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Consistency... Engine Build question #1128576
12/06/11 02:58 AM
12/06/11 02:58 AM
Joined: Nov 2004
Posts: 8,094
Sunnyvale, CA
Jeepmon Offline OP
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Jeepmon  Offline OP
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We all have our maintenance programs and pre-race rituals to be as consistent as possible.. But what about during an engine build..

Is there any tips or tricks when building the motor to help strive for consistent times?

Re: Consistency... Engine Build question [Re: Jeepmon] #1128577
12/06/11 03:25 AM
12/06/11 03:25 AM
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Posts: 19,304
Las Vegas
Al_Alguire Offline
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Do it right the first time good parts, good machine work and good assembly and all should be well. More or less power is not what makes a consistent piece. Attention to detail does make all the difference.


"I am not ashamed to confess I am ignorant of what I do not know."

"It's never wrong to do the right thing"
Re: Consistency... Engine Build question [Re: Jeepmon] #1128578
12/06/11 01:57 PM
12/06/11 01:57 PM
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Florida
Locomotion Offline
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A lot is making sure YOU do EVERYTHING the same each run. Everything the same temp, stage the same, launch, shift, etc. Of course, you have to factor in weather changes, like wind, humidity, temps, barometer, etc., so you can predict/dial-in accurately.

While the engine combos and jetting needs to be "right", engines with higher compression, more cubes and bigger carbs "tend" to be more consistent because weather affects them less. In other words, a 440 Cuda will be easier to make consistent and predictable than a slant 6 Dart!

Re: Consistency... Engine Build question [Re: Locomotion] #1128579
12/07/11 12:22 AM
12/07/11 12:22 AM
Joined: Nov 2004
Posts: 8,094
Sunnyvale, CA
Jeepmon Offline OP
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Quote:


While the engine combos and jetting needs to be "right", engines with higher compression, more cubes and bigger carbs "tend" to be more consistent because weather affects them less. In other words, a 440 Cuda will be easier to make consistent and predictable than a slant 6 Dart!




Thats good information.. Thanks

Re: Consistency... Engine Build question [Re: Jeepmon] #1128580
12/07/11 01:36 AM
12/07/11 01:36 AM
Joined: May 2004
Posts: 2,864
IN
Irun5snd8th Offline
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I have a firm belief that thicker cylinder walls increase consistency. Its logical to think that a thicker cylinder wall will distort less and have a more consistent compression.


AFCO, Rons Fuel Injection sponsored Dodge Challenger Mention Street Lethal Motorsports
Re: Consistency... Engine Build question [Re: Irun5snd8th] #1128581
12/07/11 02:45 AM
12/07/11 02:45 AM
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Posts: 52,972
Romeo MI
MR_P_BODY Offline
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Romeo MI
This is just my opinion but if the engine is a decent
build where you dont have friction from parts wearing
out it should be consistent... might be slow but it
should still be consistent... I made 8 passes in a row
all within .008 from min to max on a 10.0 set up and
that was a FEW hours spread...my engine isnt anything
fancy but I also believe fuel has a big factor.. I run
E-85 and I believe alky is even better for consistency


Re: Consistency... Engine Build question [Re: MR_P_BODY] #1128582
12/07/11 10:30 AM
12/07/11 10:30 AM
Joined: Jan 2003
Posts: 9,963
Frostbitefalls MN (Rocky&Bullw...
gregsdart Offline
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A motor build that will go the most rounds with the same power will let you establish a better history to dial from.
If I were to build a motor just for the purpose of being as deadly as possible, both me and car, it would have just enough power to go 10.00, (no heavy suit,etc) have high compression but a street roller or flat tappet cam so the valvetrain is as reliable as possible. Build the motor big, keep the revs down. Example- Small port 512 low deck with a 590 mopar cam, 13/1 compression with E85, probably with mechanical injection. This motor would only need a 5800 to 6,000 rpm shift point and last a long, long time.
If you have a light chassis and a smaller motor will do the job, I have considered a low deck 400 with an offset ground 383 crank to build a 406 to 426 cube motor. Cheap to build, easy on parts.


8..603 156 mph best, 2905 lbs 549, indy 572-13, alky
Re: Consistency... Engine Build question [Re: gregsdart] #1128583
12/07/11 10:37 AM
12/07/11 10:37 AM
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United Socialist States of Ame...
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Good point,Greg!! My 512 likes shifted at 6200-6400,has a baby roller and way too small of heads. It is consistant if the driver does his job!! It will do 10.40s...Would be nice to find another .2 somewhere and get the mph up from 127 to around 130...It just takes time to find everything!! Just have to keep plugging away!!


The end is near.....
Re: Consistency... Engine Build question [Re: tboomer] #1128584
12/07/11 12:22 PM
12/07/11 12:22 PM
Joined: May 2004
Posts: 3,210
robin hood country
deaks Offline
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Have you tried shifting it lower, you might be suprised.
Mick


69 Dart GTS 440 mopar .590 cam, Edelbrock heads, 3200#
best et 6.45, 106.78, 10.14, 132.88 mph, 1.47 60ft
best 60ft 1.36
Re: Consistency... Engine Build question [Re: deaks] #1128585
12/07/11 12:46 PM
12/07/11 12:46 PM
Joined: Jan 2003
Posts: 27,421
Balt. Md
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383man Offline
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I like to keep everything as simple as I can. Less problems to worry about throwing anything off. And I think making the most of a nice simple combo can be much more consistent then a faster complicated combo. I always felt that many combo's dont make the most of what they have and they look to just put on better high dollar parts instead of fine tuning the most out of a basic simple combo. Ron

Re: Consistency... Engine Build question [Re: Jeepmon] #1128586
12/08/11 03:14 PM
12/08/11 03:14 PM
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Posts: 5,399
Aurora, Colorado
451Mopar Offline
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Well I have had the 505 short block together 3 times so far. Once with no rings or piston locks for mock-up, clearance checking, deck height measurements, crank index check, rod side clearance, thrust clearance, etc.
Then I gapped the rings and put the pistons in, but noticed that I may have not had the rings square in the bore when gaping them, so I pulled it apart and double checked, and found two rings that were just a bit tight on the gap when squared correctly. I also re-verified the rings were installed correctly (not upside down) and put the short block back together again for the third time.
I did degree the cam with just one piston installed (no rings) so I can spin the engine easy. I checked the #1 and #6 cam timing.
It looks like #6 is slightly advanced 1/2 degree from #1. I think to account for cam twist?

Re: Consistency... Engine Build question [Re: 451Mopar] #1128587
12/08/11 03:37 PM
12/08/11 03:37 PM
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Posts: 43,007
Bend,OR USA
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Cab_Burge Offline
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Quote:

I checked the #1 and #6 cam timing.
It looks like #6 is slightly advanced 1/2 degree from #1. I think to account for cam twist?


I think the cam is ground different on the lobes due to manufacturer defects, not by design


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: Consistency... Engine Build question [Re: Cab_Burge] #1128588
12/08/11 05:11 PM
12/08/11 05:11 PM
Joined: Jan 2003
Posts: 9,866
Weddington, N.C.
Streetwize Offline
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Part of the reason the big boyz spend so much on Indexing the lifter bores, when every HP counts you don't want even slight cylinder to cylinder variations in cam timing.

Over-build the motor with the best machining and best parts, build carefully and cleanly. For consistency don't go with the most radical lobe profiles and save a few 100 RPM in the bank. I tend to over "head" the motor and then back off just a tad on the cam. Tune it for the most consistent power, not necessarily the highest. And finally when you got it running good...you gotta know when to leave it alone.


WIZE

World's Quickest Diahatsu Rocky (??) 414" Stroker Small block Mopar Powered. 10.84 @ 123...and gettin' quicker!

https://www.youtube.com/watch?v=-mWzLma3YGI

In Car:

https://www.youtube.com/watch?v=PjXcf95e6v0
Re: Consistency... Engine Build question [Re: Locomotion] #1128589
12/08/11 10:30 PM
12/08/11 10:30 PM
Joined: Jan 2003
Posts: 19,304
Las Vegas
Al_Alguire Offline
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Well you have driven a car that has a lot of attention to detail in it and a lot of laps down the track.

If you build it right, pay attention to the small things you will have a good base to work from. However I dont think there is a lot to be found with consistency on engine building. That comes from having a good working overall combination that is well sorted out and predictable in what it will do, and a driver that is also doing the right things. It takes time to build consistency to win at a National, Divisional or even at a consistent level at local bracket races.

There is no secret engine tricks to consistency no bracket racing. It is about having information, knowing how to use that information and being able to repeat, as a driver and the car as a whole. IMO there is plenty more you can do wrong than anything you will do in building an engfine. As long as the engine is built correctly that is all you need to worry about. Dont overthink this stuff, there is no one secrect magic bullet to being able to be consistent on a regualr basis. It comes down to hard work, dedication and of course lots of $$$$$$


"I am not ashamed to confess I am ignorant of what I do not know."

"It's never wrong to do the right thing"
Re: Consistency... Engine Build question [Re: Al_Alguire] #1128590
12/09/11 03:57 AM
12/09/11 03:57 AM
Joined: Jun 2007
Posts: 103
NEW JERSEY
BIGSPEED Offline
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For consitent performance you need a flat torque curve engine developed with minimul cycle to cycle variation and the torque converter perfectly matched with minimul rpm swing.Bill C.


Ceralli Racing Engines & Checkered Flag Machine Racing engines , CNC porting & induction development http://www.checkeredflagmachine.net/
Re: Consistency... Engine Build question [Re: Streetwize] #1128591
12/09/11 07:49 AM
12/09/11 07:49 AM
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Posts: 9,963
Frostbitefalls MN (Rocky&Bullw...
gregsdart Offline
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Quote:

And finally when you got it running good...you gotta know when to leave it alone.



Thats the part I haven't gotten down yet!


8..603 156 mph best, 2905 lbs 549, indy 572-13, alky
Re: Consistency... Engine Build question [Re: Cab_Burge] #1128592
12/09/11 10:26 AM
12/09/11 10:26 AM
Joined: Jul 2010
Posts: 2,091
Delray beach, Florida
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Performance Only Offline
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Quote:

Quote:

I checked the #1 and #6 cam timing.
It looks like #6 is slightly advanced 1/2 degree from #1. I think to account for cam twist?


I think the cam is ground different on the lobes due to manufacturer defects, not by design




crankshaft indexing will cause that as well as lifter bore angle being incorrect.


machine shop owner and engine builder
Re: Consistency... Engine Build question [Re: BIGSPEED] #1128593
12/09/11 02:39 PM
12/09/11 02:39 PM
Joined: Jan 2003
Posts: 19,304
Las Vegas
Al_Alguire Offline
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Al_Alguire  Offline
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Las Vegas
Quote:

For consitent performance you need a flat torque curve engine developed with minimul cycle to cycle variation and the torque converter perfectly matched with minimul rpm swing.Bill C.




Well my junk has a VERY peaky torque curve, almost as peaky as the HP. I think anyone has seen the car run can tell you the converter is WAY out in left field. Having said all that it is about the most consistent car I have ever had. It has takkng lots of laps and tweaking to get it there though.


"I am not ashamed to confess I am ignorant of what I do not know."

"It's never wrong to do the right thing"






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