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Senior Contributor
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Discussion Starter · #1 ·
Roller rocker wear.

I just tore down a used head with roller rockers now that it has seen some use by the last owner and discovered flat spots on 3 roller rocker tips (not the round side but rather the centering ones that look like a spool of thread) and one cracked rocker.

I am hoping that the tips can be had from T and D or some other source, as they look standard.

It seemed that the fit is not quite right on the centering tips on mine but this can be hopefully be rectified by taking a bit off the lock keys or so the machine shop says during rebuild so they will roll properly.

The head that I have did not have titanium retainers but rather alu ones that are about 2.5 grams lighter than the titanium’s however they are showing serious wear where the roller rockers didn’t hold up right. During its use the head did not have a stud girdle installed so that might have something to do with it. The springs on the head were 260 pound max total and I am going to use ones that are 360lbs max (Pontiac 400) along with the heavier but more durable longer lasting titanium retainers after the rebuild unless someone who knows more that me (which is 99.9% of the people here) advises otherwise.

In setting the valve lash on a roller rocker set up should the intake and exhaust both be at.012 or should the intake be at .010 and the exhaust at .0.12?

Carbwise I am going to use DCO 48’s now instead of the 40ies that I had.

The h330 cam that I had (486 236 @ 50 110 Sep) is now going to be the cam that came with the head cam as when the last engine ate the rocker it messed up 2 lobes on the h330 cam. So the new cam is the one that came from the new (used) head I just don't know much about it except that it is in good shape and the only one I have. The new cam is marked G 2106 F277 275 08 which if I knew the rocker ratio I could at least figure out the lift I am guessing that it is around 430 and that the sep is 108 but that is speculation on my part.


The roller rockers that I have now are blue and were put into the head by the Rodgers Opel Eng. who did the porting and building for the original owner. Th previous owner had it on a Euro 2.4 I am going with a Legere style 1.9 with 305 pistons and a stroked crank as the bottom end of my old engine held up fine when the head cracked on the trip to Vegas but the crank will have to be turned to the next size bearings because it got a bit hot the last 100 miles with the fried rocker and the droped float on one of the carbs (the cause of all the problems) thinning out the oil as it dumped gas into the engine.. The broken # 7 rocker cam to rest on the #8 so they both were working at the same time. Despite the agony I was in over the engine lunching itself it was fun to watch the 11th Cav types (my old unit no less too) sprawl on the ground for cover as the wounded manta backfired its way across the Boulder dam as the grand canyon seemed to amp the sound. still they are tough little engines cause with all the damage it still kept ticking at least till the head gasket went and I had to push the last 2 blocks of the 1600 mile trip
 

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Old Opeler
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5,564 Posts
Roller rockes need lubrication - not a lot but enough to ensure they never run dry. Also the valve tips and lash caps on the cam followers need to be square and flat to the centre line of the valve and cam follower respectively.
It is a real good idea to use synthetic oil like Mobil 1 or semi-synthetic like Castrol Magnatec in an engine like this due to the high contact pressures and lubrication requirements inside the rollers. It is important that the oil holes up through the rocker studs are clear and letting oil through.

Also your first spring pressures seem pretty high at 260lbs. The use of 360lb springs seem far too high. Hope someone with more experience with Opel cam gear can advise you better than me on the necessary spring pressures.
 

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Senior Contributor
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GTJIM said:
Also your first spring pressures seem pretty high at 260lbs. The use of 360lb springs seem far too high. Hope someone with more experience with Opel cam gear can advise you better than me on the necessary spring pressures.
The 260 dual springs were what Rodgers O E had used. The 360 dual springs are springs that are out of my last engine and had worked fine for 5000 miles or so. I am debating going with the lighter springs due to wieght but the since I use the car mainly on the street with autocross I might go with the hevier springs as the shop says they seat much better and floating will not be an issue..

I will look on here and see if I can find what Bob says about springs and thanks for the mobil one advice
 

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Senior Contributor
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499 Posts
Discussion Starter · #5 ·
after talking to the folks at GTsource today I decided to go with the 260 springs due to the imfo that was combined by kieth and this quote from Bob
> On valve springs
>
> Does anyone know the
> 1. Seat pressure?
> 2. Open seat pressure?
> #. And/or the max open pressure for springs for a
> 1900 head
> (Specifically a late 1971 w/ a bearing cam).
>
> 1.84 Chevy intake
> 1.50 Chevy exhaust
> .435 lift, 242 duration @50 290 ad duration 108
> degree separation
>

valve springs


*****Stock valve springs? They're 90-95 lbs on the
seat, and 180 open @ .390" lift. Not enough for the
cam you're running, and they'd be right on the verge
of coil bind anyway (.450"). I ran an identical cam
(Chevy 409 profile BTW), and used springs with 115 lbs
seat pressure and 240 lbs open. I'd prefer to use
105-110 lbs of seat pressure, especially with stock
rocker arms (they don't like high seat pressure).
With 240 lbs open, the point of valve float was
8400. That cam, set up with 4 degrees of cam advance,
has it's best power from 2500-6500, and shift points
at 7200 put the car into the meat of it's powerband in
each higher gear.




*Springs and retainers. I use Crower 86031 titanium retainers, they're 1.25" in diameter. For springs, I use 1.25" double springs, Crower #68106/208. They install at around 1.675". I also use Crower billet keepers, #86107. I use viton valve seals, V.S.I. brand, they're for a .341" stem and to fit a 1/2" valve guide. Part number is 45341 .
 

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Senior Contributor
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499 Posts
Discussion Starter · #6 ·
The wounded roller rockers are being shipped back east to be checked out by the experts. It should be noted that the newer purple roller rockers are more heavy duty than the older blue models. The cracking came from when the pin was pressed in we think here but we will defer to the pro's opinion on what actually happened.
 
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