I have a 461, hyd comp cam, roller rockers w/polylocks, rhoads lifters & the engine was rebuilt about 1500 miles ago. Ran fine until today. I got off the highway & the car had a terrible ticking. I stopped & it really sounds like a valvetrain noise. I tried adjusting the rockers but it makes slight backfires through the intake when rev'd up. Any ideas?

Thanks,

Ken

If nothing else changed...Bad spring, bent pushrod, collapsed lifter.

I forgot to mention the noise was more on the driver's side than the passenger's side.
Where should I start?
I thought maybe a bad spring, but they are dual springs & they all passed visual inspection. If a spring failed it would keep the valve open too long right? That might account for the slight backfire through the intake.
If a pushrod was bent it would not open the valve up enough, would that make it backfire through the intake?
If a lifter collapsed it would not open the valve enough or at the right time right?
I'm not sure where to start looking from here.

Thanks.

Check oil pressure, if that is ok compression check. Did you notice any pushrods were very loose when you tried to adjust?

I hate to say it and I hope I'm wrong but I have a feeling your cam might be losing a lobe. Check and reset your lifters. Rhodes lifters are hard to adjust and are very noisey even when working correctly.

Hopefully you didnt adjust the Rhoads till they became quite at idle?

I adjusted the Rhoads correctly, the car ran great for about 1000miles, just all of a sudden when I got off the highway it was acting really weird. I thought maybe the valvetrain had come out of adjustment, but I have polylocks so it's unlikely. I will try to readjust the valvetrain & I'll let you know what the problem is.

compression test might help you pinpoint a cylinder?

If you're going to re adjust the lifters anyway I would go ahead and pull the pushrods out and check them to make sure none are bent. You're there already and it doesn't cost anything but a couple of extra minutes. I recently had a roller rocker fail and it was really bad. Worst noise I ever heard. You might inspect the distributor real well too. Pull it out and check the gear. If nothing looks amiss next step is to pull the intake and do a visual of the lifters and what you can see of the cam. You might want to take a look at the oil to see if there's any metal particles.

Cut apart the oil filter and look between the pleats. I do this on all the race engines and some of my street engines, real easy (if a bit messy) way to check on the internal health.

The slight backfires through the intake sounds like a timing chain problem.

I had that backfire as well. My timing chain was stretched!

Also had an issue with my engine after 1000 mi.
The piston rod(s) were out of round and had to be turned.