Rebuilding the Hemi

Well... I can honestly say with my hand on my heart that I never thought I would have to make a page like this but, as most of you reading this know, it's not all roses in the custom car game. Big boys toys can come with big boy problems.

Sadly, with only a mere 2,000 miles on the odometer... the 540 Hemi started to make a "knocking" sound. I picked up on it early and knew something wasn't right and stopped driving it. It wasn't a loud "bashing" knock, but enough to signal the engine wasn't happy. Most may not have even picked up on it. I will share a video of it in case others are having a similar issue.

I took it into Henrys Rod shop to see if they could help me figure it out. With some advice from the original engine builder (Tim Banning) he suggested we try a valve cover space kit as it sounded like rockers hitting the valve covers, after several weeks waiting for the kit to land, sadly it didn't cure the issues. Worth a try though.

Next we tried to replace the flex plate as it sounded very close to this area. Brand new plate in, ARP hardware and installed to spec, still the noise was present. Sadly, Henry's and I knew there was only one real way to get to the bottom of it... pull the engine out and tear it down. Gutted.

A week passes and the Hemi is out, on a stand and off to a local Automotive engine / machine shop in Tauranga to tear it down. Long story short, it remained here for nearly 4 months, yes 4 MONTHS and all that had happened was a disassembly. I chased them up, went in, called, but just a lot of talk, excuses, and no movement. Nice enough people so they will be saved the embarrassment of being called out. The time was one factor and appalling, actually terrible, the other was they felt and seemed way out of their depth with Hemi experience and really had no idea. 350 Chevs and similar seemed like their area of expertise.

I made some calls and talked to a good Mopar friend (Wayne) who owns, races and has a lot of real world experience with Hemis. He recommended two places, one being Marsh Motorsports. I called them up and instantly felt at ease. They had worked on many Hemis, hads all the machines in house and Timonthy (the Father / original owner) has a lot of histroy in NZ drag racing, in particular with Hemis. I was sold and trusted my gut and to commit to the build with Marsh Motorsports.

After a full tear down, we found various concerns. Namely, the pistons had been scuffing on all cylinder walls. No fuel was located in the pan / oil itself and no sign of injector or rail leakage of any kind which ruled out "cylinder wash".

Pushrod holes were also not big enough, allowing the pushrods to make contact with the holes themselves (not good). My machine shop confirmed these were simply not enlarged enough. I'm not blaming the engine builder but I can say that after only 2,000miles, these big issues shouldn't be happening, it's that simple.

I did everything right, engine always warmed to operating temps, never left to idle for extended periods, or "thrashed", oil changes and using the engine builders oil recommendation, fresh this, that, filters, etc. For this to happen so early on when I thought the build "was all done", was extremely frustrating. I will let the folks reading this see the photos and they can determine what went wrong, nothing but facts.

Summary: Thankfully, I'm not a downer, and I'm lucky enough to be in a position to be able to afford a rebuild. These things can happen, to any engine, any brand, it comes down to the builder and sometimes even luck (good or bad). The engines don't build themselves so word of advice, make sure you research everything about who you use. If you can do it yourself, awesome! Even better. Sadly I'm not that mechanically inclined. Also, if in doubt or you don't feel right at any shop, never feel bad about trusting your intuition and going in to pull your gear out. A lot of money and time is spent from the owners pocket so make sure you're happy.

The photo gallery below will show the process of tearing it down, the rebuild, parts used, on the dyno and once again back in the car. I thought I would share this experience, I could keep it quiet, and hide it trying to save face, but why? I'm not ashamed or upset and it may actually help someone going through a similar issue. That and funnily enough, it's still a fun project LOL. Even this shit excites me. Researching pistons, rings, why and how all hours of the night to once again, resurrect and bring this big beast back to life and this time, built properly and locally from the start!!

Build in Progress (Check in for updates...)

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As soon as I heard the knock, driving ceased immediately. The Dodge went straight up on my hoist to try and locate the "knock" myself...
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Time to start checking some basics by process of elimination. First we tried the flex plate and new ARP hardware as it did sound close to that area and flex plates can be off or "wobble". Installed and no change.
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Next after some advice from the original engine builder, he suggested we try to install a Spacer Kit as it is possible for the rockers to hit the valve covers. Not sure why after only 2,000miles and a new build they would start to hit, when surely those spacings should have been dialled in prior but I followed his advice. Longer spark plug tubes were also needed other wise the originals would stretch and get damaged. They arrived after several weeks and installed but sadly, no change. Knock still present.
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After a few more diagnostic attempts, pulley system wobble, transmission, converter, rockers, checking for collapsed lifters, etc with no success, there was really only one thing to do... time to tear down the engine.
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In order to do a proper tear down inspection, and eventual re-build, there is no other way to do it than the engine being removed. Within a few days of making the call, the 540ci Hemi was hoisted out from the Challenger's engine bay.
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Lucy waiting with all the other cars who also need work. I decided to bring her home while work was being done and help free up space at Henry's since the engine inspection and build would take several months. With parts delays, waiting for custom spec pistons, push rods, shops working on other vehicles, etc. If you've been through these builds, then you know exactly what I'm talking about! lol. Two lessons. It never gets done on time and it definitely never gets done under budget!!
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Back at home while the engine work is being completed. She looks amazing, good to see the engine bay, k-frame, etc all looking solid and fresh (as they should). Making the most of this bad experience! lol
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Closer up...
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The original #'s matching 375hp "440 Magnum" looking on wondering why all the fuss. lol Still stoked to have the Hemi and will get her dialled in properly (and locally!). Will eventually build the 440 up as a display engine, half way there. Just need manifolds, 4bbl carb, paint air cleaner, timing chain cover, etc. Very cool display piece!
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With the Hemi out, the transmission obviously had to be removed at the same time. I used this opportunity to really pep up the TF727 and change something that had always bugged me, the forward pattern manual valve body setup. Currently, while in traffic, going from [3] to [N] to let her idle or a quick rev while rolling, or even hopping in every time going from [P] to [1] (furtherest apart on a FMVB) was a rigmarole in a ratchet shifter. I had always wanted to rectify this at some stage by installing a REVERSE manual valve body (RMVB). [1] to [N] was one shift, [R] to [1] was 2. Clean easy and when the Hemi was at WOT, you're pushed back into the seat so grabbing the pistol grip to shift up a gear was easier to pull back with the flow, vs. against it, pushing the shifter forward. While getting this done, Chuck Mann installed a whole bunch of 727 racing goodies I ordered. You can see the full build on this website on the "Torqueflite Race Build" page.
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Some people might say it's a little bit overkill to build the trans as well since it was performing nicely and everything was perfect. Good to inspect it (no harm) while the Hemi was getting the same treatment and BEEF it up too.
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The 540ci Hemi block after being completely torn down. Sad sight!
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From the front...
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The bottom end...
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Keith Black 426 Based Block.
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Findings: Scuffed cylinder walls from piston/ring contact. No sign of fuel leak ("cylinder wash") no fuel in the oil, no EFI injectors were faulty, not leaking and running at perfect PSI. Same with the EFI fuel rails. All perfect. It simply appears to be inadequate ring / piston clearance. No piston / ring combo should be making contact after only 2,000 miles of running time. End of story.
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The 4.505" bore showing very significant contact.
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Scuffing aside, the polish / cylinder sleeve work also not the prettiest.
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All cylinders scuffed...
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The CP pistons themselves (great pistons by the way and not their fault at all). You can clearly see the contact point and darker grey damage resulting from scuffing the wall.
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Worse! The entire side profile making contact...
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All pistons had this damage, not 1 cylinder "having a bit of bad luck", all 8!!
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Another finding was damaged 3/8" HD Manton push rods from inadequate tunnel clearance. The damage is clear to see, enough contact to literally make a groove.
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Some more push rods, again, this wasn't 1 or 2, all push rods had this damage ruling out a "collapsed lifter" causing 1.. maybe 2 to fail. No. They all had this damage. Simply not enough clearance.
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The contact point on the "tunnel" or pass through hole where the push rods were making contact.
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The 540 Hemi standing out in the machine shop waiting room with Fords, Chevs, Holdens, Japanese, all kinds of builds and work going on. Very cool! Good or bad, you simply have to enjoy the experience. :)
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After being at a local Tauranga Engine / Automotive Reconditioning shop for nearly 4 MONTHS, my patience had worn thin. All that happened in that time was disassembly. Not good enough. Actually embarrasing. That and the fact they seemed out of their league with Hemis. I collected the Hemi and took it to Marsh Motorsports Ltd in Auckland whom came recommended by a good Mopar man I know who has, races and owns big cubes Hemis. I trust his wisdom. Very pleased to get it out of the Tauranga shop!
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A better overview of all the parts in my van: block, crank, heads, intake, EFI, damaged pistons, sump, valve covers, the internals, bolt ons, etc, all accounted for. Right... now to take it to a proper Mopar shop!!