time for a new engine build - thoughts and input appreciated.
 

my 3.0 is moving to the 'roadster' and I'm building a new engine for the '67 '912' .

here's what I have / where I'm at so far:

- 3.0 case

- 3.2 crank

- I have JE 9.5 95mm pistons but I just picked up these.....

http://forums.pelicanparts.com/porsche-911-used-parts-sale-wanted/641505-fs-97mm-ross-pistons-cylinders.html

which puts me into a 3.4. I'll do a check on my engine to confirm CR. I may have to shave a little off the crowns to get below a 10:1 CR.

- SC heads with intakes at 36mm

- solex cams

- 40mm weber IDS

- M&K two in one out with headers

( and shhhhhhhhhhhh..... a 100 horse nitrous system ;) )

that's it so far. I could certainly go bigger ports and a more aggressive cam but I'm all about the torque.

any thoughts much appreciated. Don.

You're addicted to that laughing gas, aren't you. :)

I just threw that in there ;) I probably won't put it on this engine, I think it'll move with the 3.0 to the roadster. it's just too much parasitic weight for this car.

Sure, you say that now...:)

bottom end together. next, check deck height and C/R.

http://forums.pelicanparts.com/uploa...1325835941.jpg


http://forums.pelicanparts.com/uploa...1325835959.jpg


http://forums.pelicanparts.com/uploa...1325835996.jpg

Lvn it

slow going, too many other projects in the way.

had the pistons milled. I kinda guessed at how much to take off. I used piston pins to put one JE piston ( 9.5:1 CR ) between two of my Ross (10+:1?) pistons. put a straight edge across the two outer (Ross) pistons and measured the gap at the center (JE) piston. added a little for comfort and came up with 4mm. got the newly milled pistons back from the machine shop the other day and checked the CR today. came in at 9:1. pretty much what I was aiming for. a little low perhaps but safer considering decent gas is getting harder to find. around here only Chevron has 94 octane ethanol free.

also checked deck height, with a .5 base gasket I'm at 1.25mm, seems OK to me.

next, hone the cylinders. lap the valves, open head intake ports to 36mm. and get the cam towers on.

here's the basics.

- 74.4 crank
- 98mm P&C's
- 36mm intake ports
- solex cams
- 40 webers




http://forums.pelicanparts.com/uploa...1339539129.jpg


http://forums.pelicanparts.com/uploa...1339539148.jpg

got the pistons into the cylinders, serious pain in the *ss! the oil ring is a four piece assembly that doesn't want to stay in the groove so you can get the compressor on.



http://forums.pelicanparts.com/uploa...1340560267.jpg

http://forums.pelicanparts.com/uploa...1340560317.jpg

Great photos!

Thanks for posting your engine build.
Keep up the good work :)

Regards,

it's been a while and slow progress but here's an update. time to install rockers and time cams. John D. ground me some 'big time bottom end torque' cams for this one.

mocked up the intake so I can start figuring out how to fit the engine in the car :rolleyes:

a 13 inch intake run should help out the torque.

http://forums.pelicanparts.com/uploa...1363420285.jpg


http://forums.pelicanparts.com/uploa...1363420344.jpg

Two thoughts:
3 inch runner extension will offer little or no noticeable change in performance.
When Chrysler (under the design leadership of David Long) experimented with extended intakes runner back in the 50s, the data showed a need for runner extensions of 32 inches or more to effect real change. Even VarioRam intake have almost three feet of runner change.
If you insist on running spacers, you might find putting the spacers between the head and manifold will make the linkage easier to manage.
Just my 2 cents. Cheers

BTW: nice work so far, your project looks great.

I just noticed that you're using 40 IDS carbs. They are way too small for this project.
The high speed enrichment never really lived up to it's potential so you should sell them the someone restoring a 67 S who will pay stupid money for them and invest in a set of 46 mm PMOs.

thanks for the input Henry. I actually sold the IDS and am now using IDA's.

I see what you mean by the intake runner length. my 2 inches isn't much. but why are the 100mm tall intake manifolds so desirable?

for the carb sizing, I'm afraid to go too big and lose my bottom end torque. I truly don't care what happens past 6k.

I'll be doing a dyno on this engine and I'll make a point of swapping out the spacers. should be interesting.

and in the end, it's just fun to play around. at least I probably won't put nitrous on this one ;)

Much like many of the things that happen in the search for performance, theory and reality often travel different paths.

There is no way that a properly tuned set of 46 will challenge your performance at any rpm range. Volumetric efficiency is enhanced when the fuel delivery system is properly sized for the proposed build.
The other issue is the function of the carburetors in question. There is little question that the modern design of the PMOs exceeds anything offered by the out-dated Weber design.

you've got me thinking Henry. maybe it's time to sell off a couple of sets of webers and spring for some PMO's.

Just trying to help.
Cheers

Haycait911, congrats on your interesting build. I sent you a pm on your air horns...but maybe it got misrouted. Thus I figured this posting, here are my questions: anticipated increase with these enlarged air horns and based on efficiency, where can one source a set?
Thanks for your time.

I made these up. used some spun aluminum stacks I found on ebay and the bottoms are cut down regular weber stacks. friction fit together with a little epoxy for good luck.

power increase? no idea, if any. but they're pretty cool :cool:

http://forums.pelicanparts.com/porsche-911-technical-forum/576675-made-my-own-bell-end-velocity-stacks.html

Thanks for the info on the air horns- yes they look good :) All the best with your hot rod build.

Don,
I am digging it. What are you doing for air filters?
Al