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Chevy L6 250" harmonic balancer

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Chevy L6 250" harmonic balancer

Postby BrazilianZ28Camaro » Sun Nov 22, 2009 12:41 pm

Hello fellows

I'm helping a friend select the parts to his L6 mild N/A engine...since there are no decent harmonic dampers for it here in Brazil and that engine have harmonic problems by nature, I'm wondering if a SBC harmonic damper can be used with out major milling/mods on the crank ,damper or cam gears cover.

Somebody did this before??
Which would be the ideal damper OD size?

Thanks for replies :wink:
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Postby robert1 » Sun Nov 22, 2009 1:24 pm

I used a 350 balancer on a L4 with no problems or trouble.
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Postby BrazilianZ28Camaro » Sun Nov 22, 2009 1:27 pm

robert1 wrote:I used a 350 balancer on a L4 with no problems or trouble.


153" L4 ?
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Postby robert1 » Sun Nov 22, 2009 1:32 pm

151", 2.5, Pontiac.
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Postby BrazilianZ28Camaro » Sun Nov 22, 2009 1:41 pm

robert1 wrote:151", 2.5, Pontiac.


If memory serves me right , the 151 crank snout and timing cover retainer is the same 250"... :?:

The engine you mean had a previous damper or only a crank hub?
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Postby robert1 » Sun Nov 22, 2009 1:59 pm

The 153 is the same as the I6. The Pontiac only had a hub. It has a damper ring that bolts to the hub but not suitable for racing.
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Postby BrazilianZ28Camaro » Sun Nov 22, 2009 2:02 pm

Thank you Robert for the helpfull info :wink:
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Postby speedymatt » Sun Nov 22, 2009 6:21 pm

we use a fluidampner on a couple of inline six engines we do. you just have to make/modify a timing pointer as the marks don't line up with the six cylinder pointer
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Postby BrazilianZ28Camaro » Sun Nov 22, 2009 7:02 pm

speedymatt wrote:we use a fluidampner on a couple of inline six engines we do. you just have to make/modify a timing pointer as the marks don't line up with the six cylinder pointer


thanks for reply :D

Can you tell a little more about the L6 you build? (power, combo, usage)

Just curious because I never hear/read about a N/A Chevy 250 modified in the US...maybe I need read more :roll: :oops: :lol:

Here in Brazil we have plenty of Chevy 250s on street and drag cars...It was factory installed in Chevy Opala and Chevy Caravan... The fastest drag cars running with it run the 1/4 mile in 11.1s @ 2800lbs N/A and 7.8s @ 2400lbs on single turbocharged Opalas.

Here we have a factory "hot" L6 , called 250-S that was equipped with a mechanical cam and more CR and had 171 factory ponies :D
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Postby ProPower engines » Sun Nov 22, 2009 10:15 pm

We did one for a guy that we sleeved out to 4"
Used a 11-1 327 LW piston with Crower rods(custom made for the 250 engine)
Used a ported 194 cyl head and a modified 350 balancer to finish the job.
Used a Clifford 4bbl intake and 650 holley in a pu truck.
A tri-y header was all that we could get at the time but made good power did not get any dyno numbers on it but would blow the tires off through 2nd gear with a th350 2200 stall and 308 rear gear
He would turn it to 6800 all day long.
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Postby BrazilianZ28Camaro » Mon Nov 23, 2009 10:55 pm

ProPower engines wrote:We did one for a guy that we sleeved out to 4"
Used a 11-1 327 LW piston with Crower rods(custom made for the 250 engine)
Used a ported 194 cyl head and a modified 350 balancer to finish the job.
Used a Clifford 4bbl intake and 650 holley in a pu truck.
A tri-y header was all that we could get at the time but made good power did not get any dyno numbers on it but would blow the tires off through 2nd gear with a th350 2200 stall and 308 rear gear
He would turn it to 6800 all day long.


Coooollll :D

With 194 head you mean 1.94 valves?

You remember what cam that engine had?

Here, some builders overbore the 250 block to 4" with out sleeves...good street L6 have about 330 hp :roll:

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Postby Tuner » Tue Nov 24, 2009 12:19 am

http://en.wikipedia.org/wiki/Chevrolet_ ... gine#194_2

Same head with smaller chamber, gives higher compression on larger engines.

Do you remove the head bolt column from the intake port and use a short stud and nut?
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Postby ProPower engines » Tue Nov 24, 2009 12:43 am

No a 194 head is from a 194cid block.
It was the first engine of that model run then came a 230 then a 250 ect.
We put 1.94 valves in the head but needed to massage the chamber quite a bit.
The 230 head work out better and with .080 off was about the same size in the end.
Going to 4.00" is getting real thin and especially #1 hole behind the water pump.
if the sonic checked the block I would bet they may had .080 of cyl. wall left and # 1 would be paper thin. What ever floats your boat I guess but would not go out that far with out sleeves in at least #1 and #6. Seen too many crack.
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Postby ProPower engines » Tue Nov 24, 2009 12:52 am

Tuner wrote:
Do you remove the head bolt column from the intake port and use a short stud and nut?


No I used a allen head cap screw and put a 1/2" pipe plug in the top of the bolt hole to seal it.
A bit of a pain to get the threads down far enough to get the bottom of the plug flush with the inner port side of the hole.
It probablly did not make any diffefence to flow but seem like the right thing to do.
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Postby BrazilianZ28Camaro » Tue Nov 24, 2009 11:22 pm

Tuner wrote:http://en.wikipedia.org/wiki/Chevrolet_Straight-6_engine#194_2

Same head with smaller chamber, gives higher compression on larger engines.

Do you remove the head bolt column from the intake port and use a short stud and nut?


Here we have ethanol L6 with 54cc heads...

Acually, if you remove the bolt column and put a bolt inside the port, the turbulence generated negates any possible gain. Not a good mod. :roll:

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