engine rebuild

[BRPORSCHE]

i have a 73 911T MFI that i am beginning to restore and i have two questions one pretaining the engine one with the heat exchangers.

1) Would be easier (cost less money) and still produce more hp to add E piston heads and cams or to just upgrade to a newer 3.6 litre engine?

2) Is it possible to run the MFI without the heat excahangers? I don't live in a cold climate and having heat in the car isn't a necesity. Can i remove the heat exchangers and just run headers?

thanks for the replys

[David]

I don't have a '73 or MFI, but since nobody's chimed in I take a swing.

1) a 3.6 engine will probably run $7500 to $9000 plus a few thousand in parts to adapt it to you're car. I would imagine parts for a good '73 rebuild would be under $5000.

2) I didn't know the MFI had anything to do the heaters so I don't see how running headers would be a problem.

[ChrisBennet]

My MFI experience is limited to a few days so take it for what it's worth...
The stock MFI has a hose to bring warm air up from the left heat exchanger to the pump/rack cold inrichment thingy. If the hose comes off it's been known to cause problems. I'm not saying you need to run the heat exchangers but you might want to find out what the "solution" to the problem removing the hose may cause.
-Chris

[BRPORSCHE]

thanks chris
i was just thinking about plugging up the hose and seeing if any problems were to arise. seeing how i live in baton rouge i don't really need the heat, but if the car will not run properly with the heat exchangers off i will put them back on the car

[Shuie]

Assuming that everything for the MFI on your car is in place and is working properly, you will need the heat exchanger on the LHS to feed the hose that runs to front of the thermostat on the MFI pump. If you remove the heat exchangers, you will need to block off the fan shroud properly.

You can see from my sig line that Ive changed my mind a couple of times about the motor I want in my car. The 3.6 is a great option, but its going to cost $10k for the swap alone if you DIY. There are a lot of other mods that either should be made or need to be made in addition to the motor.

rebuilds are not much cheaper when they are done right. The biggest mistake I made with my rebuild project was not putting the motor on a pallet and sending it to Henry at Supertec. I honestly thought I could do it right for less money than he quoted me. By the time I had bought all of the tools and had the machine work done I was over his quote for a longblock rebuild with warranty and a 30 day turn around.

If you are entertaining the idea of a rebuild, DIY or from a shop, you need Waynes book. He breaks the costs down really well, so it should give you a good idea of what it will cost you to do it right.

[BRPORSCHE]

i do have the book and i haev many more books, but i am very interested about this guy henry. Do you think if you would of just sent the engine to him that you would of paid less? how much?

[Henry Schmidt]

........ but i am very interested about this guy henry. Do you think if you would of just sent the engine to him that you would of paid less? how much?

WE ARE ONLY CHEAPER IF YOUR TIME AND OUR WARRANTY HAVE VALUE

About the heat riser:
The purpose for the hose that hooks to the heat exchanger and the MFI pump is to bring hot air from the heat exchanger to the thermostat on the pump. This thermostat is the primary enrichment devise for cold starting your engine. If the hose is disconnected the engine will run very rich for a very long period. The pump gets oil from the engine so as the engine oil heats up the pump the thermostat will also heat. This will take far too long for comfortable driving. The cure for this problem is to install a SUPERTEC MFI enrichment devise.
We are the only one to sell this devise so check the website for more information.

[Tim Walsh]

I've done a 2.4T rebuild into a 2.4E+ (higher compression) for about 5K. I haven't ever driven anything other than T's and E's so to me an E feels like a super T.. more torque and horsepower, just at a slightly higher range and a nice wide torqueband. My trick was to find a 2.2E motor and grab the pistons, heads, and cams out of it.

I'm also running headers, and I use a screw in place of the thermostat. Can't say it's the best solution, it can be hard to start when the motor is cold. This part is a work in progress

Also do a seatch for 2.4T and you'll find loads of information on what to do with a motor like that.

[BRPORSCHE]

Thanks so much did ur 2.4 have MFI? and is a E more powerful than a S. My uncle has a 73 2.4E and i envy it i want my car to be vry much like that car. Would the 2.2 pistons fit into a 2.4 engine or would they have to be machined in anyway?

[Tim Walsh]

BR,
The S is the top of the line at 190hp, but it's very peaky, the E is the next step down at 165hp, followed by the T at 140.

My 2.4T had MFI on it but I had to make some changes to the injection system. I bought a used 2.4E pump and stacks and had my throttle bodies bored out to 32mm (from 29mm) since they passed light test.
The 2.2 pistons will fit without any problems. I have heard of a few isolated cases were 2.2S pistons needed some slight machining to avoid interferance but I think it's rare. I've personally used 2.2T and trial fitted a set of 2.2E pistons and neither had any trouble.

BTW I'm not much of an expert on these compared to Henry, I've only built 2 different versions of a 2.4 and researched a few more. Just someone who's run the gauntlet of rebuilding their own motor.

[BRPORSCHE]

would this modification work? 911S MFI CAMS with E pistons or should i just go with S cams and S pistons? which combination would be of the best?

[Walko]

BRPORSCHE

you can get away without the heat exchangers however you need will need to remove the thermostat and relplace with a flat plate and an adjuster so that you can set the pump so that it assumes the motor is already hot.

THis means the motor is a bit cranky when you start it for the first five minutes but after it runs as normal.

ask me how I know.

My two cents worth is whilst i have done that modification on two motors I prefer to have heaters in the car.

Michael

[BRPORSCHE]

u prefer to have the heaters? isn't australia a rather mild country or is it to just keep the orginnality of the car?

[Walko]

Australia is a mild country but I still take my car when I go skiing and to do Targa Tas.

and let me tell you a race car always needs heat.

Michael

[Henry Schmidt]

would this modification work? 911S MFI CAMS with E pistons or should i just go with S cams and S pistons? which combination would be of the best?
"S" cams with "E" pistons will have a valve clearance problem. The "E" valve pockets are not as deep as the "S" pockets. Another option might be the solex cams. They should clear the "E" pistons and still give more performance than the "E" cams. Another bonus is they seem to be fairly easy to find used.

Fixed bolt method??
We have used the preset bolt system and without exception the cable operated system we build works the best. Better than stock, better than a fixed bolt and as a matter of fact we even tried an electric worm drive mechanism and non worked as well.
The other benefit to our cable operated system is that you can eliminate the cold start injector. These are prone to fire and wash unwanted dirt past the throttle valves (butterflies) and into your engine.

[BRPORSCHE]

fixed bolt method?

[Henry Schmidt]

Originally posted by BRPORSCHE
fixed bolt method?

Walko
...you can get away without the heat exchangers however you need will need to remove the thermostat and relplace with a flat plate and an adjuster so that you can set the pump so that it assumes the motor is already hot.

[Walko]

Henry,

I thought I must be going mad. I just checked my original post and I clearly stated that you needed a flat plate and an adjuster.

Every one is talking about a "FIXED BOLT METHOD" can you clarify.

Michael

[Walko]

BRPORSCHE

[Walko]

BRPORSCHE.

OOPS

I would suggest that whilst it is possible for a capable person to do a rebuild at home I would still recommend getting an organisation like SUPERTEC to do the build.

Reasons
1) they do so many they won't make mistakes
2) With the amount of experience they have you should gain a few extra HP that you might not otherwise get
3) Warranty ??
4) THey usually have a better buy price on parts than an individual.

Now I have no connection to Supertec and I am downunder but every thing that I have heard about Supertec is good and Henry always seems tonopt have an issue in correcting / providing teh correct advice.

IMHO we should support people like this they are the true backbone to our hobby.

Michael