Title: Rebuilding my 440 (or how to fix an oil leak in only 18 months)
Date: June 2004
Author: David Fesmire

I decided to convert my ’69 Roadrunner from an automatic transmission to a 4-speed in January 2003. This was partially because the car originally came with a 4-speed, but mostly because I like banging gears. I looked into options for installing the 4-speed behind my 440 with a cast crank, but eventually decided I needed to convert to a steel crank (which I happened to have). I’d never rebuilt an engine, so I farmed the work out to a local machine shop in Lexington TN that also did balancing. That’s where things started getting interesting.

The machine shop had the engine for well over a month before they were able to assure me that my steel crank was okay. Several months later they finally finished the work and I installed the engine. Oil then began to pour out of the back of the engine. The machine shop told me they’d have one of their assistants look at it in their parking lot. I visualized some kid lying on his back out in the cold wrenching on an engine he didn’t know a thing about. No thanks.

I couldn't get the steering to drop, thus paid a local shop to put the car on their lift and check the rear main seal. They were able to lower the cross-link and remove the oil pan. It was a bit hard for them to check everything due to the water leaking on their heads. A typo? Nope, the #2 cylinder was full of water due to a local machine shops attempt to pocket port the heads. Both heads ended up being ruined, but I digress. The oil seal was chewed up a bit so they replaced it. I then towed the car to a nearby storage place where it sat for two weeks while I found another set of heads.

I'd made it around 2 miles before oil started spraying out the back of the engine. I somehow made it the 25 miles home without starting a fire. The steering was loose, so I was able to drop the oil pan myself for a look at things. I talked to several people and decided to replace the rear main seal again. This was a two-piece rubber seal that will leak if installed backwards. As many of you know, high performance big block Mopar engines use two oil pan gaskets: One above the windage tray and one below. That makes for a lot of extra work when pulling the oil pan. It turned out the seal was damaged, but not backwards. I also found a small crack in the aluminum rear main seal retainer. After unsuccessfully looking for a replacement, I called Mancini Racing and ordered a high-performance seal retainer made by Indy Cylinder Head. I replaced the seal, buttoned everything up, and found I still had an oil leak. I drove the car 200 miles hoping things would clear up, but it just got worse.

I pulled the oil pan again and carefully inspected everything. This time I noticed gouges in the crank in the area which contacted the oil seal. These looked like rust pits up to ¼” across. I called the machine shop again and they said “We noticed the pits, but didn’t have a rock small enough to fit in there”. IDIOTS!!!!

I sure didn’t want the machine shop touching my engine, so I pulled it and disassembled everything. Here’s a partial list of what I found wrong:
1. The #1 and #2 rods were backwards, thus they were binding and the rod bearings had eaten into each other.
2. The crank had been turned but not chamfered leaving jagged edges on the crank that ripped the center out of two rod bearings.
3. Lots of metal was left in the hole where they drilled the block to accept a ½” oil pickup (stock is 3/8”).
4. Low-performance rod bearings had been used with no provision for the oil squirt holes.
5. Three rod caps had been machined so much the oil squirt holes were blocked.
6. All the bearings were covered with deep scratches (trash left in the engine?).

I sent the crank to “Crankshaft Specialists” in Memphis. They turned the damaged area, plasma welded it back up, turned it back to stock specs, then followed up with chamfering and polishing. I reassembled the engine with fresh bearings. When I raised the completed engine with the cherry picker oil began to drip out the rear of the engine.

The Indy rear main seal retainer uses two round rubber seals on each side instead of the conventional single flat seal. It is nearly impossible to install without a side seal slipping loose. I later found the side seals will retract away from the crank once the engine heats up. Bottom line: Don’t use the Indy part. I’ll give you one if you feel like punishment.

I special-ordered two sets of Indy side seals then, once again, removed the oil pan and replaced all the seals. This time I was able to get the engine installed with no sign of leakage. I fired the engine up and was greeted by an oil leak. I drove the car over 100 miles to the Music City Mopar Club show in Nashville with only minor oil leakage. The leak continued to get worse over the winter. I was starting to run up a serious bill for pairs of oil pan gaskets!

I was getting desperate and had talked to everybody I knew. John Garner told me a trick for installing stock side seals so I decided to give it one last shot before packing the engine up, stuffing it with pictures of Ben Franklin, and sending it to Hensley Racing Enterprises or Ray Barton Racing. I’d learned that Mopar Performance has the stock seal retainer available, thus was able to order one and use it for the install. During this process I learned that you can’t install a Milodon windage tray with the engine in the car (I reused the stock tray). The Milodon tray is a far superior design since it allows oil to more easily run back into the pan.

John Garner installed the new seal and everything sat there open for a few days while I worked up the motivation to (once again) get things ready to button up. I was cleaning up under the car when I spotted the REAL problem: I’d used ARP main bolts which have larger heads than stock bolts. This resulted in the bolts hitting the rear main seal retainer, thus it wasn’t seating against the block! I looked back at my other retainers and confirmed that had been my problem all along. The ARP bolts will clear the stock retainer if the bolt head is turned sideways. They’ll hit if the pointed edge of the bolt head is towards the retainer. They won’t clear the Indy retainer no matter how they’re turned. Some quick work with my dremel tool fixed the clearance issue.

I have now driven the car 400 leak-free miles and learned a lot about big-block Mopar engines. I’ve also learned how important it is to either assemble your own engine or find somebody who knows Mopars. Don’t let a Shivey shop touch your Mopar engine!

A note about oil pump springs: Springs can make a big difference. My new MP hi-volume oil pump was producing 95 PSI while idling cold. This was obviously on my list of suspects for causing the oil leak. I ended up purchasing a stock replacement oil pump and comparing the springs. The stock spring was the same length, but used thinner wire. The stock pump also used a thicker metal gasket beneath the threaded cap that held the spring in resulting in the spring having less tension. I moved both the stock spring and thicker gasket to the MP pump and was able to drop my oil pressure by 30 PSI. The engine now idles at 65 PSI cold and 55-60 PSI hot. And the cylinder heads? I ended up installing a new set of Edelbrock aluminum heads due to the shoddy work done by the local machine shop. Keep your Mopar machine work away from Shivey shops.