Cam degree effect on ignition timing

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Re: Cam degree effect on ignition timing

Postby Bluejay » Tue Jun 18, 2013 4:40 pm

Since bigger jets weren't available for carb, I thinned down metering rod with file and sand paper. Mic'ed both so they match. It worked , only a little more the 4bbl would kick rite in.
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Re: Cam degree effect on ignition timing

Postby Hot Stuff » Tue Jun 18, 2013 5:03 pm

I still think you have a timing issue. Did you install the dist drive gear? Its real easy to get it one tooth off.
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Re: Cam degree effect on ignition timing

Postby Bluejay » Tue Jun 18, 2013 10:12 pm

No I didn't do anything except drop new summit distributer in the crate motor. The motor was complete minus intake, carb , and distributer, all assembled by gm. Brought her up to TDC on timing tab , pointed rotor button to #1, dropped er in , wired it, n fired it. If it were off a tooth one way or other vacume advance would hit something preventing me from adjusting it far enough in either direction. Timing is real close now that carb is adjusted right. Too lean and too low compression allow these puke pollution motors to run way advanced. ! Switched back to street tires and drove about 20 miles today. 600 rpm smooth idle with 15#s of vacume. I really miss the idle of the .488 303 duration cam. Got other problems now. Felt vibration under acceleration , checked nearly new ujoints, they were still ,kinda, tight. Bought new ones anyway. Pulled rear diff cover to see how welds were holding on lincon locker and brass came running out. Little bit of left over slag must've washed out head bearing on pinion. Damn it ! Should've bought a spool after all. Three different neighbors came over wanting me to fix their crap. And Thurs, fri, sat am. I have plumbing jobs lined up. had to get a tooth pulled today ! Wife's jeep still on death row , needing wheel bearings, tow rig outer door latches both quit, trailer has four flat bald tires ,no lights! This, pro jeep racer , fantasy life is wearing me down. Now gotta tear rear apart again before sat. Lol. If the dog don't quit chasing neighbors kitten I'm gonna shoot his ass with the bb gun. The b&m 2000 stall convertor ticks me off too ! Even at 600 rpm the motor is pullin so hard on manual brakes I have to shift into neutral at red lights to give leg a rest. Power braked it against a Ballard today it locks tight about 1400 rpm. No matter how much throttle is applied. My ol lady's gonna really be ticked she sees new crate motor and torque convertor dumped in back corner of garage.
Last edited by Bluejay on Thu Jun 20, 2013 6:44 am, edited 1 time in total.
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Re: Cam degree effect on ignition timing

Postby Bluejay » Thu Jun 20, 2013 6:41 am

Oops lost a couple needle bearings last time I put drive shaft in, no wonder she was vibrating. Pinion is in I'm ready to race. Thanks guys I do appreciate your willingness to help us new guys figure out what we do wrong.
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Re: Cam degree effect on ignition timing

Postby Bluejay » Thu Jun 20, 2013 6:58 am

grey ghost wrote:Could you have rolled the timing chain and not know it when you had put it on

Yeah and when I flipped gear I never marked other side like supposed too. So couldn't check it put together. If something is messed up on my ride it's usually something I touched? That's why I bought new crate motor and I ain't messin with it.
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Re: Cam degree effect on ignition timing

Postby Hot Stuff » Thu Jun 20, 2013 10:45 am

I won't be at the race this weekend. We had our baby last Thursday and they shipped him to Toledo children's hospital that night. He was there until Tuesday and finally got t come home. So we're taking this race off. Gonna stay home with the boys and wife. Hopefully I'll have the cash to get to the July race. I will definitely be at the East Coast race the end of July, but that's a sanctioned race not a bracket.
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Re: Cam degree effect on ignition timing

Postby Bluejay » Sun Jun 23, 2013 11:29 pm

I'm wrong again, adding lots of fuel to the mix did not result in a more correct timing performance relationship. Rapping on 4bbl free rev. New crate motor was still popping in intake, so added 107 pri. 104 sec. Jets which put a little trace of black too rich stain on plugs. And it still popped wot.at roughly 38 degree ignition advance. Ticked me off ! determined to run rite or blow it I don't care, kept rapping on 4bbl free rev while giving her more timing advance and finally it quit popping. But timing mark is way out like 80degrees advance. At the trak during time trails I tried again to back timing down a little but it only resulted in slower times, 60 foot and top speed. Screw it I don't care what timing light says anymore its gonna meet mr.east wing if it don't stay in the tool box drawer. Now I have had three different engine combinations in my jeep and they all have run same times ! One 350 stock cam, one 350 303 .488 cam, and new crate 350 dm. Go figure ! What ever is limiting my time is external. Here are the numbers for you bros that like to crunch. Best ever .623 reac. 2.683 60' 54.11 mph. 6.193 time. That was tired stock cam 350 with 305 heads. The last race with new crate and b&m convertor .518 reac. 2.36 60' 53.93 mph. 6.407. I've been working like a dog welded diff, ladder bars, new tires,stall convertor, new motor ! And no improve ment ! Grr. Crate motor wheezes out 4,000 rpm. Is 600 cfm carb too small, mufflers ain't helpin either . Should've bought that 283 n put my 305 heads on it ! when I get time I'm pulling new crate motor out and putting it in the tow rig. If consistency is king guess rigs rite there 20 passes all within .3 , but I will never be happy as long as Bills rusty stock 304 is hittin better times.
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Re: Cam degree effect on ignition timing

Postby Bluejay » Tue Jun 25, 2013 6:44 am

Mallow415 wrote:that shouldnt have anything to do with your timing did the balancer ring move? Need to make sure you have TDC first and make sure it lines up with the timing mark? Thirteen deg advance is a bunch?

Dude I tore down new crate motor , and further inspected the old blown motor, and both engines have bad harmonic balancers. Crate motor had wack in balancer and rubber is uneven thick on one side thin on other. Blown motor the rubber is swelled up fat and gushing out. You nailed it rote off . Thanks gonna have to take you more experienced guys advice more seriously.
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Re: Cam degree effect on ignition timing

Postby Bluejay » Tue Jun 25, 2013 11:37 am

I was gonna put new motor in my tow rig , and put tow rig motor in jeep. Tow rig crate 350 has been good one it's different than new crate motor. It has 882 heads .450 .460 cam and a little more compression, about 150 psi. But the new crate totally sucks on fuel. 7.98 to one compression , no wonder they offer three year 100,000 mile warranty . I ain't ruining fuel mileage on the tow rig which hovers around 12-14 MPG. With 36" military surplus tires and 5,500 trailer weight that's pretty good for an old gasser. Instead the new crate motor is goin on the chopping block, scored a nice set of factory corvette fuelie heads 2.02 valve. I'm lappin in valves swapping springs out of new crate, and if I have time cleaning up ports a little. It'll be a little short on compression ,62cc head on stock pollution pistons maybe 9:1. Can't figure compression ratio cause don't know pollution dish volume, deck height, gasket thickness , don't care any way. Like to see cylinder pressures be around 190. But it's probably not gonna happen. new .488 303 duration cam with summit spec 8 degree advance , stock double roller with no foolhardy flip games. Can't wait to hear the cam again except this time it'll have tighter bottom end and bigger valves. Hope she don't blow hate to butch a new motor.
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Re: Cam degree effect on ignition timing

Postby Bluejay » Tue Jun 25, 2013 10:35 pm

Mallow415 wrote:that shouldnt have anything to do with your timing did the balancer ring move? Need to make sure you have TDC first and make sure it lines up with the timing mark? Thirteen deg advance is a bunch?


Tore heads off blown motor. Rolled #1 up , checked timing mark to balancer. Positively , it slipped balancer ring by over 25 degrees. Thanks mallow 415 you were rite. Wish I could learn how to post pics. Good thing I didn't smash my new china timing lite. It was hard to check positively with heads on.

Pulled head on new crate motor, no wonder it is a top end dog, the valve size is wimpy 1.71 intake. Head combustion chamber is huge , the pistons are even a deeper dish than 80's smog pistons.
My newly acquired 327 heads are little rougher than I hoped. Way loose valve guides. Scrap metal , I always get what I pay for. Not much time till next race, not much money left, or I'd buy new dart platinum 2.08 heads. I'm Definatly buying a looser converter, and new harmonic balancer, so it looks like 416# 305 heads will have to go on new crate. It's better than putting junk 2.02 heads and blowing new motor. Ports on 416 heads are real nice size , fresh and mildly ported, it'll be fun to see if they change et.
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