This is gonna be lengthy, so bear with me...

I found a '90, 302, bored .40 over, crank and rods ground .20. Had the entire block cleaned, new everything, except for pistons. Everything was in really good shape. I rebuilt it with a new cam, 255 Comp cam, Comp Cam High Energy lifters, new pushrods, and a set of Scorpion RR's 1.6 ratio.

Got the engine completely broke in, and after about 200 miles, started noticing a "whooshing" sound after start-up on some days, most being if the motor had sat for 8+ hours. Also around that time started noticing light ticking noise coming from the driver side head. Not quite a lifter tapping, but light ticking. Well after 500 miles, it wasn't light, just more noticeable. After a thousand, I could hear the ticking in rthym from the driver side valve cover+head. Well, I pulled all the stuff outta the way and removed the valve cover. Checked for looseness, etc. Nothing seemed to be wrong, other than some slack in the RR's. Checked torque, all Good! The *1* strange thing I did encounter when I was checking the valve tips and RR's, was that #6 Intake looked *ROUGH*. Now, lemme clarify this. Rough being that it appears that someone had tried to use a cold chisel on the tip, somewhat in a stamping motion..yet I never saw any metal in valve cover, the head, the filter, or the oil. I even strained the oil thru a filter and never have noticed any. The RR roller appeared to be ok as being that there really wasn't any scoring to it.

Well, this "whooshing" and "ticking" noise has increased. The motor seemed to be surging more @ idle and had some hesitation. I'm at nearly 3K, second oil change since break-in, and I pulled the driver side valve cover again, just this Thursday. Well, when I pulled the valve cover the first time, I checked my preload and using my feeler gauge I found it to be unique I needed .50 longer pushrod, instead on my original 6.881 pushrod. I went ahead and changed the pushrods on the driver side with the longer set 6.934. I also noticed that I had some metal flake on the underside of the valve cover, where #6 intake valve had that deformed look. Well, I took special care and carefully smoothed it down and cleaned it. I finally put the VC and all other EFI parts back on and started the truck. The ticking noise was virtually eliminated....until about 60 miles of driving...Now mind you, it's very light, but it wasn't there when I started the rtuck and let it run for 30-40 mins @ different RPMS.

I must say, I'm disgusted. I cleaned all lifters, soaked them, cleaned all pushrods, Used Valvolin Racing oil, 10-30 for break-in, used Lucas break in oil additive, used another high dollar ZZDDP and Phosporous addtive, I'm sure I broke the motor in right, because if I didn't, would I have more problems with the cam? If the lifters weren't pumping up wouldn't I have the sound consistently and have more driveability problems??....What else is left to do......All my money, time, effort, seems to be lost and any attempt to correct this problem seems futile. I can't afford another teardown and it's my daily driver...

Is it possible to remove the EFI stuff, and just hook up ignition and necessary vac lines, after removing the valve cover, to watch the RR's and valves running? I haven't tried on these motors and I'm up for any interesting input.

Sorry for the novel, but I'm out of ideas on this!!!!

 

I had a cam lobe go flat on a Big Block Chevy engine years ago.It happened really fast.It started ticking lightly after start up and got progressively worse very quickly while driving.It got so bad that I pulled over and had the car towed home.One lobe failed completely.Some other lobes (7 or 8) were also going flat.The engine had about 3100 miles on it.2 oil changes.Rebuld time.Do you have pedestal rockers or stud mount?New valve springs?Maybe too much spring pressure.It sounds like your valvetrain has been getting progressively worse over a length of time from the begining.The fact that you only changed one row of pushrods is interesting.Is the pass side still within specs?Did both heads come from the same engine?Same valve springs on both heads?Flat cam lobes are generally caused by improper lubrication,lifters not turning in their bores or excessive spring pressure.Once a cam goes flat,the next concern is the metal shavings scoring up engine bearings and possibly pluging up oil passages.Sorry to tell you but it sounds like you're in for an engine teardown.I would pull off both VC's and measure lift on ALL the valves and go from there.Drain the oil and inspect it for shavings.I'm sure others with more knowledge will chime in.

 

I thought about a cam lobe being wiped out, but there never was any metal shaving's in the oil or the filter. The heads were checked at the machine shop and everything except new valves and valve springs were installed. I have pedestal mount rockers. I had pulled the pass. side when I first checked the driver side. everything was okay there. Both heads came off the same motor.

Edit: Wouldn't the engine run like complete crap if "A" cam lobe or lobe(s) were wiped? That would make more sense to me...I don't know..

 

Until you pull the cam/heads, you are not going to know for sure but,

Comp has by appearance - seems to be a company that has experience more cam lobe failures than most and places the blame on the low ZDDP in the oils. Is it a factor yes, but I highly suspect that they are also using Chinese cam billets & they do not include Parkerizing their cams (Parkerizing is the final step and a crucial step to help break the cam in- a heated acid bath that microscopically etches the metal surface and adds a very thin layer of graphite coating which allows the cam lube to hang onto and penetrate into the cam surface during cam break in) unless you specifically request and pay additional money for it.


if the cam/lifters have been scored, I would highly recommend Iskenderian & Crower & Chet Herbert & Lunati...all are family owned, been grinding cams for decades, and both will even re-grind your oem cam if possible- saving you even more $.

As you are probably aware, many of the cam mfgs in the past few years either sold, closed their operations to re-open elsewhere (typically with new staff) or .......

In addition to Isky & Crower, I use to very highly recommend....
Sig Erson & Crane...

Both became part of corporate entities, eventually leading to periodic quality issues and closing their doors- I think Crane re-opened, but with a different staff. Typically the staff is very, very young and well- requires a learning curve.

If you do a search on the net, Harvey Crane has posted a little summary of the history of the people who made the cams at Crane, his opinion of what happened and the eventual outcome of several of the staff.

 

You can measure each lobe by removing the rockers and leaving the pushrods in place.Turn the engine over by hand using a dial indicator or vernier caliper to measure the pushrod travel.That will give you actual lobe lift.And ,yes the engine will make loud noises if one lobe goes flat,especially an exhaust lobe.It will backfire through the carb if the intake charge cannot exit through the exhaust valve.Not all cam lobes wear quickly.If the lifter still turns in its bore the lobe could wear slower.If you had to replace OE length pushrods with longer,then something had to get shorter to allow them to fit.The lobes had to wear to allow the use of longer pushrods.Once a lobe starts to wear,it won't stop until you cease the pressure on that lobe.The lifter base can also show wear and should be inspected.I have a comp cams 4x4 grind in my 351w and 460.I add lucas oil break in lube with ea. oil change.Your situation makes me nervous,even though I have ~3000 miles on my windsor and no issues.The 460 has less than 500 miles.I've remeasured lobe lift on my 351w twice.So far there are no changes. The Crane roller rockers tick louder than others I've used.They're the Energizer series.Low budget.I am attentive to every ticking noise.It is very possible that there are some defective/inferior COMP CAMS cam cores circulating in the marketplace,which would make proper break-in procedure and lubrication irrelevant. That being said yours is not an uncommon issue with comp cams.I've used Howards Cams in the past without any problems and will use one in my LS2 GTO when I do a cam swap this summer.

 

Well, i guess I'll have to get around to it when time allows....Guess if the cam is going or is shot, then Comp won't help reimburse me for all my time, energy, or effort..

I'll pull the upper plenum next week hopefully and remove the lower intake to check the lifters. More $$$$$ for gaskets, etc. for the parts store.

If it is indeed a cam going bad, I'll never purchase another Comp product again. (BIG PERIOD)!!

Also, I never got an answer about the having the valve cover removed and starting the truck to listen to the ticking sound. anybody done this on these truck motors?

EDIT: If the ticking isn't there @ startup or after sitting and cooling off, what could that represent, if the truck only does when it gets to operating temperature?

 

If you have roller rockers mounted on studs.... I would do this first:

Start the engine... Let it run for a few minutes... Pull the valve cover on the one side.... One at a time loosen the posi locks on the top of each rocker and back off the nut until the rocker is loose and begins to tick.... Then tighten it down until it stops ticking for zero lash.... Or a quarter turn more... I do zero one quarter is also fine.... Do that on each head like this and see what happens... This will eliminate a loose rocker and finds a collapsed lifter really fast....

Bad lifters are always a possibility.... I used ford rollers on a motor with a retrofit roller cam... And i had a ticking just like you describe.... Well the tick was the lifters.... Pulled them and went to crower roller lifters and it was gone....Problem fixed....

It was said comp seems to be blaming a lot of failures on oil.... But i would say a lot of people pick comp versus isky or crower or crane....

Myself personally no longer use flat tappet cams... Thr oil issue is a real issue... I put together a junk mill with lunati bare bones cam and lifter and it lated great until i let a friend use it to replace a blown motor and turkey changed the oil without adding an additive... And when we pulled it from his truck and i finally pulled it down i never saw such damage to the cam and lifters... So its a real problem.

That being said try the easy stuff first

 

Fyi roller rockers are noise and can create a whooshing sound.... Especially al ones... And the surging is most likely carb tuning or a vac leak...

 

While it is really not necessary to pull the heads to check the cam/valvetrain for damage, I would do as recommended regarding turning the engine by hand and checking to see which lifters are 'short"....once verified I would definitely pull lifters to check the cam, if any indication is seen, then pull the cam to visually inspect the lobes to see exactly what is going on & if i saw damage, i would definitely pulls the heads just to visually inspect & ensure the cylinders are clean as well (although you could use a scope), I would also pull the pan to check for shavings in the bottom emd and definitely run a pipe cleaner (tobacco type) through the oil passages & cooling kackets in the head to make sure they are clean as well....cheap insurance at this point, especially if you are going to replace the cam (due to damage).

IMHO, I would not start the engine until a complete inspection (as required0 is done, again, cheap insurance.