the lvferraripilot engine rebuild thread

Total timing is not coming in until about 6200rpm. While I have quite a bit coming in at 2000-3000, I don't think it is affecting the upper power band. I just sounds like the engine is starving for fuel by say about 6k causing the plugs to get really scorched and before knocking by 6500rpm. I could help things a little by backing off timing but the lean condition wasn't making anything easy

 

Update:

I installed autolite AR50 race plugs which are fantastic btw and rejetted the carbs again. I fire the engine and go through my usual warm up process and proceed to go for a drive. The engine is running substantially better.

I noticed above 4k rpm ish under load the engine cut out as if the ignition system cut things off or jetting was far too fat etc. First thing I do is check the plugs. All looks right. Second, I check the ignition at various rpms while not under any load. All is right. After much head scratching, I peered down below my distributor and noticed the rather low-tech solid-state square box fuel pump taking up space in my high performance engine compartment.

The fuel pump is a facet unit the PO must have installed at some time due to the OEM unit dying. I searched for a receipt for this service but could not locate one. No worries, I looked up the specs and found this to be a 30GPM unit with about 6psi max. This may have been enough for my previous engine but this is not even to OEM standards. Matter of fact, I am surprised the engine ran so well prior to this rebuild with this anemic little pump barely fit for a stock alfa engine.

Replacement will be one of these nifty 110gpm capable Holley blue fuel pumps. They are set to about 8psi stock. Well, they used to be blue, now they are just called 'blue'. I used one of these in the past when I had an identical issue with a Maserati Merak ss engine I rebuilt. Worked beautifully.
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Did a little more research and am going to use a Carter 4070 fuel pump available from Napa. They are about 5psi but have fabulous volume or 72gph. No regulator needed and easier to mount.


I have decided to mount the P6 cams. I drive the car over 3500rpm almost all the time so I figure they might be a good fit. I have run into a couple issues I am currently overcoming.

First:
The P6 cams I have had the early style distributor cam extensions which I removed. The later style are the splined extensions most everyone has, but the issue is the splined extension outer diameter is about .080 less than the earlier extension. I made a sleeve on a lathe which makes up the difference. No problemo. Note: removing the pin to get these extensions out is quite difficult.

Second:
The pins which hold the early camshaft extensions are drilled deeper on the journal than the later which means a new hole must be drilled and back cut so the pin mounts a few tho past flush with the journal just as the factory did. Not a big deal for a good machinist with a mill and a carbide bit. The cam is of course case hardened so the carbide bit in question will probably die after this one job.


below is a pic of the fuel pump and a pic of the proper type of hole I will need to drill from the stock cams
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I was told the 5psi Carter pump requires no regulator as the psi is perfect for webers. Did you use the 7psi Carter pump?

 

Here we go. Drilled and pinned P6 cams. A .090 sleeve was made to fit between the cam extension and cam itself to make up for the difference in diameters. The case hardened cam is surprisingly easy to drill. A roll pin was used to keep everything tight, not that everything didn't fit tight already! Great tolerances. This one took a good amount of time.

A pic of the early style cam extension is attached. Please note they are NOT interchangeable with the splined cam extensions and the sleeve is a b*$%^ to make.
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I saw the pin with peened over ends as a flaw on Ferrari's part as there was less than a few thousandths holding the pin in place. With this there is positive contact greater than Ferrari's method. I thought long and hard about Ferrari's pin method and went back and forth several times. Not going to worry about it. She will be fine

 

I saw the pin with peened over ends as a flaw on Ferrari's part as there was less than a few thousandths holding the pin in place. With this there is positive contact greater than Ferrari's method. I thought long and hard about Ferrari's pin method and went back and forth several times. Not going to worry about it. There is lots of tension in there. She will be fine

 

How on earth did that get double posted..............

 

P6 cams dialed in last night. Note: degreeing the 5-8 bank cams is stupid difficult. Took me 3 hours for that one side most of the time was spent figuring out how the dial indicator fit. I ended up mounting the thing at an odd angle off the head with the arms getting the dial indicator in place. Barely!

Surprisingly, the timing marks on these cams are dead on with the specs.

All else will be bolted on later today and I should have it fired up by tonight.

 

P6 cams fired up. Took a while for this one, but once it fired up it was as if someone attached a solid rocket booster to the crank counterweights because this thing revs with the alacrity of a new Ferrari V8. Quick revving.................oh, and there's a snarl to it now.


Didn't drive the car as it was too late and dark etc. I will make a vid and post it later.

Cranking compression prior to this was about 170-175lbs per cylinder with stock cams timed at 110 degree lobe centers. Cranking compression with the P6 cams is down 10lbs. No biggie. For those of you who do not know what these cams are, they are big. Really big. The intake valve is closing much later with these and there is a ton of overlap.

Here's the best part. It idles fine :0) Can't wait to drive it

 

About 270-280 @ 7500-8000rpm at the flywheel with 32mm venturis. 34mm or 36mm with different jetting could probably get it up close to 290 but a lot of low end vacuum and driveability would be lost. 36mm is what Ferrari ran at lemans with this setup.

Glad you like my adjectives!

 

Not too long ago an identical engine was built with 32mm chokes and made 277 @ 7700rpm. Another 10bhp from 36mm chokes and different jetting is not a stretch. I have the dyno sheet at work somewhere.....But I've posted it before

 

found it
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