The car has 125k on it now and for the last few years I have had problems with hesitation when cold and very slow coolant loss. Last year it became so bad ... Show morethat it felt like the car was being held back by something extremely heavy when cold. I gave it gas, but it just would not go. It was time for an intake rebuild and a change of the valley pan. I used RSMillars intake rebuilt page as a base of information.
RSMillars Intake Rebuilt Page.
This page is so good that I am not going to go through the same things that RSMillar has already said, only new things. Read this page before going forward if you are going to do this project.
Once I took the intake apart, I noticed a few things that made me want to go a little deeper then RS did. These things were:
1. the plastic intake ports right by the injectors and the runners in the head going down to the valves were extremely carbon fouled in 4 of the 8 ports. They needed to be cleaned.
The easy ones were quickly cleaned with carburator cleaner and a toothbrush. The 4 bad ones needed to have the carbon deposits scraped off the walls with a screwdriver and then the walls were cleaned with the carb fluid and a toothbrush. A few things you need to consider here. Some of the valves will be closed depending on the cycle, but a few will be open. What this means is that in some of the ports when you scrape the walls or spray the carb fluid it will just sit on the valves, but in a few you have to be carefull to make sure the large carbon deposts to not fall into past the valves and into the cylinder. I used a shop vac to pick up the carbon deposits after a few scrapes in the ports that had the valves open. Once I got all the heavy carbon deposits out, I sprayed the port with carb fluid and brushed with the toothbrush. I kept using the shop vac to pick up the carb fluid before repeating the procedure. It took 3-5 cleaning cycles to get the ports really clean. In the few ports were the valves were open and the carb fluid went down to the cylinder try to get what you can out the cylinder. What you will have to do is take the coils out, loosen the spark plugs, stuff rags in the valve covers to cover the spark plugs and turn the engine over to let the carb fluid escape through the loose spark plugs. The rags covering the spark plugs should soak up any carb fluid before it sprays in the engine compartment. You have to be carefull, because carb cleaner will spot and damage the paint in a second, so stuff a LOT of rags in there. That is also why I was using the shop vac to pick this stuff out of the ports instead of using air to blow it out. If I used air, it would just spray carb cleaner ALL over the engine compartment and spot the paint wherever it hit. If you have a vac with a super small collector, you may be able to just vacumm it all out anyway. I could not, so this was my best option. If you do not get all of the carb cleaner out, them your motor will not turn over when you attempt to start it. It will lock up. With the loose plugs, you should be able to blow any fluid out the cylinder, have the rags stop it from spraying all over, and have the engine crank over easily. The trick is to have the spark plugs loose enough to let the fluid pass, but not so loose that they will blow out themselves.
2. The next thing I noticed was in the intake manifold itself. All the runners have nice round openings at the top and bottom, but the sides are sharp angles and pointed toward the inside of the port.
I wanted to have the best, least restricted air flow possible, so I used a small file to round out the side walls.
3. The reason for my intake leaks was one of the bottom orange rubber gaskets. It was probably incorrectly installed and just deteriorated with time.
If you are doing the valley pan, some things to consider:
There is very little difference in the old valley pan vs. the new one. The rubber gasket that goes around the edges is glued on. If you are working on a very tight budget, you can just use a good gasket maker to seal up the valley pan.
The parts guy at the dealer where I purchased my supplies for this project asked me if I had oil stains in the valley pan. I did not. He said they have seen cars with the oil stains in the valley pan and the reason was the BMW EGR valve blocking up. The BMW EGR valve is the center piece in the back plate of the intake manifold. About a $70 item, so make sure you really need it before you spend the money. If you do not have the oil stains in the valley pan, then just get all new gaskets, including the blue ring that seals the aluminum tube that runs by the left head.
The round rubber rings for the water manifold pipes and the EGR Valve are easy to put in their respective places. The problem is to put the pipes in or over them. It is really hard to assemble the water manifold back section and to connect it with the front untill you apply some oil on the rubber rings to help push the pipes into the front and rear manifolds and screw the rear manifold bolts into the block.
Last item I did was sand and paint the valve covers in an aluminum color. The old paint was flaking and looked like crap. Show Less
JB Racing Aluminum Flywheel and Spec Stage 3 Clutch
ARE YOU SURE YOU ARE HAPPY WITH THIS?
PRETTY AND SAFETY WIRED FOR ADDED PROTECTION.
I WOULD RATH... Show moreER HAVE THIS FOR @ $1500
This was the culprit for my cluch jamming. VERY LIGHT sanding takes out the clutch jamming spots. @ $100 part to replace.
VERY NICE ORGANIC STAGE 3 CLUTCH
Parts provided with the JB flywheel, new bolts and bolt pressure plate. Lock-tite and safety wiring was for OVERKILL. Show Less