refinish plenum on 308 QV

mask it off an paint in place. taking it apart just for paint is asking for trouble. like little washers hiding under there just waiting to drop down inside the manifold. if you did a search then you read about the problems you could run into. "if it ain't broke don't fix it". i did mine in place and it looks fine. i think i posted a pic in a former thread on the subject.

 

I recently cleaned-up the plenum and throttle body on my 328. Not the same color scheme as the 308 but.... I took off all the throttle linkage but I did not remove the throttle plate and shaft. If you carefully document everything before starting you should be able to put it back together without anything being out of adjustment.

If you're not fully confident about the job I would try doing it with the parts in place first and see how you like the results. Or just remove the throttle body. Murphy's law and all that.....

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Is the plenum for the 308 QV powder coated?
and if it's not, is it a good Idea to powder coat it?

 

I don't know if the 308 or 328 is powder coated. I think the red portion on the 328 is powder coating.

The silver portion on my plenum was painted kind of a silver/gray from the factory. I removed the paint with abrasive blasting and then sprayed-on, clear, high-temp. paint. Same with the trottle body.

 

Here are some past threads on the subject (some are from the "archives", so there may not be any pics):

http://www.ferrarichat.com/forum/showthread.php?t=16536&highlight=308+plenum

http://www.ferrarichat.com/discus/messages/256120/4741.html

http://www.ferrarichat.com/discus/messages/256120/8709.html?1018146687

http://www.ferrarichat.com/forum/showthread.php?t=26660&highlight=308+plenum

Removal of the throttle assembly is fairly easy and straightforward from my recollection. Be very careful when removing / lifting the plenum from the intakes as there are spacers there which the bolts go through between the plenum and intake, and they can very easily fall into the intake if not careful.

Regular paint stripper works well for stripping the old paint off the plenum. Use a wire brush and rag to get into the crevices.

 

Man that is a nice bay! How did you get the aluminum looking so clean?!

 

Well, it is easy to have it so clean. I took a lot of parts off and cleaned them The engine has not been run since. Once I drive it again it may not look so pretty in a couple of months.

I spray my engine with a garden hose after using degreaser. You just have to be a little bit careful and have a can of WD-40. Spray things down with the WD-40 when you are done, especially the coils, plug wires and distributors. Then start the car and go for a drive to dry off any remaining water. You should be okay. A pressure washer may be a bit powerful to use in this engine bay.

If you get any water into an electrical connector by mistake just take it apart and spray WD-40 into both connectors.


Joe, I removed the valve covers, intake manifolds, plenum and throttle body and then abrasive blasted them. Then I sprayed them with high-temp clear paint.

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There are pins on the bottom of my intake manifold that kept the rubber gaskets on the plenum. Then I used some vaseline to keep the metal spacers on the studs.

Open your radiator drain plug or loosen one of the lower coolant hoses to drop the level of your coolant throughout the system. Then you should not have much spill onto the block. Why not just change all the coolant unless it has been done recently?

The little hose is hard from old age and heat. Mine was normal rubber. I replaced it with a silicone hose. It sounds like maybe you should consider changing all your coolant hoses instead of one by one or when one springs a leak. How are your fuel hoses? They may need it too. There are a lot of hoses on these cars and all kinds of different sizes! A real pain to change some of them but once you do it you should be good for 10 years and you'll have the peace of mind that comes with knowing none of them are going to burst.

 

No problem Kim.

The compression and leak down test have nothing to do with the fuel lines/fuel system. If you have fuel injection I would not worry about any of the plastic lines that feed the injectors but all the other rubber fuel lines I would change.

If you will be changing all the coolant hoses then you will pretty much lose all your coolant so you will be doing a coolant change anyway. Not a bad thing. I change coolant every two years and brake fluid every year.

The expansion tank is where you re-fill the system on any car with an expansion tank. Make sure your heater controls (probably levers on your car) are set to max. heat. Not the heater fan but the controls that allow maximum hot water to flow in the little radiator in the cockpit. This helps avoid air pockets in the little radiator and hoses feeding it. There should be a bleed screw somewhere on the top of your radiator. Open this with the engine running and close it when only water (no more air) comes out. You may have to do this a few times. The 328 has a bleed screw on the thermostat housing also. Maybe not on the 308. I would drive around the block a number of times with the expansion tank cap off until you reach full temp. (fans come on). Drive easily and you will not overheat or spill coolant out of the tank. Add more coolant as you go along to keep it at the correct level. Eventually you should get all the air out. Mid-engined cars take a little more time and effort in this respect.

What can I say about taking things off/apart? It's the only way to get experience. Document.. take notes, make drawings and take photos. If you don't drive your car in winter then this is a perfect winter project. Go slowly, take your time. Never forget.... the more things you take off the more things you will find wrong or the more things you will want to change "while you're at it." My cambelts and bearings change turned into a huge project for me. One year later and I'm close to being finished! Granted, I didn't do much work in the winter. In retrospect that is exactly when I should have done more work. Now with the beautiful Autumn weather I'm laying on the floor in my garage instead of driving :-(

 

What kind of paint did you use? I am wondering if we can get it here. I've never seen high-temp clear.

 

The spray paint is called Dupli-Color Tuning Supertherm "clear 500 degrees C heat-resistant" made by Motip Dupli GmbH
On the can it says it's a special silicone-based heat resistant paint. After spraying you're supposed to expose the part to 160 degree centigrade heat to harden the paint.

I would doubt if they have it in the U.S but I would think there must be some equivalent.

 

We have Dupli-color here, but I've never heard of that product. I'll head to the hardware store and see if they can order it. Thanks for the help!

 

If they don't stock it maybe they can special order it for you. I think I paid about 10 Euro (around $13.00) for a medium size can (400ml). I can't comment on its performance because I haven't run my engine yet but generally speaking Germans make pretty good paints, chemicals, greases etc.

Good luck

 

You're welcome Kim. I think I misunderstood you initially. I thought you were referring to a leakdown test where they check how well the valves and piston rings are sealing. It seems the check they did was to see how long the fuel accumulator on your car will hold fuel pressure after you turn the engine off. It should hold pressure for a certain amount of time. Otherwise you can have problems re-starting the engine if it's hot. In any event, this test will certainly NOT tell you if all your fuel hoses are okay.

See if you can get a parts manual for your car. Either on paper or CD (ebay?). It helps a lot when trying to figure things out.

Erich