Engine "Recipe": Heads? Carbs?

Ovis · 12-23-2021, 02:14 PM

So, still in the long and arduous process of obtaining parts and research for the rebuild of my motor.

My last big purchase will be heads, and therefore I am looking for any advice or recommendations, concerns, etc that the brain trust here has. If you think I am overlooking anything or should change any aspect of my "recipe", please let me know.

Case: 2.0 Aluminum
Crank: 66mm
Rods: 2.0 OE
Cylinders: 87.5 LN Nickies
Pistons: JE 9.5:1
Camshafts: WebCam 104/102 (Solex grind from my understanding)

Heads: 2.4, should I build to 'S' Specs???
Carbs: Weber 40 IDA, should I have these rebuilt to 'S' Specs???

My last big procurement will be sourcing heads and having them rebuilt if needed. Should I have the heads rebuilt to 'S' Specs, ported with bigger valves?

Also, when I have my Weber's rebuilt, should I build them to 'S' Specs as well? Any suggestions on who should do the rebuild? I was planning on Paul Abbot, but just learned he is out of the game now so any other recommendations?

Thank you in advance for any advice, informations, roasting, etc.....I greatly appreciate it!!!

Ovis

Richey · 10:24 AM

All 2.2 , 2.4 or 2.7 heads have the same valve size , just different port sizes . With the 87 mm cylinders I would recommend S port sizes , and you will have to find manifolds . Early S manifolds are made for 35 intake ports . The carburetors can be jetted as early '67S carburetors , but will not be like the IDS's because of the S's fuel enrichment tubes and circuitry , but the early S jetting enlarged for todays fuel and S venture size will work , just don't drive at 6,500 rpm for an hour .

Ovis · 12-24-2021, 07:31 PM

Quote:

Originally Posted by Richey

All 2.2 , 2.4 or 2.7 heads have the same valve size , just different port sizes . With the 87 mm cylinders I would recommend S port sizes , and you will have to find manifolds . Early S manifolds are made for 35.5 intake ports . The carburetors can be jetted as early '67S carburetors , but will not be like the IDS's because of the S's fuel enrichment tubes and circuitry , but the early S jetting enlarged for todays fuel and S venture size will work , just don't drive at 6,500 rpm for an hour .

Thank you for that Richey. Is there any concern with having my current manifolds ported to 35?

stownsen914 · 12-25-2021, 07:32 AM

Porting manifolds is definitely possible, but it's not straight-forward since the runners on the ends are angled, so might be cheaper to find some already done, or buy some PMO manifolds. In fact, I think there was recently a set of factory ones done to S spec for sale on the 911 classifieds for a reasonable price.

Richey · 12-25-2021, 10:23 AM

The later thicker walled manifolds can be ported , not so much the earlier ones .

Walt Fricke · 12-25-2021, 03:28 PM

Are you planning on aftermarket 200,000 or so psi rod bolts?

Ovis · 12-25-2021, 04:07 PM

Quote:

Originally Posted by Walt Fricke

Are you planning on aftermarket 200,000 or so psi rod bolts?

I've purchased the ARP rod bolts, are these sufficient? As I am newly learning about all this, I appreciate the help and any insight!

My goal is to build this motor and have it last me the rest of my life, thats the goal anyway.

stownsen914 · 12-25-2021, 05:24 PM

ARP are good quality aftermarket rod bolts. Be sure to have your rod big end dimensions checked with the ARP bolts. The higher torque of the ARP bolts can slightly change the critical BE dimension.

Black 993 · 12-28-2021, 09:03 AM

Quote:

Originally Posted by Ovis

Camshafts: WebCam 104/102 (Solex grind from my understanding)

I have these cams in my 2.2 911T motor, along with Mahle S p/c's and 40IDA's. It's a great street motor but I wish it had a little more top end -- runs fine to redline but by 5K rpm's it starts becoming a bit more noise than acceleration. I improved this a little by moving from 30mm venturis to 32mm. But I suspect this isn't the cams, but the T ports in the heads, which I should have opened up to S spec. I don't know much about this cam grind, though, so if you do please feel free to share your understanding of its characteristics.

chiroracer · 12-28-2021, 02:47 PM

Solex cams with S ports will rev through 7k but probably peak at 6500. Nice torque cam too.

Emo993 · 12-29-2021, 02:52 AM

I started with a 2.2E long block that has S pistons and cams. Was told with the E heads I should change out the cams to Solex....So, in went the DC-30 ( Mod-Solex) cams, 40PMO's, MSD, and Ben's headers and sport exhaust. Just a great engine, very good power up to 5,000rpm and then hold on to 7,300 redline. Have fun on the build. Mark