Engine Build Advice for 71T

[Neil Harvey]

Originally Posted by mepstein

“There is life still left in these older engines. I believe that the early mag cases have probably done all of their shape changing and have seasoned into some sort of reliable engine case. As the lively revvy engine is part of the sum of all parts required to get that performance, car weight play huge part here too. A mag case certainly helps in weight reduction.”

Neil - I was under the impression that mag is such a reactive metal that it just keeps getting more and more brittle until it crumbles. I don’t think time is it’s friend.

Yes very true, but many are discarded with life still in them. Not all are trash. There is also treatment that can be done to mag to help it last longer. Dow (number) I think its 7, is a treatment yo can do to mag.

But yes, you are correct, some are well past their shelf life. These are generally from engines that have never been looked after.

[spyerx]

MORE POWER! :-)

I have a 964 hot rod, and a 997 GT3RS to feed that dragon.

Having driven a few of these, it feels to me that low-mid 200HP range is just 'right' for the chassis. But that's me!

[spyerx]

Ok so I'm mentally getting closer here. I'll likely buy a core and build that, or if a good core swap it in car and build what I have...

Question: What are folks doing on oiling? I think the stock oil pump is a weak point? 3L or 3.2L pump?

[lvporschepilot]

Originally Posted by spyerx

MORE POWER! :-)


Having driven a few of these, it feels to me that low-mid 200HP range is just 'right' for the chassis. But that's me!

A 2200-2300lbs 911 is just right with 250-280ish bhp. Stock brakes are scary tho!

[spyerx]

Originally Posted by lvporschepilot

A 2200-2300lbs 911 is just right with 250-280ish bhp. Stock brakes are scary tho!

I find them pretty good for the weight of the car and keep in mind i have 2 other cars with insane brakes to compare to.

[Trackrash]

Originally Posted by spyerx

Ok so I'm mentally getting closer here. I'll likely buy a core and build that, or if a good core swap it in car and build what I have...

Question: What are folks doing on oiling? I think the stock oil pump is a weak point? 3L or 3.2L pump?

A couple of things to keep in mind, depending on what core you are talking about.

'71 was the last year of the smaller oil lines and oil tank. Newer motors had more oil capacity and flow. So you will need to address oil lines and the tank. Adapters are available but with a larger more powerful motor you may want to upgrade the tank, and most likely you will need a front cooler. With your 2,7 perhaps some of that has already been addressed?

What intake, exhaust, ignition, and gauges will you need to match the new motor? If you are sticking with a 2,7 it will be easier than a 3,0 or newer.

[spyerx]

Will do a 2.8
Have a carrera cooler already installed
Intake will be some sort of itb efi plan there isnfull motec dual coil on plug crank fire ignition
Exhaust is ssi currently with dansk sport muffler.
Not sure if my oil tank has changed, likely not but, seems to be ok with current 2.7 and car runs cool

[spyerx]

Originally Posted by Trackrash

'71 was the last year of the smaller oil lines and oil tank. Newer motors had more oil capacity and flow. So you will need to address oil lines and the tank. Adapters are available but with a larger more powerful motor you may want to upgrade the tank, and most likely you will need a front cooler. With your 2,7 perhaps some of that has already been addressed?

What intake, exhaust, ignition, and gauges will you need to match the new motor? If you are sticking with a 2,7 it will be easier than a 3,0 or newer.

Hey have a question:

On the oil tank. So the car has a carrera cooler with the thermostat installed. It runs a rock solid 170-180 in normal use. Hard driving in the mountains in hot (like 90+) i've seen it get up to 200 or so.

If I were to get a later tanks, I assume, need a 73 tank? (72 is totally different right?). What other 'parts' would be needed for hoses, etc?

I have a 77 911S 7R engine core I just got we are starting to disassemble. I'm going to build a different engine and then swap when done, and then refresh the one i have in the car now for another project. (won't 'build' it). First order is a huge machining bill from Ollies :-) I'd love to get 250 wheel, will be doing EFI, dual plugs coil on plug, 2.8L, and all the tricks. With EFI, suspect 10.5:1 is doable on 91 pump gas?

For gauges, will keep it all stock, will update the Tach for a new redline, I suspect around 7500. Will use stock oil pressure/temp senders. For tach signal, not sure.

[Trackrash]

Without knowing the details of your current setup, it is hard to answer.

What engine case are you running now and which thermostat for the front cooler?

Maybe post some pictures of your oil tank and set up?

I am assuming you have a 2,7 from a '74 or newer car? If so it seems that all the issues have been dealt with already by whoever did the upgrade.

[spyerx]

Originally Posted by Trackrash

Without knowing the details of your current setup, it is hard to answer.

What engine case are you running now and which thermostat for the front cooler?

Maybe post some pictures of your oil tank and set up?

I am assuming you have a 2,7 from a '74 or newer car? If so it seems that all the issues have been dealt with already by whoever did the upgrade.

Thermostat + front cooler are elephant racing setup - so a carrera type thermostat in front of the rear passenger wheel. It works very well. Although fitment was not "bolt in " but I told them what we needed - 77 engine with a 71 body and they got 95% of it right. All the stuff in the rear/piping was good.

I'm 99% sure oil tank is stock

Case is a 7r from 77. New motor will be same, 7R case with all the tricks done once completed.

Anyway, car runs cool with current motor, after cooler never seen it over 210 even with very hard driving in hot weather. The new build will be a more powerful motor. It will also be running EFI (Motec most likely) which should allow for better control and engine management.

So the new motor will bolt in. I suspect if I wanted a later tank I'm looking at modifying some of the piping from the scavenge back to the tank? I DO plan to use a larger oil pump, probably a carrera pump.

OK - I found some pictures at EarlyS
http://www.early911sregistry.org/forums/showthread.php?44022-Pictures-of-the-different-oil-tanks-amp-senders

Looks like: i need to modify the body sheet metal some due to swap of filter and filler. And, adapt existing hoses or go larger with new made hoses. Hm.

[Trackrash]

It sounds like you have the adapters or special hoses for the '70 tank you have now. Yes, you would have to change the two fittings or oil lines that hook to the tank if you choose to upgrade to a newer tank.

Yea there is some minor sheet metal work that needs to be done in the engine compartment due to the different orientation of the filter.

What type of hose do you have now that connects from the oil cooler on the motor to the oil tank? Do you have a hose that goes over the trans from the right side of the motor to the thermostat?

Here is my tank. You can see the patch for the original filter location.