Avanti HELP needed!

[mfg]

Okay Avanti comrades...mfg needs some help here!........An engine noise has developed in my '83 Avanti, (stock 305 V8), over the last few weeks that has me 'stumped'!

To cut to the chase....the noise sounds EXACTLY like the clicking sound a hydraulic valve lifter makes if it's defective or simply needs adjustment. (yes, I know 305's are notorious for soft camshafts!)

HOWEVER, after isolating that sound with a length of hose held to my ear, moving the hose around a running engine, I find the noise is coming from inside the stock GM HEI DISTRIBUTOR!

As I had a good used cap and rotor handy, I swapped in those parts to see if the noise would change in pitch or hopefully be eliminated...but changing those parts had no effect at all.

This noise sounds like a loose clicking lifter...but it's definitely originating from inside the distributor.

I'm wondering if anyone else running a Chevy V8 has ever experienced such a thing??.....Thanks!......Ed

 

PS....The engine runs very nice...no roughness whatsoever.....Smooth idle.

 

[studegary]

Is it safe to assume that you checked the interior of the cap that you removed to see if there had been any interference/rubbing?  Is there shaft play/bearing wear?    

[Avanti83]

Considering the miles you put on your Avanti and the fact you have pin pointed the sound to the distributor, it might be time to just replace it. These are usually under $75.

We can speculate on other causes - exhaust leak, bad lifter, worn oil pump, internal sparking, worn distributor bearings, broken piston skirt, etc. but if it's the original it's probably worth replacing as if the problem is more serious you'll want a new one anyway.

I hate just throwing parts at a problem so you could just pull it and see if something shows up but then you're already 1/2 way to replacing it anyway.

Good luck, I hate to see it off the road.

Edited September 22, 2020 by Avanti83

[mfg]

Gary, Bob..thanks for your input...yes, something has to be up with the HEI distributor, as the noise (checked again) is definitely originating from it. (quite loud, I can hear it inside the car!)

Actually, I installed a new distributor when I purchased the Goodwrench 305 replacement engine.....but that was ten years and MANY miles ago.

I will purchase a new distributor....either locally (Advance Auto has them in stock) or perhaps through Summit.....I have a used one from another engine I could install to see what happens, but as Bob says why tear into things twice!....thanks again....Ed

 

[Gunslinger]

There are some good aftermarket distributors available but whatever you do...avoid one made offshore.  They simply do not last.  

[arkus]

what might our choices be for an american made for my '80 ll. i could probably figure it out, BUT, i just spent 7 hours replacing the 4 p.s. hoses and i'm VERY tired of anything avanti right now! thanks for the help.

[arkus]

got a 2nd wind and did some research. according to the tech at summit, they carry 4 american made distributor manufacturers, fast, pertronix, davis and edlebrock. many choices!

[mfg]

UPDATE.......I installed a replacement distributor yesterday and the noise is gone.

The only difference i noticed about the one I removed compared to the replacement is the replacement has very little up and down movement of the distributor shaft. (In the body)

The distributor i removed has about 1/4" up and down play of the shaft in the distributor body.

[studegary]

9 minutes ago, mfg said:

UPDATE.......I installed a replacement distributor yesterday and the noise is gone.

The only difference i noticed about the one I removed compared to the replacement is the replacement has very little up and down movement of the distributor shaft. (In the body)

The distributor i removed has about 1/4" up and down play of the shaft in the distributor body.

Thanks for posting the conclusion.  You may be able to adjust the shaft or shim it to make the old distributor usable again.  Or there may be a worn bushing that needs to be replaced.  

[Avanti83]

Glad it worked out. My guess is that movement is not good for the teeth on the cam so the replacement was timely. Time to deep six the old one. Just curious, what does a replacement go for these days if you don't mind me asking.

[mfg]

19 hours ago, Avanti83 said:

 Just curious, what does a replacement go for these days if you don't mind me asking.

Once a caso always a caso I guess!!....A friend of mine with a '70's Vette GAVE me a small block Chevy distributor he knew was OK....I replaced the ignition module, which was only about one year old, (from the worn out distributor) and installed the 'good used' distributor...Problem solved!

Edited September 27, 2020 by mfg