Motor problem

wade w · 05-31-2010, 06:05 PM

I got this other lightning to work on. It just cut off on the guy driving normal on the way home. They told me it sounds like it has no compression when they turn it over. The rocker arms can be taken out if the cam is on the base circle. The cam isnt even touching the rocker. I was also told it was really low on oil. Would you think it lost oil presure and pumped the rocker stands down that bad? I turned it over by hand with one of the valve covers off. It did open one of the valves. I only turned it over enough to see if it would open that one valve.

wade w · 05-31-2010, 06:41 PM

I went out and tryed to turn it over some more. I think it has some bent valves. One of the rockers would not come out. The rocker stand for that one was not as high as the ones were the rocker would come out. Guess it just has to come out. Ill see what happened when I get it apart.

gearmesh, inc. · 05-31-2010, 11:40 PM

I just got done on a 4.7 Dodge that overheated and caused an exhaust valve seat to drop out of the head. Since the valve couldn't rise up far enough in the head with the dislodged valve seat, it let the roller cam follower jump out of place when the cam came around on the base circle. Keep an eye out for dislodged valve seats when you tear that 5.4 down. Dislodged seats can cause valve bending, too.

Sounds like you may have an oil pressure problem, too. From what I can remember from my Ford technician days (whew, long time ago!) when mod motors first came out, mod motor oil pump gears might be powdered metal like the factory con rods. We all know how strong those are, now don't we?

wade w · 06-01-2010, 06:55 AM

Thanks. I'll check it out when I get it apart.

DolSVT00 · 06-01-2010, 09:57 AM

if the springs are giving the correct extension and the valves are in the full up position, the lash adjusters even with no oil pressure and sitting at the bottom of their seat will supply the cam followers enough pressure to stay on the cam journal.

Example: When everything is installed and you go to put a cam (any cam) in a PI head you have to set the cam in and tighten all 6 cam caps evenly so that the cam goes down evenly and applies pressure to the valves. If you stuck a cam in without caps it wolnt even go down to the journals without enough force to compress the springs, and thats with no oil at all in them.

Those heads need to come off, and their most likely trash.

DolSVT00 · 06-01-2010, 10:01 AM

Quote:

Originally Posted by gearmesh, inc.

I just got done on a 4.7 Dodge that overheated and caused an exhaust valve seat to drop out of the head. Since the valve couldn't rise up far enough in the head with the dislodged valve seat, it let the roller cam follower jump out of place when the cam came around on the base circle. Keep an eye out for dislodged valve seats when you tear that 5.4 down. Dislodged seats can cause valve bending, too.

Sounds like you may have an oil pressure problem, too. From what I can remember from my Ford technician days (whew, long time ago!) when mod motors first came out, mod motor oil pump gears might be powdered metal like the factory con rods. We all know how strong those are, now don't we?

This situation could be spot on^^

The oil pump goes through the crank, the impellar is forged aluminum, there are no moving parts eccept the impellar and it is cut to fit slots (big slots) on the crank. I don't think i have ever seen one fail, however they can loose seal at the block flange and at the pickup tube.

wade w · 06-01-2010, 09:04 PM

Quote:

Originally Posted by DolSVT00

if the springs are giving the correct extension and the valves are in the full up position, the lash adjusters even with no oil pressure and sitting at the bottom of their seat will supply the cam followers enough pressure to stay on the cam journal.

Example: When everything is installed and you go to put a cam (any cam) in a PI head you have to set the cam in and tighten all 6 cam caps evenly so that the cam goes down evenly and applies pressure to the valves. If you stuck a cam in without caps it wolnt even go down to the journals without enough force to compress the springs, and thats with no oil at all in them.

Those heads need to come off, and their most likely trash.

I agree. Damn hes going to hate that. Its a built motor with ported heads.

DolSVT00 · 06-01-2010, 09:47 PM

Quote:

Originally Posted by wade w

I agree. Damn hes going to hate that. Its a built motor with ported heads.

Patriot heads?

wade w · 06-02-2010, 06:03 PM

Quote:

Originally Posted by DolSVT00

Patriot heads?

I dont think so, but Im not sure.

05-31-2010, 06:05 PM	#1
wade w Senior Member Join Date: Aug 2007 Location: Savannah GA Posts: 1,725	Motor problem I got this other lightning to work on. It just cut off on the guy driving normal on the way home. They told me it sounds like it has no compression when they turn it over. The rocker arms can be taken out if the cam is on the base circle. The cam isnt even touching the rocker. I was also told it was really low on oil. Would you think it lost oil presure and pumped the rocker stands down that bad? I turned it over by hand with one of the valve covers off. It did open one of the valves. I only turned it over enough to see if it would open that one valve. __________________

05-31-2010, 06:41 PM	#2
wade w Senior Member Join Date: Aug 2007 Location: Savannah GA Posts: 1,725	I went out and tryed to turn it over some more. I think it has some bent valves. One of the rockers would not come out. The rocker stand for that one was not as high as the ones were the rocker would come out. Guess it just has to come out. Ill see what happened when I get it apart. __________________

05-31-2010, 11:40 PM	#3
gearmesh, inc. creepy azz cracka Join Date: Nov 2008 Location: Summerville Posts: 1,587	I just got done on a 4.7 Dodge that overheated and caused an exhaust valve seat to drop out of the head. Since the valve couldn't rise up far enough in the head with the dislodged valve seat, it let the roller cam follower jump out of place when the cam came around on the base circle. Keep an eye out for dislodged valve seats when you tear that 5.4 down. Dislodged seats can cause valve bending, too. Sounds like you may have an oil pressure problem, too. From what I can remember from my Ford technician days (whew, long time ago!) when mod motors first came out, mod motor oil pump gears might be powdered metal like the factory con rods. We all know how strong those are, now don't we? __________________ "I came into this world kicking, screaming,and covered in someone else's blood, I have no problem leaving the same way!" ÔÇ£If you carry a gun, people will call you paranoid. ThatÔÇÖs ridiculous. If I have a gun, what in the hell do I have to be paranoid about?ÔÇØ -Clint Smith, Thunder Ranch.

06-01-2010, 06:55 AM	#4
wade w Senior Member Join Date: Aug 2007 Location: Savannah GA Posts: 1,725	Thanks. I'll check it out when I get it apart. __________________

06-01-2010, 09:57 AM	#5
DolSVT00 Moderator Join Date: Jan 2007 Location: Goose Creek Posts: 3,913	if the springs are giving the correct extension and the valves are in the full up position, the lash adjusters even with no oil pressure and sitting at the bottom of their seat will supply the cam followers enough pressure to stay on the cam journal. Example: When everything is installed and you go to put a cam (any cam) in a PI head you have to set the cam in and tighten all 6 cam caps evenly so that the cam goes down evenly and applies pressure to the valves. If you stuck a cam in without caps it wolnt even go down to the journals without enough force to compress the springs, and thats with no oil at all in them. Those heads need to come off, and their most likely trash. __________________

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