Valvetrain Noise After DOD Disable/Cam Swap, Bad Lifter From Factory?

[JPutnam]

I have a 08 Suburban with a 5.3 that was having problems with the DOD. It has 160K miles on it. On a trip to the beach the pressure kept dropping to 20 and the engine would run rough and start tapping. After a while I noticed the pressure only dropped when it went into V-4 mode. Later on that day the engine started ticking intermittently while idling. I thought it was something really bad like a spun rod bearing, but it was consistent with the spark plug firing, which meant it was something cam related.

I ended up ordering the DOD delete kit from Texas Speed and a new cam, the stage 2 low lift cam. Everything looked fine when I did the swap, no wear on the cam or lifters, and it went together without a problem (besides the rust welded collectors, guess the headers will have to wait for new cats.) I programed it with my HP Tuners with a tune from mailordertuner.com and I ran perfectly after a quick drive. But as soon as I took it for a trip to the drive thought it developed a tick in the valve train. So loud it overpowered my cherry bombs when standing from the back of the vehicle. The only problem is it is intermittent and only happened away from the driveway.

I finally got it to do it with the valve cover off one time and narrowed it down to the number 5 intake valve using the hose trick. Nothing seems obviously wrong with the set, but I did notice once I pulled the rocker arm and pushed on the pushrod there was play in the lifter. I removed both rockers from cylinder 1 and they are solid.

Does this mean my lifter is bad? The kit came with replacement non-DOD lifters. Could it have been bad out of the box?

 

[mrrsm]

Some Suggestions:

(1) Pull the involved Valve Cover and after turning the Crankshaft Bolt with a Socket & Breaker Bar slowly Clockwise to ensure that both Valves are closed and that the Camshaft is positioned on its Base Circle.

(2) Then loosen the Roller-Rocker Arm Fasteners and after removing the Rockers... examine them for any possible failures of their side Roller Bearing casements. Failures of these portions of the GM OEM Stock 1.6:1 Rockers is rare... but it has been known to happen from time to time. If obviously damaged, avoid gyrating these Roller Rockers while still installed as it will be wise to avoid the slightest chance of having any loose roller bearings dropping down inside of the engine block.

(3) Lay the Push Rods on a Flat Surface and observe each for any indications of being bent as you roll them back and forth with the beam of a flashlight angles upon them to see any variations in their straightness. ANY bending is TOO MUCH bending.

(4) If your installation was nominal, with Engine Assembly Lube or Non-Synthetic Zinc improved Motor Oil applied upon the ODs of the Roller Lifters... sudden failure is highly unlikely so soon after the R&R of the New Camshaft & Lifter assemblies.

(5) In the original, related Repair Thread you penned... You mentioned having had a problem with one of the Rockers and replacing it with a "Used" one of similar wear. If this particular cylinder with the errant "tick" is the same one involved with that repair, look to that replacement part as the possible cause of the problem and replace it again.

(6) Full sets of "Gently Used" GM LS Roller Rocker Assemblies can be found on eBay for $40-$100 if you want to have an assortment to choose from, clean up and Swap in. Avoid using Used Push Rods if possible. Make certain that any you purchase can be used on both the Intake and Exhaust, as some LS Roller-Rockers are 'side specific' and therefore NOT Universal.

(7) In some cases... if the Base Circle of the Texas Speed & Performance Roller Camshaft is different from that of the Stock LS Camshaft... an adjustment in the length of the Stock 7.4" Push Rods may be required. Investigate your TS&P 'Cam Card' for the specific measurements, just to be sure.

 

[Mooseman]

What's your oil pressure like? Did you replace the oil pump?

 

[JPutnam]

Oil pump is old. I did notice the oil pressure is a little low. 30 in idle and about 60 WOT. Cruising is around 45-50. A friend that used to work on engines with me had me try and use 10W30, but the pressure is the same. Not much improvement.

As far as the used parts, everything is the same except for the lifters, guides, and cam. Of course I used new gaskets and head bolts. The sticking lifter from before was a DOD lifter and it was on cylinder 6, this is cylinder 5. I did make sure the rocker and push rods went back into the same location as they came out. Old habit from working on Apache Helicopters.

One thing I think could be wrong is now I am noticing there was a gasket on the cam retaining plate. Mine looked a little flat and probably needed to be replaced. I think maybe I am loosing pressure from there maybe. I did notice it only really does it when the pressure drops down to 30 for about a minute and goes away while driving.

Also, in case I have to tare apart the engine, can I reuse the head bolts and gaskets since they were just installed? Is there a limit to this or do I just have to bite the bullet to be safe? I am guessing the head bolt replacement requirement is due to a torque-to-yield situation?

This is my first LS build. I have built two Gen1 engines and didn't have a problem with them. Well, besides oil pressure, but that was due to wrong rod bearing sizing which was fixed.

 

[Mooseman]

Your oil pressure is good. I had low oil pressure in my DOD delete because I put in the wrong pump but it didn't cause any noise.

Maybe give TSP a call and see what they say. They may have some ideas. It's possible a rocker has gone bad or one of the lifters is defective. Were all the lifters replaced? Some kits just have the lifters to replace the DOD ones.

Unfortunately, the head bolts are torque to yield and are only one time use as they get stretched. Reusing the head gaskets is risky too.

 

[JPutnam]

Yeah, kinda figured that on the gaskets and bolts. Was kind of annoyed when I took the valley cover off and realized there was no access to the lifters, used to the old school gen1 and L31 blocks. A lifter swap in those is cake. Oh well, I guess I will be doing a swap.

The lifters were 16 new regular lifters. I am thinking maybe some dirt got clogged up in the lifter valve and is keeping it from closing. I had a few people tell me that I can probably fix it by adding some Marvel to the oil and driving it some hoping it would free it loose. It only acts up when idling for long times so maybe a good cruse would help it. If not, then I will have to pick up a gasket, bolts, a lifter, pushrod to be safe, an a bottle of Fireball. At least I have been there once, minus the slight impairment after the job is complete.