Engine Timing Driving Me Nuts

[tincan1966]

You can also just get a replacement HEI from any parts store for a '75 and up chevy 250/292. T

[ACK]

Originally Posted by Sharps40

Watcha runnin for timing?

I dialed it in at 12 and we're both happy. I want to get some more miles on her before deciding if I should fine tune it some more.

Originally Posted by tincan1966

You can also just get a replacement HEI from any parts store for a '75 and up chevy 250/292. T

I came real close to getting a new one at Autozone. I went with Stovebolt figuring that the price is good, it's a remanufactured Delco and not Chinese, and I've heard only good things about Stovebolt. The book keeper would have me sleeping on the sofa for a month if I went for an MSD.

[luvbowties]

Originally Posted by ACK

I'm giving this thread closure in case someone comes across it down the road because they're having a similar problem.

Thanks to everyone for their suggestions and guidance, here's what I've learned ...

1. TIMING CHAIN: the 230,250, and 292 don't have a timing chain. The crank and cam gears mesh together, so it's rare (but not impossible) for them to be out of sync

2. FLAT CAM LOBE: Todays oils have way less additives that prevent metals from wearing away, if you don't use one, seriously consider a zinc additive. The easy, but not the most accurate, way to check for a worn cam lobe is to take off the valve cover and see if any of the lifters are barely moving up and down while the engine is running. If you want to get real accurate, get a dial indicator and rotate it by hand to see if a lobe is lower than the rest.

3. HEAT RISER: Located on the underside of the exhaust manifold, when the engine is hot, if the flat side is pointing towards the drivers side you're good and if it's pointing down, that's not good. Read this link for more info.

4. RESISTOR WIRE: It's suppose to be a white cloth wrapped wire. We'll, when a P.O. paints it gloss black, it' looks like all the other wires. When I started unwinding the black tape around the wire harness, I found out that I still had a resistor wire. The resistor wire's casing also yellows and even turns dark brown over time. I read many different opinions about the resistor wire if you have a Pertronix unit, one thing is for sure, it can create problems if it's not hooked up correctly. Below is the passenger side wire harness for a 64 C10 with the wires labeled.

5. HARMONIC BALANCER: GM made balancers with marks at 2, 2:30, and 12 o'clock, so you might be top dead center on the #1, but your timing mark could be pointing someplace crazy if it was replaced with the incorrect year. One way to test it to see if the rubber is separating is place a mark on the rubber part below the timing mark and hit it with a timing light. If it appears to be moving separately from your timing mark, time for a new balancer.

6. TIMING LIGHT: If don't need a pro timing light, get the one with the advance dial at Harbor Freight. Sure, it's inexpensive and the knob moves a little too freely, but having the advance control is fantastic. Avoid getting an older timing light off of Craig's list. If you do and they say "Well, it worked 5 years ago when I last used it", either test it before handing over the cash or ask if they'll give you your money back if you can't test it then and there.

All the above is just one man's experience, if any of this is inaccurate or could use some clarification, chime in. Now to end this tale. I ordered an HEI from Tom at Stovebolt Engine Co. and HALLELUJAH, my truck has been cured! I'm not going to speculate if it was the Pertronix unit or the camouflaged resistor wire, all I know is it feels like a new engine –*best $100 I've spent on the truck. Again, thanks to everyone for their help and advice.

...a very good, comprehensive, and well-written article--your grammar teacher would be proud! I'm sure it will help many down the road. Kudos to you! ...and glad you cured the problem.
Sam

[Sharps40]

My 230 ran great with the Rochester B and the HEI set at 10 BTDC. Once I went to the Weber DGEV I bumped it to 12 BTDC and then up to 15 and then to 18. I have to measure this tank of gas for mileage. Been pulling 17.8 mpg with great performance. Did some final jettin on the carb and hopein for 18+ mpg with the stock peanut trans and the 3.73 rear gear.