TDC issues

[Ocalarunner1969]

Hello all. I am stumped and need some suggestions. I have a 69 Road Runner, 383 4 speed. Been doing some work on the engine, replacing old with new, fuel pump, oil pump, harmonic balancer, all leaky gaskets, etc. I am running into "back pressure" I guess the best way to explain it when I try to turn the crank over and get #1 into position. I removed all the spark plugs, I wanted to inspect them and maybe replace. I took a section of wire and carefully went through the spark plug hole but I really don't think I'm in the right position for #1 yet. What's puzzling me is the back pressure. I can actually hear the hiss when I try to force the crank. I immediately back off when hearing the hiss. Anything you can recommend would be extremely appreciated. I have a few Mopar big block rebuild manuals but can't get the answer to the current problem. Thank you all.

 

[69 Sleeper Bee]

Did you mess with the timing chain or remove distributor by chance ?

 

[diesel_lv]

Air is going to "hiss" escape from cylinders through spark plug holes as you rotate engine. Continue rotating engine until harmonic balancer and pointer on on TDC. Did you remove distributor or plug wires from cap? If not, nothing should be different.

 

[1 Wild R/T]

If you only pulled the one plug your compressing whatever cylinder is on the compression stroke... When cranking the engine with a breaker bar it's spinning slow enough that the pressure bleeds past the rings & you hear it hissing into the crankcase..... 100% normal...

 

[BeepBeepRR]

18436572 Distributor rotates counter clockwise and number one usually points towards the alternator. Make sure your firing order is correct. Bank 1 is the driver side 1,3,5,7 Passenger side is 2,4,6,8 Front to back. If you have all of the spark plugs out there should be no back pressure. I mean it will hiss when rotating but it should not be hard to spin. Since the plugs are out there is no compression.

 

[Ocalarunner1969]

Man you guys are fast. The timing chain and sprocket are fairly new and I left them alone. Play in the chain was within normal limits. Yes I did remove the distributor but left the spark plugs in place and numbered them using blue tape (1,3,5,7 and 2,4,6,8). Glad to hear that the hiss I'm hearing is normal. I'll take it easy and continue rotating it until I can confirm #1 is TDC. I also took pictures for reference. I really want to thank you all for your quick response and instructions. I really appreciate all your help!

 

[Cranky]

Man you guys are fast. The timing chain and sprocket are fairly new and I left them alone. Play in the chain was within normal limits. Yes I did remove the distributor but left the spark plugs in place and numbered them using blue tape (1,3,5,7 and 2,4,6,8). Glad to hear that the hiss I'm hearing is normal. I'll take it easy and continue rotating it until I can confirm #1 is TDC. I also took pictures for reference. I really want to thank you all for your quick response and instructions. I really appreciate all your help!

What 1 Wild R/T said just above is what you are hearing if you left the plugs in place.

 

[Ocalarunner1969]

What 1 Wild R/T said just above is what you are hearing if you left the plugs in place.

Awesome! Thanks for your help.

 

[440 Charger]

If you only pulled the one plug your compressing whatever cylinder is on the compression stroke... When cranking the engine with a breaker bar it's spinning slow enough that the pressure bleeds past the rings & you hear it hissing into the crankcase..... 100% normal...

Good is around 200 psi after 5 rotations.

 

[440 Charger]

If you only pulled the one plug your compressing whatever cylinder is on the compression stroke... When cranking the engine with a breaker bar it's spinning slow enough that the pressure bleeds past the rings & you hear it hissing into the crankcase..... 100% normal...

No wait that should be the catasrophic convert kicking in on the hiss.

 

[BSB67]

Maybe take the other plugs out. And maybe leave the #1 plug in.