What to do with this lot !!!

shawn63deluxe · Post by **shawn63deluxe** » Sun Feb 27, 2005 11:10 pm

Hi all, posted on the welcome section earlier now i'll give you an idea of my plans,
I have a '69 2.0E MFI motor requiring a rebuild, it is complete apart from the fan & alt, it also has some of the linkage between the throttle bodies missing.
I also have a '73 2.4 carb motor that has had the rod exit the case and barrel on no. 3.
I have a full set of '69T complete heads with excellent valves, one of the heads has the thread that the stud screws into snap off but doesn't look impossible to repair.

My problem is that I wanted to make a 2.4/2.7 out of this lot using my 2.0 case but would like to use the Mfi for maximum power, the 2.0 heads are not the best design and i have 5 heads from the 2.4 that will have bigger valves, can these be machined to accept the mfi injectors-i obviously need to source one barrel.
Are the small short linkages between the bodies easy to come by and is the mfi really difficult to set up??
i've got some tubular headers with the 2.0 engine but would then have probs with the cold start set up.
The engines have their respective flywheels which i do not need and would need to sell.

Should I sell this lot ( the pump must be relatively pricey ) and start again with a complete runner or soldier on / does anybody have a runner to exchange etc ? i'd be happy to go with carbs if necessary.

Any advice would be greatly appreciated and my apologies for so many dumb questions from the start !

ChrisF · Post by **ChrisF** » Tue Mar 01, 2005 8:33 am

I have been looking at building a 2.7 or 2.9 and have come to the following conlusions about a spec.

I am planning to use early aluminium crankcases as these are supposed to be stronger than the later magnesium blocks and may not have suffered with as many stud problems.

I still plan to fit Timeserts to stop studs pulling out.

I have ordered some Nikasil barrels form the States and some JE forged pistons.

I still need to find a 2.4 "S" crank to get the capacity.

I have sent a set of heads to a Porsche specialist in the States to have them ported and larger valves fitted.

I plan to have the crankcases boat tailed, the barrels half-mooned and the crank kife edged.

We also intend to fit anti-shuffle pins, piston squirters (and mod the oil system to suit) and a turbo oil pump.

I will probably use 46IDA Carbs on tall PMO manifolds as I have read several articles which suggest that throttle response is better on carbs but the real reason is that I believe they will be easier to set up.

I haven't chosen cams yet but hope to have looked at the alternatives and decided in the next couple of weeks.

Luke · Post by **Luke** » Tue Mar 01, 2005 9:28 am

that's one hell of an engine your building there Chris!! Sounds mighty, mighty expensive though!

Shawn,

The old 2.0 ltr sand-cast cases are apparently the best to build any engine on as they are verfy strong, but do need serious modification to turn itnot useabel larger capacity engines, not least a widening of the spigts, oil squirtered and intermediate bearing mods.

If your 73 case is a "7R" that would be just as good to use and has most althoguh not all of the case moidfiactions that all the yanks tell use us indespensible.

I think the first thing you need to decide is what are looking for form the engine? 250bhp twin plugged screaming hell cat with little torque, or a more torquey less revvy unit. What's the engine going to go in? be used for?

ChrisF · Post by **ChrisF** » Tue Mar 01, 2005 1:38 pm

Luuk,

Do you have any details of the spigot and intermediate bearing mods.

I think I have most of the other information.

I thought that the problem with 7R cases was the likelyhood of the studs pulling out and that it was more or less essential to use case savers or is this only the case when the engine was already a 2.7.

If a 2 litre 7R isn't a problem I may change my plans and find a 7R block.

I have access to a 2.2 litre S engine at the moment but I am not sure if this is a 7R or not so I guess i need to spend the evening reading up.

Luke · Post by **Luke** » Tue Mar 01, 2005 2:33 pm

Chris, 7R's were from 1973ish onwards, a 2.4 with 7R case is unlikley to have any head stud problems associated with 2.7ltr engines, although it would be prudent to time-cert or case-save them anyway.

I'll check the books for data on the spigots and intermediate bearing issues, as I didn't have a 2.0 case when i looked into all this I didn't pay too much attention!

the 2.2 won't be a 7R case

shawn63deluxe · Post by **shawn63deluxe** » Tue Mar 01, 2005 3:53 pm

Hi Luke, thanks for the reply. Firstly the 2.0 mag case is very solid and already recently case saved, the 2.4 is apparently 2.7 cup spec inside but I haven't even had time to open it up to check, more importantly the no. 3 rod has exited the case and barrel leaving those parts unuseable, everything else should be usable.
I have decided over the last few days to sell on the 2.0 mfi set up as I simply do not have the time to set it up etc, weber ida's are my plan!
The engine is destined for my 63 split bus (see the new members section) so it would be lethal to make it any more than a nice usable mildly modded 2.4/2.7. I am a self employed property maintenance contractor and the cash jobs come in thick and fast so this is an ideal project to use some of that cash, that is why I am in no real hurry either, I realise that doing all this work on a 2.0 case is not the most economical way of doing it but short of a 2.4/2.7 block being available (are there any out there?) it's the easy option at the mo!
i'll get some photo's sorted of all my spares and post them up on the for sale section.
Cheers, Shawn.

Lightweight_911 · Post by **Lightweight_911** » Tue Mar 01, 2005 7:09 pm

Chris - you don't need to look specifically for a 2.4S crank. By the time the 2.4 models were introduced all models (T/E/S) used the same crank.

PAUL CALDERBANK · Post by **PAUL CALDERBANK** » Wed Mar 02, 2005 1:23 pm

I plan to have the crankcases boat tailed, the barrels half-mooned and the crank kife edged.

Just curious........what's boat tailing?
Come to think of it, what does the rest do specifically? half mooned and knife edged is fairly self explanitory in terms of what you're doing to the individual components, but what exactly does it do to help improve the engine performance.
Whilst I understand the basics of how engines work, I don't know much about the modification side of things. Does it show!!?!

Alan @ CanfordClassics · Wed Mar 02, 2005 5:15 pm

Hi Paul,

How's the 2.4?

The idea is to reduce windage, or the air resistance/turbulance caused by the cylinders going up and down. Also I guess it helps oil flow.
I have read there is no real benefit until the 7k maybe 8k rev range, ie a high rev'ing race motor and even then the HP gain can be very small.

I did plan on doing this on my SS 3.2.

Cheers

Alan

ChrisF · Post by **ChrisF** » Fri Mar 04, 2005 9:24 am

I agree that reducing windage has more effect at high revs. Our existing 2 litre revs to 8000.

Reducing windage will also give the cooling system an easier time , which I hope will help to increase longevity and reliability.

I think that the extra cost of carrying out these mods is quite small compared to the overall cost of a motor.

Good news about not having to specifically source a 2.4 S crank. A typical price in the US seems to be about $900 for a crank which has been micro-polished and magnafluxed, which at current exchange rates is quite cost effective.

Gary71 · Post by **Gary71** » Fri Mar 04, 2005 10:46 am

Do these mods make a difference on a 'dry' sumped engine? I can see how it works when the crank is slapping about in a bucket of oil, but not in air. No experience as such, just what I've read up on conventional engines.

Seriously cool bus by the way

. I have a long term plan (that the wife is unaware of!) involving sourcing a similar, but rotten, bus and parking it over the top of a overwise scrapped Boxster on a tube frame...and joins dots with the welder

Best thing to do with a Boxster, at least you'd know which way it was pointing!

Luke · Post by **Luke** » Fri Mar 04, 2005 10:57 am

Chris, have you asked on Pelican for a crank? I got a magnafluxed and micropolished 2.2 (66m) crank resized rods for USD400.

ChrisF · Post by **ChrisF** » Fri Mar 04, 2005 1:28 pm

I believe that there is quite a heavy oil mist inside a 911 crankcase and this could result is a serious waste of power at 8000 rpm.

I have heard numbers of between 10 and 15 HP savings quoted for all three mods with similar running temperature reductions (degrees F ?)

Even air can cause a problem and most industrial gas turbine couplings that run at 8000 rpm are supplied with anti-windage shrouds over bolt heads. These shrouds are used to reduce guard temperatures rather than to prevent power loss.

This level of power saving on a 2 litre engine seems quite important as I think the the head design on a 2 litre makes it quite difficult to produce more than about 180HP without losing all of the bottom end torque.

Our current engine has had all of these mods and oil temperature is fairly consistent at 95 deg C and power is around 160 BHP at wheels on Solexes.

I will try Pelican for a crank as this price sounds very good. All I need to do then will find some "cheap" titanium rods and we can really make it go!

Gary71 · Post by **Gary71** » Fri Mar 04, 2005 6:49 pm

I learn something every day!

Herr Kuult · Post by **Herr Kuult** » Thu Mar 10, 2005 1:38 pm

ChrisF wrote:All I need to do then will find some "cheap" titanium rods and we can really make it go!

Are these legal for your historic rally car?