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Help! New Motor willn't strat Why

Marv02

Well-known member
Joined
May 4, 2010
Messages
472
Location
California City Ca
Corvette
1986 C-4 Corvette
New Motor willn't start Why

I totally lost.
Just put the engine and Trans back into the Vett and hooked everything up and No Joy it won’t start cranks fine just won’t start.
I made sure everything was TDC both valves are shut on number 1 cylinder.
Made sure the rotor in the distributor was pointing to the correct plug wire lug in the distributor cap.
Did a compression check 120 on every cylinder?
Pushed the bleed valve on the fuel rail fuel coming out of it.
New Fuel pump.
So I have compression fuel and great white spark coming out of the plugs there self.
I tried starting fluid still nothing.
Still not running.
I going to try to put the old know good fuel pump back in tomorrow see if tis i fix anything.
Anyone out there has any ideas why this motor won’t start.
HELP
 
Go back to basic trouble shouting

Gas
Air
Spark
Are they all getting there at the right time?

Do not try to make it complicated... It seldom is!

It the starting fluid does not make it go "bang" it sounds like the Spark and Valves are 180 deg. out.

I would pull the Dist. back off all of the lifters and start over again as if I had never seen the motor.
 
180 Out

Just went and check it out and yes it's 180 out I set it up in the morning.

Thanks
 
I swapped the wire out 1 to 6 and so on now it back firing thought the intake.
 
If the distributor was in 180 off, you can't just swap #1 and #6 plug wires to fix it.

You need to pull the distributor and index it correctly.

What I'd do is roll the motor over by hand so both valves on #1 are closed and the timing mark on the balancer lines up with 10 deg. advanced on the index. Put in the distributor. If it won't drop down into the oil pump drive, bump the starter until it does. Connect the plug wires then fire the engine. Once it's warm, disconnect the timing wire and set the base timing then reconnect the timing wire.
 
Did all this you can hear the motor pop and smoke back up through the intake but still wont run.

If the distributor was in 180 off, you can't just swap #1 and #6 plug wires to fix it.

You need to pull the distributor and index it correctly.

What I'd do is roll the motor over by hand so both valves on #1 are closed and the timing mark on the balancer lines up with 10 deg. advanced on the index. Put in the distributor. If it won't drop down into the oil pump drive, bump the starter until it does. Connect the plug wires then fire the engine. Once it's warm, disconnect the timing wire and set the base timing then reconnect the timing wire.
 
Did all this you can hear the motor pop and smoke back up through the intake but still wont run.

Its easy to miss a tooth or 2 when stabbing the dist....first, go thru the wires, and make certain that they are in the correct position/order. Then as Hib says, turn the crank by hand with a wrench to dial the dist rotor to the number 1 post, and look at the timing index.There should be a mark for TDC, then several marks for BTC(advance. Then look at the #1 cyl valves.They should be closed. When you;re sure its dialed in, rotate MORE and make sure #1 valves do not open for the next stroke, it should be power-stroke if its timed right and #1 valves will stay closed for 1/2 crank revolution then the ex-valve should open.

The ONLY other things could be the cam timing being a tooth off on the chain.

The comp is a little low but thats probably from nothing being seated yet. If the valve timing were off, it would make it low because a valve would be opening too soon or open too late to get full compression. This is likely just rings that are not seated. It'll hit 160 once it seats.

it;ll run, just slow down and focus. Its always frustrating when it don;t lite right up after all that work and effort, but it will.
 
Bad things has happen.
I started to play with the car some more and found the push rod on the intake side are all bent.
I gettting hold of Trick Flow and find out are these the correct size push rods for these roller rocker arms.
I don't think I bent any valves The motor was and turned over by hand before it was installed into the car all valve lash was checked I think the Liffters pumped up and it could be to long of a push rod.
And I was told I just need to make #6 #1 and #6 #1. Ya.
 
Bad things has happen.
I started to play with the car some more and found the push rod on the intake side are all bent.
I gettting hold of Trick Flow and find out are these the correct size push rods for these roller rocker arms.
I don't think I bent any valves The motor was and turned over by hand before it was installed into the car all valve lash was checked I think the Liffters pumped up and it could be to long of a push rod.
And I was told I just need to make #6 #1 and #6 #1. Ya.

Man, sorry to hear about that.
I hate to say it,. but when all the intake push rods are bent, to me that says cam timing...or the wrong cam? we sure assmue lots when we buy stuff and the dealer says its the right part.

if it were hyd lifters pumping up that caused this, the damage would be random, i would think. I dunno....sure is a helluva set back though.
 
Ok more I read into it oit seems like I have the wrong push rod length that why I think thet bent on me.
I wish some one else out there ran about the same combo so they could tell what length there push rods are.
350 with Trick flow @23 195 Heads with Roller rockers.
 
Jeez, sorry to hear the bad news. Who instructed you on push rod length?
 
You have the 1.6 rockers on the intakes only? If so I would agree that it is the rod length rather than valve timing or you would have exhaust rods bent also.

Glenn
:w
 
You have the 1.6 rockers on the intakes only? If so I would agree that it is the rod length rather than valve timing or you would have exhaust rods bent also.

Glenn
:w

either way,

its a damn shame.
 
Who built this engine? Did they follow the book?

Bent rods only happen when the rocker stops rocking before the rod stops rising. :ugh

The rockers could not be adjusted correctly to start with if the rods were totally wrong.

SBCs are a lot like Glocks. If you follow the instructions you just can't get it too wrong to fire.

After building over 20 SBCs I still have the the books open and the critical pages photocopied, plasticized & hung over the workbench.

Here is a good link about valve train geometry but I think the problem is in the basic assembly. If it were mine I would pull it down and start over again. It will cost a lot less in the long run if you do it right in the beginning.


If worst comes to worst talk to Frankie at Frankiesgarage.com he is the closest GM genius to you. Tell him the "yank" from R-E. sent you.

Good luck

Igeaux:w
 
I uesd the guide plates that came with the Trick Flow heads and a set of Comp Cams standered type Push rods.

:duh

Were the proper guide plates and hardened pushrods used? Rollers will not be happy with the slop factory rockers allow.
 
Well I ended up using a Adj push rod to find out whats going on it measured for the push rods I aready have 7.794, stock lenght.
The valve springs on the head have a 120 LB to 460 LB with the rating of .480 lift the springs that the cam manufacture is saying to use is 110 to 433 and a .460 lift with a 1.5 ratio rocker arm I using a 1.5 roller rocker arms.
The cam has a .447 lift so I in spec's.
Oh ya No bent Valves. good compression 120 pounds each cly.
So I ordered a new set of push rods The only thing we can come up with I t was 180 out we think and it was back firing though the intake it could tryed to shut the valves that in turned bent the intake push rods.
I still think the Hyd lifter pumped all the way up that caused some of this and the 180 plus the out of time back firing did me in.
I hand cranked thew the motor over 5 or 6 complete rotations every thing seems good I used the Black marker trick to check the valve stem to rocker arm tip wear is good the vavle springs are not binding rocker arms are working good.
So I set the motor back to TDC 8@ advance and go from there Buit I will TDC all 8 Cyl just to make sure this push rod Issue willn't happen again.
 
Well I ended up using a Adj push rod to find out whats going on it measured for the push rods I aready have 7.794, stock lenght.
The valve springs on the head have a 120 LB to 460 LB with the rating of .480 lift the springs that the cam manufacture is saying to use is 110 to 433 and a .460 lift with a 1.5 ratio rocker arm I using a 1.5 roller rocker arms.
The cam has a .447 lift so I in spec's.
Oh ya No bent Valves. good compression 120 pounds each cly.
So I ordered a new set of push rods The only thing we can come up with I t was 180 out we think and it was back firing though the intake it could tryed to shut the valves that in turned bent the intake push rods.
I still think the Hyd lifter pumped all the way up that caused some of this and the 180 plus the out of time back firing did me in.
I hand cranked thew the motor over 5 or 6 complete rotations every thing seems good I used the Black marker trick to check the valve stem to rocker arm tip wear is good the vavle springs are not binding rocker arms are working good.
So I set the motor back to TDC 8@ advance and go from there Buit I will TDC all 8 Cyl just to make sure this push rod Issue willn't happen again.

Anythings possible...

Thats very possible,. Firing 180* can cause some extreme reciprocating stresses...

I think ( its been awhile) it was early cross-fire motors that fired twice each cycle, once at the end of compression stroke, and again at the end of exhaust stroke. That 2nd spark would send that motor into a mechanical spasm if the timing was off by much, making it backfire and burp flames out the intake. GM said that the 2nd spark was to help scavenge the cyl after exhaust stroke to help with emissions. The design changed at some point.
The early cross-fire motor was AKA the "back-fire", by GM. Bent push rods were the common complaint.
 
Anythings possible...

Thats very possible,. Firing 180* can cause some extreme reciprocating stresses...

I think ( its been awhile) it was early cross-fire motors that fired twice each cycle, once at the end of compression stroke, and again at the end of exhaust stroke. That 2nd spark would send that motor into a mechanical spasm if the timing was off by much, making it backfire and burp flames out the intake. GM said that the 2nd spark was to help scavenge the cyl after exhaust stroke to help with emissions. The design changed at some point.
The early cross-fire motor was AKA the "back-fire", by GM. Bent push rods were the common complaint.

There's something I didn't know!

Hey, can you post some info on this I'd be really interested in adapting this to my 1990.

What distributor do I need and which spark plug wires? Would there be more to the conversion? Maybe a coil?

I think this is a great idea, practical and functional.

I'd love more information on this system, please post what you can.

Thanks
 

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