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1971 C10 350 with a tick


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justmatts
New User

Nov 11, 2012, 5:50 AM

Post #1 of 10 (1813 views)
1971 C10 350 with a tick Sign In

Engine has a constant tick. Used a temp gauge on header for each cylinder and found that one, ( front passenger side ) was way cooler than the others. Thought maybe bent pushrod so I tore it apart and that was not the case. Does this sound like a cam issue? Motor supposedly was rebuilt 10,000 miles ago. I just bought the truck so that's all I can go on. Thanks.


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Nov 11, 2012, 7:04 AM

Post #2 of 10 (1793 views)
Re: 1971 C10 350 with a tick Sign In

Unless that trick is isolating to one specific cylinder, it isn't telling you much of anything. You really need to have someone listen to that that has the ability to identify what the noise is.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



justmatts
New User

Nov 11, 2012, 7:12 AM

Post #3 of 10 (1787 views)
Re: 1971 C10 350 with a tick Sign In

Ok thanks.


Tom Greenleaf
Ultimate Carjunky / Moderator
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Nov 11, 2012, 9:48 AM

Post #4 of 10 (1767 views)
Re: 1971 C10 350 with a tick Sign In

"Just rebuilt" whatever that really means. 1971 you should be able to isolate which cylinder quite easily if not running very smooth tick or not so if tick is the reason it should be easy to isolate. If you think it's front right and not running right that spark plug will look different than another one now,

T


justmatts
New User

Nov 12, 2012, 2:54 AM

Post #5 of 10 (1730 views)
Re: 1971 C10 350 with a tick Sign In

The sparkplug looked as though it was corroded or had some gritty looking build-up on it.


Tom Greenleaf
Ultimate Carjunky / Moderator
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Nov 12, 2012, 4:29 AM

Post #6 of 10 (1723 views)
Re: 1971 C10 350 with a tick Sign In

Hmmm? Toss that plug or swap it with another but wouldn't use that one again. Use same type and brand for the one. That just testing till perhaps all go.

These are taper seated so BE WARNED not to over-tighten them. Cheaper plugs + some others can get so stuck it's a nightmare breaking off leaving just the threads and center electrode in the head -- no hex to grab. Because of that long standing warning it could have been left too loose! Sounds just like an internal engine ticking, may or may not fire properly and would likely ruin the plug and hopefully just the plug.

For the vintage I'd look for OE spec plugs if set up is OE but go with names like Delco or Autolite -- concentrating that they are one piece plug metal not crimped together hex and threads separately. Never did find the wild multi electrode or other games make any difference. For a while liked NGK as they were (may still on some) brassy plated and didn't get broken off.

(NOTE: FOR CURRENT NEWER ENGINES WITH COMPUTER CONTROLLED EVERYTHING) Always go for exact OE replacements.

Except for loose plug the tick wouldn't be solved yet. May be improperly set hydraulic lifter(s) Memory tested but think these are one rocker, one stud for each valve 9/16th and setting has to do with bottoming out and back off six turns if all was correct but don't quote me on that yet. Lifter would run wrong for a short while till it pressured up and then could stay in range. As these cams and parts got old and worn you could just snug up at rocker just a little at a time with a feeler gauge while running then remove it to zero clearance and they would behave for quite a while. Dunno what got replace or checked with the rebuild. New cam, all new valves and seats, springs. Was it the works or just what would make it operational again? You may not know. A valve too tight would burn in short time.

IMO - good basic engine that isn't too hard to diagnose where the noise is coming from. Should be able to run this with valve cover off and watch the show with some mess but long enough to plain watch. AYOR for the mess that could make. I would if only to watch that oil came out all push rods. In this case if not the rebuild failed,

T


justmatts
New User

Nov 12, 2012, 6:12 AM

Post #7 of 10 (1712 views)
Re: 1971 C10 350 with a tick Sign In

Replaced spark plug with same ac delco plug. No difference. Yeah, not sure how in depth the rebuild went. Was rolling engine over with valve cover off the one rocker arm didn't appear to be traveling as far as the others. That's why I was wondering about maybe a cam lobe being the issue but didn't know about the tick. Friend thought maybe a bent pushrod but we took it out from that cylinder and they were straight. Looks like its time to take it in to the shop. I appreciate everyone's help on here. Thanks


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Nov 12, 2012, 6:39 AM

Post #8 of 10 (1709 views)
Re: 1971 C10 350 with a tick Sign In

Worn cam lobes were fairly common in those.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Nov 12, 2012, 9:45 AM

Post #9 of 10 (1698 views)
Re: 1971 C10 350 with a tick Sign In

I do recall cam lobe issues and you really can see a real bad one by sight. Some you could just snug down, tick stopped and ran fine if no damage for a good while and not go nuts on vehicles that were on their way out as a whole anyway,

T


nickwarner
Veteran / Moderator
nickwarner profile image

Nov 12, 2012, 7:30 PM

Post #10 of 10 (1668 views)
Re: 1971 C10 350 with a tick Sign In

It would be worth a mention that this motor may have been rebuilt properly but has failed because of the oil being used in it. To meet emissions requirements easier in vehicles which are now using roller lifters or OHC setups, the oil manufacturers dramatically reduced the amount of ZDDP additive in todays oil. Don't ask me to remember what that acronym stands for, but its a zinc phosphate compound which helps in the shear force conditions that a flat-tappet cam operates in. Remove it and older valvetrains go to hell fast. There are various companies that make a ZDDP additive that you can add with each oil change so that older engines are protected. Comp and Crame Cams both recommend it during the break-in for any cam and at every service for flat-tappet cams. Usually wipes them the fastest on higher-lift ones but even a stock grind of this vintage wouldn't hold out too long. For this truck I'd make sure you put it in at every service, and have this shop you are going to be sure that a bottle of it is in there when they first fire it up on your new cam.






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