- #Porsche 911 engine assembly guide upgrade
- #Porsche 911 engine assembly guide full
- #Porsche 911 engine assembly guide crack
The seat insert should be changed if the step is too large and cannot be blended without cutting away the chamber. If you keep the existing top angle the same there will be a step to the chamber and when this happens the chamber will have to be cut to blend to the seat. This requires the top angle or transition angle to be more acute so that it blends into the chamber.
#Porsche 911 engine assembly guide full
Care must be taken to make sure you can get a full 45° cut on the existing seat without cutting the seat too deep. If the guides have no wear and have the correct amount of clearance to the valve stem, then the seats can be cut. Upon receiving authorization, we start the repair work. Now we know the exact condition of all parts and what repair work is involved, we assemble a written quote and contact the owner. Most of the time the springs are replaced as a precaution. We also test the valve springs for their rates to be sure we know their condition.
#Porsche 911 engine assembly guide crack
Now is the time the heads are Zyglow crack checked (a nondestructive crack checking process), top spring retainers are magnufluxed checked, the valve guides bores measured for out of round and taper, valve stems measured for wear, valves measured for run out, valve seat heights measured to establish if another seat cut can be achieved without sinking them too deep or if they need replacing. Now that the parts are thoroughly cleaned further inspections are carried out.
Hand washing in solvent, carbon removal often requires abrasive procedures, hot recirculating washers, and ultrasonic cleaning processes are all used. Valves, retainers, springs, spring bases, locks, and shims all must be cleaned and inspected. Head exterior, ports, chambers and EGR ports all must be thoroughly cleaned. You cannot correctly check the heads for any damage with dirt covering any fault. Removing every piece of dirt, every particle of carbon, is intense time-consuming work. Grit can be caught between the guide and the head which can fall out and into the combustion chamber, scoring the cylinder walls. Care must be taken here and just blasting them with sand is not in the heads best interest. Once we have all the parts disassembled the heaviest or most time-consuming part of the rebuilding process begins. This also gives us an idea of how much spring forces there were as a counting of the base shims gives a good idea of what the installed seat pressures were.ĩ93 heads typical of the condition of head as they arrive. At this stage, we can see if the guides have any wear (the wiggle test) the valves, and their stems have any damage or wear, how the valves were seating and any damage to either the valve or seat sealing faces. Once the heads are at least in a condition where they can be handled, they are placed on our assembly machine and disassembled. This is when we can get some idea of how the heads sealed against the cylinders. We do this so that we can relay back to the owner or shop that the cause of the performance degradation was or was not from the heads. We now perform a vacuum test on the valves which gives us a good idea on the condition of valve sealing. We do not wish to contaminate our machinery and tools. We then do a general cleaning of the heads in their assembled state. Once we have the heads at a point where we know exactly what needs to be done based upon measured condition, we quote the cost to do this work. We would waste a lot of time if the owner wants to pay a few hundred dollars for all the work but requires a high level of quality and performance. Then we can give some sort of estimate as to what this may cost. A good look at the heads shows any damage, often some idea of age and mileage incurred and a good idea of what we may expect needs to be done. Type, year, condition, and a basic brief from the owner. When the heads are delivered to us, the first part of the rebuilding is to establish what we are working with. This will go through all the steps we take to ensure the heads are at their highest performance level and quality. We have been asked many times how we do this work. This is an outline of how we go about the repair of these heads. This covers all 911, 964 and 993 air-cooled cylinder heads. Porsche 911 Type Air-Cooled Cylinder Head Rebuilding Porsche 944 and 968 Crankshaft Upgrades.Porsche 911 Type Air-Cooled Cylinder Head Rebuilding.
#Porsche 911 engine assembly guide upgrade
Porsche 944-968 Engine Block Lower Member Upgrade.Replacement CDI Ignition for Porsche 911 Carrera and Turbo Engines.996 and 997 Turbo Crankshafts and Rod Bearings.Porsche 996 and 997 Turbo Cylinder Head Sealing.