Last week I installed longer intake pushrods which were the ones recommended for my PPP cam. This was to make up for the way the cam was ground (shorter base circle?). My motor has always been a little "valve train noisy" and I figured this would finally fix that. Cam noticed it when I was at his place last month so this prompted me to get things fixed. Andy at PWR sent me the pushrods, .050" longer than stock, and we put them in. On startup the motor ran like shit initially...I assume because the lifters were pumped up and the intake valves were not seating. We shut it off, restarted and drove the car around the block. Now it seemed to run fine. The next day I noticed the car felt like it had a miss at idle. In gear at stop signs, it has a small surge equal with the engine RPM. It seemed to run fine otherwise, except for this. I didn't like it as something had changed, but so far had no ETC or anything. Two days and quite a few startups later, I finally had an event... Today while putting around I noticed my CEL lit up. P0300 Random U0103 Unknown P0108 Manifold Absolute Pressure P0301 Cyl 1 Misfire I am not digging this at all...is it possible a valve smacked the piston and bent a pushrod when I first installed these longer things and the lifters were pumped up? I just don't see this being an easy solution as the car seems to run well...not like a pushrod slipped out or something where it is a total cylinder not firing. Where should I start looking? Pull the driver's side valve cover and inspect the pushrod? Inspect all of them? Thanks and help!
Damnit...yea bud, that's a good place to start. Make sure your MAP sensor is seated and fully connected. Did you have a Miller tool for installing the push rods? Hope you triple checked the seats, very common to have one or more not fully in it's pocket on the rocker. Hope it's something easy and painless.
Hehe, ya, hangover and all this morning. Everything seated properly. No pushrods laying around. It feels exactly like when I used to burn a spark plug wire against a header on my SB Chevys...the idle just had a miss. Easing up to a stop sign I can feel a definite pulse, like a dead cylinder. Once I get going I feel nothing and the car feels normal. IF I had a dead cylinder would I feel it cruising around at 30 or 40 mph? Would HAL let me know with a code or two? I have never had a cylinder not fire...I guess I could pull the coil pack connector and go for a drive...see how it feels My motor is quieter at idle now, no doubt about it. Less valve train noise...but sitting in the car at 750 RPM I can feel a cyclical bump that rocks the car slightly.
Well, I got after finding out WTF was going on with my valve train after shoulder surgery, sooo, here is my titty Anyway, I fixed the problem outlined in my original post by going with intake pushrods that were 6.665" long. I have no idea where the cut-off is as to what is too long a push rod with my particular cam/head combo, but I can definitely say a stock pushrod is too short (noisy) and a 6.700" pushrod (.050" longer) is too long by a some amount bit and will cause a pulse, similar to a dead miss, at idle as you maneuver around town at stop signs and such. A stock length is probably fine but will be a little noisy. My cam specs are listed earlier in this thread, and getting a hold of the manufacturer is not happening. It is a cam sold by PPP as their 6.1XL Pro Series, the big dog for a 6.1L, or something like that...just FYI for the next guy. A year ago I changed the exhaust pushrods for a length .015" longer and have not had any issues. Here are three pushrods: #1 is a stock length replacement pushrod (6.650") #2 is the set I just had made and installed that fixed my issues (6.665") #3 is the set I installed before this thread that jacked me up (6.700") All I can say really, is that with non-milled PPP stg2 heads and the PPP cam listed above, .050" longer intake pushrods will hang open an intake valve or two. Stock intake pushrods will make your motor noisy. (Phucckkk my shoulder hurts )
Ha...hope your shoulder heals as well as your car. FWIW...I run the 6.70 Manley's with a 224/236 592/581 114 cam. Quiet valve train and no problems.
Yup, I agree Kyle. I can't see how I bottomed out a lifter with a .050" longer pushrod...BUT, it is what it is I guess. I was hanging an intake valve open a little bit and that was probably confirmed by the MAP and cyl#1 misfire code I got later. There just isn't really any way to screw up a pushrod install...it either is in or it isn't. After changing things out, car runs perfect. Don't know... I think I'll have a Jager and a Lortab
