ll just order a new one. But what did concern me was that the motor had been running for several seconds and I was not seeing any oil pressure on the gauge. Wtf? I let it go a little longer and blip the throttle gently a couple of times but nothing. So I shut it down. The car was running fine last time out the only thing I did since it last ran was have it up on jack stands in the front for a week.

I wondered if maybe the gauge was bad. I really didn’t think that was likely but I couldn’t see why else I would suddenly not have oil pressure. So I started it one more time and quickly powered up the traqmate. I have an oil pressure sender in addition to the mechanical gauge. Crap the traqmate was also showing no oil pressure so I shut the motor down again. Ugh. Now what!? Why can’t stuff just work?

My next idea was to start pulling lines to see if any fluid was moving. So I disconnected the oil gauge feed line at the oil pump port and spun the motor with the starter. I could see some fluid dribble out. I then did the same thing with the line to the remote oil filter in. When I turned the motor over with the starter some fluid dribbled out.

The next day I called Doyle and told him what I was going through. He said if the fluid isn’t blasting out there’s a problem. He reminded me that it should be at 50+ psi. Not dribbling but like a garden hose when you put your finger over part of the nozzle. So what was the problem? I started to think that having it jacked up for a week allowed all the oil to drain out of the lines and that I needed to prime the system. That meant pulling the distributor. Great more work. I really didn’t want to but it seemed like I didn’t have a choice so out the distributor came.

That’s when things went from bad to worse. I pulled the distributor and saw that the gear was wearing badly. This was not a new problem. After I blew the motor up in 2012, during the tear down, we discovered the distributor gear and cam gear were badly knife edged. This is a common problem on AMC motors and you can find lots of threads online discussing the problem. There are many different solutions people recommend but the common reasons cited are cam walk and/or poor lubrication of the gears. The walk is supposed to be solved with a cam button or cam retaining plate. The lubrication issue is dealt with by making sure the oiling holes in the cam gear are not blocked. Some people also add an external oil feed line to spray the cam gear directly. I opted to replace both gears (bronze for the dizzy gear) and put my head in the sand and hope it didn’t happen anymore. Well that didn’t work. It was happening again.

Doyle said I was going to have to pull the timing cover to check how bad the cam gear was. No! I don’t want to keep tearing this car apart. I could whine all I want but it had to be done. So drain the radiator and yank it. Unbolt the power steering pump and move it aside. Yank the alternator. Remove the pulleys and water pump. Are we having fun yet? Finally it was time to pull the harmonic balancer. Doyle came over with his box of pulling tools. It’s good to know people who have tools, know what they’re doing and are willing to come over and bail you out of a jam. So we get the puller set up and start cranking on the bolt. Thing won’t budge. The tool just starts bending. Oh boy. Of course it’s going to fight us. It hasn’t been hard enough already. We keep working at it. We put spacers behind the tool to support it so it can’t bend. We try a breaker bar. We go get a shorter grade 8 bolt so that there is no slop in our pulling setup. We try the half inch electric impact gun i have. Nothing. Doyles starting to think we’re going to have to cut it off. Finally I get my air impact and crank up my air compressor pressure and hit it. Yes!!! It starts to move. Finally things are going my way.

With the balancer off we could finally pull the timing cover. And sure enough the cam gear was badly knife edged. The cover itself confirmed the cam walk as there was a deep gouge where the end of the cam had been digging into the cover. There was also evidence that the timing chain was rubbing on the rib that runs around part of the crank seal. Sigh. Guess I was going to have to actually fix it this time. I had a spare cam gear but I had to order a replacement bronze dizzy gear. The plan was to replace the gears, make a cam button and then index the gears as Doyle felt the reason for the wear was that the gears were not aligned properly.

So while everything was apart and I was waiting for a new dizzy gear to show up I took the opportunity to do some timing cover/oil pump housing mods. We opened up a few ports and cleaned up some casting flash. I used JB Weld to fill in the gouge in the cover and I got the die grinder out and clearanced the “rib” that was contacting the timing chain. There’s a great YouTube video showing the improvements you can make to your timing cover/oil pump housing here. AMC Timing Cover Oiling Modifications V8 https://youtu.be/-_t2U2UPEZs

When it was time to start putting everything back together I first installed the cam gear. Then I put a bit of clay on the end of the cam (wrapped in wax paper) and reinstalled the cover. Then I pulled the cover and measured the depth of the clay. Using that I made a cam button on my lathe out of a piece of Delrin Doyle gave me. Next I installed the dizzy gear. For some reason the roll pin hole did not go all the way through both sides. Doyle said that wasn’t right so we drilled all the way through. Then we used some distributor shims he had to make sure the dizzy gear lash(?) was correct and then more shims to make sure the housing was in the block at the right height for the gears to mesh properly. We coated the dizzy gear with spray on dykem to help with that.

Getting the cover back on the motor was a real chore. There are two dowels you have to get lined up while trying not to rip off the rubber gasket you’ve glued to the cover. Very stressful and I couldn’t have done it without Doyle’s help. Really hoping this thing isn’t going to leak!

Next I reinstalled the balancer. This went smoothly. Doyle had me really sand the inner diameter of the balancer with some fine sandpaper. I did an honest job of it and it was paying off now. Balancer went on without drama and i was able to continue putting everything back together.

But I wasn’t done. Another suggestion Doyle made was for me to rotate my oil cooler. I had it on its side with both ports facing left as you look at the front of the car. He pointed out that this meant the oil was constantly draining out of it when I shut the motor off. He said if I rotate it 90* with the ports facing up then it would stay full. So I bit the bullet and made the change. And then I put everything back together (radiator in, accessories back on, etc).

Finally the moment of truth. I used the priming tool in my drill and spun the pump for 30 seconds… nothing. Crap. So I decided to try to prime in stages. I disconnected the oil filter in line and ran the drill. YES! I got oil out of the end of the line. And it was definitely under pressure. Then I disconnected the filter out line at the oil cooler. Hit the drill again and waited… YES! got oil out of that line. Then I reconnected that I disconnected the oil cooler out line at the engine in port. Ran the drill… YES! got oil. So I connected that line back to the motor, crossed my fingers and ran the drill. YES! Oil pressure on the gauge! Whew…

With that taken care of I put the motor at TDC, installed the dizzy, advanced it a bit and tightened it down. Got in the car and fired it up and still have oil pressure. Then I just timed the motor, filled up the accusump and closed the valve and shut down the motor.

So that was the detour from hell… I believe the problem was just that the system drained and needed to be reprimed. But digging into to it revealed that I am still chewing up gears. Hopefully the indexing we did will solve or at leave improve the situation. After a couple of events I’ll pull the dizzy again and check the gears. I think I’m ready for the Oct. race at this point. Hopefully nothing else breaks between now and then!

1974 Javelin-road race, Drive Train


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