Rat Patrol
Well-Known Member
1st off - I have no pics to go along wth this question - so please be pateint .
2nd - These are NOT MY HEADS . ..I'm postng this as a favour to a guy in my home town.
3rd - The facts have been verified by hard core race guys And TWO engine builders - please don't make any assumptions about ability in relation to this issue - the problem was genuine and did exist.
OK - here we go...........
Background
About 12 mths ago local guy down here in Melbourne Australia ordered a set of OOTB 1.92 valve RHS LA-X heads from the local wholesaler - The local Wholesaler is the Comp rep. for Australia amongst other brands.
I have no idea who supplied them in the US - I am assuming Comp did?
I know it wasn't IMM, Hughes or Indy.
He took them to an established and reputable hi performance engine builder which is how I know about the issue - I was in his shop today discussing something unrelated about piston shaving.
Issue
Put simply - when std 1.5:1 ratio roller rocker gear is fitted up - the rollers hangs on the edge of th tip, and things get worse when the valve spring is compressed....
The builder tried Harland, Comp Pro Magnum and Crane Gold and the same issue came up - as the valve opened, the roller tip fell off the tip of the valve! ops:
Put simply - the shaft stands in the heads have been cast in the WRONG PLACE -
Engine builders on here will know that it doesn't matter what length valve is used..or if the shaft is shimmed - the distance between the shaft and the tip is simply too wrong to achieve sound geometry.
The roller starts on the ist 1/3 of the tip, and as the valve is pressed down, the tip jsut rolls off the end of the valve!
Action
The Comp rep called Comp who didn't want to know.
The owner called Indy and Hughes - here were the responses.
Indy said - "you have to use our rockers"
Hughes said - "you have to use our rockers"........
These are weird responses - why would Hughes or Indy create a rocker set up just for RHS heads?
If they worked for these heads, they clearly wouldn't work on any others like Eddies or OEM.
:wack:
RESULT
The owner of the heads gave up - the local Comp rep took them back but now the user is worried about ordering any further sets either direct from the US or through the rep because of this casting issue.
QUESTIONS
before i ask - please no "suggestions" on how to fix it - it was unfixable and the only option would have been to drill and tap for pedastal rockers.
Q 1 - Have any users or engine builders on this forum experienced a similar issue with rocker gear not lining up in the correct position on the LA-X castings?
Q2 - Was there a bad batch that has now been recitifed?
Or are most guys just putting their hands up and going with pedastal stands.?
Please understand - Australia is 18000 miles away and if there was a bad batch issue - we never heard about it and we need to know.
Partly so people can buy them without fear now - and partly so any "returns" can be done with the correct information supplied back to the sellers.
Any feedback gratefully received.
Thanks for your patience.
RP
2nd - These are NOT MY HEADS . ..I'm postng this as a favour to a guy in my home town.
3rd - The facts have been verified by hard core race guys And TWO engine builders - please don't make any assumptions about ability in relation to this issue - the problem was genuine and did exist.
OK - here we go...........
Background
About 12 mths ago local guy down here in Melbourne Australia ordered a set of OOTB 1.92 valve RHS LA-X heads from the local wholesaler - The local Wholesaler is the Comp rep. for Australia amongst other brands.
I have no idea who supplied them in the US - I am assuming Comp did?
I know it wasn't IMM, Hughes or Indy.
He took them to an established and reputable hi performance engine builder which is how I know about the issue - I was in his shop today discussing something unrelated about piston shaving.
Issue
Put simply - when std 1.5:1 ratio roller rocker gear is fitted up - the rollers hangs on the edge of th tip, and things get worse when the valve spring is compressed....
The builder tried Harland, Comp Pro Magnum and Crane Gold and the same issue came up - as the valve opened, the roller tip fell off the tip of the valve! ops:
Put simply - the shaft stands in the heads have been cast in the WRONG PLACE -
Engine builders on here will know that it doesn't matter what length valve is used..or if the shaft is shimmed - the distance between the shaft and the tip is simply too wrong to achieve sound geometry.
The roller starts on the ist 1/3 of the tip, and as the valve is pressed down, the tip jsut rolls off the end of the valve!
Action
The Comp rep called Comp who didn't want to know.
The owner called Indy and Hughes - here were the responses.
Indy said - "you have to use our rockers"
Hughes said - "you have to use our rockers"........
These are weird responses - why would Hughes or Indy create a rocker set up just for RHS heads?
If they worked for these heads, they clearly wouldn't work on any others like Eddies or OEM.
:wack:
RESULT
The owner of the heads gave up - the local Comp rep took them back but now the user is worried about ordering any further sets either direct from the US or through the rep because of this casting issue.
QUESTIONS
before i ask - please no "suggestions" on how to fix it - it was unfixable and the only option would have been to drill and tap for pedastal rockers.
Q 1 - Have any users or engine builders on this forum experienced a similar issue with rocker gear not lining up in the correct position on the LA-X castings?
Q2 - Was there a bad batch that has now been recitifed?
Or are most guys just putting their hands up and going with pedastal stands.?
Please understand - Australia is 18000 miles away and if there was a bad batch issue - we never heard about it and we need to know.
Partly so people can buy them without fear now - and partly so any "returns" can be done with the correct information supplied back to the sellers.
Any feedback gratefully received.
Thanks for your patience.
RP