spetz01

Hi Guys,

I have my friends 455 out of his 73 Ninety Eight. Just doing gaskets and a refresh with out touching the block really.

I have the heads off and am having issues finding out how to re set the rockers. His uncle "the Olds Pro" had given me totally wrong info.

To me these look like non adjustable, like the Chev's I'm used to. Twist the pushrod until its tight and then give the nut an extra turn. Well I broke three bolts doing it his way.

What I ended up doing, after some searching here, is this. TDC on #1, tighten the 2 bolts to 25 Lbs, I think I did the next one in the firing order too, say #8. I'd turn the crank 90 degrees and do the next to and so on.

Is this right? I still have the intake off and the engines on a stand.

Thanks.

MDchanic

Olds rockers are non-adjustable.
This has been a constant annoyance to Olds hot rodders (and a relief to Olds mechanics) for about sixty years.

Any "Olds expert" who told you to adjust them is far worse than an idiot.

The answer is: You don't adjust them. You rotate the engine to TDC with valves closed and tighten them to a normal tightness (I think the spec is 25 ft/lbs, but it's the spot that "feels right" anyway), one cylinder at a time.

- Eric

Seff

What if the valves are within the allowed max height off the head, but not the same height as the other valves?

MDchanic

You mean if the seats are recessed or ground too deeply?

I believe that the CSM says you are supposed to grind and polish the stems to achieve the correct height (but I may be remembering inaccurately).

- Eric

edit:

Yup, I remembered correctly:

Octania

If the valves have been messed with, and/or head gaskets replaced... and you don't use adjustable rockers, then a lot can go wrong. But, sometimes it works out OK.

the torque spec on those grade 8 flanged rocker bolts is 25 ft lbs
any Olds V8 can donate more, I have 100's.

What you want is about 0.050" lifter plunger depression. Much like a brand c engine, but instead of 1 executing turn after clearance is gone, you can't just choose. Also, c brand studs are fine thread, I believe, vs Olds' coarse threads. When the Olds rocker bolt comes snug against the pedestal/ head, it is not going to -move- more with more tightening, it will come to torque and that's it.

You would LIKE this to be at least 1/2 turn of the 5/16-18 rocker bolt, and no more than oh 1.5 turns. That way, the lifter plunger is depressed 0.050 to 0.150" or so, in its range of operation as designed.

I have had engines such as my recent 403, assembled by a PO with many errors, that have ZERO lifter depression, or less. That is to say, the rocker comes tight just as, or before, all the clearance is taken up. This is of course is not good for engine operation.

So, yeah, at TDC compression, with the neighboring rocker fully slack, using your finger feel as you appear to be skilled at, bring out the clearance, then tighten to lightly snug [pedestal against the head]. If this is 1/2 to 1&1/2 turns, perfect, slack it off so it does not affect its twin while you do that one- they are interconnected, right? If both are in the correct range, then bring 'em down tight and torque to 25.

If too many turns, thin steel shim washers can be put under the pedestals, or more extensive voodoo like valve tip grinding, adjustable rockers, etc.

If too few turns... because, say, the head is further out due to a fatter head gasket, valve tips are lower than they should be.... etc., well, that's not so easy to fix. Adjustable rockers or different length pushrods come to mind.

spetz01

Thanks for the info.

Now I've ran into a problem with the pedestals. I've broken 2!!

I found some replacements 5/16 bolts that I thought would work. Unlike the stock one's that are threaded right to the top, mine stopped short. I don't think that was the problem. I think when I first attempted to tighten them down I stressed them. One broke while torquing, the other while we were rotating the engine while I was attaching the flywheel to the TC. It came of with quite a lot of energy.

Just to remind you, we did not delve into tearing the motor down at all. Everything is staying were they came originally from.

I did locate a pair of new rockers and pedestals from Summit Racing for $12.00. Do you think I'll be ok if I replace the 2 I broke and leave the rest? Its a shame they don't come with bolts.

MDchanic

Or you could just get the pedestals for two and a half bucks each (or a pair of them with rockers for eight and a half) at Advance Auto.

And, yeah, it's fine to just replace the bad ones.

- Eric

spetz01

I'm up in Edmonton,Alberta, we don't have Advance Auto. I'm gonna try my parts guy on monday.

Hey MD would you what is mounted in the intake that is inline with the heater hose's. I don't have a pic right now, but is looks like a diaphragm and a sensor on the other end, 1" nipple into the manifold. I've had no luck finding out what it is or does. I'd like to replace it.

Thanks,

MDchanic

Okay. You've probably gor NAPA. They're a bit pricey and get $3.29 for it around here.

You mean this?



It's the Hot Water Valve and Engine Thermal Switch.





The Hot Water Valve closes when set to High A/C or when the Temp lever is all the way over at Cold, to keep hot water out of the heater core.

The Engine Thermal Switch opens below 40°F (about 6°C for youse North of the Border) so that the heater fan, which is always on its Low setting, turns off when the engine is cold, and then on as the engine warms up, so it doesn't blow cold air on your delicate ankles.


Why? If you don't know what it does, how do you know whether it's working?

- Eric

spetz01

Yup that's the unit. I was going to replace it cause mine looks like yours in the picture. This cars getting the AC yanked out and not put back in during this process as well. The condensers a mess and the system is empty.

Are those valve obtainable?

MDchanic

Well, that depends.

You say that you're removing the A/C.
If so, since this is a part of the A/C system, would you be removing it as well?
If you would not be removing it, then how would you be operating it?

They are definitely available, generally from Four Seasons or Factory Air, which are the major aftermarket heat / A/C replacement parts manufacturers, either with or without the screw receptacle for the electric switch.

Here's one at Advance for $25.



- Eric

olds 307 and 403

Use a nipple from your local Home Hardware or Canadian Tire. They gavanized and come in various sizes. I believe 3/4" is the size in the plumbing section and about $2.