Roller Rockers

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I'm under the impression that this is not a racing engine or anything super-high-performance. So, honestly, doing the geometry correction seems like going overboard for this one (to me). But he can if he wants so spend the extra $$. Engines have been running hard and pretty well without it for a long, long time, and IMHO, .474" lift is in the 'questionable zone' of it being worth the $$. He is not going to gain all that much lift back with that level of lift; and, it will just effect the high end of the rev range, not the cruising operation, which sounds like 98% of this engine's operation.
 
And besides, that 280/280/110 cam may not be in there all that long.
Depending on;
the elevation of sport la and
how much the heads were shaved,and whatever
the Duster has for Torque Multiplication,trans,gears,and/or TC
it could be a tad lazy out of the gate;
 
Warning; Opinion to follow;
not what AJ would like for a cruiser,cuz for AJ,
cruise only happens between blastings,lol. And
when AJ nails it, chit better happen right now! And
AJ don't care if it doesn't rumpidy-rump-rump.
IMO........a cruiser has a lot less cam than 280/110, and a lot more wheelbase than 106 to 110.But, I've been wrong about cruisers before.
One thing I have not yet been wrong about, is that a high pressure streeter can use just about any street-worthyTM and have a lot of "cruising" fun. Whereas 120psi sucks by anyone's standards, and while 140 to 150 is bearable, iron heads like 160 or a tad more; aluminums 185 to 195, or more if you are brave.If you have never run 185plus, then you cannot know what's missing. It has very little to do with power. It has everything to do with the engine taking WOT instantaneously, whenever you ask it to, no matter how much street-tire is under it. When it does this, you can run a lotta carb and not have to suffer the dreaded;B-O-G, hesitation, or stumble.
Yeah sure,you can overcome this with TC and gears; but that takes the car out of cruiser status, and puts it straight into weekend bomber status. Whether or not the operator/owner is willing to put up with this is, I guess, up to him.
The 280/280/110 sits kindof on the borderline between these two worlds.
No matter what, it's gonna be hard on gas.And the price of gas is climbing almost everywhere you look. And so, a day will come in the not too distant future, when the car will become too expensive to cruise because of the cost of the fuel,and that cam will want to come out of there.
It's just a matter of time.
And that's my opinion.
It doesn't mean you can't have fun with it, in the immediate future. And if you only cruise it occasionally, 25/35/45 bucks a crack doesn't sound so bad..............
 
dad69dds said:
72 Duster 340 number matching with j heads wanting to buy some roller rockers not sure what will fit, don't want the best and don't want anything cheap either yes I just put a cam in her that's why im needing one.
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Are you wanting roller rockers for their adjustability? If you are looking to just raise the rocker shaft to get it back where it was before the heads were milled I have a full set of aluminum shims you can have for the price of shipping if you want to try them. Geometry will be a little off as the valve height didn't move. Much less expensive than a new set of rockers.
 
threewood said:
Are you wanting roller rockers for their adjustability? If you are looking to just raise the rocker shaft to get it back where it was before the heads were milled I have a full set of aluminum shims you can have for the price of shipping if you want to try them. Geometry will be a little off as the valve height didn't move. Much less expensive than a new set of rockers.
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Yes I have low compression on the motor backed off on rocker shaft and the compression came up, so apparently someone did a valve job, or shaved the heads, or shaved block I don't know. I bought the car this away just finding out this when I put a cam in her. Doesn't smoke or burn oil so I want some roller rockers to adjust valves one by one. the stock rockers have a off set to the left on eight rockers and to right on eight rockers. So straight rockers will not work because it changes the geometry of the push rods, if anyone has been inside of a stock 340 72 and I know a hole lot of u guys have they will know what im talking about, and yes I know I can remove the heads and redo the valves but trying to advoid that. I have found out they don't make these any more unless u want to pay 1200-2000 for them
 
Comments inside the quote

dad69dds said:
Yes I have low compression on the motor backed off on rocker shaft and the compression came up, so apparently someone did a valve job, or shaved the heads, or shaved block I don't know. This is not making a lot of sense. Well it sorta is but not really. I get what you are trying to say but low-compression is not what backing off the rockers proved. All that proved was that
A) the valves were not all the way closed in the first place. or
B) they were, but when you closed the intake earlier by backing off the gear, the compression came up,.................... which would be normal.
Adjustable rockers will only cure A) and have no effect on B) when properly set.
A) is easy to prove with a Leakdown test.
B) is normal
Is there a C)?, I don't think so.
While high compression can make your engine a powerhouse, Typical ratios of 9/1 or so can still be a lot of fun in a streeter. At this point I would be most concerned with proving that the valves can actually physically close...... and a LD test will prove that. I would back off the gear and pressurize the cylinders with the pistons at the bottom; keep your hands away from the fan.
If that works, I would reinstall the gear and now test with the pistons at TDC-compression, using air regulated down to say 45psi.
If that works, I would increase the pressure,slowly and carefully to 80psi.
If that works, then maybe you just have a really raunchy cam.
I bought the car this away just finding out this when I put a cam in her. Doesn't smoke or burn oil so I want some roller rockers to adjust valves one by one. the stock rockers have a off set to the left on eight rockers and to right on eight rockers. This is correct. So straight rockers will not work because it changes the geometry of the push rods, if anyone has been inside of a stock 340 72 and I know a hole lot of u guys have they will know what im talking about, and yes I know I can remove the heads and redo the valves but trying to advoid that. I have found out they don't make these any more unless u want to pay 1200-2000 for them
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