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, had all the machines in house.

Tony Marsh (the Father / original owner) has a lot of history in NZ drag racing, in particular with Hemis and set many records. Marsh Motorsports also built the current fastest naturally-aspirated small block in the world. Between Wayne, Marsh's records, customer feedback, their Facebook page following and their history, I was sold and trusted my gut and to commit to the build with Marsh Motorsports. That's the best way to do it, do your research, find the shop that suits, don't overthink it or second guess, back them, yourself and commit!

After being handed a disassembled pile of Hemi parts, within a few weeks and in between other builds, Marsh Motorsports had a closer inspection of my engine, they said without a shadow of a doubt, it was "cylinder wash". All cylinders had a decent amount of gasoline go through them and clean off the protectant layer of oil, leaving the pistons and rings to scuff.

Pushrod holes were also not big enough, allowing the pushrods to make contact with the holes themselves along with skimping on various items like timing chains and smaller parts that I had no say in. These were all thankfully picked up by Marsh Motorsports who rectified the issues using high quality parts. 

Cylinder wash can be caused by faulty injectors, poor tune or poor break in procedure. I was truely unaware of how bad it can be with a new engine. Knowing this, Marsh Motorsports advised that once built, NO ONE is to start it until it's at my choice of tuner. The tuner shop will then call Anthony to run through a few pre-start checks, timing, oil, etc, and then proceed to fire up for the first time with sensors and EFI / ECU all connected and reading out the required stats to keep an eye on fuel, air, timing etc.

But before this can take place, once built, the 540ci Hemi was taken to Henrys to reinstall it, then Hamish my auto sparky removed all the old, dated shitty F.A.S.T XFI software that could have also contributed to my issues. He then installed and connected all the brand new LinkECU G4+ XtremeX ECU and wiring which thankfully was just a bit of pin work. With this modern and trusty (New Zealand built) ECU system controlling all the gauges, EFI, and other perimeters, I already felt a lot safer! I also used a LinkECU Can Gauge to keep an eye on various read outs, namely air and fuel ratio and fuel pressure.

Once everything was hooked up and the car had still not been started, it was time to truck the Dodge to D-Tech Motorsports to fire it up for the first time and to complete the break in and tuning procedure. D-Tech break in many engines on the dyno, from race to street cars of all walks of life. They use a run in program which goes for 30km at varying light loads. Then they stop, cool down, drain oil, remove oil filter, cut open filter and check. Once all is OK, fit new filter, fill engine with Marsh's recommendation (Castrol) and carry out the tuning.

In terms of tuning, I wanted to run 95 fuel like last time, I can make plenty of power on it, while not 98, it's the convenience and safety factor that 95 fuel is everywhere. When you have a 8.8L Hemi with a drinking problem, you don't want to be in the middle of Buttfuck nowhere with no place to tank up. Unlike the original build which had a 10:1 compression, talking to Marsh they said with our shitty fuel in NZ, 10:1 comp would be too much for 95 fuel. He made adjustments in the pistons to lower compression to low 9s.

Doing this also lost a bit of power, from around 660hp/691ft-lb to possibly 30 less on each figure. I didn't want this so Marsh said there's many ways to gain that back, one being port and flow work on the heads. I said I'd love to stick to the 660hp I had but if he hit 700hp+, I wouldn't be disappointed either! I didn't want much more than that, like 800hp+. On the street, it's just useless. At the old 660hp, she hooked and BIT perfectly. Throw you back in the seat stuff. And as the old saying goes, "Spinning ain't winning! "

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 can come down to a bad tune, single part (often a low value one FFS) and sometimes even luck (good or bad). 

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, bigger and badder than ever.

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