Triumph Repair: 1974 Triumph spit 1500, heavy duty clutch, performance exhaust system

Question
Howard,
I just bought my 1974 spit.  The previous owner had some major work done on the engine.  

here is what he has done...
completely overhauled and performance upgraded dual 1.5” SU Carbs w/K&N filters, bored and honed block cylinders 0.030” over factory, new block plugs, surfaced block, all new gaskets and seals, mild crank polish, balanced crankshaft rotating assembly, new 9.75:1 compression pistons, heavy duty moly rings, heavy duty main, rod and thrust bearings, high performance oil pump, fast road camshaft (very nice idle) , completely ported and polished head with 1.255” stainless exhaust valves and 1.475” stainless intake valves, hardened three angle valve seats, valve guide oil seals, recessed bronze valve guides, dual core high performance valve springs,  new pushrods and rocker arms, electronic ignition for very easy starts, new engine and transmission mounts, new water pump, new fuel pump, new alternator, all new belts, hoses and gaskets, clamps, plugs, ignition wires, distributor cap, rotor and sundry perishables, no leaks at all, New headers w/performance exhaust system, upgraded to maximum full size radiator with electric fan, heavy duty clutch and throw out bearing, high performance light weight aluminum flywheel.

????  my first time in it I thought the fan was temp gated, and "smartly" soon found out this was not the case, the car quickly overheated and popped the gasket just behind the water pump.  I thought that this was my only problem until I noticed some other symptoms.  I heard a lot of air noise, thinking it was just the carbs, but it is actually air rushing out of the dipstick.  I have been checking the oil continuously since and I have not seen any signs of emulsion.  Is it normal to have air pressure in the dipstick, enough to easily hear and feel when running?

thanks,
Mac


Answer
Hi Mac,
That is a lot of work and expense. To first answer your question, No, it is not normal to have a lot of crankcase pressure. However having crankcase pressure after over heating is normal if the overheating was extreme.
I always tried to explain to my customers to scan the instruments as they drive because when you see a loss of oil pressure on the highway, you have seconds before major engine damage. When you see over heating you only have a couple of minutes before major engine damage. The damage starts in #2 & #3 cylinders first and usually the first damage is the loss of spring tension on the valves and the rings. The loss of tension of the rings causes "Blow-by" into the crankcase and then forces out the seals, gaskets and the dip stick.

Then the cause of the over heating must be found. This can be many possible items or even a group of items. You should run some tests BEFORE you tear the engine down. Everything is much more critical on a hopped up engine than a stock engine and more prone to failure.

Before you do anything, you should run a "Dry & Wet" compression test. To evaluate the rings. If you are not familiar with these tests let me know and I will walk you through them.

You need to remove the thermostat and put it in a pan of water and heat it on a stove with a meat thermometer to see at what temp it opens.

If you have compressed air available you need to acquire a fitting that adapts the air hose to your sparkplug hole. Set a piston at TDC and put the car in 4th gear and hand brake on and apply 125 to 150 PSI to the combustion chamber and open the throttle and listen for a hiss and then listen at the tail pipe for a hiss (none acceptable at either) then remove the radiator cap and watch for the coolant to raise or show bubbles. (this would be a 100% sign of a head gasket leak or a crack in the head. Gasket most likely)

The items that can cause overheating are,

Leaking head gasket
Thermostat failure
Water pump impeller failure
Clogged radiator
Carburetor jetting too lean
Ignition timing wrong
Low octane fuel used in a hopped up engine
Engine run too hard with no break in after rebuild

These don't take into account a possible mistake in building the engine. Was this rebuilder a British car specialist? Let me know and let me know the compression test results.
Howard