Re: 351 v6 noisy?
 

Update on the noise.. It is exactly the same. Just sounds like it is rattling, with a fairly distinct "tonge-clicking" sound. Goes away with RPM's about 900 or so. Maybe a normal sound? Or masked by higher RPM fan, muffler, etc., ? But it is definitely louder than a SBC V8. It's the one and only V6 BB I have ever heard run, so no way to tell if it is normal. Can anyone point me to a video of one running that I can hear? Thanks.

Re: 351 v6 noisy?
 

For anyone else that needs to know the SPECIAL way to adjust valves on the 305 engines:




It also shows the running engine.

Re: 351 v6 noisy?
 

These engines have an noisy valve train that has a "clackety-clack" noise that is NORMAL and has to be heard for the engine to run properly. the only V6 engines that DO NOT have this sound is ones like Pete Chronis' LD-478 which has a SPECIAL GROUND CAMSHAFT FOR USE WITH HYDRAULIC LIFTERS. If your camshaft hasn't been reground with the profile like Pete's, it must make this noise or you will burn up the valves. I hope this helps with the understanding of the operation of the GMC V6. Also, the video that Fetch provided is a spot on tutorial for running the overhead on the V6 engines.:wub::wub::wub::wub::wub::wub::wub::wub::w ub::wub:

Re: 351 v6 noisy?
 

Thanks for the reply. Yes, for sure, valve clatter is to be expected, I have them adjusted properly. And I have seen this video before. His delivery makes me laugh! Love it! I feel like my noise is lower in the engine, but could be echoing.. It runs nice and has good oil pressure, I have to hit some car shows and hear one run in person to put my mind at ease...

Re: 351 v6 noisy?
 

If you're willing to make a video (if you can capture the sound) and share it with us, we could possibily offer some input.

Re: 351 v6 noisy?
 

I have 2 videos. One video is at 1000rpm, the other is at 650 rpm where I have the idle set. Note the vacuum gauge, if that provides any info. Flickering a little at idle. However, I can't see where to upload a video. Pictures, yes... but not videos. Please let me know, thanks

Re: 351 v6 noisy?
 

I usually just upload them to youtube or some other tube place and post a link. If you do youtube this place can show it but it codes it weird. You code it like this, without the 0s on the ends:

Re: 351 v6 noisy?
 

I think I found my noise. In addition to the normal ticking valves, I see I have about
035" play on all 4 most rearward and forward rockers along the rails. Is this normal? The rockers in the middle are kept in place with the springs

Re: 351 v6 noisy?
 

Lewis, actually the custom ground cam in my 478 remained the solid lifter type so my 478 has plenty of the clackety clack noise going on.

Re: 351 v6 noisy?
 

Update: I found in my service manual that the clearance along the rail for those 4 rockers is .030", which is about what I have. When I slide them back an forth, the "clang" it makes is what I am hearing (pretty sure) At idle, is it common for those to move back and forth?
I also read where they want the valve clearance adjusted with the engine running. That must be interesting to do. Thanks for any additional thoughts.