L-72 tune up - Page 2

**YENKO DEUCE REGISTRY** · #11 04-25-2006, 12:21 AM

I have to agree with Rob on the LSA thing - I too tried a 'better' cam when I built my engine, and kept all else stock. I could not get that thing to idle at less than 1300+/- RPM because of the tight cam.

I then took it out, put in the stock cam that I bought from my local dealership, and was able to get the engine tuned through conventional means - with the help of others

Now, it's a solid 14.2 @ 99MPH runner, looking to get another tenth out of it at SCR9

**Mr70** · #12 04-25-2006, 04:00 AM

With that ET,what RPM does it idle at now Marlin?

**Alss** · #13 04-25-2006, 06:15 AM

Cam was selected as it was suppoed to be close to the stock L-72 cam but be a roller..machinist is very knowledgable and has done alot of motors for me. Going to try the dialback method when I get some time to play. I have had bigger cams work with stock components..this one will just require some time..and I'm learning as I go

Thaks for all your inputs

ALbert

**YENKO DEUCE REGISTRY** · #14 04-26-2006, 08:28 PM

[ QUOTE ]
With that ET,what RPM does it idle at now Marlin?

[/ QUOTE ]

The car idles around 900 - special thanks to K.Marple for that.

At SCR7 I was launching just off idle around 1200rpm, but last year at SCR8 I got my spring clamps installed - 2 per side, and continually raised my launch rpm until the final round where I think I was hitting the tires at around 2000 rpm. There was still a slight bog, without tire squeal, so that tells me that I could have raised it higher. I was a bit timid however, because my car has it's 'born-with' original drivetrain - and I do this for fun, not to get my best ET by breaking something.

Not sure who I'll banter with this year without Frankie

**Alss** · #15 04-27-2006, 04:23 AM

OK, had some time to play with the motor a bit..here are the results..set timing by ear and test drove..ran good but.....timing mark(flash) is at 12 o'clock instead of on the tabat 2 o'clock!!!!, almost 50 degress out of place!!..any ideas of what I have skrewed up!! Runs great otherwise..HELP!!!!!!

ALbert

HS PROFESSOR · #16 04-27-2006, 07:09 AM

possibly wrong balancer or timing pointer??? if it runs well,doesnt ping, and turns over when hot........crank it up some more!!!! you'll know your close/gone too far when it doesnt crank very fast when hot. good luck....

bob

TDW · #17 04-27-2006, 12:45 PM

If it is the original balancer, chances are the rubber has slipped some. Did you check where the timing marks are at TDC? That is where I would start checking things.

**YENKO DEUCE REGISTRY** · #18 04-27-2006, 02:59 PM

Mine was the same way, the balancer was fine, it was just me over compensating for other items that were out of tune! The real test was a shot down the 1320, what felt fine on the street was like a dog on the strip

**Alss** · #19 04-28-2006, 02:29 AM

well, checked the marks at TDC and the balancer mark is dead center of the tab..I rember this from assemble but double checked anyway..balancer mark is in direct line with the keyway (correct?)..gonna check the dwell next then pull out my hair

..have some time tomorrow PM and will go at it again. Thanks everyone.

ALbert

VintageMusclecar · #20 04-28-2006, 03:24 AM

Are you checking the timing with the vacuum advance disconnected?

Disconnect the vacuum advance and set the total timing to 36*-38* at 3000 rpm. Then jazz the throttle just a little more to make sure the timing doesn't continue to advance. If it doesn't, lock the distributor down, re-connect the vacuum advance and take it for a test drive. If it does, you may want to look into having your distributor re-curved to bring the advance in by 3K.

HTH.

Eric

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