4.9l V8 Crankshaft

Hi fellahs.
Have stripped the 4.9 engine which will power my Tipo 151/3 tribute car.
The crankshaft is in good condition, but, the method of oiling the big end bearings is a little odd (through crank rather than via mains).
Has anyone here done work on improving the oil flow so that the rear con rod bearings get a better supply than as "the last orphan at the dinner table"?
Appreciate any input about work folks have done and what sort of result it provided.
A note to my everyday email [email protected] would be brilliant for any off-thread discussion.

Cheers

 

Check with Dr. Doll on this website and see if he will contact you about his fixes for the crankshaft oiling situation.

 

When previously trying to search out specifics regarding this crank, and motor generally, most mentions lack any real useful detail. Any guidence to the contrary most appreciated--my search clearly nsf.

No deficiencies have shown up in my uses, much as I may press the redline. However, racing is another level altogether, with sustained operations at the high margins. I'd like to see a 3d scan of the crank and mains... and any other crtical area.

As Dr. Doll is the most referenced expertise I've seen mentioned on this, and there just has to be historical comment in some detail previously, I'd surely appreciate findable reference that I can find.
Thanks in advance!

--NE

 

If memory serves some (all?) of the 450S motors had external oiling to deal with this. Probably be easiest to drill into the saddles from outside and plug the crank.

 

I'll search Dr Doll for comments, but last search I got swamped and didn't find 'himself'.
The odd design is that all main bearings are oiled directly from the gallery, but are un-drilled, so no feed goes from there to the big ends.
The crank is centre drilled through its entire length, then cross drilled from the big ends to the crank centre. The oil is fed from Main bearing #1 block tunnel to; heads/cams and the crank centre drilling plus perhaps a small feed off to chain oiler.
This means that oil is fed down the length of the crank from #1 to #8 big end in a snakelike flow path, with the last big ends being the orphans to any drop in pressure and flow at the end of the line. The old big end bearing conditions reflect this. Although still viable as shells, they show significantly more heat and oiling deficiency than others.
The other downside is that the cross drillings in the big end act as sludge traps, so all plugs in the crank need to be removed for cleaning, and there are a LOT of those.
So, I'm most interested to hear from anyone who has done any work on the cranks, which otherwise look great.

 

What ever happened with the super duper engine you were building? Were you able to finish it? Is it running? (I hope it didn't blow up on the launch pad.)

 

If the oil-feed to the last set of big-ends is wanting with the oil-pressure OK, it suggests that the drilling in the crank may be too small. This can of course be remedied relatively east, but you may then find that the capacity of the pump can't keep up demand, which in turn then necessitates for a larger capacity pump.

It may be possible to modify the system in such a way that the big-ends get fed from the mains. Mains would need a path in the shells, and I have no idea if there is enough 'meat' there to accomplish this.

Another way may be to reduce crank-pin diameters; there is less space for the oil to pass before it reaches the last set. Careful study of the crank and its' engineering calculations is needed to define how far one can go. I believe that the torional stability of the 4.9 crank isn't the greatest to start with, or perhaps it is the block that is unstable in this respect? Elliot, didn't you fit a stiffener?

These engines were not built with the same incredibly fine tolerances of today: they perform fine in normal use situations, but if you want to go racing you certainly want to go over things with a fine comb, i.e. blueprinting.

None of the above are cheap processes, and one may find that other parts prove to be the next weakest link.

Just my 2 cts,
Jack.

 

The original factory engine is supposed to go on the dyno on Tuesday, October 18, The only upgrades to that engine are fast road cams from Piper in England, lighter pistons, lighter connecting rods and intake valves that have be increased in size from 44 mm to 47 mm and some light porting and polishing. I don't have my hopes up for the actual test as there have been so many setback so far but if there is a G-d in heaven, then I will get to see the engine run in two weeks. Engine number two is still waiting the custom dry sump system. Otherwise all the other parts are ready for assembly. Engine number two, when assembled, will be an easier task to get running due to the fact that all the hard work will have been done on engine number one. If we do get the engine running on the 18th, I will post all the information generated on FerrariChat.

 

AS to the question about a stiffener in place of the standard main caps, yes I did use one supplied by Dr. Doll. It is a direct replacement for the main caps but requires different studs and some work on the block to use those custom studs. It is known that aluminum loses some of its strength over use and time so the idea was to offset this by using the block stiffener which transfers the main cap loads for each journal over the entire bottom end rather than just each cap take individual loads. I can contact Dr. Doll if there is a need for such a stiffener and have him deal directly with whomever might be interested.

 

Elliot, I seem to recall that you had a 4.9l V8 that you were fitting a custom FI setup to. Was that you, or am I mixing your engine up with someone else's?

 

Unfortunately, the initial conversion to fuel injection ran into a problem with the ECU that was chosen. When the problem with the ECU software couldn't be overcome, it was back to square one and another manufacturer's ECU was purchased. Currently we are going to use the latest ECU from Bosch, the MS 6.2. Due to the difference between the Bosch unit had the previous unit, a new harness was cobbled together for the dyno run. If the dyno run proves to be successful, then a permanent ECU harness will be constructed and put into the Bora. I'll let everyone know what happens after November 18th.

 

Thanks for the discussion fellahs.
We are considering the option to spark erode oilways from the main bearings to the big ends, machine an oil groove into the main bearing block channel, slightly modify the main bearing journal to take a wider (Ford) main bearing, and then put a girdle on the main bearing caps.
These large diameter journals have such high surface speed, raising the revs places an exponential load/degradation on the oil that is held there during each rotation.
The motor is going to be dry sumped, so we have plenty of oil pressure. Keeping oil flow to all the journals is key.
Interesting comments from you regarding porting and fuel injection.
We noted the 'edge' in both the intake and exhaust port castings which look to disturb airflow, so simply planning to ease these and possibly go up just a tad on intake valve size. We'll be running in historic racing so need to use period mechanical fuel injection as and when we get there, so if anyone has a Lucas 8 port mechanical injection pump, be most interested to discuss a purchase.
Another question; I've dropped an enquiry out to JE and Ross regarding higher compression pistons. Any advice regards a supplier for 9.5:1 pistons using the std bore and conrods?
Cheers and many thanks fellahs,
Ollie

 

Ross made me pistons for the standard engine 93.9 mm bore with about a 9.5 to 1 compression ratio. They looked very nice to me. We'll see how they do shortly.

 

Mine work fine. Had one set for a Ghibli that rattled cold but they were replaced and all is good now. Using Ross in high-rev 4.2 also with good results.

 

Great to see extensive objective details from real life experience. Thanks!! Please keep it going. I'd appreciate being copied or to have access to any offline documentation, pictures, etc.

My Bora well maintained here by Greg, at Historic Race Engineering. He has worked magic on much Exotica, including prior fuel injected, dry-sump, forced induction Bora 4.9 several years ago. As well, esteemed opinion may be available also from another expert here on winning high-horsepower domestic-engined cars, in several race formats including top dragsters and record-setting LSR at Bonneville. Tim, at Gibson Precision.

I've discussed this with them, related some prior details and features, and asked their opinions for my own interests... admittedly not so extreme as your own, as to my own Bora that I do not expect to race formally. Mine is not dry-sump, still 8.5 compression, still stock webers, but recent SS complete euro exhaust, sans corner cans. Hopefully they will read this discussion and contribute, if time available between clients.

Meanwhile, Bravo! Carry on...
Will continue following with much interest, and hope of maximum detail.

-- Ned
949.551.4770 mobile/text

 

There is a wealth of information (and of course, a fair bit of misinformation) in this forum and I'm most grateful for the input. The information trolled (dredged?) so far regarding crank harmonic damping and actual compression ratios is most illuminating. Haven't found the Dr Doll yet but his treatise on the 5 litre engine is of great benefit insofar as there are generic issues across the range of engines.
If in doubt, get back to basic principles when engine building.
As I'll be dry sumping this engine and fitting an electric pre-lube pump (as I have on the V12 for pre-start lube), we will be able to assess crankshaft oil flow on the bench, to each main and big end journal. It is looking more likely that we will modify the main bearing edge radius very slightly, fit a wider bearing shell (with a groove) and feed big ends from those.
Elliot, did the Ross piston come with a 'code'?
I haven't had a reply from them yet, but if I can provide them a code number, it'd be a huge bonus.
Cheers everyone. Really appreciate the input.
Ollie

 

Many high-performance high-stress engines use this very plan... so should have very convincing evidence to change away. Why is this engine provably inadequate? Looks otherwise.

What failures do you know of that were directly traceable to this design itself and not just inadequate preparation and between races re-inspection? Did not the Trepenier engine supposedly make well over 425hp without failures? Harmonic balancing can be finely done with great precision but it is not a simple process. Porting, blueprinting, etc should be done for any race engine. Piston choices and compression is a whole discussion apart, but no changes undertaken without sound evidence. Cams are a study unto themselves, but at least you have chains, not belts. Valvesprings can be an interesting discussion... and your tolerance for frequency of servicing.

If there's a fully disassembled engine available, can it be fully photo'd and even 3d scanned? What deadlines exist? What critical parts limitations are there? What ignition system? If there's class rules, what are they? When's the chassis ready, other milestones up to first track outing?

Maybe pursue some of this offline?

 

Hi Ned.
Will drop you an off thread note.
For other readers, my purpose for this discussion is to find out if anyone has done work on the cranks to support the ability to run the 4.9l motor in sustained med/high rev ranges, such as 4000 -6500 rpm.
The car we are building is a tribute Tipo 151 but we are taking care to meet;
Period construction, parts, intent and design as much as we can.
Race construction rules which meet more modern safety standards, yet also fulfil the historic 'limitations' expected for a period car.
Meet 'low volume vehicle certification rules' for road registration, yet also not compromise the historic build specifications (single unvented disc rotors, period tyres, etc, etc).
As you can imagine, it is a bit of a juggle, but the authorities are being very helpful.

Feel free to add your 5 cents worth.
Cheers

 

Capricorn has done a replacement crankshaft for a 5000 engine that made substantial changes to the design from the original and it performed rather well at high rpm. You might want to contact Capricorn and see what they can tell you bout the work they did.

 

Thanks Elliot. Appreciate the advice.
Cheers