updated March 25, 2010

Here is the MGB in 1992 delivering the family Christmas Tree - the "before" picture!

The basis of any competition engine must begin with a sound block and crankshaft.  The stock block was bored, deburred, and hot tanked.  The top deck was not milled so we could maintain a low compression.  Here you can see the later model connecting rods - lightened on the large and small ends, with the later model low compression pistons fitted.  What you can't see is the enlarged oil pocket in the bearing shell and larger "oil squirt" hole in the rod.  ARP bolts are used to keep it all together. 

There have been some questions about what was performed here.  The small end of the rod originally was square when viewed from the wrist pin opening.  What I did was mill the end to a radius to remove the extra weight of the square casting lug.  The big end has the modification you see here in the photo.  It also had a large square "blob o'steel" on that end too.  I milled the end flat, then ran a radius nose end mill down the middle to remove more weight.  All of these modifications were followed with directional grinding and shot blasting.  When finished they were checked for straightness and balanced individually, and then checked end to end.  

The next photo is the head after combustion chamber "smoothing".  Stainless Steel "Rimflow" valves were used.  These have anti-reversion features to keep gas and air flowing in one direction only.  Not a big deal on turbocharged engines, but I figured it wouldn't hurt!  This is the small valve head, and I chose to use this for two reasons, one is that it was the head on the engine I already had, and two, the thicker cross-sections may be more resistant to warping at higher temperatures.  This head has about 150k miles on it and is dead flat, a good indicator I hope...

Here is the engine partially assembled with the ARP hardware in view.  These studs are great to use because they install with an allen wrench which is a lot easier than doing a double nut lock!  Two other things to note here are the ceramic coated pistons and alloy front engine pulley.  I also went with an alloy water pump for weight savings.  The dynamo too will be replaced with an alternator for reduced weight.  Is anyone offended by the Austin-Healey green metallic paint?  I have seen this color on MG engines, notably the MGC.
Here is the turbo oil drain back line fitting in the pan.  I would have preferred to put this fitting in the block, but the turbo elevation is pretty low, so this ended up being the solution.

In an effort to reduce weight, I decided to replace the rear engine plate with an alloy version.  The price was higher than budgeted, so I ordered a 3/8" aluminum plate and rough cut it to shape using a hole saw and saws-all.  I then bolted the original steel plate to it and used it as a pattern to run a standard router with a 3/8" bit 4-flute end mill.  It took about 4 hours to make using this method, but was a fraction of the cost and I was able to increased the material width around the starter, a traditionally weak spot on the steel version of these plates, and probably suspect on the aluminum versions as well.  Total weight savings is 11 pounds!

Now we get to the fun part - safety equipment.  Some people have noted that this MGB-GT is a fairly rare model.  It features the "First Anniversary Special" dealer installed package.  There were 1000 of these kits shipped to US dealers in 1967, and it is estimated that half of those kits were actually installed on MGB-GTs.  Some dealers, it is reported, didn't move many GTs during the summer months and would install some of the components of this kit onto Roadsters.  Items such as the Personal brand steering wheel were more appropriate on the Roadster where someone would be likely to see it.

The cage is modern and complies with regulations for the NHRA Compact Series, SCCA RallyCross, Formula Drift, and most club racing series.  Tubing is 1.75" Steel with 0.120" wall thickness.  Corners are braced and both the rear hoop and main hoop are cross-braced.   

Our MGB-GT is mechanically sound, but traveled from Oregon to Alaska on the dreaded "Alcan Highway" in 1974 before the highway was paved.  As a result the car body and glass bear the scars of thousands of miles of gravel roads and there are literally hundreds of small dents on every panel of the car.  For this reason, we concluded that it was not a good candidate for an original restoration and would never be a trailer queen or concourse car.  There are no regrets in this camp for caging this car...

Here is the double door bar arrangement.  The main hoop attachment to the monocoque is tied into the vertical and horizontal panels using steel plates.  The door bars tie into the sill in two places and are heavily reinforced at the front as well.  This reinforces the central section of the car, a traditional weak point in the MGB design. 

With the engine in the car, we get to start laying out the plumbing for turbo, intake, etc.  The fitting seen in the center branch of the exhaust manifold is for the the exhaust temperature sensor.  Pressurized oil is fed from the oil pressure sensor port fitted with a 0.060" flow restrictor.  The small IHI turbo is oil fed and water cooled.  Since the heater was removed, the coolant lines are now routed to the turbo. 

 

Previous Page