BLOWN HEAD GASKET

Not a great idea.

Solid head gaskets on these motors cause more problems than they cure. The liners stand proud of the deck to assure good sealing with conventional gaskets and copper is too hard to allow imbedding of the liner into the gasket. The end result is leakage of water and oil that some address by applying sealant during assembly. I have seen that cause all manner of problems but even worse is the head distortion caused by torqueing it to and uneven surface. The head is not rigid enough not to bend down at the sides, actually breaking the seal at the liners at the 3 and 9 O'clock positions. On the QV heads it also typically distorts badly enough that the valves leak at the seats as well. The heads are elastic enough that upon unscrewing the nuts it returns to shape and all that leakage stops.

This all even takes place, but to a lesser degree with some composition head gaskets that use a very hard base material.

 

Talk to Nick at Nicks forza Ferrari. They have been boring and stroking and blowing 308's for awhile. I'm sure he could help

 

I have been using rather plain composition aftermarket head gaskets from a custom head gasket maker in high compression motors and F40 motors with zero problems. It becomes a matter of quality of materials, quality of assembly, quality of fasteners (I never use the Ferrari trash) and boost level. Also detonation will kill head gaskets so that needs to be avoided at all costs.

 

Head gasket failures usually manifest themselves as either external oil or water leaks.

Under normal circumstances compression leaks or exchanging fluids is quite uncommon.

 

Just checking here, are you saying to remove the old head studs?

 

Hi Oz, yes just what I was thinking ;-)

 

Take a look at cometic gaskets. Been running those in my drag cars for years and now have a trouble free set in my 308. Superior to the stock elring gaskets in my opinion.

 

http://www.summitracing.com/parts/cgt-c4428-045/overview/make/ferrari

-Barf

 

RE: Detonation

I experienced detonation twice in my 5.0 Mark VII. Possitive displacement Kenne Bell at 7.5 psi. Like I hit a brick wall when the engine tried to turn backwards at 3,500 rpm. Normally you either blow a head gasket or scatter parts across the contryside. In my case nothing broke at all. So the Ford Small Block has earned my respect.

It was my own doing since I locked 2nd gear and applied full throttle at about 3,500 rpm. That was too fast for the fuel management unit to spike the fuel pressure. [This never happened when I let the AOD transmission do its own thing.

However, that set aside, I recommend a boost timing retard unit if you have not already done so.

 

What psi where you running?

 

MSD sells a unit that retards timing when it sees boost. It has a simple hose connection to splice into the manifold air flow someplace after the supercharger. It is also adjustible to how much boost will activate it and perhaps even how much you want it to retard.

The unit has timing trigger in/out wiring. It intercepts the trigger pulse and delays sending it to the coils. One concern with our cars is access to the timing trigger wire. It activates TWO coil packs and you would need take that into account. I suppose you could disconect both at the coils. Send one to the MSD unit and split the MSD outlet wires, one to each coil.

The unit is especially useful on centrifugal superchargers because they do not give much boost before 3,000 rpms. [On my positive displacement supercharger full boost would come on at 2,000 rpms. However, on the Mark VII the stock 10 degress btdc can be bumped to 14 degrees and there is a big difference in torque up to 3,000 rpm.]

The trouble was a big need to radically reduce timing after that. So I had a micro switch to turn the boost timing retard on. You will not need to do that with a centrifugal. I am not sure the best amount of retard on our Mondis. However, after about 3,000 rpm it does not make that much difference on power.

You are running 7.5 psi which is a nice tame boost. I would start rather agressively since retard power loss is not much at high rpm. Perhaps start retard at 4psi and retard to deduct 4 degrees? Ask around. Or contact MSD.

I have used various MSD products for decades and they have always worked well. I installed mine so long ago I forget particulars, but I remember the most serious problem was finding a place to mount the small box. It was about half the size of a cigar box.

 

MSD 6 BTM (or perhaps newer version).

Can be adjusted from 4 to 8 cylinders.

Not sure about dual coil, worst case is one box per side.

It has a manually adjustable timing retard switch inside the cockpit. It is timing degrees per psi. I used to run one on my Audi turbo 5 cyl, running 24 psi (stock 11 psi). I ran 1/4 degree per psi, so 24 psi was 6 degrees. It pulled hard!!

But at 7 ish psi, I wouldn't bother. That is pretty low boost, If you are getting detonation, something else is not right. Check the fueling maps as well as the fuel pump and fuel filters. Sounds more like not enough fuel.

Regards,
Jerry

 

We recently stopped using cometic gaskets, too many problems with quality control and basically they not caring about it. Using a new mfg and testing them out this yr. Always a PITA to do R&D of this nature but it needs to be done.

As Brian stated solid copper is not a good idea at all on these engines. Even MLS has it's issues even when going to a flat deck. Then there are stud issues, won't touch the factory parts and getting them made is getting hyper expensive. M14 to M10/M11 is odd.

If I were you I'd strip the engine down and pull the liners and replace the 'O' rings as well.

 

Fuel starvation is deadly. I do not understand the fuel system in our cars. The intake has a flapper valve that opens ever further as more air is sucked into the engine. If you increase air flow by 50% [7.5 psi] I am not sure how the fuel system copes with it.

In my '91 Mark VII 5.0 the O2 sensor apparently managed to do it in fine fashion as long as the fuel line to the injectors had plenty of reserve pressure. That was achieved with a fuel return cut off valve that closed when it saw boost. I believe that about doubled the pressure. You would think that would send things haywire but it ran like a clock.

Further, my '91 5.0 Mark VII was speed density. There was NOTHING in the entire fuel system that actually measured air flow into the engine. In fact, The Manifold Absolute Pressure (MAP) sensor was fitted with a check valve - included in the supercharger kit - so that it would NOT see boost.

Accordingly the entire mixture was controlled by the O2 sensor as soon as boost came on. This seems analogous to our cars. I sort of doubt the flapper valve is actually able to open 50% more then stock. I could be mistaken. However. I would consider adding a higher volume fuel pump up stream. [I assume the fuel distribution system has its own pressure regulator separate from the fuel tank pump].

One last note. On my first installation at 5psi the fuel management unit (FMU) failed to activate under boost. Accordingly the fuel pressure to the injector rails did not spike. But I did not get detonation. I simply got fuel starvation at 4000 rpms. Weird.

So it can be a touchy business. I am building another Mark VII with possitive displacement Kenne Bell at 7.5 and am mulling whether to install higher flow injectors. The old car did just fine with the stupid dumb FMU so I am still mulling.

 

For CIS it's the WUR aka warm up fuel pressure regulator, but a specific one found on the turbo Porsche of similar vintage. Ferrari for what ever reason also used the same WUR as the turbo Porsche but it seems to be a spattering of which model got one, more random and probably based on available units during the assy. CIS if anything provides more fuel then you'll ever need, the vane though is a bit of restriction and delays throttle response.