Piston hitting head after rebuild

tykuhn · 12-30-2010, 02:16 PM

My EZGO 295cc had a rod cap come loose. Had to replace crankshaft, rod, rod cap, piston and rings. When reassembling all went well until I put the head on and tried to time engine. Crank would turn over just so far and then clunk. Dissassembled and found that the piston/s are hitting the head. Is there and adjustment? Should I consider more than one head gasket?

Any ideas?

H munster · 12-30-2010, 03:00 PM

Did you replace both rods? If so im guessing they are the wrong ones or they are not seated on the crank properly.

tykuhn · 12-30-2010, 03:13 PM

No, just replaced the damaged rod. Sure looked the same though. I did get the rod from EZGO. Will recheck the numbers to see if somehow I got the wrong rod.

Rod cap is seated well on both rods. Piston extends above the cylinder wall the same for both pistons. Other rod and piston ok.

I might pull the piston and rod that were replaced and see if it hits then. Might isolate problem then.

H munster · 12-30-2010, 03:34 PM

Sounds like they sent you the wrong one. You should be able to measure the new one against the old if its not too tore up.

tykuhn · 12-30-2010, 03:57 PM

Update.

I pulled the new piston and compared the rod to the old one. Other than being new it is the same length and has the same number on it...251 and fan on the reverse side of the rod. I put the head on with one piston installed and the old piston hits the head also.

That really only leaves one possibilty and that is whether the crankshaft is somehow not the right one as it too has been replaced. They look identical but I guess it could be wrong. I hope not as these are expensive.

Does anyone know if the top of the stroke is supposed to be flush with the top of the cylinders? If so it has to be the crankshaft.

Arghhhh!

berthasquare · 12-30-2010, 05:05 PM

Not even flush. It's a teeenie lower in fact.

H munster · 12-30-2010, 05:13 PM

Try rotating one of them 180 degrees and see if it still hits

tykuhn · 12-30-2010, 07:18 PM

I reversed one piston (rotated 180 degrees) and it changed nothing. So, I pulled the crank out and looked at it. It sure looks identical but one crank has some numbers on it that the other does not. I cannot tell any difference but it is not working so I probably need to get another crankshaft. This one I acquired online from someone telling me it was a crank for a 295cc engine. It sure looks the same and everything lines up except the pistons protrude. Do you or anyone know if there are more than one crankshaft for the 295cc engines?

thewskrs · 12-30-2010, 07:52 PM

Sounds like you got the wrong stroke crank. Maybe from a 350? I really don't know the measurements on these as I have a clone engine, but I know the pistons on everything but hemi's are a smidge below flush.

scottyb · 12-30-2010, 08:03 PM

I do not know the specs but I will tell you this; the 350 head has a lot more vertical space for a piston to come up out of the black than a 295... my guess is you have a 350 crank...

12-30-2010, 02:16 PM	#1
tykuhn Getting Wild Join Date: Oct 2008 Posts: 95	Piston hitting head after rebuild My EZGO 295cc had a rod cap come loose. Had to replace crankshaft, rod, rod cap, piston and rings. When reassembling all went well until I put the head on and tried to time engine. Crank would turn over just so far and then clunk. Dissassembled and found that the piston/s are hitting the head. Is there and adjustment? Should I consider more than one head gasket? Any ideas?
tykuhn Getting Wild Join Date: Oct 2008 Posts: 95

12-30-2010, 03:00 PM	#2
H munster Not Yet Wild Join Date: Dec 2010 Posts: 10	Re: Piston hitting head after rebuild Did you replace both rods? If so im guessing they are the wrong ones or they are not seated on the crank properly.
H munster Not Yet Wild Join Date: Dec 2010 Posts: 10

12-30-2010, 03:13 PM	#3
tykuhn Getting Wild Join Date: Oct 2008 Posts: 95	Re: Piston hitting head after rebuild No, just replaced the damaged rod. Sure looked the same though. I did get the rod from EZGO. Will recheck the numbers to see if somehow I got the wrong rod. Rod cap is seated well on both rods. Piston extends above the cylinder wall the same for both pistons. Other rod and piston ok. I might pull the piston and rod that were replaced and see if it hits then. Might isolate problem then.
tykuhn Getting Wild Join Date: Oct 2008 Posts: 95

12-30-2010, 03:34 PM	#4
H munster Not Yet Wild Join Date: Dec 2010 Posts: 10	Re: Piston hitting head after rebuild Sounds like they sent you the wrong one. You should be able to measure the new one against the old if its not too tore up.
H munster Not Yet Wild Join Date: Dec 2010 Posts: 10

12-30-2010, 03:57 PM	#5
tykuhn Getting Wild Join Date: Oct 2008 Posts: 95	Re: Piston hitting head after rebuild Update. I pulled the new piston and compared the rod to the old one. Other than being new it is the same length and has the same number on it...251 and fan on the reverse side of the rod. I put the head on with one piston installed and the old piston hits the head also. That really only leaves one possibilty and that is whether the crankshaft is somehow not the right one as it too has been replaced. They look identical but I guess it could be wrong. I hope not as these are expensive. Does anyone know if the top of the stroke is supposed to be flush with the top of the cylinders? If so it has to be the crankshaft. Arghhhh!
tykuhn Getting Wild Join Date: Oct 2008 Posts: 95

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12-30-2010, 05:05 PM	#6
berthasquare Getting Wild Join Date: Apr 2010 Location: los angeles Posts: 126	Re: Piston hitting head after rebuild Not even flush. It's a teeenie lower in fact.

12-30-2010, 05:13 PM	#7
H munster Not Yet Wild Join Date: Dec 2010 Posts: 10	Re: Piston hitting head after rebuild Try rotating one of them 180 degrees and see if it still hits
H munster Not Yet Wild Join Date: Dec 2010 Posts: 10

12-30-2010, 07:18 PM	#8
tykuhn Getting Wild Join Date: Oct 2008 Posts: 95	Re: Piston hitting head after rebuild I reversed one piston (rotated 180 degrees) and it changed nothing. So, I pulled the crank out and looked at it. It sure looks identical but one crank has some numbers on it that the other does not. I cannot tell any difference but it is not working so I probably need to get another crankshaft. This one I acquired online from someone telling me it was a crank for a 295cc engine. It sure looks the same and everything lines up except the pistons protrude. Do you or anyone know if there are more than one crankshaft for the 295cc engines?
tykuhn Getting Wild Join Date: Oct 2008 Posts: 95

12-30-2010, 07:52 PM	#9
thewskrs Gone Wild Join Date: Apr 2010 Location: Malakoff, TX Posts: 381	Re: Piston hitting head after rebuild Sounds like you got the wrong stroke crank. Maybe from a 350? I really don't know the measurements on these as I have a clone engine, but I know the pistons on everything but hemi's are a smidge below flush.

12-30-2010, 08:03 PM	#10
scottyb Happy Carting Join Date: Dec 2007 Location: Southern California Posts: 73,406	Re: Piston hitting head after rebuild I do not know the specs but I will tell you this; the 350 head has a lot more vertical space for a piston to come up out of the black than a 295... my guess is you have a 350 crank...

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