440 HP2 #2 cylinder won’t fire, good compression

I am looking for some sage advice, a bit of a newby when it comes to engine building, but I have been working on my own cars for 10 years.

The car is a 69 Plymouth GTX, it has a 440 HP2 that was rebuilt (fully) about 8 years and 6000 miles ago. It has a six pack on it, the engine and heads were rebuilt at a good engine shop in Houston with all brand new parts. The heads were redone 906 cast-iron heads – new valves, springs, etc.  Went with a nice set of roller rockers and pushrods from COMP cams and a street purpleshaft cam and hydraulic lifters from Mopar performance (I have all the exact specs still at home).

My problem and source of frustration is that cylinder #2 stopped firing about 2 years ago and I haven’t had the time to figure it out until now.  I haven’t only started the car up every so often to try and diagnose it.  Still fires up like a champ, I want to drive it again this summer it’s too nice to sit in the garage.

What I have figured out so far:
#2 is wet/oil fouled (shiny black covering most everything) - and appears to have slightly more on one side
Replaced distributor cap/rotor, wires, plugs – no change
Checked for spark through #2 wire – swapped wires with one I knew was working also – no change
2 years ago I pulled the valve covers and checked the rods, they were fine. I tried to use a caliper to measure lift on both valves (how high the push rod moved up), they seemed in line with the other cylinders  both were  a little lower lift. I need to find the notes I took but my recollection is both were within 10% of the others – I thought it could be carbon buildup from not firing and so I tried seafoam
Ran seafoam treatment – no change
Compression is fine – 168 PSI (all the other cylinders range from 155-166, it is the highest)
Leakdown seems OK– between 9-10%, I could not pinpoint where air was coming from
I checked the vacuum off the carb during idle and revving – seemed normal to me, but I plan to check again based on a site I found.

Based on what I have diagnosed I feel it is one or more of the following:
1. Bad valve seal(s) – but it this enough to stop firing all together?  I have not noticed much oil loss or puffs of smoke but I don’t drive the car now. Higher compression on the cylinder could point to this I have read.
2. Bad lifter(s)
3. Wiped cam lobe(s)
4. Something weird ??

Please let me know if you have other suggestions of thing to look for, I might start with the valve seals since that’s pretty easy and I have the tools to do it. Can I check the lifters without pulling the intake?  I think I remember that they should not move at all when you press on them with the rod, if they do they are bad.  Now that doesn’t tell me if the cam end of the lifter is worn.

I need to pull a bunch of stuff off the engine soon to get to my power steering gear (spewing fluid now from a non-hose connection and long overdue for a rebuild), so it may work out well if I have to get to the camshaft.
Thanks!  

Got into it again with the valve cover off, looks like it might be a bad lifter on #2 exhaust.  I can push the rod down over a 1/4 inch with my fingers or lifting other end of rocker. #8 intake isn't very good as well, but it fires.  The car sat a bunch over the last 5 years, this must be a result.

Looks like I am pulling the intake I'll probably just do them all.  I think the camshaft should be good since it moves the rockers.  I'll look at them when I am in.

Need to get new intake gaskets and valley pan, can I reuse the bolts?  Any tips?  

take only ONE Lifter out at a time

you cannot blend or mix the lifters up or change their position.. once they have broken in.. its almost assured that the cam and lifters may go flat if you just swap in a fresh set..      please examine the bottom of the lifters also.. and the cam..



have you ever had a lifter apart...

they come out and can be taken apart quite easily...   please do so on a big CLEAN towel or absorbent mat... yep. oil is going to come out...

you could have a clogged inlet hole in the side of the lifter...  or debris inside the lifter preventing it from filling and operating properly...

you might also want to carefully examine the lobes on the cam by looking through the lifter bores...

you can also take a 1" wood auger.. think of the door lock installation kit sitting on the shelf in the garage.. drill a 2x4 or 4x4 to make a holding block for the lifters to keep them in perfect order...  so you know which ones were where..  this way you can return them to the EXACT position ...

you might want to drill two 2x4s  so you can clamp the lifters in ..  

Thanks this is great. I have taken them apart now!  The Mopar Performance lifters I have are a little different, the check ball is a disc.

I pulled all of the lifters for cleaning that were mushy (after running engine and turning off).  I have one of those valve train trays to keep the parts together that I pull.  There is no sign of improper wear on the lifters or the cam lobes.

I found a great post about how to clean lifters from a Buick site:
(won't let me do link, search for,
How To Do Series:Learn how We Disassembled, Cleaned & Reassembled the 57 Nailhead Hydraulic Lifters)

forums.aaca.org/f162/how-do-series-learn-how-we-322149.html

I set up a few jars of lacquer thinner and kerosene, donned a respirator and did them one by one and have them reassembled now and still in order.

On to oil soaking them, assembly lube, placement, pushrods, preload etc.... hopefully this fixes it.  

69GTX
They will feel Mushy with No Oil in them thats Okay. Don't pump them up either before you reinstall them. Moly lube them as good as you can. The #2 exhaust lifter was the spring broken or weaker then the others? If it was that was the problem just waiting to happen and to fail.... Did that lifter ever make noise? It doesn't matter now you found your problem...

  Heres something I've done with my race engines. If I store them for along while. If the engine will sit for more then a month. I release the rocker arm tension. Especilly high lift cams when they have high spring pressures. If you have a non adjustable rocker arms or shaft just release the shaft tension. Then put (a big  note on your steering wheel) you did that...LOL... I've done this for many years and never had a lifter or valve spring problem....

Bob  

69GTX:
Thanks this is great. I have taken them apart now!  The Mopar Performance lifters I have are a little different, the check ball is a disc.

I pulled all of the lifters for cleaning that were mushy (after running engine and turning off).  I have one of those valve train trays to keep the parts together that I pull.  There is no sign of improper wear on the lifters or the cam lobes.

I found a great post about how to clean lifters from a Buick site:
(won't let me do link, search for,
How To Do Series:Learn how We Disassembled, Cleaned & Reassembled the 57 Nailhead Hydraulic Lifters)

forums.aaca.org/f162/how-do-series-learn-how-we-322149.html

I set up a few jars of lacquer thinner and kerosene, donned a respirator and did them one by one and have them reassembled now and still in order.

On to oil soaking them, assembly lube, placement, pushrods, preload etc.... hopefully this fixes it.

69GTX, I edited your post and included the quick link below.

click on link

forums.aaca.org/f162/how-do-series-learn-how-we-322149.html

 
When The Flag Drops,,,



The Bull Chit Stops,,,


P. Engineer, Engine Builder

She lives!  I took my time cleaning things up since I had the chance to make sure everything was done right. Its cold and there is snow, ice and salt outside anyhow. I even touched up a little paint on the heads.

I ended up cleaning all of the lifters with the proceedure above and put them back in order. I replaced one lifter that had a small kiss mark on the bottom (left in second picture). Used assembly lube as recommended on all cams, lifters and push rods. Lashed valves to 1/2 turn. Replaced oil and added ZDDP additive.

I won't lie I was scarred just before I started the engine up.  It fired immediately and it sounded terrible until the lifters pumped up (~2 min, seemed like forever). But it smoothed out, and cylinder 2 was firing and was no longer dead!!  There was zero lifter noise, which in retrospect I had (small ticks).


Grabbed a photo when the intake was off:


Pictures of bad lifter and new one:


Movie of valve train running after break in (may need internet explorer):

440 RB lives

Lifters were quiet during running and had no bleed down at all after pulling the valve covers. Now on to tuning the six pak, its a bit off and my choke didn't want to back down. Still have time until driving weather...  

sweet... glad you were able to take care of it...


patience pays off in the long run....  

69GTX
Thats such a great story and I'm glad you shared it with all of us gear heads. You can never take things for granted these days.
  Back in the day when we bought HiPerformance parts they were stamped with an inspectors number. But today the way things are mass produced you have to take every bit of precaution you can. That includes taking lifters apart, oil pumps, deburring whatever you can and by checking and rechecking every part you can.
  When you fire that engine for the first time your always going to wonder if you did this or that the correct way. Mechanical Parts do and will breakdown from time to time. You can't see it. I run a rev kit on my SBC. The reason is simply this. If there is a valve train failure, the lifter will stay in the bore, and 99% of the time I won't loose an engine do to lack of oil pressure. Some say it's overkill I say it's playing it safe.

Bob