Technical what engine oil for roots blower motor and other thoughts

you dont need head studs, if you're going to keep the boost below 10 psi. They're a pain.

A bit more lift would be good, somewhere between 550 and 600

Blowers don't use a damper, they just use a steel crank hub. The drive belt takes care of damping the harmonics in the crankshaft. The steel hub p***es NHRA inspections. Two keys aren't really needed for mild boost, you can do it, or not. The big block crank snout is a lot bigger than small blocks.

Select the drive ratio based on how much boost you get out of your combination. I'd start with close to maybe 6% under and see what happens. The boost charts are not as precise as we'd like them to be.

 

Thanks. I saw the steel hub on BDS website. Good to know on head studs and keyway.
The cam I looked at is just a little smaller than yours.
I based this on my truck. I went with one for mid range and should have went a little less.

So my brother is older than me and always said to use factory parts.
He used to have the gm high performance parts book.
I think I will look into that.
I done a lot of thinking last night. I have time to piece together a good combo.
I guess stock style engine with forged internals. Keep it simple.
blower will be bought as can afford.
Engine I will get a used block then start ordering cam and heads etc.
I should be able to do this in about 3 years.

 

It can be done with thought blend in / hidden ,add just enough fuel to lube rotors, also if set up loose like a Diesel No fuel needed
(Im sure ?) but would have to spin harder to get boost psi wanting .
Also I think you mentioned E85 so your rotors end plates on inside & case would need to be anodized . Usually if running a Alky /methanol base fuel @ end of day run on gas to lube fuel system form corrosion .

 

Why do the rotors need lube? They don't touch anything.

Could be that the fuel helps keep them cool so they expand less, and can operate with a bit less clearance?

 

The reason an 8-71 is cooler is because it doesn't have to work as hard for the same horsepower versus the 6-71 which would need to spin faster, making more heat.
A blower makes variable rate compression, the more boost the higher compression, gasoline octane will determine the amount of boost (compression) you can run. If you start at a lower rate static compression you can cram more boost in to reach your compression goal, more boost equals more heat, so it's a balance of things to not build to much heat but still make power.
Say if your compression goal is 11-1 and you start with 10.5-1 you'll make less overall horsepower with the blower to reach your 11-1 due to the parasitic drag loss of the blower itself, some say it takes 100 horsepower to spin the blower.
One other thing to think about is if you can fit a conventional distributor in a sbc using an 8-71, if you use a front offset intake or blower to clear the distributor does that push everything forward into the radiator ???
These guys
https://nyesracingengines.com/blower-engines/
build great engines with matched parts that work, comparison shopping of individual parts and machining vs a complete engine might be very surprising.

 

fuel dose cool lobes / blower when converted to use on fuel tighter Clarences & type of strip used ,
& to much fuel can hydraulic case, high hp usually 25% fuel on top and 75 % below
On street I run a loose set up

 

With all 71 blower sizes you need to be knowledgeable of size ,stage , rotor & case design,.
There are so many , let just talk about the 8-71 3 lobe ,yes more air less drive , But if not spun fast enough it can heat up air/charge @ low RPMS ,& the more invaded efficient Rotor , Case designs more speed required

 

A blown big block in a model A closed cab pickup?!?! Hahaha! OK, that'll be a hoot.

 

I have one.

 

I like your plan and that little truck. When you are ready, start a build thread. Good luck and Happy New Year . Boost is addictive!

 

My final questions are : forged rods? Flat top or domed pistons or dished?
Built vs bought is really close. Built I can buy as I have the money. If I bought one finished that would be payments. I won't finance car parts. Cash or wait.
If I understand right the long block will be built like a 11.1 compression engine.
Mine will just be 8.1 with blower. Same rules should apply for parts needed to survive on the street.
I will post pics when the motor is close to done. I'm already wanting to order some things.
@mad mikey @squirrel @swade41

 

Any pics? How much clearance on firewall? I ***ume the firewall is set back.

 

Much of the build is not acceptable for this site.

That said, my firewall has been relocated forward 6-inches. That was made possible by not putting the engine in front of it.

 

Well that sounds interesting.

 

BBCs have forged rods, the Chevy ones will work, I have 7/16 bolt old design Chevy rods in mine, with good bolts. Piston dome depends on the heads, I run a slight dome with open chamber heads on my 427, but I had dished pistons on my 454. If I were building the 454 today it would probably have flat tops. also you don't need to get special blower pistons, with lowered ring lands, etc for under 10 psi boost. Stock replacement forged pistons that give you the desired compression ratio with the heads you decide on, will work, if there are some available.

 

Thanks time to make a list and start ordering.

 

Just for extra Insurance look into a gm steel crank or **** , when I Tour down the one engine with cast crank on 10 psi cracks ever where.

 

https://www.ebay.com/itm/233974388475?

of course this is for a 427, not a 454, but the number 427 sounds so much better, don't you think?

 

Thanks I will purchase the books. I know what heads I'm using. Pistons will be machine shop choice along with rings and bearings. First thing is to find a good block.

 

Your's doesn't count.

 

BTW, I'm not saying it can't or shouldn't be done, just that it'll be a hoot, and of that I am sure. Good luck. And get a big shoe horn....

 

I know it will be a tight fit. I can cut the firewall out and install a modified original. I've been measuring front to back and top to bottom.

Checking summit racing for rotating ***emblies. price isn't terrible.

 

Here is my 1930 A.I am putting a sbc with a 6.71 350 turbo and s-10 3.42 gears. It is now gloss-black with a red interior. Just turned 67 so I am a little slower than I was.RLS

 

@rlsteel That's a good start. Funny I have a 350,th350 and a 3.42 s10 rear end I'm not using.
I will go bbc with 8-71 th400 and 3.00 to 1 9 inch ford rear.
My current combo in truck is 355 th200r4 and 4.10 posi s10 rear.

 

https://www.blowerdriveservice.com/CommonQuestions This verifies some things discussed here. a lot of good info.

 

I saw parts of it. I need to watch it all sometime. Thanks.

 

Engine Masters show with David F. also has some episodes, dyno with various combinations.