2.0 S engine with 2.2 S P and Cs

[speedo]

I have access to all the parts to build up a 69 S MFI engine, and I have two sets of good P and Cs that are 2.2 S. I would like to build this and use the 2.0 S MFI I have. Other than the head work (80mm-84mm), what other challenges am I going to face if I go this route?
The idea of a stock looking 2.0 S engine with 2.2 S displacement and performance is appealing.
I have gone the other way before using 2.2 pistons with the 70.4 crank/rods and created higher compression ratio 2.4 engines and have been very pleased with the outcome.

Speedo

[speedo]

....or been done sooo many times before that it is not worth responding to.
Henry?

[bgyglfr]

The only thing I can think of is you will loose a lot of your compression gain if you machine and use the 2.0 heads. They have a higher dome than the 2.2 heads. The 2.2-2.4 heads would be better matched with the pistons.

[stownsen914]

Originally Posted by bgyglfr

The only thing I can think of is you will loose a lot of your compression gain if you machine and use the 2.0 heads. They have a higher dome than the 2.2 heads. The 2.2-2.4 heads would be better matched with the pistons.

Was going to say the same thing. I think you lose .5 - 1 point of compression compared to the 2.2 heads.

[speedo]

Knew the 2.0 heads had a high dome...but forgot about the heads. I'll need to use the correct 2.2 heads the. Other than part numbers, all 2.2 stock heads are the same with the exception of the intake ports, correct? Exhaust port and valves all the same?

Speedo

[Raceboy]

Yes, you can take 2.2 T heads and machine the ports to S size (only the front part of the port is narrower, it tapers to bigger size towards valve.

[stownsen914]

And since you're planning to use MFI, it would make life a little easier to start with MFI 2.2 or 2.4 heads. I believe the later T's had MFI (until 73.5 when they went to CIS).

[Henry Schmidt]

There are a plethora of high performance options but the path that seems less traveled in today's "bigger is better" world is the long stroke 2.2. Using everything the 69 S has to offer you simply change the crank & rods to 70.4mm (2.4/2.7) and bore the cylinders to 81mm.
The results are a phenomenal little engine that requires very little experimentation.
The 69 S heads have bigger valves, 36 mm intake ports and the 2.0 S pistons have a nice done if you choose not to bore the cylinders. There is very little pump tuning with this combination as well.
This little engine was very popular back in the early rally days.

[speedo]

The 2.2 P and Cs were higher CR that the 2.0 or 2.4s. What do I gain by longstroking a lower CR 2.0 S? I gain a little displacement?
Wouldn't a 66mm crank spin up faster or would that be more likely with a non cw crank?
Why would I bore the cylinders from 80-81? Wouldn't 80mm pistons be sloppy in an 81mm cylinder? Or is that something that needs to be done with a longer stroke?

Speedo

[bgyglfr]

The longer crank will bump your compression by almost a point. Sound like a fun motor. Long stroke with the lightest pistons at the end should add torque but allow it to still spin up nicely. Never driven a motor like that but it sounds cool.

[Walt Fricke]

81mm jugs were the allowed overbore in SCCA back when for the 2.0 motors. I've always wondered if, as seems likely, you needed 1mm oversized pistons as well. I always supposed that an overbore required larger pistons, but was only driving VWs back when these cars were new.

I suppose that if bores were only lightly scratched or oval, a tiny overbore could be done without changing pistons? But adding half a millimeter to the clearance seems pretty loose.

[JackMan]

subscribed

[Henry Schmidt]

Originally Posted by speedo

The 2.2 P and Cs were higher CR that the 2.0 or 2.4s. What do I gain by longstroking a lower CR 2.0 S? I gain a little displacement?
Wouldn't a 66mm crank spin up faster or would that be more likely with a non cw crank?
Why would I bore the cylinders from 80-81? Wouldn't 80mm pistons be sloppy in an 81mm cylinder? Or is that something that needs to be done with a longer stroke?

Speedo

The idea of adding a 70.4 crank to a 2.0 engine was simply performance with the least amount of change. The engine creates more torque and marginally more horse power. The heads, valves, ports , injection can all basically stay the same.
The increased stroke will increase the compression (.6 points)and generally speaking an increase on published compression ratios is beneficial.
Boring the cylinder to 81mm does require a new piston but at that point the rings, cylinder bore and pistons are all new and accurate as to compression.

It's important to remember that all published compression ratios for early 911 engine 2.0-2.7 grossly over-estimate compression.

[speedo]

If I am going to stroke it, and I have at my disposal the higher cr 2.2 S P and Cs,
why would I not just go ahead and replace the 2.0 S P and Cs with the 2.2 S P and Cs? Longer stroke (adds marginal compression) and larger bore. Wouldn't this get me closer to (or above) 2.4 S preformance? The only thing I will need to source would be 2.2 heads. I am assuming of course the 2.0 S pump would be satisfactory?

Speedo

[Henry Schmidt]

Originally Posted by speedo

If I am going to stroke it, and I have at my disposal the higher cr 2.2 S P and Cs,
why would I not just go ahead and replace the 2.0 S P and Cs with the 2.2 S P and Cs? Longer stroke (adds marginal compression) and larger bore. Wouldn't this get me closer to (or above) 2.4 S preformance? The only thing I will need to source would be 2.2 heads. I am assuming of course the 2.0 S pump would be satisfactory?

Speedo

Why wouldn't you is a hard question to answer. I offered another option....The why wouldn't you question is up to you to answer.
Why wouldn't you just put in a 3.0?
Why screw around with an early 911 when you could own a GT3?
Cheers

[haycait911]

Originally Posted by Henry Schmidt

Why wouldn't you is a hard question to answer. I offered another option....The why wouldn't you question is up to you to answer.
Why would you just put in a 3.0?
Why screw around with an early 911 when you could own a GT3?
Cheers

whoa

where did that come from

[Henry Schmidt]

Originally Posted by haycait911

whoa

where did that come from

My point was perhaps a little inarticulate (to say the least).
What I was trying to say is that there are a thousand different ways to build these early 911 projects and a thousand different criteria. Building one of these projects requires a plan that takes into account your own goals and budget.
The "what if" game is fun but sometimes it gets a little tedious.
The post was my frustration peaking through.
I apologize to speedo for the sardonic repartee.

[stownsen914]

Originally Posted by haycait911

whoa

where did that come from

I'd guess Henry was being a bit tongue in cheek ...

Perhaps he was making a point about a slippery slope

[Walt Fricke]

Speedo is a big boy, and doubtless took Henry's comment in the spirit in which it was offered. If you ask me how many angels can dance on the head of a pin, I would be hard pressed to give a positive answer.

Speedo has a trove of parts from old cars, so I suspect finding clever ways of using them is higher on the list than just getting a big HP boost, as would be the case by putting in a 3.0 (in which case, why stop there - the 3.6 transplants fairly easily.

Speedo did ask one question which Henry is well placed to have an opinion on, though. Is the stock 2.0 oil pump adequate for a 2.2 or 2.4? Is there even any difference between the 2.0 and the 2.0S as far as pumps go - I think they are all the same. I know that an SC pump is just fine for my 2.8 race motor, even though I'd never consider downsizing the Turbo pump I have in one of my 2.8s or my 2.7. Henry has even suggested that my beloved GT3 pump (which he repaired for me) is more than I need for these motors. Unsaid is the fact that perhaps there are $ I could have used on some other go-fast, and parasitic losses I could perhaps have avoided.

Also, when trying to figure out is a post is more rancorous than polite conversation dictates, it is worth knowing the characters. Some posters are habitually undiplomatic, but Speedo isn't. Henry doesn't take slights lightly, but when he opens up his big guns you know it (either 16 inchers, or something so understated that it is even more powerful). So I didn't read his reply as being a slam on Speedo at all.

It is a cliché that there are no dumb questions, but sometimes, on reflection, one sees that one's question was, indeed, at least not phrased to elicit the kind of technical answer one hoped for, because - as Henry pointed out - some of the terms of the equation were left out.

[speedo]

An apology wasn't necessary...
Henry is a good guy. Always been a source of parts,loads of wisdom and sarcasm.

Back on topic. Walt was right on....these cars are "erector sets" for adults. What other marque can you mix and match parts from a 1992 chassis to a 1966 chassis.
I am picking up a 2.0 S longblock this spring missing the P and Cs. I recently sold a set of 2.0 P and Cs...oh well. I do have a 2.0 S induction, and 2.2 S P and Cs, a 70.4 crank, a couple 3.0 and 3.2 pumps and various cams. As I will build this for myself, and I don't currently have an application...sky is the limit, or maybe the basement is the limit. I am not writing checks to (someone far more capable than myself) to get a sweet engine put together. I instead like to evaluate options and directions. Easiest thing and probably cheapest would be for me to do as Henry suggested...order a new set of higher cr 81mm P and Cs and just put it together as a 2.0 S engine...or stroke it. Not really fair of me to ask ..."Henry, what should I build? I'm sure he gets that regularly from his clientele that write him checks. I like to make original mistakes...which is why I enjoy the resources of this forum. If I can avoid making mistakes others have made...by asking a few questions, I'm a happy camper.

The point Walt brought up, my question about "the pump", I realize was a bit misleading...I was referring to the 05 MFI pump, not the original 2.0 oil pump, which I will definitely replace. I was asking if the OEM cam-ed 2.0 S MFI pump was enough for a 2.2-2.4 displacement engine ?

Speedo