8-71 Roots Blower Motor Build

[85zeee]

These are some pics I took of a blower motor build I did for a friend of mine.....he lives about 100mi from me but his work brings him down to my area every couple of weeks and he wanted to learn how to do a build so I was doing all the prep work then showing him how to do the assembly

If anyone has any questions or tips/comments please feel free to post them

The block is a mid 70's 350 (.030 over) 4 bolt

Here are the semi finished pictures and a price list (next time I see him I will add all of the tax and shipping to the price list since I never updated it at the end of the build)
The total cost as is in these pics including machine work (minus the bare block and rods) was $6150.79

http://i16.photobucket.com/albums/b50/s30119/Steves%20Motor/DSC01559.jpg

http://i16.photobucket.com/albums/b50/s30119/Steves%20Motor/DSC01560.jpg

http://i16.photobucket.com/albums/b50/s30119/Steves%20Motor/DSC01554.jpg

Machine Work
Hot Tank $ 68.75
Check Bores/Hone Cylinders $ 88.00
Fresh .010/.010 Crank w/Bearings $132.50
Check the rods for Straightness $ 28.00
Bore small end of rods for floaters $ 96.00
Other costs (tax environmental) $ 15.30
Total $428.55

Parts List
8-71 Polished Blower $2700.00
Heads (World Sportsman II WRL-011150)(used) $ 600.00
Pistons (Speed Pro L2441F .030) $ 311.60
Rings (Summit Low Friction Sum-133-139-30) $ 21.69
Main Bearings (Federal Mogul 4663 M10) $ Included W/Crank
Rod Bearings (Federal Mogul 8-2555A 10) $ Included W/Crank
Cam Bearings (Federal Mogul 1235 M) $ 15.95
Oil Pump (Summit H.V. SES-3-60-08-001) $ 54.95
Gasket Set (Fel-Pro KS2600) $ 39.95
Gear Drive (Pete Jackson 327-10N) $ 142.95
Cam Comp Cams (12-568-4 NX284H) $ 140.00
Lifters Comp Cams Hyd.(812-16) $ 70.00
Push Rods (Chromemoly Sum-1437800) $ 99.95
Rockers Roller (Sum-G6910B) $ 189.99
Distributor (MSD-85551) $ 205.95
Harmonic Damper (Chrome fluid) $ 100.00
Fuel Pump (Holley HLY-12-327-11) $ 65.88
Carburetors 600CFM(Edelbrock EDL-1405) 2Ea $ 470.00
Scoop Hilborn Style (MRG-5233) $ 184.95
Fasteners Polished S/S Allen Head $ 78.95
Water Pump Chrome Short (SUM-G1662) $ 98.69
Timing Cover Chrome $ 22.00
Oil Pan Chrome $ 45.00
Valve Covers Chrome (PRO-141-103) $ 44.95
Water Neck Chrome (SUM-G3801) $ 10.39
Assembly/Prep/Paint $ No Charge
Other Tax/Shipping Ect. $ 8.45
Total $5722.24

Grand Total $6150.79

[85zeee]

Here is the block hot tanked and rust prepped ready for paint

http://www.geocities.com/thirdgenblownz28/motor19.jpg

http://www.geocities.com/thirdgenblownz28/motor16.jpg

http://www.geocities.com/thirdgenblownz28/motor20.jpg

[85zeee]

Here are the cam bearing install pictures, for anyone that hasn't ever done this it is pretty straight forward. The cam bearing outer diameters are different sizes so look at the box or intructions for which journal each one goes into.The front bearing has the 2 oil holes in it...the 2 bearings with the smaller O.D. go in the #3 and #4 spots....the 2 bearings with the larger O.D. go in the #2 and #5 spots. On installation the rear two (#4 & #5) go in from the back the other three go in from the front you just have to make sure that the oil hole on the bearing is centered with the oil galley on the journal and has the oil hole clocked correctly. The 4 rearward bearings should have the hole at 5 oclock as viewed from the front of the engine the front bearing should have the oil holes at 4 and 7 oclock as viewed from the front of the engine.

http://www.geocities.com/thirdgenblownz28/motor28.jpg

http://www.geocities.com/thirdgenblownz28/motor31.jpg

http://www.geocities.com/thirdgenblownz28/motor29.jpg

http://www.geocities.com/thirdgenblownz28/motor30.jpg

[85zeee]

When installing the crank we checked the machine work with both a mic and plasti guage ( I would always advise double checking all machine work you have done no matter how much you trust your shop because mistakes happen and its a lot less work to catch it before something explodes)
Oil the bearings before you assemble them but always retorque a second time later on to make sure any excess oil does not affect the torque reading
(Also I try to never touch any surface area on the bearing with my fingers)


Crank installed w/lower bearings
http://www.geocities.com/thirdgenblownz28/motor41.jpg


Steve checking the bearing clearance w/plasti gauge after measuring the journals with a mic
http://www.geocities.com/thirdgenblownz28/motor42.jpg

Perfect .002 clearance
http://www.geocities.com/thirdgenblownz28/motor43.jpg

Cleaning the plasti gauge off
http://www.geocities.com/thirdgenblownz28/motor44.jpg

[85zeee]

Oiling the beargings in the caps
http://www.geocities.com/thirdgenblownz28/motor45.jpg

All the mains installed
http://www.geocities.com/thirdgenblownz28/motor46.jpg

Ohhh thats nice!!!!!!!
http://www.geocities.com/thirdgenblownz28/motor47.jpg

[85zeee]

Here is a good link for bearings and installation tips:
http://briefcase.yahoo.com/bc/s30119@sbcglobal.net/lst?.dir=/Bearings&.order=&.view=l&.src=bc&.done=http%3a//briefcase.yahoo.com/

[Phoenix 5.7]

very cool. i want to build a roots engine some day. even if there are more efficient ways nowadays(turbo/centrifugal), there is nothing like the site of a roots stickin out the hood

[85zeee]

If you can't tell I like them a little also lol......I think that people that have never had any experiance with roots blowers confuse "efficient" with "power" and don't realize there is no match for the across the RPM range raw power making capability of the roots blowers

[85zeee]

Here are the pistons and rods ....We had the stock rods checked then had the small end Bored for the floating piston pins. The static compression for this engine should be about 8.3:1

http://www.geocities.com/thirdgenblownz28/motor10.jpg


http://www.geocities.com/thirdgenblownz28/motor27.jpg


http://www.geocities.com/thirdgenblownz28/motor26.jpg


http://www.geocities.com/thirdgenblownz28/motor25.jpg

[85zeee]

Here are Speed Pros end gap recomendations

Speed-Pro top rings (ductile iron, 4" bore)
moderate performance .016 - .018 (.004 per inch of bore diameter)
drag racing, oval track .018 - .020 (.0045 per inch of bore diameter)
nitrous oxide - street .020 - .022 (.005 per inch of bore diameter)
nitrous oxide - drag .028 - .030 (.007 per inch of bore diameter)
supercharged .024 - .026 (.006 per inch of bore diameter)

Speed-Pro 2nd rings (cast iron, 4" bore)
moderate performance .020 - .022 (.005 per inch of bore diameter)
oval track .022 - .024 (.0055 per inch of bore diameter)
nitrous oxide - street .024 - .026 (.006 per inch of bore diameter)
nitrous oxide - drag .028 - .030 (.007 per inch of bore diameter)
supercharged .024 - .026 (.006 per inch of bore diameter)

Notes: Use the chart as a guide to normal ring end gaps. The “ideal” end gap will be somewhat different for each engine.
Piston rings should be file fitted to the desired end gap with the torque plate attached. In worn cylinders, make sure that ring
gaps are checked at bottom of ring travel. In seeking the optimum end gap for your particular engine, choose the proper
application in the chart and gap the rings to the high limit. If the ring’s end surfaces show shiny spots after use, it is evidence
of ring butting. This means that your rings are operating at a higher than average temperature and require additional gap.
If there is no indication of butting, then the end gap can be narrowed until you reach the "ideal" condition. Remember, stay on
the safe side!

When installing the pistons always double check your ring gap staggering from top to bottom I always do 180/180/90.
Also it is a very good idea to use rod bolt covers so you don't scratch the crank and a wood or plastic handle to knock the pistons in with.
And once again try to not touch the bearings.....oil them....install and torque.....re torque after it sits to make sure all excess oil is out

Here are some good links for rings and pistons

Rings:http://briefcase.yahoo.com/bc/s30119@sbcglobal.net/lst?.dir=/Rings&.order=&.view=l&.src=bc&.done=http%3a//briefcase.yahoo.com/

Pistons:http://briefcase.yahoo.com/bc/s30119@sbcglobal.net/lst?.dir=/Pistons&.order=&.view=l&.src=bc&.done=http%3a//briefcase.yahoo.com/




Sorry no pics of piston install

[204Denali]

Great addition to the FI section man, post up all the pics you can find. Great looking motor also.

[dst]

Nice build!

You Chevy guys have it nice, to build blower Mopar SB would cost well above your total.

What is the compression ratio? Your 'Here are some good links for rings and pistons' links did not work for me.

[85zeee]

I cringe when I see the chevy prices then think that it sucks for the ford and mopar guys that prices are so much higher

I fixed the links ......let me know if they go out again thanks

The static CR is 8.3:1 we should be around 9lbs boost (havent fired it up yet he is still finishing some other things up on his truck)

I should have the rest of the build pics up in the next day or two

[PNYKLR2]

Beautiful beast you got there, I think he will enjoy it.

[85zeee]

Here is the cam. I would recommend when installing the cam and lifters you you tons of pre lube (you can see it on the cam in the block pics) also using some sort of cam install handle when putting the cam in..... it makes it much easier with less risk of screwing the bearings up

Also we dialed the cam in but that is a whole nother tech write up so I wont cover that in this one



http://i16.photobucket.com/albums/b50/s30119/8-71%20Build/motor37.jpg


http://i16.photobucket.com/albums/b50/s30119/8-71%20Build/motor38.jpg


http://i16.photobucket.com/albums/b50/s30119/8-71%20Build/motor39.jpg

[85zeee]

These are the rest of the short block goodies. The oil pump is high volume with the pick up welded on and we used a needle bearing cam button and lock plate on the gear drive


http://i16.photobucket.com/albums/b50/s30119/8-71%20Build/motor7.jpg


http://i16.photobucket.com/albums/b50/s30119/8-71%20Build/motor8.jpg

[85zeee]

Ok here are the heads..... when we were picking up the block at the machine shop they had these as a non pick up from a customer. They are World Sportsman II 64cc with 2.02/1.60 valves and 200cc runners both of the castings were new but the valves were used we got the set for $600

http://i16.photobucket.com/albums/b50/s30119/8-71%20Build/motor34.jpg


http://i16.photobucket.com/albums/b50/s30119/8-71%20Build/motor32.jpg


http://i16.photobucket.com/albums/b50/s30119/8-71%20Build/motor35.jpg


http://i16.photobucket.com/albums/b50/s30119/8-71%20Build/motor33.jpg

[dst]

That seems like a mild cam for what I would think a Supercharged engine would need, how did you choose that profile?

I like the honest timing set ("NOISE"). :)

[204Denali]

You dont want the cam to be to crazy on a blower engine other wise the cam will allow to much boost to bleed off. To much overlap will result in less psi from the blower. Hence the reasoning for blower specific cams, did I answer anything for ya or did you mean something else?

[dst]

You dont want the cam to be to crazy on a blower engine other wise the cam will allow to much boost to bleed off. To much overlap will result in less psi from the blower. Hence the reasoning for blower specific cams, did I answer anything for ya or did you mean something else?
I see, you don't want to bleed off the compression. So, are the carb(s) set excessively rich then? Excessively rich compared to non-supercharged carb settings.

What is the Chevy 350 stock LSA? 110?

[85zeee]

That seems like a mild cam for what I would think a Supercharged engine would need, how did you choose that profile?

I like the honest timing set ("NOISE"). :)

The general specs for the larger blower cam fall at 112LSA and 500/500 so this one is a little bit more on the agressive side for 9lbs of boost

LOL gotta love blower whine and "NOISE"

Here is some info from holleys site:
here is the link http://www.holley.com/data/TechService/Technical/Supercharger%20Tech%20Info.pdf


Supercharger Engine Camshafts
The choice of camshaft can make or break a blower motor. A
legend in the industry, Lunati offers several camshafts specifically
designed to work with Weiand blower kits. In addition,
the following are a few basic guidelines for selecting the
proper cam for your motor.
Obviously, the amount of boost your supercharger produces
is going to be a factor in choosing a camshaft. Weiand offers
three different levels of superchargers, and each requires a
different type of cam.
The “mildest” of Weiand’s blowers are the Pro-Street superchargers,
which are set to produce from 5 to 7 pounds of
boost. The company recommends a hydraulic cam for these
applications - where the engine will not be spun past 6,500
rpm and has several grinds available. All of these cams are
ground on a 112 to 114º lobe center line, which helps maintain
cylinder pressure to maximize horsepower at these lower
boost levels. Keeping the cylinder pressure up also gives you
excellent throttle response.
The milder cams that Weiand offers are great for street performance
enthusiasts who want to gain about 100 to 120
streetable horsepower. The company also offers slightly “bigger”
cams for the next performance level up.
For 6-71 and 8-71 blowers, Weiand again recommends running
a hydraulic cam, as long as you keep the boost level
below 10 PSI. Weiand also offers cams for these type of
applications.
For your higher boost levels in gasoline burning engines, the
company recommends running a flat tappet or roller cam
with a 110º lobe center line. This cam design provides good
overall power on pump gas and also aids in engine cooling.
Plus, the 110º center line provides even sharper throttle
response and helps lower initial cylinder pressure (you won’t miss the cylinder pressure with these blowers, since they make
plenty of boost).
In all supercharger applications, Weiand recommends running
roller rockers and chromoly push rods.

[85zeee]

Here are the pics of the assembled long block with the roller rockers.....I will add for what it is worth I have been putting blower motors together since 1986 and the only time I have had a head gasket failure was the one and only time I did not use Fel Pro Perma Torque head gaskets back in 1987

also the only place I ever use any sealant is a dab in the 4 corners of the pan and the 4 corners of the intake

http://i16.photobucket.com/albums/b50/s30119/8-71%20Build/DSC01480.jpg

http://i16.photobucket.com/albums/b50/s30119/8-71%20Build/DSC01491.jpg

http://i16.photobucket.com/albums/b50/s30119/8-71%20Build/DSC01492.jpg

[badjuju342]

Excellent thread! This is just the kind of stuff I love to see! Give this man free drinks all night on the house!

[MrSkull]

I'm using Sportsman II's in my TT 383 buildup. I have run them on N/A engines and they are just all around excellent heads.

Im going with SRP 31 CC dish pistons. With the 64 CC chambers i am looking at close to 8.5 to 1 compression.

What dish do you have with the Speed Pros? Sorry if you listed that above in your specs, I looked but couldn't find it.

Great buildup and pics by the way, I'm sure it will blow you guys away!
Best wishes,

[Mojo]

Nice thread Shawn.
and to everyone else if you have questions just ask he knows his stuff he also built the moter in my truck which we promptly loaded up and broke it in at the woodward dream cruise. Talk about a test for a fresh engin
keep up the good work shawn!!

[85zeee]

:) hehe that 4k rev limiter chip didn't last long that day

[Mojo]

I dont have a clue what you mean!?! LOL