4.3L Roller rocker conversion issue

Leedanger

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Putting back together 4.3L Vortec 0L082849 and having an issue with valves remaining open. I'm torquing the rockers down to 16lbs as per the manual. This block did not originally have these heads...the heads are off a 2001 block. Seemingly, the push rods are too long as I am using the originals, but I don't see a difference in the part numbers between the years. Any thoughts?
 

Bt Doctur

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Re: 4.3L Roller rocker conversion issue

manual list 20Ft/lbs. rotate motor untill both valves are closed for that cylinder, torque rocker nuts, go to the next cylinder, both valves closed, etc,etc.
 

Volphin

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Re: 4.3L Roller rocker conversion issue

Your 2001 V heads have the pedestal mount RRs correct? The only adjustment is in pushrod length. If the valves are staying open after the torque sequence, then a shorter pushrod will be needed.

What is the head casting number?
 

alldodge

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Re: 4.3L Roller rocker conversion issue

Putting back together 4.3L Vortec 0L082849 and having an issue with valves remaining open. I'm torquing the rockers down to 16lbs as per the manual. This block did not originally have these heads...the heads are off a 2001 block. Seemingly, the push rods are too long as I am using the originals, but I don't see a difference in the part numbers between the years. Any thoughts?

Specs on your engine (1998) and the 2001 model are the same. Rocker ratio is 1.50:1, lift Int .414, Exh .428, Spring height Int 1.78, Exh 1.69-1.71, Cam lobe lift Int .286-.20, Exh .292-.296. Roller lifter restricter plate 12FTLB, Rocker arm nuts 22FTLB.

Assuming you still have the original roller lifters and standard non-roller rockers, everything should fit.
 

Leedanger

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Re: 4.3L Roller rocker conversion issue

Your 2001 V heads have the pedestal mount RRs correct? The only adjustment is in pushrod length. If the valves are staying open after the torque sequence, then a shorter pushrod will be needed.

What is the head casting number?

There is no pedestal, maybe my terminology is wrong but I would call this a rail that the roller rocker sits on. There are no studsd in the head as you would normally see. I was actually missing this rail when I first posted this, found one, installed it, it ran great for three hours while I broke the engine in, so I gave it back to the guy. He took it home, fired it up, and now it has a nasty valve tick and it seems as though a valve is still remaining open. Uhg. I'll get back to you all with the casting number after I pull the valve covers again to see what the hell is going on. Maybe I bent a rod torqueing those down the first time without the rail? Dunno.
 

alldodge

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Re: 4.3L Roller rocker conversion issue

There is no pedestal, maybe my terminology is wrong but I would call this a rail that the roller rocker sits on. There are no studsd in the head as you would normally see. I was actually missing this rail when I first posted this, found one, installed it, it ran great for three hours while I broke the engine in, so I gave it back to the guy. He took it home, fired it up, and now it has a nasty valve tick and it seems as though a valve is still remaining open. Uhg. I'll get back to you all with the casting number after I pull the valve covers again to see what the hell is going on. Maybe I bent a rod torqueing those down the first time without the rail? Dunno.

Does the rail your talking about look like item 16 ?
http://www.mercruiserparts.com/Show...bnbr=110&bdesc=Cylinder+Head+and+Rocker+Cover

Also your calling them roller rockers, the roller is on the lifter. If you have actual rollers on the rockers then someone has replaced them with after market
 

Leedanger

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Re: 4.3L Roller rocker conversion issue

Does the rail your talking about look like item 16 ?
http://www.mercruiserparts.com/Show...bnbr=110&bdesc=Cylinder+Head+and+Rocker+Cover

Also your calling them roller rockers, the roller is on the lifter. If you have actual rollers on the rockers then someone has replaced them with after market

#16 is exactly what I am talking about and yes I am aware that it has been changed, I am the one who did it....hence the title of the thread. These rollers aren't after market though, they are GM factory from a 2001 head.
 

alldodge

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Re: 4.3L Roller rocker conversion issue

#16 is exactly what I am talking about and yes I am aware that it has been changed, I am the one who did it....hence the title of the thread. These rollers aren't after market though, they are GM factory from a 2001 head.

Wouldn't mind seeing a pic of them, I cannot find them in the Merc manuals
 
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