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-   -   Another blower question (http://www.hotrodders.com/forum/another-blower-question-228670.html)

strokin 01-21-2013 04:24 PM

Another blower question
 
I'm planning a 400 sbc blown build, using eagle internal balance kit with je 36 dish piston all forged,
Using a dart shp block, carburated, haven't picked cam yet or heads, probably go with afr 220's with a 75cc chamber and a solid roller cam. Plan to run around 9 psi.
Question is, I've built many small blocks up to 450 hp but never built over that and never in a blown application. Are there any tricks for tolerance? Specs? Or any special details I should be watching for when building blown short block? I have a good speed shop here that can do all the machining. Also never done a 400, do I have to worry about steam holes with all these after market pieces?

And no I'm not interested in having my speed shop build it.

Thank guys

496CHEVY3100 01-21-2013 04:45 PM

On a street engine you will need the steam holes drilled in heads you are using,you can get by on engines no turning Less than around 3000 rpm such as circle track ,we ran Late Model Modified on dirt with alumimum block and Brodix # 7 heads prepared by Race Engine Design .we drilled heads just to be sure,some did not,but some had problems in pack out and during caution,I am assuming you will need all the help you can get to cool blown engine, I have built hundred or so racing engines But Never a blown engine ,will be building BBC with 671 crager blower later this year ,Just my opinion someelse might help us both ,Good luck

vinniekq2 01-21-2013 07:01 PM

your ring gap needs to be increased.
spin or fbird can give exact specs when they see this thread.
dont be shy with the heads,227s might be nicer

cobalt327 01-22-2013 09:09 AM

Quote:

Originally Posted by strokin (Post 1637370)
I'm planning a 400 sbc blown build, using eagle internal balance kit with je 36 dish piston all forged,
Using a dart shp block, carburated, haven't picked cam yet or heads, probably go with afr 220's with a 75cc chamber and a solid roller cam. Plan to run around 9 psi.
Question is, I've built many small blocks up to 450 hp but never built over that and never in a blown application. Are there any tricks for tolerance? Specs? Or any special details I should be watching for when building blown short block? I have a good speed shop here that can do all the machining. Also never done a 400, do I have to worry about steam holes with all these after market pieces?

And no I'm not interested in having my speed shop build it.

Thank guys

You'll have good air/fuel homogenization, but still I'd recommend a reverse dome D-cup dish if possible (example JE Extreme Duty inverted dome p/n 131633-1). Run the quench measurement as you would NA.

496CHEVY3100 01-22-2013 09:42 AM

I contacted BDS They recomend cutting a second keyway in crank snout to keep hub from stripping key and spinning crank hub and destroying crank snout,also Must run run forged cranh and forged 8.1 or less pistons for street with 7 lbs boost or less,Is this just a recomendation or a Must,anyone had any experiance wiyh this ,It is a 454 stroker=496 i have steel crank forged pistons ,but stock rods with arp bolts in rods and mains are arp studs ..671 blower i have a crager and a weiand ,which would be better.have already purchaced Comp Cam Blower Cam.roller rockers pushrods roller chain,115cc aluminum heads 225/188 valves do not want to change these

cobalt327 01-22-2013 09:50 AM

496CHEVY3100, why not start a separate thread, that way things won't get confused between your questions and the OP.

spinn 01-22-2013 04:29 PM

My god, blowers are nuts.

The power is awesome.

techinspector1 01-22-2013 05:26 PM

Quote:

Originally Posted by 496CHEVY3100 (Post 1637574)
have already purchaced Comp Cam Blower Cam

I'll bet your Comp "blower cam" is cut on a 114 LSA. Read this from Blower Drive Service...110 works best for gasoline...114 works best for ALCOHOL...

"Choosing the proper camshaft would be the most important requirement for a blower motor. An improper cam will cause a variety of problems that can easily be avoided by following a few simple guidelines. Hydraulic cams are recommended if you intend to drive the vehicle frequently, requiring little or no maintenance, and the maximum engine RPM's are kept around 6500 or lower. Roller rocker arms are recommended. Flat tappet and roller cams are recommended for high performance applications especially where the engine will see high RPM's. Exact camshaft specifications vary depending on the performance level you wish to attain. BDS offers different types or stages of cam grinds specifically made for blower motors. Refer to camshaft specs listed in tech info for BDS' individual engine camshaft specifications and their intended uses.
If you wish to purchase your cam from one of the many fine camshaft manufacturers, we suggest using our camshaft specs as a guidline. Extremely high lift and long duration cams are recommended for high RPM, high performance racing only.
The lobe center of the cam will play an important role in determining the performance characteristics of an engine. Wide lobe centers (112 to 114 degrees etc.) will create higher cylinder pressure providing more horsepower with cooler burning fuel such as alcohol and methanol. We have found 110 lobe centers to produce the best overall power on gasoline.
Whatever cam you choose, make sure that it will operate and perform properly in the RPM range required for your application."

I don't know what it is that makes you guys jump up and buy the cam as one of the first items. Cam and torque converter should be the last 2 items bought, after you've finished the drivetrain and everything else.

strokin 01-22-2013 06:29 PM

Ya I've heard about running wider gap, but yet some say to run a second gapless ring?

strokin 01-22-2013 06:35 PM

So you don't see any advantage to running a 400 vs 355 even though they will all be brand new parts? Obv we've all heard of typical problems with a 400 but even with dart block and all aftermarket parts?

vinniekq2 01-22-2013 07:10 PM

after market dart blocks are great. 400 is a good starting point for your engine

496CHEVY3100 01-23-2013 08:00 AM

Quote:

Originally Posted by techinspector1 (Post 1637732)
I'll bet your Comp "blower cam" is cut on a 114 LSA. Read this from Blower Drive Service...110 works best for gasoline...114 works best for ALCOHOL...

"Choosing the proper camshaft would be the most important requirement for a blower motor. An improper cam will cause a variety of problems that can easily be avoided by following a few simple guidelines. Hydraulic cams are recommended if you intend to drive the vehicle frequently, requiring little or no maintenance, and the maximum engine RPM's are kept around 6500 or lower. Roller rocker arms are recommended. Flat tappet and roller cams are recommended for high performance applications especially where the engine will see high RPM's. Exact camshaft specifications vary depending on the performance level you wish to attain. BDS offers different types or stages of cam grinds specifically made for blower motors. Refer to camshaft specs listed in tech info for BDS' individual engine camshaft specifications and their intended uses.
If you wish to purchase your cam from one of the many fine camshaft manufacturers, we suggest using our camshaft specs as a guidline. Extremely high lift and long duration cams are recommended for high RPM, high performance racing only.
The lobe center of the cam will play an important role in determining the performance characteristics of an engine. Wide lobe centers (112 to 114 degrees etc.) will create higher cylinder pressure providing more horsepower with cooler burning fuel such as alcohol and methanol. We have found 110 lobe centers to produce the best overall power on gasoline.
Whatever cam you choose, make sure that it will operate and perform properly in the RPM range required for your application."

I don't know what it is that makes you guys jump up and buy the cam as one of the first items. Cam and torque converter should be the last 2 items bought, after you've finished the drivetrain and everything else.

Thanks Mine is 110 lc hydi do have roller rockers& All matching parts and only 540 lift ,the alum heads i buught are good up to 615 lift as recomended by comp far gas ,114 for alcohol, compresssion is 7.9 converter is 26 00-2800 from B&M for big block app,all i want is the whine of 671 ,will nerer be raced exept to gas station ,lol,probable never over 5000 rpm. just want look and sound thanks for advice..:rolleyes::D i had the converter still in box 4 yrs and blower before i bought the engine

1932bantam 01-23-2013 08:42 AM

thing about the 400 you got to run that big heavy crankhub for ex balanced that and pulleys for alt etc. puts alot of strain on the end of the crank. As far as quench no need to worry about it on a blown engine. We just had a crank hub twist off, bent end of crank on 383 idling was running a spacer behind blower pulley, not a good setup

vinniekq2 01-23-2013 09:39 AM

Many reputable crate engine builders will build 383/406/434 turn key blower engines.They use a callies crank.Just dont try to build powerful and cheap,leave that for the low horse power guys

1932bantam 01-23-2013 09:48 AM

yes i agree . he already had engine , so we tried it


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