PRV V6 top end lubrication mod?

D

dieselnutjob

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Fellow Frogger
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I have heard mention on here of a modification which can be done to early PRVs (my 604 was built Feb 76) to help with rocker arm wear.

Can anyone tell me what the mod is please?
 
Is this a thread bounce - now with pics ? !

Cheers

Justin
 
Early PRV motors had insufficent oil flow to the rockers , the cause is a restriction in the oil gallerys feeding the heads .
The cure is to locate the oil feed gallery through the head gasket then use a long drill bit and well below the top of the block enlarge the choke point .
 
Rally said:
Early PRV motors had insufficent oil flow to the rockers , the cause is a restriction in the oil gallerys feeding the heads .
The cure is to locate the oil feed gallery through the head gasket then use a long drill bit and well below the top of the block enlarge the choke point .
Click to expand...
thank you.

Can I replay this back to you with my own understanding of what I think you are saying to confirm it?

It sounds like:-

This is a heads off job which is a pain as mine doesn't actually need the heads off.
There are two heads so it has to be done on both sides?
The idea is to drill out the holes in the block that feeds oil to the oil feed holes in the head gaskets.
At a guess this would mean poking a wire down there to see how deep that hole goes and then drilling that deeply?
I am also guessing that the existing hole is narrower than the one in the head gasket and head so I suppose the drill size that I'm looking for is to drill it to the same size as the gallery in the head?

and thanks again.
 
and some more questions (sorry): is there a definitive way to tell if my particular engine "needs" this mod? (engine number or something) and does it really need it for ordinary road use? I'm not building a race/rally car.
 
dieselnutjob said:
thank you.

Can I replay this back to you with my own understanding of what I think you are saying to confirm it?

It sounds like:-

This is a heads off job which is a pain as mine doesn't actually need the heads off.
There are two heads so it has to be done on both sides?
The idea is to drill out the holes in the block that feeds oil to the oil feed holes in the head gaskets.
At a guess this would mean poking a wire down there to see how deep that hole goes and then drilling that deeply?
I am also guessing that the existing hole is narrower than the one in the head gasket and head so I suppose the drill size that I'm looking for is to drill it to the same size as the gallery in the head?

and thanks again.
Click to expand...

You seem to understand the procedure , the choke point is in the block just above the tensioner. I always thought it was a casting error , no sure if its related to engine number or not.

How do you know your motor has low oil feed to rockers , back in the day the rockers and or cam shafts would wear and often looked dry.
 
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