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View Full Version : timing in ? . what chya think


CHEVYMATT
07-01-2007, 01:54 PM
i have a 400 bored .60 over with afr 210 heads fully cnc'd to 221 i have .125 domes and 64 cc heads i have a bowtie intake anyway .. with my throttle wide open and all plugs out i have 160psi at 6 compression strokes while cranking seems a little low to me .. my cam is 256 266 @ .050 with 625 625 im running 1.6 rockers to give me 666 666 lift . im not happy with the performance of this . im checking my valve springs to see if they are set up right even thou i know it wont affect cranking pressure. i run 105 mph in the 1/8 and 122 in 1/4 and weigh 3100 and has a 5000 convertor/glide with a 4.10 gear. it seems to struglle above 6000 rpm's and i think i have some issues to look at. im open for a cam swap even if i only go solid not solid roller like i have now... any help or examples would really help im sort of stumped where to go now ... thanks oh my cam is on a 105 and i have it installed straight up at 104 ... my deck heigth is about .015.........ok now today i noticed that if i have the timing at less than 36 degrees it acts like i have a miss but if i bring it up to 42 it sounds and runs fine , but it didnt do this a few weeks ago it just started it .. i ran it at a 11.11 at 123 before at 32 degrees now it'll hardly run there . come on guys im depending on you professionals .. thank you.

mytmouz
07-01-2007, 03:15 PM
What type balancer are you running? If it's stock it could be that the outer ring is slipping, causing the timing to be off.

CHEVYMATT
07-01-2007, 04:48 PM
i have a sfi approved fluid balancer for rp raceparts on ebay . i dont believe it's mounted in rubber i think its all steel connected..

bbchevy
07-01-2007, 05:39 PM
If you only have 160 PSI Compression,then thats a VERY Good Place to start?I just did a 408ci SBC,+.040 400 with a .150 dome piston,and it had 250-260 psi.comp.Why are you using a cam with a 105?You ned to have at least 108-110.Maybe your blreeding off some comp.with the Cam profile???Have you check your Valve springs?I'll look for the # on the Cam i just installed,i know its a Lunati.But,i will get you a Grind #?Your on the rite Track?I beleive?
Later
Greg 8)

CHEVYMATT
07-01-2007, 06:18 PM
i went with a cam on a 106 but it's installed a 104 straight up via crane. . i didnt degree it i just installed it.. i do not like the psi thou. i thought a 106 would help with cylinder bleed off to help with pump gas compression.. . i should of just put a cam on a 110 in it. thanks

Dragginby
07-02-2007, 11:21 AM
My old 408 with AFR 210 made 587hp @ 6800rpm. The cam was an ultradyne 278int & 281exh @ .050 and 630 lift int &ext. My motor ran in a 2900lb car 135mph. There is something wrong with your motor. Not sure if it timing or what. My motor made most HP @ 36 degrees total timing.

davis419b
07-02-2007, 12:12 PM
Since the compression is way down it is possible the cam is in wrong. Without degreeing it it is hard to be sure, never had a sbc with a cam in under 108.

CHEVYMATT
07-02-2007, 03:15 PM
ok today i installed another msd box and still a problem i also removed distributor and inspected for damage or movement , but still if i put timing at 36 it acts like it has a miss and has lack of responce, but at 42 it's nice.. but im going to remove the engine and degree the cam as well as check things out.. keep up the info.. thanks guys

davis419b
07-02-2007, 03:34 PM
I have heard of getting the wires from the distribtor to the MSD box on backword and it makes the timing do weird things. Try switching them and see what happens. There is a rule of thumb that should happen if the wires were in fact backwards but i dont remember what it is. Send a PM to Bill Hendren im sure i have seen him post it before

CHEVYMATT
07-02-2007, 05:15 PM
when i had it hooked up backwards it sounded like a funny car . so called msd and it hooks up opposite of what you think . i thought it was purple to purple but it not . i do have it right .. thank you

davis419b
07-02-2007, 05:21 PM
Thats weird, I was chasing a high rpm pop on mine at the first of the year, changed them around and it didnt make much difference!

hammertime
07-02-2007, 06:27 PM
I seen one time the wires had to cross to even run right, I know crazy but it worked for years like this. I crossed mine earlier this year when chasing issues and it missed bad.

CHEVYMATT
07-02-2007, 06:40 PM
when i crossed mine it sounded like i just put it on nitro. was real bad.. what do you think about a adjustable cloyes roller

hammertime
07-02-2007, 06:58 PM
I've always ran cloyes stuff with no issues.

I've chased timing issues before also, how about the timing light what are you using ?

davis419b
07-02-2007, 07:04 PM
I dont know how to do the qoute thing buy here is what Bill Hendren said about checking the polarity of the distributor:

also check the polarity on the mag pickup.to do this look at where your timing is set,unplug the dist and take two short wires.plug one end into the dist and cross the wires before plugging them into the wire loom.start the engine and see if the timing advanced or retarded.the correct position is the retarded one.Bill
_________________
Hendrens Racing Engines
1310 U.S. Hwy 221 North
Rutherfordton N.C. 28139
828-286-0780 Bill, Steve, Mike
www.hendrensracingengines.com


It should not be popping when you cross the wires!

billhendren
07-03-2007, 05:03 AM
Always check the polarity, we have had several MSD distributors come through the shop with the magnet under the pickup in backward this reverses the polarity of the mag pickup so even if you have the dist hooked up with the msd wire loom and the color codes correct you could still damage your engine. with an analog box the most retarded position is correct, with a digital its the most advanced position.Bill

CHEVYMATT
07-03-2007, 06:47 PM
today i removed the engine and removed pan and timing cover . there is no obvious damage or change but since i didnt ever degree it im going to tommorrow or by saturday anyway. i bought new lunati 74021 roller springs and a adjustable timing chain . i will check the degree asap because im having a hard time sleeping with it on my mind..thanks for thehelp

davis419b
07-03-2007, 06:50 PM
GREAT IDEA!!!! Better safe than sorry

CHEVYMATT
07-04-2007, 11:37 AM
ok i degreed it i have
intake 25 btdc
intake 53 abdc
exhaust 62 bbdc
exhaust 25 atdc.. here is my tech car
Cam Timing: TAPPET @.050
Lift: Opens Closes Max Lift Duration
Intake 22 BTDC 54 ABDC 104 256 °
Exhaust 59 BBDC 27 ATDC 108 266 °
my measurements were at .050 and this is pretty close . im going to get a little closer when i install new chain..
do you think im having a problem when the numbers dont match. also if i change my intake to 22 from 25 does does that make my intake down lobe 50 or 56.. .. . well thanks guys .. oh i also found a broken dampener in my springs..