Refresh engine, now no start.

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.

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

What he said, have you had the cam out ?

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.

Turn rotor 180

Try the old starter. Maybe the new one is junk

[quote=FastmOp]Turn rotor 180 [/quote

Definately firing on #1.

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

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.

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.

70lbs to rotate with no spring load or plugs is a ton.
Doug

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...

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.

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.......

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.

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.

Still sounds tight.

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

Please keep us up on your findings curios on what they are

Torque converter unbolted, no rocker gear, no plugs, 40lbs. Honestly, for new rings, this feels ok to turn over on the power bar. I'm using std tension oil rings in the Total Seal Plasma Moly series. I might start putting parts back on & testing the difference in drag. I have another engine, 7 years old, has nearly the same springs & thats 65lbs to turn over with the engine complete.

Going with a problem with the cam after today's tests. At the long block stage, we put the rocker gear on one side & it took 105 lbs on the torque wrench to turn over. Removed that side & did the other bank & still had the same result. The cam bearings are good, I gave them a polish with the scotchbrite when I was cleaning the block. But I'm pulling the cam & going to get it checked for straightness. Although it spins easy, it didn't spin easily unassisted, I had put that down to a burr on the bearing from a lobe catching during installation. Stay tuned.

On the 485" stock block motor the shortblock rotating with 1/16 1/16 3/16 rings was less than 15lbs When i put the roller cam and rocker gear on WITH NO sparkplugs rotating was 75ftlbs and it didnt 'feel' right but all was good. After asking others I learned that was reasonable but yours did seem unreasonably high!

Put a50mm/2 or 75mm/2 cable on it and a big starter from Grimmer and you will be right.

You said it is firing at tdc on #1. But is it firing at tdc on #1 on the compression stroke?

for this any updates on it?

Well, the engine got pulled & stripped & everything rechecked, & rechecked again. It rotates fine as a long block, but as soon as I connect the valve train, it goes bad. So I currently have some weaker valve springs in it & it turns over with the torque wrench at 62lbs, which is a lot better than 120lbs it did before. The motor is back in the car, just waiting for me to add all the accessories so we can restart it. I am hoping after I have done a few heat cycles & maybe a bit of public road rural driving, things will bed in a bit better & then I can up my spring pressure again. The springs I had in it were 640lb rated springs, I'm thinking I should drop this to 525lb rated springs. Only problem is, I have a set of them, but I recently put them into my other street/strip car. Its Summer downunder & seriously too hot to be in the shed during the day. Since we are past the xmas rubbish now, I'm guessing I'll spend the next 2 nights in the shed finishing everything off. watch this space.

My junk is the same way with the valve trane hooked up. Sux to turn

Murphy is messing with you, don't give up
I would go back through the ignition side of the engine compartment wiring to make sure that the coil has voltage in both the run and start position on the ignition switch
Let us know what you find out that fixes it, it will help others down the road

i second what Cab posted.

Progressing well, hopefully tonite I'll have the oil system primed & I can check for leaks while I'm sorting out the cooling system. Might even try to start her up if I'm lucky.

UPDATE; I got it to start last night with the weaker valve springs. Haven't been able to run for long as I now have 2x oil leaks. 1x was the rocker cover gasket, so I glued 2x new ones on last night. The other is the pressure side of my oil pump, Guess I'll need to remove & replace the O ring. Shops will be open tomorrow so I'll try n find a place that sells decent-quality O rings to repair. Don't you hate it when you can use something umpteen times, never an issue until the shops are shut & you can't just go get a replacement.
I've been working on another engine at the present point in time, so haven't had much time to dedicate to this motor.

Glad you found and fix it, what was it?

[align:center][/align]
The only thing we changed is the valve springs, the set that's on there now were staunch flat tappet springs. I've fixed the valve cover gaskets, & tightened the oil pump connection to try & remedy the oil leaks & now....the starter motor is having issues. It's a fresh rebuild of a HD ministarter variety. So that's tonites job, pull it off & see what's wrong with it. Can't even jump start with the screwdriver on the terminals. Good grief, I must have p!$$£d off some witch last year & she has a hex on me.

Finally solved my drama, bought a new 2kw starter motor, the big red one, now we start straight away. Not all mini starters are equal.

I'll leave this here.

My 15-1 572 has been started with the same factory Mopar mini starter going on 11 years. Loos like the middle one in your pic. 310 seat / 805 open.
Doug

I did actually have a few spare starters, none of them had the urgs to spin as fast as the new one. I sent all my starter stock to my starter motor rep, he checked them all & said there was nothing wrong, but he did suggest the 2kw unit over all the 1.4kw units.

The camshaft events play a role in how much loading is added or negated in rotating resistance. I'd personally put the springs necessary to control valve events on the motor and adjust other things around that 'obstacle'