valve tap question

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Patrick

Patrick

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Just did a freshen-up on my 318 and noticed that valve tap was a little louder than i thought was normal. Yes, the cam was replaced and i hope i didn't wipe it! The valves that are on the cam base circle are loose; haven't measured but that would explain the clicking... So, the question i have is: are all small block pushrod lengths and valve rocker assemblies the same? I had some 360 parts laying around that i could have used by mistake... Thanks for the information!

ooops: just did some quick research... seems that there are two lengths 7.5" or 7.389". The shorter one is for adjustable rockers... I'm *hoping* i have the shorter ones installed!
 
Is it a hydraulic cam? If so you might not have enough preload on the lifters and you might need longer push rods.
 
340s,
Yes, it's a hydraulic cam... will take out the pushrods i have and measure them tomorrow - thanks
 
What head gaskets were used? Was there any machining done on the heads?
 
stock head gaskets, no machining to heads. Just lapped the valves and installed new springs/keepers...
 
HAHA - don't like where you're going with this! :)

matched springs came with cam (essentially a 340 grind, nothing radical) so i would answer by saying i don't think they're heavier than stock
 
new lifters with the cam, yes? Which cam (as in who made it? ) and who's lifters?
 
Believe it was a Melling camshaft...don't remember the lifter brand though...
 
moper,
I didn't touch the bottom end; the motor was a runner and had good oil pressure when i bought it. I will put an oil pressure guage on it after i check the pushrods to verify though... well, if the pushrods are the correct length, looks like i'll be pulling out the cam!

Just to be sure, do all LA small blocks (318-360) use the same rockers & shafts?
 
Patrick said:
moper,
I didn't touch the bottom end; the motor was a runner and had good oil pressure when i bought it. I will put an oil pressure guage on it after i check the pushrods to verify though... well, if the pushrods are the correct length, looks like i'll be pulling out the cam!

Just to be sure, do all LA small blocks (318-360) use the same rockers & shafts?
Click to expand...

NO. I know enough to know that there are two kinds or Rockers. Adjustable 273Commando and 340T/A and non adjustable All Other LA's and Yes they have different Pushrods...

Good luck with the Tick pal. Mine was a Knock so... I am busy now.
 
Good oil pressure by ear, by ligth, or by gage? I'm thinking the old parts were gummed up enough that the lower oil pressure didnt mean much. With the new ones, I'm going to say I think it's a little low. It may not mean a damn thing except noise too. It may be a preload issue. It's worth loking into. All hydraulic LAs use the same shafts, rockers, and pushrods. But you may have wear on re-used parts that is contributing too. I will always install a new HV pump on an original shortblock if I plan to abuse it. It's a power robber, but it tends to push so much oil around it keeps things from popping up...lol. See what the oil pressure really is.
 
moper,
Will get back to you about the oil pressure and for grins i'm going to take out one of the pushrods that are loose at the rocker to verify wear and length.
Will keep you posted - thanks
 
update...

Cut the oil filter and didn't see anything metallic - am i supposed to look at the outside of the filter or the inside? I looked at the outside...

Took out the pushrods and noticed that one of them was bent - all of the other pushrods on that side of the motor were fine and they're all the same length ~7-7/16" (assuming that this length is measured tip to tip, not shaft length). Looks like i'm supposed to have 7.5" pushrods in there - maybe these were just worn out bad???

I pulled the valve cover off the other side and everything appeared to be fine - the closed valves have rockers that aren't loose so that's reassuring.

Noticed that the pushrods aren't hollow - is that normal?

So back to my original problem: sounds like the cam is fine since the filter seems clean and the pushrods aren't loose on the other side. Wondering if the rockers on the problem side were worn??? But why would things be OK on the driver side???? Can't do anything until i get a replacement pushrod. Also installed a oil pressure guage so when i fire it back up i can check that as well...
 
The lifeter galleys are filled off big passages, but you can have too lose clearance between the lifter and bore. If that's it, the stock pump may not be enough to fully pump them up. I would check preload too. If the parts are worn (meaning pushrods, rockers, shafts, or valve tips) then the preload will be reduced. You may be able to get .050" longer pushrods that will get the preload setting tighter and get rid of teh noise. but you MUST find out what you have for preload now before you think about longer pushrods.
 
moper,
Again, thanks for your advise. I'm going to pick up stock replacement pushrods today to replace the bent one and to measure how worn the old are. Will measure the oil pressure when i get it running tonight and update you.
 
Ok - good news... the new pushrods made a big difference... i still have one or two rockers that are clicking more than the others - believe that the wear on those may be more severe - so i'll look at replacing them.
Oil pressure is fantastic - 60 lbs cold and settles to ~45 warm.
Thanks everyone, especially Moper, for advice and suggestions
 
May need to buy one or two .050" longer pushrods to silence the remaining clicking rockers. Does anyone other Comp sell these? Seems a little pricey at ~$7 each.
thanks,
Patrick
 
I've always just used Comp's Hi Tech pushrods. They are thin, and very strong. I have yet to need custom length ones.
 
hey i know you might have solved your problem but heres something to chew on, i thought i had a lifter tap on my 340, that was quickly fixed by disconecting the pcv valve,yeah the pcv valve i got rattles just like a noisey valve train , like i said not likely to portain to your motor but just a little info
 
Patrick said:
May need to buy one or two .050" longer pushrods to silence the remaining clicking rockers. Does anyone other Comp sell these? Seems a little pricey at ~$7 each.
thanks,
Patrick
Click to expand...

Just a thought but could the slack be taken up with a valve lash cap. if so local machine shop might take a couple bucks.
 
moparpat, thanks but PCV valve disconnected at the moment and i can definitely hear the tap comin from the other bank - good thought though

daredevil, never heard of a valve lash cap - is it installed right over the valve tip while it's still sprung?

Thanks for the suggestions - short of the cap idea, i'll prob end up getting a longer pushrod (+0.050")
 
Most stock type retainers are not clearanced for a lash cap... some aftermarket are, but not all. They need a recess right above the valve lock.
 
moper said:
Most stock type retainers are not clearanced for a lash cap... some aftermarket are, but not all. They need a recess right above the valve lock.
Click to expand...

I've always wondered what held them on.... I've never seen one.... don't want to either!
 
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