VALVE JOB

[sharpshooter90]

Here's a little project I did recently- nothing fancy, but it saved a lot of money. A friend's son has a Nissan sports car with a V 6 motor and twin turbos- According to the boy, it just suddenly started smoking and quit running while he was driving at exactly the posted speed limit. Anyway, these cars are well made and have a lot of good features, but in order to do anything like change a turbo or grind the valves, you have to pull the motor out. So the kid fiddles around for a couple weeks and finally gets the motor out and I agree to help him with the re-build. We pulled the heads and find that one of the valves is burned like it was hit with an Oxy-Acetylene torch. He also has burned pistons etc. My guess was too much turbo boost somewhere. He checks with the dealer and then falls over in shock- they tell him the valves are titanium and can't be ground and the head requires special tools etc- so its going to cost at least 1000.00 just for the head work. The heads are OHC with 4 valves per cylinder, and like most OHC motors, they use tappet cups. However, these are like a hydraulic lifter, so they don't require that tedious changing of shims to set the lash. However, the springs and keepers are set deep into the head so a regular spring compressor won't work. The dealer has factory tools, but they don't sell or rent them. I thought, all we need is an extension, so I grabbed a piece of aluminum pipe and turned a recess in the end to fit over the OD of the keeper and cut some slots in the other end to grip with my old spring compressor. I then milled out a couple openings on the side to be able to pull out the keepers once the spring was compressed. That went pretty fast and within an hour we had all the valves out- sure enough, they must be titanium, as they are non magnetic. All but 3 were still seating ok - we did the solvent test before dis-assembling them. So we got out the trusty valve lapping compound and suction cup and after wire brushing the ports, we ( he ) lapped in all the good valves. Now came the tough part- putting those tiny keepers back in when the head of the valve is down in the hole. Not only is it hard to see, but the space is really tight. I tried all the old tricks- pencil magnet, screwdriver with grease on the tip, but we were fighting every valve for 10-15 minutes. I decided we needed something to hold both keepers in place and positively set them around the valve and into the retainer. I took a piece of round stock and drilled a recess the depth of the keeper and 11MM diameter which is the OD of the keepers when installed. I then drilled the center to 6MM and put in a little spring from a ball point pen and a piece of 6MM rod. I then magnetized the piece by wrapping wire around it and touching it to a car battery. Now the 2 keepers stick to the magnetic piece and the 6mm rod keeps them centered and aligned. As I push the tool down over the valve, the 6mm rod compresses and the keepers go down over the 6mm valve stem- once they are fully in place I just release the compressor and - voila!- they click in place. End result of this whole process was that we got all the valves lapped and installed, and only have to buy 3 new ones, plus the cost of head surfacing- Total time ( less tool inventing) was about 4 hours and he is ahead of the game about 900.00. Now we will start the block and pistons.

[pete from TN]

amazing how things look differently in the world when you have access to machine tools huh!! Great idea and good thinking. I suppose that is a 300z or something like that. Nice cars.... My father used to have a black 300zx twin turbo. Cannot remember the year but I liked the looks of it better than the new 350z. That is a nice car too tho...

I am into four wheeling and once was installing a clutch into a friends toyota rock crawler with him when we realized the kit did not come with an alignment tool. It was too late to get to the auto parts store in time and if you have ever tried to install a clutch plate without one it is no fun... SO I grabbed a scrap piece of aluminum from my bin and machined one sans splines on the lathe real quick and we had the clutch aligned and installed real quick. I have also repaired too many items under the hood of my samurai rock crawler to list. I made a bracket to support a GM 120 amp alternator so I can run offroad lights and a winch too... Could not imagine working on anything without having a mill and lathe nevermind cnc...peace

[sharpshooter90]

amazing how things look differently in the world when you have access to machine tools huh!! Great idea and good thinking. I suppose that is a 300z or something like that. Nice cars.... My father used to have a black 300zx twin turbo. Cannot remember the year but I liked the looks of it better than the new 350z. That is a nice car too tho...

I am into four wheeling and once was installing a clutch into a friends toyota rock crawler with him when we realized the kit did not come with an alignment tool. It was too late to get to the auto parts store in time and if you have ever tried to install a clutch plate without one it is no fun... SO I grabbed a scrap piece of aluminum from my bin and machined one sans splines on the lathe real quick and we had the clutch aligned and installed real quick. I have also repaired too many items under the hood of my samurai rock crawler to list. I made a bracket to support a GM 120 amp alternator so I can run offroad lights and a winch too... Could not imagine working on anything without having a mill and lathe nevermind cnc...peace

Pete,
Right-on. I have found that there are a couple of schools of thought in this field. There are those who's main concern is the perfection of the machine itself- they spend every waking hour measuring and worrying over tolerances etc. They seem compulsive about making every part to as near perfect as possible. I am of the other school- I see the machine as a tool to get a job done in the most practical manner possible. As you can see from my pictures, those parts are not made to any degree of tolerance- in fact little measuring was done. The whole idea was to avoid paying some dealer an arm and a leg to do what we could do ourselves with the right tools. We got them made- they worked, and most likely I will just toss them into the scrap barrell later, as I don't plan to go into the Nissan repair business. But just having the patriot in my shop allowed me to solve a problem and save a lot of money, and in my mind that is the real reason to own a machine.

[pete from TN]

you know that guy in the neighborhood that can do or make anything in his garage.... man was that guy cool huh!!!! peace