After rebuild - hard cranking
#1
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After rebuild - hard cranking
Just finished the rebuild of my -74 2.7 engine. Yesterday the time had finally come to start the "new" engine, but the starter has a pretty hard time to rev the engine. Its going around, but not as fast as previous, and not as fast that I can do a cold start.
I believe the compression now is higher, but is this generally a normal problem after a rebuild ?
T he battery is fully charged.
Can a high torque starter help ?
Thanks
I believe the compression now is higher, but is this generally a normal problem after a rebuild ?
T he battery is fully charged.
Can a high torque starter help ?
Thanks
#2
Team Owner
How difficult is it to turn the engine over manually with the plugs out ?
Was it tough to turn with the wench while doing cam timing ?
I had issues with the parkerizing on my cams , so polished it down s it would turn easier.
Mine was fine after that but i did throw in a high torque starter during the rebuild.
Was it tough to turn with the wench while doing cam timing ?
I had issues with the parkerizing on my cams , so polished it down s it would turn easier.
Mine was fine after that but i did throw in a high torque starter during the rebuild.
#3
Banned
The only way to rule out the starter is to throw a new one in there. If you still have this issue with a new starter, there are bigger problems at work. Yes, raising the compression sometimes requires a high torque starter, but not usually in G body 911s....you can't really raise the compression enough on these motors to significantly affect the starter. Perhaps your starter was weak to begin with. Oh, and a FULL batter means close to 14 volts, so make sure it is.
#5
RL Technical Advisor
Just finished the rebuild of my -74 2.7 engine. Yesterday the time had finally come to start the "new" engine, but the starter has a pretty hard time to rev the engine. Its going around, but not as fast as previous, and not as fast that I can do a cold start.
I believe the compression now is higher, but is this generally a normal problem after a rebuild ?
T he battery is fully charged.
Can a high torque starter help ?
Thanks
I believe the compression now is higher, but is this generally a normal problem after a rebuild ?
T he battery is fully charged.
Can a high torque starter help ?
Thanks
#6
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Thanks for the reply everyone.
I finally got it started, but with lot of time and patient. The second time start up, it once again struggled and with no success.
A new high torque starter is ordered, and hopefully it will help.
The engine is line-bored back to standard, but I guess with all new parts inside it need its time to settle.
I finally got it started, but with lot of time and patient. The second time start up, it once again struggled and with no success.
A new high torque starter is ordered, and hopefully it will help.
The engine is line-bored back to standard, but I guess with all new parts inside it need its time to settle.
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Its hard to start rotate with a wrench, but it feels lighter/ more normal as soon I get it going. I have to squeeze the fan belt in order to rotate the cranckshaft when using a wrench.
For information I changed the fan belt, and its extremely tight compare to my old one. Do not know if it matter much.
For information I changed the fan belt, and its extremely tight compare to my old one. Do not know if it matter much.
#9
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Probably not a reason for the engine to be tight, but you don't want that belt too tight either. Should be about 1/4-inch of deflection when you press against it.
The new belts are a bit wider than the old ones. If you just put the shims back where they were with the old belt, it could be too tight because being wider it could be riding higher on the pulley. Make sure you have all six shims, and try moving one from outside to inside if you need to reduce the tension a bit.
Mark
The new belts are a bit wider than the old ones. If you just put the shims back where they were with the old belt, it could be too tight because being wider it could be riding higher on the pulley. Make sure you have all six shims, and try moving one from outside to inside if you need to reduce the tension a bit.
Mark
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Timing?
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I believe I have figured it out, and you are partly right. I reinstalled the distributor and moved it with one tooth in the crank. That resulted in sporadically ignition when cranking - more than ever and understood I was on the right track.
Then I turned to the fuel distributor and since the engine always started for a few seconds every time I disconnected the wires to the fuel pump, I turned the air/fuel mixture screw counterclockwise about one round. Was a little suprised I needed to correct the mixture, but now it starts right up and on a second startup the cranking seems pretty easy. The tightness is mostly gone.
Problem solved.
Then I turned to the fuel distributor and since the engine always started for a few seconds every time I disconnected the wires to the fuel pump, I turned the air/fuel mixture screw counterclockwise about one round. Was a little suprised I needed to correct the mixture, but now it starts right up and on a second startup the cranking seems pretty easy. The tightness is mostly gone.
Problem solved.
#12
I believe I have figured it out, and you are partly right. I reinstalled the distributor and moved it with one tooth in the crank. That resulted in sporadically ignition when cranking - more than ever and understood I was on the right track.
Then I turned to the fuel distributor and since the engine always started for a few seconds every time I disconnected the wires to the fuel pump, I turned the air/fuel mixture screw counterclockwise about one round. Was a little suprised I needed to correct the mixture, but now it starts right up and on a second startup the cranking seems pretty easy. The tightness is mostly gone.
Problem solved.
Then I turned to the fuel distributor and since the engine always started for a few seconds every time I disconnected the wires to the fuel pump, I turned the air/fuel mixture screw counterclockwise about one round. Was a little suprised I needed to correct the mixture, but now it starts right up and on a second startup the cranking seems pretty easy. The tightness is mostly gone.
Problem solved.
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