Pelican Parts Forums - What the "L", Supertec 2.8

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Pelican Parts Forums (http://forums.pelicanparts.com/)

- 911 Engine Rebuilding Forum (http://forums.pelicanparts.com/911-engine-rebuilding-forum/)

- - What the "L", Supertec 2.8 (http://forums.pelicanparts.com/911-engine-rebuilding-forum/863538-what-l-supertec-2-8-a.html)

Henry Schmidt

05-02-2015 08:22 PM

What the "L", Supertec 2.8

Henry Schmidt

05-02-2015 08:31 PM

Jcslocum

05-03-2015 05:26 AM

Beautiful....

Henry Schmidt

05-04-2015 06:48 AM

Henry Schmidt

05-04-2015 06:57 AM

atcjorg

05-04-2015 07:15 AM

beautiful work Henry

Speed Buggy

05-05-2015 05:09 AM

What is the pink looking jig for in the fifth pic of the third post? Is that a piston ring?

Henry Schmidt

05-05-2015 08:14 AM

Quote:

Originally Posted by Speed Buggy (Post 8608828)

What is the pink looking jig for in the fifth pic of the third post? Is that a piston ring?

This thingy?

http://forums.pelicanparts.com/uploa...1430842401.jpg

It is an electric piston ring trimmer. It's used to custom fit rings by adjusting the ring gap to the desired measurement. For years we used the hand crank method but this little tool allows for incredible accuracy and speed as well.

Speed Buggy

05-05-2015 09:20 AM

Yes, that. Cool tool.

Jack Stands

05-05-2015 02:56 PM

True engine porn! Looks amazing.

Henry Schmidt

05-05-2015 06:07 PM

Henry Schmidt

05-05-2015 06:13 PM

nvr2mny

05-05-2015 06:54 PM

Very cool Henry! A VERY lucky guy is getting that engine!

Emo993

05-06-2015 03:55 AM

WOW , thanks for sharing Henry. That is just beautiful.

tharbert

05-06-2015 06:51 AM

Very cool! Quick question if I might, Henry? I don't think I've ever read about this mod? What's going on here?

http://forums.pelicanparts.com/uploa...1430626029.jpg

http://forums.pelicanparts.com/uploa...1430626331.jpg

http://forums.pelicanparts.com/uploa...1430626766.jpg

jpnovak

05-06-2015 07:23 AM

He is drilling the case for the cross-drilled crank. Notice the larger oil galley hole and the grooved bearing on #5.

Henry Schmidt

05-06-2015 07:30 AM

Quote:

Originally Posted by tharbert (Post 8610793)

Very cool! Quick question if I might, Henry? I don't think I've ever read about this mod? What's going on here?

When we cross drill the crank (a mod that adds oil flow to the crank to feed rod bearings #2 & 5) we groove the bearing for constant oil supply. We also increase the volume of oil to the bearing/journal by increasing the diameter of the feed hole.

Some people groove the crank as illustrated on our SuperCrank but for street use we find grooving the bearing easier.

http://forums.pelicanparts.com/uploa...1430925772.jpg

tharbert

05-06-2015 08:30 AM

Nice! I did notice the bearing on #5 was different. I just wasn't sure why the case mod. Please keep it coming. I'll be working on my case soon. Need to get a sealing kit from you , Henry. Will call...

Turbo_pro

05-06-2015 09:22 AM

Quote:

Originally Posted by tharbert (Post 8610958)

A small correction just for clarity: the modification in this engine is on the # 4 main bearing.

Henry Schmidt

05-07-2015 07:36 AM

Quote:

Originally Posted by Turbo_pro (Post 8611033)

A small correction just for clarity: the modification in this engine is on the # 4 main bearing.

Jim is correct. The bearings are counted from the flywheel forward with the thrust bearing bearing # 1 and the nose bearing being # 8.

burtm5

05-07-2015 08:31 AM

supertec 2/8

Henry, based on your vast experience with building these motors what are you expecting at crank and wheel horsepower (and at rpm) for this build? All other things being equal, what are differences between mfi, webers and newer injections and management in horsepower, torque and mileage figures. thanks for your instructive postings on this list, Henry

Henry Schmidt

05-07-2015 08:56 AM

Quote:

Originally Posted by burtm5 (Post 8612606)

Given the relatively low compression and Mod'S" cams I would put the performance at around 260 crank hp @ around 6500RPM. The general number for loss from crank to wheel for these cars seems to be around 15%.
The difference between MFI, Webers and more modern systems is a discussion for a thread of it's own.
As for mileage: Considering this engine will run 46 Webers, fuel efficiency might be measured in yardage rather than mileage.

Henry Schmidt

05-07-2015 04:45 PM

http://forums.pelicanparts.com/uploa...1431045732.jpg
http://forums.pelicanparts.com/uploa...1431045750.jpg
http://forums.pelicanparts.com/uploa...1431045767.jpg
http://forums.pelicanparts.com/uploa...1431045793.jpg
http://forums.pelicanparts.com/uploa...1431045812.jpg
http://forums.pelicanparts.com/uploa...1431045834.jpg
http://forums.pelicanparts.com/uploa...1431045855.jpg
http://forums.pelicanparts.com/uploa...1431045874.jpg
http://forums.pelicanparts.com/uploa...1431045896.jpg

Henry Schmidt

05-07-2015 04:52 PM

fanaudical

05-07-2015 06:46 PM

Wow! Beautiful! Thanks for sharing.

jpnovak

05-07-2015 06:50 PM

I see such an incredibly useful technique in this picture. Thank you Henry.

Quote:

Originally Posted by Henry Schmidt (Post 8613492)

http://forums.pelicanparts.com/uploa...1431045732.jpg

Trackrash

05-07-2015 07:23 PM

This motor is a work of art.

I noticed that you are using 4 bearing cams. How does this affect the choice of valves and heads? What valve springs are you using?

Henry Schmidt

05-07-2015 10:01 PM

Quote:

Originally Posted by Trackrash (Post 8613700)

This motor is a work of art.

I noticed that you are using 4 bearing cams. How does this affect the choice of valves and heads? What valve springs are you using?

A little history. Production 911 cams were originally designed with three, 47mm journal and this design was used in production engines up through the 2.7liter.
Back in the early 60s, factory race engines were built with four, 47 mm journal cams because 4 journal cams offered more stability.
In 1975, Porsche decided to make cams for all 3.0 and larger engines with four journals. They also wanted a larger base circle to accommodate higher lift cams so they transitioned to 49mm journals.
Being a small company, Porsche elected to make one casting that could function as a three journal 47mm cams or a four journal 49mm depending on the finish machine work.
What you see in the pictures are 2.7 liter, 47 mm cam towers that were modified (drilled and plugged) to accommodate a 4 journal 47mm cam. For years, in order to get 47mm 4 journal cams you had to find factory race cams but since the advent of billet cams (from the likes of Andial, DC, Web and Elgin) most cam blanks are 4 journal and the cam grinder just determines what size journal diameter to grind on it.

Henry Schmidt

05-08-2015 04:38 AM

2.7 liter cam towers converted for 4 bearing 47mm cams. Note the set screw where the cam tower was drilled and plugged.

http://forums.pelicanparts.com/uploa...1431088426.jpg

Because this engine is going in an early version of the 68"L" we also needed to covert the towers to six bolt to accommodate the early aluminum valve covers. The extra studs are removed, the holes drilled and custom made plugs are pressed in then the sealing surfaces are machined flat.

http://forums.pelicanparts.com/uploa...1431088453.jpg

Trackrash

05-08-2015 08:49 AM

Thanks for the update.

Are the heads 2,4? I think I see a 73 date? Why aren't the combustion chambers chamfered for the larger bore? Who made the pistons? Factory valve springs?

I can't wait to see the finished product. Will you be posting dyno runs?

Henry Schmidt

05-08-2015 10:51 AM

Quote:

Originally Posted by Trackrash (Post 8614314)

Thanks for the update.

Are the heads 2,4? I think I see a 73 date? Why aren't the combustion chambers chamfered for the larger bore? Who made the pistons? Factory valve springs?

The heads are 2.7 liter, CIS heads. Originally installed on a 1974 911. The CIS injector notch has been welded to produce a cleaner intake port.
If you look closely you'll see a slight chamfer. The pistons are made by JE and a closer look at them shows a perimeter flat on the piston dome for piston the head clearance. The valve springs are Eibach racing springs.

http://forums.pelicanparts.com/uploa...1431110995.jpg
http://forums.pelicanparts.com/uploa...1431111018.jpg

Quote:

Originally Posted by Trackrash (Post 8614314)

I can't wait to see the finished product. Will you be posting dyno runs?

We rarely run engines on the dyno. We are engine builders not turners and as such, leave the finer points of tuning up to the customer. Of course we are happy to tune one of our engines whenever asked. We can do it, no matter how must it costs.....lol

Classic

05-08-2015 12:52 PM

I just drooled all over my iPad

Simply beautiful work

KTL	05-08-2015 01:14 PM

Great stuff as always from Henry. What installed height do you choose to set the springs at with the Mod S cams? Reason I ask is because I have a set of the Eibachs for a WebCam 120/104 cam. The 120/104 is a bit more cam than the Mod S (DC 40) and nearly same as DC 60 I believe?

Henry Schmidt

05-08-2015 03:33 PM

Quote:

Originally Posted by KTL (Post 8614686)

From memory, I think 120/104 has an intake lift of around .475".
If you set the Eibach spring at around 36mm the seat pressure will be around 90lb and the over the nose pressure will be around 275lb. Those are numbers I could live with.

Trackrash

05-09-2015 06:12 AM

One more question. I noticed that the cylinders were not "mooned". Can you give us your thoughts on this mod.

Thanks,

Henry Schmidt

05-09-2015 06:32 AM

Quote:

Originally Posted by Trackrash (Post 8615468)

One more question. I noticed that the cylinders were not "mooned". Can you give us your thoughts on this mod.

Thanks,

Much like boat tailing the case, "mooned" cylinders offers negligible if any enhancement to overall performance while compromising the integrity of the part being modified.

Henry Schmidt

05-10-2015 07:51 AM

Henry Schmidt

05-10-2015 08:06 AM

http://forums.pelicanparts.com/uploa...1431273270.jpg
http://forums.pelicanparts.com/uploa...1431273296.jpg
http://forums.pelicanparts.com/uploa...1431273327.jpg
http://forums.pelicanparts.com/uploa...1431273390.jpg
http://forums.pelicanparts.com/uploa...1431273420.jpg
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http://forums.pelicanparts.com/uploa...1431273505.jpg http://forums.pelicanparts.com/uploa...1431273932.jpg
http://forums.pelicanparts.com/uploa...1431273945.jpg

KTL	05-11-2015 07:04 AM

Quote:

Originally Posted by Henry Schmidt (Post 8614850)

Your memory is correct. Intake lift is .476" and .450" on the exhaust

Thanks much for the 36mm recommendation. Same as the Eibach published number, but theirs would seem to be just generally speaking and not cam related. I'll be sure to check for coil bind and retainer clearance with the stem seal. Probably not going to be an issue for either of those things but worth looking at since in their measuring things anyway

Henry Schmidt

05-11-2015 08:35 AM

Quote:

Originally Posted by KTL (Post 8617901)

When working with an after market spring all you really need to know is total valve lift and spring pressures. Porsche is notorious for running very low spring pressure to reduce parasitic loss and wear. The point of an after market spring is to reduce valve float at high RPM.
As long as your valve lift is less than Eibach's published pressure @ full lift number and you can live with those numbers, you're good to go.
If you desire higher full lift (over the nose) pressure then calculating spring height becomes an more challenging endeavor.
When we first encountered these springs we were skeptical so we invested time and resources into testing the validity of Eibach's claimed number. At this point we are satisfied that they (Eibach) did their homework.
Of course for all of you "engineer types" that struggle with believing an "old dog" you are more than welcome to do your own homework.

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