- Posts: 2070
- Joined: Sep 7th, 2009 5:31 pm
- Tell us about your Corvette: 1971 Coupe, restoration in progress.
- Location: Waterboro, Maine
I've spent the last several weekends wiring the engine in preparation to get it started. So far I've just roughly routed the wires and made the necessary connections to run the engine. My plan is to get everything final wired and cleaned up once I've verified the engine is running properly.
After getting everything set up and ready to go I checked the engine fluids and pulled the distributor to prime the engine. After spinning the primer for a good 2 minutes or so I dropped the distributor back in, gave everything a once over, and turned the key. The engine turned over a couple times and... nothing. Maybe a couple backfires out of the carb but that's it. Long story short I got my timing all screwed up when I pulled the distributor. I had added a temporary alignment mark on the distributor flange and manifold as a go by but, for reasons that quickly became apparent after thinking about it for more than 2 minutes, that just doesn't work.
I ended up pulling the plug from cylinder #1, found top dead center on the compression stroke, and then backed the engine back it down to 8 degrees before top dead center. From there I dropped in the distributor and aligned the distributor rotor with the terminal for cylinder #1. After getting the plug wires reconnected I gave the carb a few squirts, turned the key,and the engine fired right to life. I was pretty impressed! After not being started for two years it turned over 3 or 4 times at most before starting. Pretty cool! The engine ran like a top and I brought it up to temperature to make sure the electric fans kicked on at the right temperature. After a good 5-10 minute run in the garage I turned it off and was pretty happy over all. I even managed to take this quick video. https://youtu.be/FvG4M3C8mog I'm running headers and partial exhaust (no mufflers) but it wasn't as loud as I expected. The microphone on my camera didn't like it though - it got a bit staticy. Either way I thought it sounded pretty good.
However, I learned long ago that these restorations are never without their issues. I have two that I need to deal with.
First is the engine timing. This one has me really scratching my head. I set my initial timing manually as described above and the engine runs great. However, when I put the timing gun on the balancer (with the timing gun set to 0 degrees of advance) it's reading 40 degrees of initial timing and 60 degrees total . Obviously this isn't right, the engine just wouldn't be running if it was. I verified the balancer hasn't slipped so I'm beginning to wonder if my timing gun is bad. I've been scratching my head about this one for a couple days now and haven't figured it out. Any ideas?
Second is my water pump. Going way back to when I dynoed the engine I had an issue under high RPMs (4,000-5,000) where the backing plate on the water pump allowed water to spray out under pressure. Basically, the backing plate would flex under pressure and allow water to escape. Once the RPMs were brought down the leak stopped and everything was fine. I chalked it up to the fact that I bought a low budget water pump so I bought a different brand and replaced it. Fast forward to this weekend and, you guessed it, same thing. Water spraying out at about 4,000 RPM. Now I highly doubt that two water pumps made by different manufacturers would have this same defect so I'm wondering if it's something specific to my car that's causing too much pressure to build in the water pump. I have removed the bypass hose from the manifold to the water pump but that's a pretty common modification and I haven't heard lots of stories of people having issues with their pumps. I could remove the thermostat all together to eliminate pressure but that doesn't seem like a great solution. At a minimum, I plan to pull the water pump, remove the backing plate, roughen up the mating surfaces, and install a new gasket with some red RTV sealant. I've also thought about removing the backing plate from the first water pump and possibly adding it to the current water pump over the existing backing plate - basically putting two backing plates on my existing pump to reduce flexing in the pump. However, I'm not sure how effective this would be or if it would even clear the timing cover.
Anyways, I'm open to ideas and suggestions! Hopefully I'll be able to get back into this next weekend and continue to make some progress. If I got the brakes hooked up I'd actually be able to drive it!
Track my progress at The Corvette Restoration Page http://www.corvette-restoration.com