308 Intake manifold gaskets and temp sensor

I am replacing the intake manifold gaskets on my 308 GTS. As you can see from the pictures, Ferrari gaskets were not used, and a bunch of rtv or silicone was used. I purchased the genuine Ferrari gaskets. I don’t think you are supposed to use rtv or silicone on these gaskets. Does anyone know for sure.?? I was going to install the gaskets dry…..
Also, where can I get the coolant temp sensor for this car – 78 euro 308. is there a bosch part number for it??
Thanks
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Those simple black flat gaskets seem like the stock parts to me (and they have a slight engineering flaw that might show up after ~10 years of use -- since yours have been replaced before, they only show the early stages of the "disease" -- see attached). Are your new "genuine Ferrari gaskets" of a different design/material?

If it was fresh-machined bare Aluminum that had never been contaminated with oils nor scratched from scrapping, I would have no concern about using the gaskets dry/bare, but, non-virgin, I'd be temped to use a thin, spray-on type sealer, but not RTV -- too slippery and too thick for this application with too much potential to ooze out.
View attachment 308 Intake Manifold Gaskets FML Tech Tip.doc

 

HI Steve, awesome writeup. Thanks. My new gaskets are from the dealer and are much thicker and a light green color – same color as cam cover gaskets. So, according to your article, I cut two - 15mm holes, and two - 25 mm holes as shown?-so 4 holes total? I did notice the buldging in my old gaskets when I removed them. And a light spray on sealer - any recommendations for that?

 

Yes, 4 holes in each gasket (although I did some hand shaping to even better match the areas where the bulging occurs) -- the goal is to remove that gasket material without compromising the gasket's general planar rigidity. Any records on how long that set had been in use? Mine, at ~12 years from birth, were fully bulged and completely blocked the flow from the side passages (although I never detected an operational symptom -- but maybe it shortened the outer cylinder's valve life).

Are the new gaskets still the same shape?

No specific recommendation on the spray, but it's a fairly common product -- I know Permatex makes one -- it's almost like a spray contact cement that stays tacky longer in feel, application, and thickness. Since the gasket material is changed, maybe not so necessary, but, if the clean-up is difficult (and it will be ) might be some insurance. If this gasket was just for sealing the air path it wouldn't be needed, but having some coolant weep out (after all the later reassembly work) would be an aggrevation.

 

hey Steve. as far as i can tell, those gaskets were put on in 1994 after an engine rebuild due to dropped valve. the passageways in the manifolds are completely blocked - is this how the cylinder heads get coolant? if so, they have not been getting any. incidentally, this is the source of my incurable vapor lock!!!!

 

Thanks for the time update. I wish someone was paying me to do thermal FEA on F heads , but, just guessing, you'd have to assume that, with those side passages blocked, the cooling would be less effective and less even so there'd be a greater difference between the hot and cold spots and the hot spots would be even hotter than usual.

If your 308 is still in bits, how did you confirm that this was "the source of my incurable vapor lock"?

 

Hi Steve, with the blocked coolant passageways, i am just assuming that the intense heat below the carbs due to no coolant there was my problem. unfortunately, i will never know, since i am dumping the carbs and going with throttle body injection.

 

If the new blue gaskets have the red sealant stripes around all the openings, then you shouldn't need any additional sealant.

 

Rather than just cut holes in the gasket opposite the water channel, would it be wise to cut out the gasket to match the water channel, ie: the cutout would reflect the whole passageway instead of a couple of holes, i can do this with applying purple dye (kind of like oil paint) on the head, putting the gasket on and cutting out the channel outlined by the purple stuff. or will this (huge cutout) defer from the integrity of the gasket???

 

Could you let us know what TBs you are going to use and what the rest of the setup will be? Haltech? etc, thanks

 

I actually did some hand trimming myself to better match the shapes in the larger areas, but I wouldn't cut it all away -- it would leave a long small strip that might shift sideways or get pushed out by the pressure.
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Steve, basically what you're doing is match porting gasket to the manifold for better flow, is this correct? Thanks.

 

No, it's: 1) removing the excess gasket material that gets "bulged" out from the intake manifold side and blocks the openings in the cylinder head, and 2) providing relief openings so that pressure can't build up behind the gasket in these areas to force it away from the intake manifold -- please see the WORD attachment in post #2. If the stock gasket remained perfectly flat over time, there'd be no problem, but it doesn't.

 

Thanks Steve, I saw where the bulge are forming, looks almost like a total blockage, excellent improvement by cutting excess gasket and enlarging tho holes.

 

Thanks Steve, Yes, i agree about cutting too much away as there would be one very long strip of gasket left hanging without too much support. I am configuring 4 TWM throttle bodies. I have setup the electromotive tec GT with 2 DFUs (direct Fire Units). All the sensors too - what a project. I will post a separate thread when i get closer to firing it up. see pic of the twm setup on my manifolds, pic of tec gt and of cylindr heads fo rreference of the water channel. - i was able to salvage ALL the old linkage from my webers - sweet setup
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thanks for the pics. are those 44mm? what do you expect in performance gains.

 

I believe they are 44mm bodies. I am looking for driveability mainly, tired of dinking with the carbs over the last 10 years. i live at 7800 feet, and drive to denver at 5280, and sometimes drive to 10,000 feet - the altitude and temp difference plays havoc with those carbs. from what i have read, the performance is gained by a much more efficient management of the injector pulses over the operating range, resulting in a better burn measured over all parameters dealing with temperature, engine temp, and altitude. Airflow is improved because there is no venturi in the throttle bodies. Also, since these throttle bodies mimic the webers, i will not be losing any of the gloroius intake music. There are so many parameters that can be dealt with by interfacing with a laptop to the tecGT module. Its all in the burn!!

 

Please tell us the ID of the manifolds @ carb also ID @ head. Then please ID of head. How do the manifolds match up to the heads? I quess that the manifold is not 44mm stock? I guess that the head port is 44mm? Thank You for your post.

 

Please tell us the ID of the manifolds @ carb also ID @ head. Then please ID of head. How do the manifolds match up to the heads? I quess that the manifold is not 44mm stock? I guess that the head port is 44mm? Thank You for your post.