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Refresh engine, now no start. #3092479
11/08/22 03:29 AM
11/08/22 03:29 AM
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aotearoa
rebel Offline OP
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I've done a refreshing of my race motor, replaced some consumables, valve locks. Springs, Rings etc... but for some reason it dont want to start & if the plugs are in, it's a slow spin 28rpm, but if the plugs are out, 135 rpm spin off starter motor. I've replaced the main feed with 35mm cable & soldered new connectors. I've replaced the isolator switch, added extra earth leads from the battery to ign earth sources, plus another earth to the motor plate. It's not spinning fast enough for the Grid to fire when under load, but if the plugs are out, but still in the leads, they spark like crazy. I'm stumped. I've run the 35mm jumper leads direct from the batteries, 2x new 800CA 960CCA Calcium, to direct to the starter, plus other locations, but no go. Who's got an idea I haven't tried already. Oh yeah, Starter motor is a new HD unit too.

Re: Refresh engine, now no start. [Re: rebel] #3092490
11/08/22 07:05 AM
11/08/22 07:05 AM
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dvw Offline
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How about if the ignition is switched off? Timing correct? I'm assuming clearances were checked so nothing is tight. Cam in correct? No coil bind? Lash correct?
Doug

Re: Refresh engine, now no start. [Re: dvw] #3092504
11/08/22 08:17 AM
11/08/22 08:17 AM
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A shed in England
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iagree What he said, have you had the cam out ?


'74 Challenger..9.46 and 145.9 so far. 4023lb!!!# N/A, Marsh performance 655ci, Indy Maxx, T/R, Indy 600-13 X's, Street legal, pump gas, full interior, Cal-Tracs, mufflers, 3:73's and real 10.5 radials.
9.51 @142.4 with our old mule 580 wedge
RHD '68 Barracuda Fastback 323ci street/strip. Best ET 13.88 @ 99.03
Re: Refresh engine, now no start. [Re: dvw] #3092648
11/08/22 05:40 PM
11/08/22 05:40 PM
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Originally Posted by dvw
How about if the ignition is switched off? Timing correct? I'm assuming clearances were checked so nothing is tight. Cam in correct? No coil bind? Lash correct?
Doug

No, ignition is on, it's a Grid & I can see it gets the crank trigger signal as the green light flashes when you turn it over. Timing is set for 20* at idle, no coil bind, the springs have done a few seasons & I have my own bench spring tester to check them everytime they come off. Clearances were all checked, 0.0025 rods, 0.003 crank, 0.004 end float on an alloy block. Cam was degreed in at 105* centerline as it always is. The main change was I swapped out the carb in favour of MPEFI, done tests on that & the EFI is triggering, but the engine just doesn't spin fast enough for the Grid to fire the plug with plugs installed. Compression is not that high, 12.5:1 static.

Re: Refresh engine, now no start. [Re: rebel] #3092660
11/08/22 06:28 PM
11/08/22 06:28 PM
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Hot Rod Ridge
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Turn rotor 180

Re: Refresh engine, now no start. [Re: rebel] #3092673
11/08/22 06:59 PM
11/08/22 06:59 PM
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Try the old starter. Maybe the new one is junk

Re: Refresh engine, now no start. [Re: FastmOp] #3092681
11/08/22 07:24 PM
11/08/22 07:24 PM
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[quote=FastmOp]Turn rotor 180 [/quote

Definately firing on #1.

Re: Refresh engine, now no start. [Re: carnut68] #3092682
11/08/22 07:25 PM
11/08/22 07:25 PM
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Originally Posted by carnut68
Try the old starter. Maybe the new one is junk

Did that, have 3x starters, they all do the same.

Re: Refresh engine, now no start. [Re: rebel] #3092773
11/09/22 08:30 AM
11/09/22 08:30 AM
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What is the cranking compression number? If it's in the ballpark, the cam should be close. Disconnect the coil and see if it cranks quicker. If so my bet is the ignition timing isn't where you think it is? Maybe it's being influenced by something during crank only?
Doug

Last edited by dvw; 11/09/22 08:31 AM.
Re: Refresh engine, now no start. [Re: dvw] #3092963
11/09/22 07:35 PM
11/09/22 07:35 PM
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Originally Posted by dvw
What is the cranking compression number? If it's in the ballpark, the cam should be close. Disconnect the coil and see if it cranks quicker. If so my bet is the ignition timing isn't where you think it is? Maybe it's being influenced by something during crank only?
Doug

Cranking pressure is 120 psi atm, taking in that that's new rings & a valve n seat job on a big duration cam, I would say we are about right. Timing on the crank trigger is set at 38* which is normal for us, but I will check the laptop for the timing curve to see if anything has changed, but we have been running this combo for 5x seasons now, just strange how this time it's a turd.

Re: Refresh engine, now no start. [Re: rebel] #3093041
11/10/22 06:05 AM
11/10/22 06:05 AM
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Took the rocker gear off & it spun at 175 rpm off the starter motor with the plugs out, BUT with the plugs in, the starter motor almost spat out its hemroids. Why when we have pressure does it struggle? With the plugs in & rocker gear on, it took 120lbs on the torque wrench to get it to spin. with plugs & rocker gear off it took 70lbs.

Re: Refresh engine, now no start. [Re: rebel] #3093046
11/10/22 07:06 AM
11/10/22 07:06 AM
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70lbs to rotate with no spring load or plugs is a ton.
Doug

Re: Refresh engine, now no start. [Re: dvw] #3093086
11/10/22 09:55 AM
11/10/22 09:55 AM
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Could something in the bellhousing be wrong? Perhaps converter not seated or something? Sometimes its the simple crap that gets us and its usually the last thing checked.


68 Barracuda Formula S 340
87 "Chrysler" Conquest
Re: Refresh engine, now no start. [Re: Bad340fish] #3093098
11/10/22 10:41 AM
11/10/22 10:41 AM
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Originally Posted by Bad340fish
Could something in the bellhousing be wrong? Perhaps converter not seated or something? Sometimes its the simple crap that gets us and its usually the last thing checked.


This would be my guess as well. Just went through this. Engine ran fine on the dyno. Turned over by hand when dialing in the bellhousing, then would hardly turn over in the car. Input shaft was locked up to the throwout bearing collar...


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Re: Refresh engine, now no start. [Re: dvw] #3093125
11/10/22 11:33 AM
11/10/22 11:33 AM
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Originally Posted by dvw
70lbs to rotate with no spring load or plugs is a ton.
Doug

X1000 Something is wrong and thank the lord it didn't start. I think the nominal target rpm to start any engine is over 200rpm.

Re: Refresh engine, now no start. [Re: HardcoreB] #3093136
11/10/22 11:58 AM
11/10/22 11:58 AM
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At this point I woudl yank it back out and see whats causing the excessive force to spin it over by hand. If its not on the trans end I would look at the cam bearings.......


"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: Refresh engine, now no start. [Re: Al_Alguire] #3093210
11/10/22 05:22 PM
11/10/22 05:22 PM
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Many of the race short blocks I have built take 15 -18 pounds rotational torque on the short block. Rear main in, cam in, no valve train.
That’s a Hemi with dykes rings. The 1/16” race ring line up - maybe 25 pounds.

I would disconnect the converter if it’s so equipped. If that doesn’t help I’d yank the motor.

Re: Refresh engine, now no start. [Re: Transman] #3093227
11/10/22 06:44 PM
11/10/22 06:44 PM
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ok, i'm even more confused. I was removing headers, intake etc... to pull it out, turned the crank so i could get to the converter bolts now its only 45lb on the torque wrench to turn over.

Re: Refresh engine, now no start. [Re: rebel] #3093290
11/10/22 10:19 PM
11/10/22 10:19 PM
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Still sounds tight.

Re: Refresh engine, now no start. [Re: rebel] #3093311
11/11/22 01:29 AM
11/11/22 01:29 AM
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Originally Posted by rebel
ok, i'm even more confused. I was removing headers, intake etc... to pull it out, turned the crank so i could get to the converter bolts now its only 45lb on the torque wrench to turn over.

It is talking to you, time to figure out what it is saying work scope
It was good before, now it's time to figure out what is different and making it tight work wrench
You can do this up

Last edited by Cab_Burge; 11/11/22 01:30 AM.

Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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