Sunday, October 2, 2016

Additional work required on the GT40 Mustang Heads

I am running a Comp Cams Performance Cam with matching springs. Unlike my last V8 I had in the 1979 Ford Mustang I have double springs installed with this one.

On the last post I left off with the testing completed verifying what I suspected early on and everyone else was on complete denial on. Machine shop left me with a leaky valve. Now after removing the valve I have found no corrosion in the seat.

As you can see below those cheap universal valve spring removers will not work on this application. The jaws do not reach in far enough to grab the inner valve spring. 

The tool for the job this time will be this lovely new piece of lifetime warranty equipment from Sears. 

No lie this tool will require both hands to operate and there is a lot of pressure behind these springs, so I will be taking great care while performing this task. Be sure to read the instructions with removing tool and do release of springs as slow as possible.

New issue found that I wasn't expecting to see. Valve seals went to crap and now I will have to completely dismantle the heads to inspect and replace. I am just going to replace them all and this is going to take awhile. 

Thursday, September 29, 2016

Problems found with the 79 Mustang Engine

So I paid a machine shop to do all the work of inspecting and assembling these heads, but the engine sat on the stand for 5 years not moving due to budget constraints and time it took to cut all the rust out and re-weld the 79 Mustang back together. That being said I can hardly go back on the machine shop for the issues I have found.

The Mustang had a popping and backfiring issue that just wouldn't go away when the engine was warmed up to normal operating temp. In fact it would get worse as it warmed up, however at idle it would purr like a kitten. What the heck is going on right, so I went though valve adjustments and I swapped plugs and even plug wires. There was improvements because I did find a bad plug wire but it did not totally fix the problem. 

I ran compression tests and the engine came back with results within parameters, so the final test I did was a Cylinder leak down test. Now this problem has plagued me all summer long and I have burned through at least Sixty bucks worth of fuel. Now the cylinder leak down was 35%, which says on the gauge from harbor freight good but everywhere online says it needs to be under 20%. Now Hotrod says you can sometimes get the valve to re-seat if you use a plastic dead blow and beat on the top of the valve. Before you do this I would advise taking the roller rockers off. No way in hell would I beat on an aluminum roller rocker. I removed my roller rockers and tried to get them to seat further unfortunately I was only able to get the leak down from 35% to 25%. This is not good enough so I pulled the engine apart. 

Clearly you can see some of these cylinder are not firing. Very unclean. 
Next test after the heads were off was to fill the the valve ports with Carb cleaner and check for fluid leakage. 

And here we found a leaky exhaust valve.

Saturday, August 20, 2016

Diagnosing a misfire

Diagnosing a misfire. 
Check your plugs and look for tell tale signs of misfiring or improper running issues. They will be easy to see. 

A good plug wire will keep the same continuity no matter how much you move it. 
Next check for continuity using your digital multi-meter to diagnose. Video below