mazdized

So I have about 1,500 miles on motor after cam install. Initially with the cam in and when I was installing the rocker arms back in I noticed there was not any free play at all at the rockers, I figured the lifters will bleed out a little after driving and rockers will be loose. The motor at first did not have any ticking or valve train noise except the typical sewing mechine sound at idle. After about 300 mi. I took a 800mi. round trip with it and on the way back I started to notice more and more valve noise. It is not damaging sounding at all but definitely louder then when the motor first started running. I pulled the valve cover off and now I have valve clearance, not free play but just enough so the rockers can wiggle back and forth. I pulled the oil filter to check and no sign of metal and the magnet on the oil drain plug is as clean as it can be. Is what I am experienceing normal? the motor runs great other then valve train noise around 1,900 rpm.

ArcticZ28

iTrader: (14)

You gotta retorque those rockers. They should not have any lateral freeplay. And if you want to eliminate a lot of valvetrain noise, make sure they have the proper pre-load on them when you retorque. Loosen all the bolts then tighten them down just enough to where you can't wiggle the rockers back and forth with your fingers. Then it should only take ~1.5 turns past that to get to the 22 ft/lb of torque needed on them.

02sierraz71_5.3

iTrader: (2)

how did you account for the smaller base circle of the cam?
do you still have the stock length pushrods?

PREDATOR-Z

I reduced my noise with 7.425 p-rods. Not gone completely but really reduced over 7.40's

SideStep

Where did you get them at???

VortechC5

iTrader: (6)

That is what we did with mine. A slightly longer pushrod quieted down the valvetrain noise noticably. I still have some but that is to be expected because the XER lobes that I have are quite agressive.

mazdized

I see. I did retorque them but it seems like the lifter will bleed and I can wiggle them again in about 30sec. I am still using stock P rods, but I don't understand why it took over 1,000 mi. for them to start making noise.

RPO_Z06

iTrader: (11)

Adjustable rockers is the only real way to get rid of the noise that I know of.

greatwhite99

stock push rods? That may be just enough cam to bend those by itself. I am running the same cam with TSP hardened pushrods and it is fine. Check those stock pushrods for bending....

Grimes

iTrader: (3)

The lifters take up the slack. But I am interested what the actual reduction in base circle is exactly.

Comp cams sells the longer pushrods - sponsor Thunder Racing has some in the 7.425 length and others.

PREDATOR-Z

Base circle size is relative to lifts so the way to do it is get your cam> measure base circle> calculate variance > order p-rods to the closest number obtained on the low side.
This is relatively easy on unmilled stock heads, stock gasket setups, but get more complicated as you factor in thinner gaskets, milled heads, longer/shorter valves, different lifters etc...
Most poeple do not want to mess with calculations but if you establish an excell sheet with formulas it becomes a snap.

Mat

Very interesting indeed! Anyone have a copy of a spreadsheet like the one mentioned? I'm going to be doing a 224/228 .581/.588 on a 113 in my car soon (Cartek 2X) and would like to know the exact length of the pushrod that I need to use before I go just ordering up a set of hardened 7.4's.

mazdized

Well at this point it is not getting any louder, may be 7.425 rods are what I need... but wouldn't the hydraulic lifters fill up to make up the extra clearance from the smaller base circle?

PREDATOR-Z

Theoreticaly yes,
But factor in lifter bleeding, type and weight of oil used, etc...

That is why the sewing machine effect is more pronounced at low rpm than at higher ones.

Basically the mission is to get tighter preload.

mazdized

hum,,, I still don't get why it took that many miles for the noise to show up. Wouldn't it start to make noise with in minutes after the initial start with cam?

SS Enforcer

Your oil went off a bit which is why it showed.

cheers

skeeters65

iTrader: (1)

Did you change your oil??

I am haveing the same problem.. It showed up after about 800 miles when I switched to Mobile 1 synthetic.

I also think it is a bad lifter but not sure how to check the lifters..

PREDATOR-Z

This is a 4 year old thread. It is dead. and buried.

slothy

iTrader: (2)

at least people are using the search function ahahah

LS1-450

iTrader: (33)

Understood, but this morning your comments regarding the base circle differences has confirmed how I set up the new cam, thanks for the post & to a working search function.