Your thoughts on rbuild specs

[Phoenix]

I'm posting this again as I think it fell off a few radar screens. I totally screwed up my last rebuild by not doing enough research and asking the experts first. I should have found this board sooner. I'm trying to do everything I can to avoid that this time around.

Here's a link to the original post: Technical newbie taking the leap...

After reading tons of posts here and Wayne’s book, here’s what I’m thinking. It's pretty much the RS spec listed in Wayne's book only with E or Solex cams and an E MFI system in hopes of keeping the torque in the lower RPM range. What do you think?


• 7R case
• ’76-’83.5 oil pump
• Oil bypass update
• 2.7 crank
• Carrera Pressure-fed Chain Tensioners (currently have)
• Updated idler arms (930.105.509.00 = L / 930.105.509.00 = R )
• Case savers on cylinder head studs
• 911 turbo oil squirters
• 2.7 RS Euro pistons & cylinders
• 2.7 heads - not sure if I can use my current 2.4 heads?
• E or Solex cams - Which is best to help keep the torque in the lower bandwidth?
• Camshaft housing oil pressure restrictor upgraded (901.105.361.01)
• 11 blade cooling fan (currently have)
• Air baffles modified (between cylinder baffles narrowed 1” )
• Turbo valve covers (currently have)
• E MFI system
• High pressure fuel pump
• SSI (2 in 1 out)
• Front oil cooler (does this have to be in the front bumper or can I use this with an “S” spoiler
• All the replacement parts listed Wayne’s book

To help keep the costs down, I’m hoping I can salvage many of the parts in my current motor and sell off its PMO carburetors and Electromotive Ignition. Though I would need to pick-up a 7R case.

Or I could sell my curent motor and buy a 2.E with a 7R case and build up from there?

[Phoenix]

jparker: I'm not sure which studs to go with. I prefer MFI for response, fuel mileage and the fact that, for me, they epitomize an early 911 enigine. I've heard and read that "S" cams put the power in the higher RPM range vs. the "E" or "solex" cams which keep it down in the more frequent "street RPMs"?

[jluetjen]

Oliver;
Let's see if you can put a number on your rev range. Pick a 2000 RPM rev range (for example 1000 to 3000 RPM) where you want your engine to be strongest. Based on that you can then spec out the rest of the engine.

[Doug Steinel]

Oliver,

don't use Dilavar head studs... too many broken ones. I say use the original steel ones. Got anything against using your PMOs?

[Phoenix]

John:

I'd have to say the 2,000 to 4,000 range. I spend most of my time between 2,000 and 5,0000 on both on the street and on my favorite track (Lime Rock). Focusing on 2-5k seems ot make the most sense.

[jgparker]

Then you are absolutely right, Solex or E-cams might be better for you. S-cams make most of their HP from 5,000 to 7,000 RPM.

I like plain old steel head studs too. Bulletproof and inexpensive.

It sounds like you are short-shifting at the track...

Good luck,

JP

[KobaltBlau]

Oliver, you're being realistic, that's great. Stock 3.0 CIS is good in that range

Seriously, I think you're going to want to be on the milder end of the cams you mentioned. I'm sure people much more knowledgeable tham me will help you with cams and port sizes etc.

[KobaltBlau]

Originally posted by jgparker
It sounds like you are short-shifting at the track...

Phoenix, you may want to look into shorter gears as well.

[Henry Schmidt]

[i]

• 7R case - ok
• ’76-’83.5 oil pump - 78 to 89 Alum. not mag
• Oil bypass update - good late 7 Rs have it.
• 2.7 crank
• Carrera Pressure-fed Chain Tensioners (currently have)
• Updated idler arms (930.105.509.00 = L / 930.105.509.00 = R )
• Case savers on cylinder head studs - CaseSaver with Supertec Head Stud kit
• 911 turbo oil squirters- no (overkill and oil pressure loss)
• 2.7 RS Euro pistons & cylinders- ok for low compression
• 2.7 heads - not sure if I can use my current 2.4 heads? 2.2, 2.4, 2.7 most 2.2 and 2.4 are for MFI no mod necassary accept porting, 36 or 38 mm
• E or Solex cams - Which is best to help keep the torque in the lower bandwidth? - Solex for more all around fun
• Camshaft housing oil pressure restrictor upgraded (901.105.361.01)
• 11 blade cooling fan (currently have)with 1.3 to 1 drive (early crank and alternator pulley)
• Air baffles modified (between cylinder baffles narrowed 1” )
• Turbo valve covers (currently have)
• E MFI system- will work well on 2.7
• High pressure fuel pump - only need 12 lb, Holley blue or black pump works fine
• SSI (2 in 1 out)- good choice
• Front oil cooler (does this have to be in the front bumper or can I use this with an “S” spoiler NOT SURE OF THE QUESTION
• All the replacement parts listed Wayne’s book

To help keep the costs down, I’m hoping I can salvage many of the parts in my current motor and sell off its PMO carburetors and Electromotive Ignition. Though I would need to pick-up a 7R case. - Trade off the Electramotive and PMOs

Or I could sell my curent motor and buy a 2.E with a 7R case and build up from there?

What you describe is what we just built accept for the update tensioners. We used turbo tensioners, chain savers and update arms.

[Eagledriver]

I have a perfect set of 3 journal solex cams with MFI pump drive. They worked great for my engine but I changed to "S" cams due to car being primarily a race car. I'd like to sell them if you're interested.

-Andy

[Eagledriver]

Forgot to through in my 2 cents worth on the head studs. I'd go with dilavar. I think we will start seeing case savers pull on mag cases using steel studs. I believe Wayne has already seen this happen though that was with Time-serts.

-Andy

[Doug Steinel]

Henry,

If I had an engine as fine looking as the one you have pictured, I would put it in my kitchen rather than the engine bay.

[Doug Steinel]

Andy, I have never heard of a stud pulling out of an aluminum case. Am I missing something?

[Eagledriver]

Yes, you are missing the aluminum case!

-Andy

[Henry Schmidt]

Originally posted by Eagledriver
Forgot to through in my 2 cents worth on the head studs. I'd go with dilavar. I think we will start seeing case savers pull on mag cases using steel studs. I believe Wayne has already seen this happen though that was with Time-serts.

-Andy

Everyone is entitled to their own opinion, but I wouldn't put a Dilavar stud in anything but a trash can. Every quality engine builder I know refuses to use this sub standard stud.
It's true I don't know every engine builder but Porsche has even moved away from this stud. They tried and tried to resolved the quality problem with Dilavar studs and they gave up.
If a CaseSaver pulls from an inserted case, the culprit is most likely improper installation of the insert or overheating. We have never seen a Supertec stud pull from a case that was properly inserted. Granted we have only installed them in 55 or 60 engines so who knows what is to come.

[Phoenix]

I love this board. Having you guys to turn to will sure put my mind at ease as I go through this a second time; hopefully avoiding the major mistakes I made the first time around (though I'll likely make a whole set of new ones )

Henry: thanks for the great input. being able to keep my current heads means one less thing to worry about and source. My oil cooler question clarified: I have an "s" spoiler up front now and am wondering where I could place a front oil cooler while keeping the existing spoiler? I've only seen front coolers used with RS/ RSR spoilers which have a cut-out specifically designed for a cooler.

jparker: what/ how do you mean "shortshifting" (i'm just starting to get out on the track more and learning my way around. The RS motor won't go in until I'm comfortable on the track and much, much "smoother".) Do you mean braking too soon and going through the corner in too high a gear?

[Jim Richards]

Oliver, do you still have your right-side battery box in place? What type of oil cooler do you have or plan to get? I have a Carrera cooler, S spoiler, and I still have my battery box in place. Oil temps on the street are fine. At the track they can get up there on a hot day. I will experiment with removing the right side turnsignal assembly to see if airflow to the cooler improves. Maybe even fabricate some scoop to direct air from the turnsignal opening to the oil cooler.

[Phoenix]

Jim:

Battery boxes are all still there. I'm waiting for a set of Sonnenscheins; one for each side. Is your cooler mounted in the right front fender onto the battery box? (pic)?

BTW - I love your car!

[Jim Richards]

Thanks! Yours is gorgeous, too.

I don't happen to have a pic to post at the moment, but it's mounted to the body (trunk) and to the battery box in the right fender. I tried to keep it as far away as I could from the battery box but not too close to the right front tire. The battery box impacts the airflow somewhat, so on the hottest days I need to do more for oil cooling. Grady Clay has suggested altering the ratio that the engine cooling fan runs, by use of a different 11-blade fan, fan pulley, crank pulley and fanbelt. I'll give this a try when the engine's out for rebuild. Here's the thread that talks about the engine cooling fan ratio change.

Engine Fan Drive Ratio

[jgparker]

Oliver,

Sorry, I was just jerking your chain. By short-shifting, I meant your shift point is well below your red-line (5,000 vs 6,500 RPM). My shift point is 7,300 RPM at the track, but I just love the sound of my engine when it winds up.

JP