Porsche 944 Few key pointers on rebuilding the engine

Few key pointers on rebuilding 944 type engines. Re post from our web siteCreated on
The 944 block is very reliable if treated right. Most blocks require no honing. Rebuilding head, replacing rings, barings, rollers and seals will give you thousands of reliable miles of driving pleasure. The engine can be rebuilt without taking one out of the car if not replacing pistons or lower gasket.
HEAD
It is not necessary to install new valves if old ones can be glass-bead and fitted again to their seats. The head rebuilder will let you know parts you need for the head to be properly rebuilt. Freeing up the head from the engine, remember to;
NEVER use a crowbar. NEVER insert any metal object between the head and the block. Keep metal contact surface free from being scratched. 944 head has a lifting notch. Even the smallest scratch can leak gepression. You will not be able to install the head nuts back if you are using " drive with 10" handle from (Craftsmen Metric Set) We regemend Craftsmen DIGITORK 4990648726 for all torque need of this engine. It reads both Foot/P and Newton/M.When rebuilding the engine and the headers are out, always replace oil cooler gasket. Rubber coupler melts from oil additives and eventually fails. Mixing of coolant with oil will occur.
CRITICAL;
Do not bee cheap! All timing belt sprockets MUST be replaced. DO NOT KEEP THE OLD SPROCKETS EVEN IF THEY LOOK GOOD. Porsche no longer makes these sprockets from the same material. Old material happens to shatter like glass, under prolong stress. Many engines have been lost to this problem.
Keep in mind "rebuilt water pumps do fail" since you do not know who rebuilt it or if it was ever rebuilt and not just steamed cleaned. Even the most reputable place does not know what happened to the pump they sell. Get New! Do not begin your work without flywheel lock. One tooth timing belt jump when first time cranks, will destroy your head valves. It is a good time to replace your clutch with engine out. It is a good economics. It will cost you much more to do it when the engine is installed. Even if not replacing your clutch, clean magnetic pegs on the flywheel. These pegs send piston position signal to DME. Dirty, they impair the signal making starting of your car difficult. When installing and handling your engine be careful not to damage these pegs in the process. Just incase you decide to clean some carbon deposit on the top of your pistons, remember not to use anything that is acid based. Someone we know, used "Easy Off" oven cleaner for the job. He left it to soak overnight. It lifted the carbon better than any automotive product on the market! However, it also ate through the cylinder walls as well, all around the piston's head to be precise. Good quality injector cleaner should do the job right without a damage to the cylinder walls.
Many people overlook the small orange gasket ring the size of a quarter, located inside balance shafts rear plug. This little gizmo shrinks and contributes to untraceable pesky oil leak. Somehow, this seal is not a part of any set sold today. Always ask for it when rebuilding. Pay particular attention to the cork seal at the end of the camshaft. Many 944 engines have oil leaks right from that spot. In many cases camshaft not need to be replaced unless wear is clearly visible on the lobes.
Remember to disassemble and clean your pressure relief valve. Two "O" rings must be replaced as well. Pay surgical attention when inserting this valve back in to its place. Make sure the "O" rings remain in their places during this operation. If not, you will ruin your rebuilt project.
Remember to fill your hydraulic lifters with oil before installing them back, else they will knock viciously when engine is started. And will continue to knock for days until full of oil. Use injector cleaner to wash down your idle regulator inside. If you have injector pulse tester you can jump the unit to see if operational else brief contact with 12 Volt DC unit will do. Soaking oxygen sensor in acetone works too to loosen the carbon deposits. All houses leading to and from the idle regulator must be replaced too.
We also flush-clean engines oil reservoir. It is a long black tube with yellow fill in cap.
FUEL DELIVERY
Keeping your old injectors in the newly rebuilt engine is like transplanting an old mans hart to the young boy"s body. Consider getting a rebuilt MAF unit and a new injector set with a new injector boot. Most if not all MAF units we see are bad. Why? Just grab your valet and pick your oldest credit card. Look at the magnetic strip. Do you see the lines of wear on it? After several years your magnetic strip is harder to read. The same magnetic strip that is on your card, is inside your MAF unit. Two copper prongs move about the magnetic strip back and forth relaying information to your DME unit. The last time your DME unit received legitimate information was probably 5 years ago! For this misdeed, the DME retards your timing to gepensate for the loss of data. You get less power available to the rear wheels as a result. All above thoughts brings me right in to the "Performance Chip" upgrade business. The car manufacturer, foreseeing engine abuse, builds some clever safety mechanism in to the electronic management system. I the smash, it basically takes a consideration of derivability vs. geponent failure. By anticipating failure your engine never worked at its peak. Simply put, properly designed chip basically removes safety consideration from the agenda delivering extra 15 to 20 HP. The engine must be up to the challenge, else no results will be realized.
...AND LAST
Buy your replacement parts from gepanies that do repair 944 cars for living and not from Acura to VW discount parts places. At the end, you will save, by getting proper advice and the parts you need. After all, you tell them what you WANT and they will gave you what you NEED and nothing more.
At 9xauto, Porsche restoration is our hobby and business. We are happy to help you even if you did not buy parts from us.