manifolds and exhaust valve clearance

Hi, (Bonjour en français)

I'm french

I speak english very badly, but I'm going to try to ask several questions :

I own a european 246 gt sold by Pozzy in 1971 on 12/03/1971. (N°1310)

The motor of my car has certainly be replaced by an "E" motor.

I have two questions to ask :

1 - What is the exhaust valve clearance ? On "M" model it is between 0.30 and 0.40 mm, on "E" model it is between 0.25 and 0.30, for the same motors....

2 - I purchase a stainless exhaust with superformance. but the two manifolds of my motor are too short (5 cm missing on each side). Superformance propose to replace the two manifolds. Two questions before purchasing these items : Is there a différence between exhaust on "E" and on "M" model ? If I must replace the manifolds, is the rear manifold can be replaced without remove the engine, may be I must remove the right fuel tank ?

Many thanks for your answers,

I'm sorry for my english language,

Congratulations for your forum where I have understood a lot of things about my car

Congratulation particularly to John Corbani for the dino sagas, and to omgjon for his extraordinary restoration !!!

Best regards

Gildas

 

Hi,

Sorry It isn't the rear manifold replacement which is difficult, but the front manifold that I would like to know if it can be replaced without removing the engine.

Best regards

Gildas

 

Gildas - Welcome to the world of Ferrari, and to FerrariChat in particular. You will find a great deal of expertise and help from around the world.

First, I am working from memory. My comments below should be verified by removing the exhaust manifold nuts. Then simply try to lift the manifold out. You may find that it comes out quite easily.

Unfortunately, you will likely find it easier to remove the engine to replace the forward (front) exhaust manifold. I believe that it can be done with the engine in the car, but that the amount of work required, when balanced with the advantages of removing the engine, would lead me to remove the engine.

To remove and replace the forward manifold while in the car would require that the alternator be removed, along with its bracket. The right fuel tank would also have to come out of the car. (I assume that this car is not equipped with air conditioning - too early). In addition, the oil/water heat exchanger may have to find its way to the bench (be removed). This will depend on the added clearance provided by removing the fuel tank. Be careful when removing the fuel tank that the soft aluminum tubes are not bent when removing the old fuel vent hoses.

In addition, if you are re-adjusting the valve shim clearances, you will find this to be back-breaking work while leaning over the car (for the forward bank).

Another option would be to simply remove the engine mount bolts. This will allow for a little movement of the engine when hung from a cherry picker (engine hoist). One unforseen challenge can occur if the exhaust manifold studs are too long. The forward clearance - to the firewall - is quite tight, and if the studs are too long you may not be able to free the manifold from the studs. Removing the engine mount bolts and hanging the engine from the lift will provide for a few centimeters of movement, which will greatly ease the task.

Finally, removing the engine is quite easy, and provides opportunity to replace all of the rubber hoses, adjust the valves on the bench, detail the engine bay, etc.

Good luck with your project. My opinion, and many may offer other thoughts, is that removing the engine will ultimately save you time and frustration.

Jim S.

 

Dear Jim,

Many thanks for your response so quick !

I have understood that it is easier to remove the engine in front of the difficult to work between the firewall and the engine.

Concerning the valve clearance, I just finish to check it after replacing nine spacers.

Note : I was surprised : The spacers are all and rapidly available in FIAT from 325 to 490. Price in France : 9,10 euros VAT included

Valve clearance are now :

exhaust inlet

cyl 1 : 0.30 0.18
cyl 2 : 0.31 0.15
cyl 3 : 0.30 0.17
cyl 4 : 0.27 0.15
cyl 5 : 0.30 0.16
cyl 6 : 0.30 0.18

Concerning the exhaust valve clearence, I have prefered staying around 0.30 which is the ultimate clearance up for later engine and down for earlier engine.

I hope that it's a good idea ? I think that it is better that the clearances are upper than lower especially with the unleaded petrol.

I have and other question concerning my column switches light whose I have broken the head light switch with my knee !

I would like if it is possible to buy only this switch, because it is easy to replace on the column, and the complete column switches is very expensive (900 euros - 1400 US $) ?

May be I must open a other thread for this question ?

Best regards

Gildas

 

Gildas - your English is better than mine...Anyone who can learn two or more languages can fix Ferraris with their eyes closed. I, however, must keep my eyes open as I am not smart enough to learn a 2nd language.

The early Dinos called for a larger cam-shim clearance. This specification was later changed to provide for a tighter clearance...there were issues with too much wear and too much noise. Imagine that...someone complaining about mechanical noise emanating from a Ferrari engine.


I believe that 0.25 to 0.30 millimeters (mm) (.010 to .012 inches) is the specified clearance for the later cars. If one is unable to adjust in the middle, then it is best to err on the side of too loose. Your measurements suggest that you are perfect.

By the way, you can obtain the spacer shims from Volvo...I believe that they will cost less. You are paying a bit more than I have found them here in the U.S. (approximately $3.00 each).

As far as the steering column switch, I am afraid that you are out of luck. I do not know of anyone that makes only the headlight stalk (stick). The entire steering wheel switch assembly (directional, windshield wipers, headlights) can be rebuilt here in the U.S. for approximately $1200. It is very expensive, wherever you are in the universe.

If you have already adjusted the valve shim clearance, then you have accomplished much of the heavy lifting (hard work), and you may decide to try to remove the exhaust manifold without taking the engine out of the car. By loosening the engine mounts AND SEPARATING THE TRANSMISION LINKAGE, you may provide enough clearance to accomplish the task without removing the engine.

Jim S.

 

Hi

I will try to be brief, but do not apologise for your english, seems OK to me!!

1. Your Exhaust clearances appear to be OK, as you quite rightly point out, stay nearer the upper end of the specification. You may want to check No 2 again.

2. Do not be tempted to reuse old ones, flip them over once only, but if you are unsure then replace. Much cheaper than new camshafts.

3. When you have finished the shims, turn the engine over several times (dont start) and then recheck before replacing the covers. If its very hot were you live (above 35C) for example, try doing them in the morning before the Sun gets to hot

4.You do not need to remove the Engine to do the front exhaust manifold. You need a car hoist really but a ramp works OK. As Jim rightly points out you need to remove the alternator and ancillaries. However i didnt have to remove the fuel tank, engine mounts or heat exchanger when i did this some years back. Take the exhaust manifold out past the clutch housing. It is very awkward and does make you swear alot, but the joy of defeating what is a challenging task is a reward in itself.

Good luck.

Tony

 

Dear Jim, dear Tony,

Many thanks for your precious informations.

According these ones, I think that I'm going to replace the front manifold by a new which will be bought with Superformance. I note that it easier to remove it by the left side (clutch side). I haven't think up this way ! In fact, I have already removed the right tank in order to restore the wiring loom. So two ways are now possible !

Concerning the shims, I'm going to replace the last old shims too. I have seen that the surface of the old shims is a little scored, while the lobes of the four camshaft are perfect. The new shim's surface is brown, while the old shim's surfaced is polished. I have placed them without polish it, to preserve the surface treatment.

Concerning the temperature, I live in Brittany, in Quiberon Bay, facing the ocean, so it isn't a hot country. Temperature is between 17 to 24 °Celsius. So I can verify the valve clearance anytime...
(Note : Quiberon Bay is important for USA history because, it's, just in front of my house, that the American flag, the Stars and Stripes, was recognized for the first time by a stranger nation, the 14 february 1778 : The USS Ranger under commander John Paul Jones was saluted by France represented by the french fleet under Admiral La Motte Piquet for the first time of the USA history. Ranger fired a 13 gun salute, answered by the French with 11 guns).

Concerning my steering column switches, I have noted that the head light switch is the same mounted on Daytona, or on all the 70's ferrari. I have remove it, it's easy. Before purchasing a new steering column switch, I'm going to try to restore it with synthetic resin.

I join pics

Best regards

Gildas
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Hi Gildas

If you haven't removed the heads or cams then everything should be OK. Temperature does play an important part in setting up the shims. If you are not in a hurry to do the job, then leave them for a while and recheck. Turn the engine in the opposite direction to how you first did it.

It shouldnt make much difference but does help to settle the shims down in their seats.

Those shims you removed were only good for another 1500 miles then it would have started on the cams, wise choice

Cannot help you with the headlamp stalk as we cannot get them over here, i believe the Superformance ones are in fact 308's and are no good for the 246.

Tony