Tag Archives: Rear Main Seal

Rear Main Oil Leak – Diaper Fix

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Healeys, as well as most other British cars of the period, like to leave their mark! That is, one can expect oil leaks on their garage floor or driveway. When I rebuilt my engine ten plus years ago, I installed an improved rear main seal designed and sold by Dennis Welch Motorsports. Disappointingly, it failed to correct the oil leak problem, although to be fair, it might be worse had I not made the modification.

If you can’t get rid of a leak, then perhaps you can at least do something to keep the leak from hitting the floor. Jim Shope came up with a plan for a little drain pan that basically serves as a diaper for the Healey. The pan catches the slow drips, and every month or so the pan can be wiped out. The following images illustrate the template and measurement for making the drain pan – thanks, Jim!

The Template is 9″ x 7.5″. I used aluminum but steel sheet could also be used. After making the cuts with some tin snips and drilling the two holes, I used a small sheet metal brake to form the box. I then used JB Weld to seal the edges of the box.

Oil Drip Pan Template

Oil Drip Pan Template Mounting Hole Dimensions

Oil Drip Pan Cut Out Ready for Bending

I used some engine green spray paint available from Moss Motors to paint my little diaper. I plan to use a small piece of Pig Mat (Oil absorbent pad) in the pan to collect the oil. Hopefully, I can then just switch out the the dirty pad for a clean one without having to remove the pan. We will see.

Oil Drip Pan Painted and Installed

Main Seal Diaper in place

Bell Housing Oil Drain

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Healeys, as they came from the factory, did not have a rear main oil seal. The factory must have anticipated oil leaks from the crank because they put a small hole in the bottom of the bell housing to provide a place for the leaking oil to go other than to accumulate and potentially get thrown onto the clutch – not good. They even placed a small split rivet in the hole so that the hole was kept clear from any clogging. As the car moved around while driving the split pin would vibrate and move around keeping the hole free for drainage. The image below is not my car but you can see the split rivet in the bell housing.

Bell Housing Drain Split Rivet

Some Healey owners install rear main seal kits available from a couple of different vendors to help keep the oil in the engine. I did that when I restored my car and used the Dennis Welch kit. Some Healey owners also install PCV valves to help with reducing oil leakage by pulling air from the rear of the engine into the crankcase. I did that too! These changes do seem to help but some Healey owners report that even with these changes they still have some leakage. I did.

I decided to take the PCV valve off of my engine. Some controversy surrounds the use of the valve particularly as it relates to leaning out the rear cylinders. I figured that after removing the PCV valve I would get some more oil leaks and I have. Not bad, but definitely more than I used to see. 

I have a Smitty 5-Speed gearbox on my car. The Smitty bell housing does not have the little drain hole the factory included. I checked in with the guys on the British Car Forum and Steve and Dave were particularly helpful. They were ahead of me in that they had both already incorporated a small drain hole in the Smitty bell housing on their cars. Steve suggested a 3/16″ hole drilled right between the mating of the steel backplate of the engine and the flange lip of the aluminum bell housing. As the photos show below, I drilled my hole at the low point of the bell housing right where Steve and Dave suggested. The depth of the flange is approximately 1 1/4.”

Oil began to drip out immediately, so much so that it got me a little worried. However, it stopped almost as quickly as it started so I didn’t seem to have too much oil accumulation. You may recall that I had already installed a little catch pan under the mating point of the bell housing and backplate. I removed the pan to drill my hole and then reinstalled. This will make it easy to monitor how much oil I lose from my new drain.

Smitty Bellhousing Oil Drain

Smitty bellhousing Oil Drain Closeup

Initial Oil Drainage

Main Seal Diaper in place

Engine Rebuild

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Clean-up Before Rebuild

I had thought about outsourcing the machine block cleaning and machine work and then rebuilding the engine myself, but thought better of it given time limitations and decided to go ahead and give the complete engine to Mike Gassman at Gassman Automotive http://www.gassmanautomotive.com for a soup to nuts rebuild. Mike and his team had done XK motors before and are experienced with the motor, ignition, fuel system and etc.

I spent a few days cleaning the block and head to remove as much grease and grime as possible before turning everything over to Mike.

Front of Cleaned Engine Before Rebuild

Front of Cleaned Engine Before Rebuild

RH Side of Engine

LH Side Engine

Underside of Engine

Rebuild Engine

Machine Work:

  • Resurface Head
  • Valve Job
  • Install Guides
  • Pressure Test
  • Resurface and weld Exhaust Manifold Cracks
  • Drill for Oversize Lifters
  • Drill for Hold Downs
  • R&R Pistons
  • R&R Bushing Under Over
  • Recondition Big End
  • Grind and Polish Crankshaft
  • Magna-Flux Crankshaft
  • R&R Crank Plugs
  • Rebore and Hone Block
  • Pins
  • Replace Core Plugs
  • Balance Pressure Plate, Cylinder Block
  • Resurface Flywheel
  • Magna-Flux Block
  • Resurface Cylinder Head
  • Polishing Two Valve Covers, Two Carbs Dashpots, Intake Manifold, Oil Cap, Cover and Water Neck

Parts:

Where possible used components in good shape were used in the rebuild; however, in many instances new parts were required to replace worn or broken bits. The original compression for the 3.8 MK2 engine was 9:1; however, primarily because of the lower octane rating of fuel today and due to the way I plan to use this car, I decided to use 8:1 compression Mahle pistons in my rebuild. This is not a complete list and it is in no particular order, but new parts ordered included the following:

  • Cam bearing Set
  • Engine chrome hardware
  • Oil Filter
  • Spin-On Oil Filter Kit
  • Payen Brand Head Set
  • Cylinder Head Studs
  • Seal Kit
  • Lock Tab Kit
  • Thrust Washer Set
  • Piston set
  • Tri-metal Connecting Rod Bearing Set
  • Tri-metal Main Bearing set
  • Core Plug Set
  • Pilot Bushing
  • Clutch Kit
  • Water Pump
  • Timing Chain, Guide and Tensioner kit
  • Lower Gasket Set
  • Tappet Hold Down Kit
  • Tappet Guide
  • Valve Spring Set
  • Oil Pump
  • Oil Pump Adapter
  • Bronze Valve Guide Set
  • Intake Valves
  • Exhaust Valves
  • Oversize Tappets
  • 10W30 Break in Oil with Zinc Additive
  • 15W50 Oil with Zinc
  • Engine and Bearing Assembly Lubricant
  • Sealants/Sealers/Cam Lube
  • Gloss Black paint
  • Metallic Blue Spray Paint for the Cylinder Head
  • Flamethrower Coil
  • Chrome Coil Bracket
  • Flamethrower Ignition Leads
  • Spark Plugs
  • 123 Distributor
  • Brass Nuts
  • Thermostat
  • S.U. Throttle Shaft 1 3/4″ Butterflies
  • S.U. 1 3/4″ Butterflies
  • 5/16 22 BSF Banjo Bolt HD Starting Carb
  • 3.8 MK2 SM/1402 Carb Kits
  • Drive Belt
  • Hoses to Radiator
  • Radiator Hose Clamps
  • Heater Hose
  • Heater Hose Clamps
  • Gear Reduction Starter
  • Engine Ground Strap
  • Oil Pressure Sender
  • Oil Quick Drain Valve
  • Blast, Anneal and Porcelain Coat Exhaust Manifolds
  • Carb Banjo Bolts and Washers
  • Alternator and Mounting Bracket

Rear Main Crankshaft Seal

I did some research on the replacement of the rear main crankshaft seal. A number of the usual vendors sell modern upgrades for this seal to help prevent oil leakage. The apparent most popular upgrade kit does require some machining of the crank.

After checking with those on the saloon-lovers forum and a few other MK2 owners, the consensus seemed to be to stay away from the upgrade kits. However, Peter Wise aka “Old Goat” [email protected] recommended a GraphTite seal made by BEST Gaskets as a modern material upgrade to the original rope seal. The kit is available from EGGE Machine http://www.egge.com  part number: 6382S and it is for a Pontiac 1968-76 8 cylinder 428-455. It is a direct replacement for the rope and does not require any machine work. I cannot explain why the Pontiac V-8 seal works in the MK2 3.8 but Pete claims that it works quite well. I have ordered the kit and Mike and his team installed the seal upon rebuild. The seal kit included an installation tool for $17.39!

GraphTite Rear Main Seal

GraphTite Rear Main Seal

Dynamo Mounting Bracket and Spacer

I probably will not use the dynamo bracket with my alternator, in favor of a turnbuckle brace, but I cleaned it up and painted it  – just in case.

Dynamo Adjustment Bracket

 

Dynamo Bracket

Coil Bracket Extension

Coil Mounting Bracket Extension

Spin-on Oil Filter Kit

Oil Filter Assembly

Oil Filter Assembly

As seen in the image above, the original oil filter is a full flow type and has a renewable felt or paper element. Modern spin-on alternatives are available and I installed the kit provided by SNG Barratt. Purists may object, but most who have installed the spin-on arrangement report success and it is certainly much easier to change.

Spin-on Oil Filter Instructions

SNG Barratt Spin On Oil Filter Kit

SNG Barratt Spin On Oil Filter Kit

Harmonic Balancer

I decided to have the harmonic balancer rebuilt by Dale Manufacturing http://hbrepair.com/harmonicbalancer_018.htm in Salem, Oregon rather than purchase a new one. The rebuild was under $150 and the final product looked pretty good.

Harmonic Balancer

Harmonic Balancer

Timing Marks

Oil Sump Dipstick

Got the dipstick back from the plater. I vaguely recalled that the background on the handle was a somewhat unusual blue color. Someone on the Forum indicated that Revlon’s After Party nail polish was the perfect color, so I ordered some and painted the handle:

Revlon's After Party Nail Polish

Revlon’s After Party Nail Polish

 

Revlon's After Party Nail Polish after Application

Revlon’s After Party Nail Polish after Application

Oil Drain Plug

I ordered an EZ Oil Drain Valve for XK Engines from Cool Cat Express just to make the oil drain process a little easier. As their advertisement says; “This all aluminum drain valve mounts permanently in place of your drain plug. A simple twist of the wrist will open and close it. No more stripped threads, no more lost plugs. One piece aircraft quality 6061 aluminum and 302 stainless steel. Aluminum has clear anodized finish for long, corrosion free life. Seals are replaceable. Nothing to break, nothing to lose: saves labor, saves your oil pan, save aggravation. The perfect companion for our spin on conversion kits! Fits all Jaguar oil pans with 5/8″-18 thread. This includes ALL XK motors, and many V12’s.”

This is a photo of the Valve and the plug it replaces:

Cool Cat Express Oil Drain Plug

Here is a photo of the new valve installed:

Cool Cat Express Oil Drain Valve Installed

Engine Rebuild Process

Mike Gassman Installing bearings

Mike Gassman Installing Bearings

Engine Block

Engine Block

Crankshaft

Crankshaft

New Main Bearings

Connecting Rods

Timing Gear Chain

Pistons & Timing Gear

RetroAir Aluminum Pulleys

 

 

 

123 Distributor

New Porcelain Exhaust

Primary Coolant Hoses

Engineering Art

Compressor & Shield

New Belt Routing

Distributor

Spin-on Filter

Front View

Engine Run-In

After Mike and his staff got the engine together they made a test stand so that we could do preliminary adjustments and make sure we were leak free. I am trying Evans Waterless Coolant in this engine and it was used in the testing.

All of the attention to balancing really paid off as the engine runs very smoothly with very little vibration. Everything checked out beautifully.

Thanks to Mike for a beautiful engine and a beautiful job. I recommend him to others without reservation.

The Gassman Team

The Gassman Team

Engine Testing

Engine Testing

Engine Testing

Maestro Mike

Maestro Mike