3500 GTI Performance Modifications

I have done quite a few Italian engines now with significant modifications, it's not easy and it's a very slippery slope because you want to keep it looking original and keep it running as a road engine. I would highly recommend doing for little to a 3500 engine other than very minor easily reversible changes, such as maybe a small bump in compression. That's the extent I'd alter a 3500 engine, and I might not even do that.

Modifying any engine comes with a massive amount of other changes that are required to make it all work together, such is naturally aspirated engines. So if the compression and camshafts are even slightly altered, then the valve springs have to be considered, fuel/intake system and possibly the ignition curve will also have to be tuned to accommodate, and rotating assembly balanced again, are consideration to the intake/exhaust ports must also be given to the camshaft profile in question. The engine will also run hotter as a consequence. It is an awful lot on ones plate and in the end it will be an unknown quantity for any future owners, who may just want a standard 3500 engine.

I can tell you every old Maserati (and Ferrari for that matter) camshaft I have measured on a cam doctor shows a very lazy ramp speed, as in, the valve is opened and closed quite slowly. This allows for pretty light valve spring seat pressures, but at the penalty of somewhat poor performance. It was fine for the time, but even altering that camshaft profile a little by modern standards will lead to an awful lot of other things that will have to be dealt with for it to run right. Slippery slope.

 

Slippery slope, but still very interesting. Please keep us posted on anything & everything you find out.

 

John's answer in post 2 is golden wisdom.

Play around with Detroit engines, loads of cheap spares and kits but not a good idea for this motore.

I remember a grease monkey in Boca Raton ruining the engine of a Mistral Spyder 20 years ago because he thought he was smarter than the factory engineers...it ended up as a complete mess which in the end I sold to the late Doug Magnon who had had it put back to normal.

Furthermore classic Maseratis are traditionally not tampered with but kept original.

 

If you still want to spend a lot of money, find a second engine out of a too far gone Maserati and work with that but be advised, as you have been informed, changes to the engine performance require upgrades to other parts of the car. All in all, just as an overhaul to factory standards of a Maserati engine is not cheap, upgrades run will run so much more money.

Beware!

 

One other factor is that the lucas fuel injection does not like to be messed with and once the internals of the engine are reconfigured the fuel delivery system will no longer be in sync. I guess a modern electronic fuel injection could be crafted to work but at great expense. Kinsler can make anything work but just a rebuild of the existing metering unit as stock costs $15K with new injectors. Just did that very thing with the 5000 Indianapolis, I hesitate to think what a new system would cost.

If it is not broken, don't fix it!

 

Imho, a 3500 GT is an "old" classic Maserati to be restored as close as possible to its original condition, keeping its patina wherever possible.
It will never be a sports or even a GT car by today's standards!
Why attempting to "improve" its performance?

 

Certainly you can do weight reduction of internal parts but if you don't go to the next level, valve size, fuel injection modification, head work, etc. you really won't get much for your efforts or great improvements in performance. No one will see the internal weight modifications but I doubt the expense will be worth much without doing a great deal more and that will get very expensive and ruin the originality of the 3500. You are certainly entitled to do what you want as the car is yours but to what end?

 

Please note that there are not a lot, if any, of aftermarket upgrade parts for Maserati cars of this generation. There just isn't any demand to make significant changes. It is not a money thing as there are Maserati people who have the money to make performance upgrades but have not chosen to do so, particularly when it comes to cars with the Lucas fuel injection systems. There must be a reason for that and that should be clue as to why it is best to leave things as things as they come from the factory. If you want to make performance upgrades,, there are those who have done so but have switched over to Weber carburetors as they much much easier to work with when it comes to fuel delivery for enhanced performance but a mechanical Lucas system that is properly done is a great daily driving car that is more difficult to achieve with Weber carburetors.

 

I fully understand the question at hand here. I too would be most interested in any improvements available at this point of a rebuild. In this case, it appears that the basics of this engine are already good though. When I can, I try to use the various "coatings" on engine parts; ceramic coating the tops of the pistons, "wet" coating friction surfaces like piston skirts, valve stems, etc.... "Wet" coatings are a process that allows the surface to become more "slippery". There are various brands & names. Not sure if our crankshafts lend themselves to be nitrided or not, but his process gives the journals a very tough "skin" which if anything, should prolong the life of the crank. Grinding a radius on the oil holes of the crankshaft journals is always a good idea also, if they are not done already. A small radius at the hole allows for much better flow if the edge of the hole is sharp; as if it was just drilled.

 

I will admit, purely for academic purposes, I have ruminated on a fire-breathing 3500gt engine, call it a 3.5L version of a 300s engine, at least 350hp. I would never do it but I bet I could make something hilarious and it would remain almost entirely stock looking. A 3500gt is just not that kind of car, it would be entirely wrong.

 

FGM had the engine in one of his "recent"/sold 3500's built by "Ed Pink Racing" in LA, and had it built for extra HP, it was a rebuilt with basic upgrades and I believe they got close to 285 or 300 HP, so it is very possible to,... over bore/larger pistons, increase compression ratio, port the head and regrind the cams for better breathing, and total blueprinting,...it just costs $$$.

 

I'll bet it was done using Weber carburetors rather than Lucas fuel injection.