Harmonic Bal is bad - can I test this 250 anyway?

[Lugnutz65]

The basic question is - Can I start and test run an engine (just inside the shop) if the HB is completely shot? What bad things might happen? I guess the HB could fly apart - maybe.

I'll need to make some basic assumptions like - I need to hope the timing is already set properly. I understand the alternator and fan pulleys will not spin properly.

I just don't want to take the time to install another HB if the engine is really bad. I pulled off the rocker cover and things looked pretty clean, so I'm hoping this engine is good.

Back story - I bought a 1963 Custom SBFS with BBW in January. Straightest (as far as fewest dents and dings) I've ever seen for a 60-66 original truck but more rust than most would want. All original for the most part but the engine was replaced with a 1971 250ci. I just now figured out that the rubber on the HB is completely shot. I can spin the HB outer ring by hand turning the fan.

The 250ci doesn't have a bolt in the end of the crank, or I'd hand turn the crank to see if I had reasonable compression.

Pics are for interest.

[68gmsee]

If the HB outer ring is so loose you can turn it by hand, I wouldn't run the engine. I'd disconnect the distributor to coil cable and use the starter cranking to check compression. That's the normal way to check compression.

[Lugnutz65]

Originally Posted by 68gmsee

If the HB outer ring is so loose you can turn it by hand, I wouldn't run the engine. I'd disconnect the distributor to coil cable and use the starter cranking to check compression. That's the normal way to check compression.

Yes. Agree completely. But I sure would like to hear this engine run. Isn't that the fun part?

To do it your way, if compression checks out then it'd be worth the effort to replace the HB.

[68gmsee]

Yeah, Lug, I agree that hearing it run would be nice.

You could try to start it by first removing the belts and outer ring itself. Just run it with inner HB but I wouldn't run it for more than a few seconds. Or, if the belt or belts are on tight they may keep the outer ring on the HB, but it's still taking a chance. Your call, I guess.

[Lugnutz65]

Well, you provided me with the motivation I needed. I quickly found a double groove HB I had stashed away. It came from a scrap yard 250ci. That was more than half the battle right there. The radiator was draining while I looked.

I had the old HB off in 1/2 hour. The double groove HB was on within another 40 minutes or so.

I used a remote starter button to spin the engine. It seems to have great compression. Unfortunately I didn't get it started. I gave up rather quickly 'cause I'm pretty sore right now from the sunburn I got boating on the lake this morning.

Tomorrow I will check to make sure I have spark. Not certain if the fuel pump works. I'll check that too. If the timing mark seems off, I'll static time it. Of course I'll check compression as well.

[TJ's Chevy]

I woulda run it.....but not revving and only for a few seconds. lol But yes....I live life on the edge. Smart move to pop another one on.....can't wait to see if she fires!

[Lugnutz65]

Watch the video. I replaced the harmonic balancer, and installed a distributor with points elimination (Accell or Pertronix - I can't remember). Thankfully I had these parts in storage. My good friend and hot rodder helped. We finished by flashlight in the shop. I love my new shop but no power in it just yet. Here's a short video. Timing has not been set yet. Stay tuned, pun intended.
VIDEO LINK

[88Ironduke]

Looks good, maybe a freshen up on the carb and tweak in the timing you'll be in good shape. It's starting right up do i don't think timing is too far off. Keep us posted.

Paul

[Lugnutz65]

Originally Posted by 88Ironduke

Keep us posted.

Paul

UPDATE:
Same carb. Timing set at 6 degrees advance. Since it has a Pertronix ignition in the dizzy, I might advance it a little more later and see.

The brakes need going through. That's next.

If you wanna keep up with this project, you can follow any progress HERE on my BLOG.

LINK to NEW VIDEO of engine running 6/1/17.

Lugnutz65