I have a odd problem. I have a 1963 Valiant with a 170 and automatic that I just bought from a friend. The engine was rebuilt by a local shop about 50,000 miles ago. At the time they said that they were "upgrading it to a hydraulic cam". To make a long story short, it now appears they only did half the job. The motor has a hydraulic cam and lifters but it still has the adjustable rockers and push rods. I have recently learned that this is not recommended! Although the motor has run surprisingly well, with only a few problems with noisy lifters that were caused by using oil stabilizers, aka Lucas, STP, ect. Now to my question. What can I do to correct this situation? Would installing hydraulic rocker arms and pushrods allow the proper amount of oil to get to the lifters? Assuming that the correct cam bearing was installed. Or is a mechanical cam and lifters the best thing to do?

It's doubtful you have a hydraulic cam and lifters retrofitted to a 170 with the old mechanical rockers and pushrods. This combination is just not possible. The hydraulic lifters receive their oil from the rocker shaft, through the special hydraulic-only rockers, then through the special hydraulic-only pushrods. Mechanical rockers and/or pushrods would never let oil get to the lifters. To top that off, your 170 engine block is shorter than the 225 block and would have required special custom built pushrods because the factory never made any 170 hydraulic pushrods.

It's doubtful you have a hydraulic cam and lifters retrofitted to a 170 with the old mechanical rockers and pushrods. This combination is just not possible. The hydraulic lifters receive their oil from the rocker shaft, through the special hydraulic-only rockers, then through the special hydraulic-only pushrods. Mechanical rockers and/or pushrods would never let oil get to the lifters. To top that off, your 170 engine block is shorter than the 225 block and would have required special custom built pushrods because the factory never made any 170 hydraulic pushrods.

So what your telling me is that you don't have any experience with this odd ball combo. Unlikely as it seems I'm almost certain I'm dealing with hydraulic lifters. I've adjusted solid and hydraulics many times and these lifters just adjust like hydraulic. The only way to know for sure is to pull one of the lifters and I'll let you know what I find. I do know that when this motor was built the shop had a lot of trouble getting the valves adjusted. The solution included changing the pushrods. Thanks for the insight.

If your engine has a hydrolic cam, but everything else is essentually standard, then your shop screwed up.

I don't think a 1963 170 block can be made to work correctly with a hydrolic cam.(without some very complex modifications) I'm no expert, but here are just a few of the problems.

Primary:
oiling, the later blocks (1980 and up) where modified to provide oiling to the hydrolic lifters. Without it, they won't work correctly (this is conjecture without full understanding)

Cam 'ramping' is not ground the same on hydrolic cams as solid cams. That means, with a 'correct' valve lash setting, you'll get excessive valve train noise. When adjusting out the noise, you'll loose .....

Ouch, my brain hurts.... It's just a bad idea..... I don't know exactly why, but if it where a good idea, somebody here would tell you how to make it work.
That sounds like a load of crap, or excuses made up by a shop that did something they shouldn't have done.

I suggest that you find a mid 1970's solid lifter cam and put things back to the way they should be.(please note that a suggestion is not a demand, it's more like my opinion, based on the information that I have.)

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1980 Aspen 225 super six

Ummm....... Don't slant-sixes lack a pressurised oil feed to the lifters? Isn't that the reason that the factory did it bass-ackwards and fed the lifters DOWN through hollow pushrods from the rocker shafts in the late engines with hydraulic lifters?

IOW, I don't think you've got hydraulic lifters, and if you do its no surprise that they're noisy because they're collapsed from lack of pressurized oil feed! What is much more likely is that you have mechanical lifters with a hydraulic-grind cam, and that will ALWAYS be noisy because a hydraulic grind doesn't have a gentle ramp to quietly take up lash the way a mechcnical grind cam does.


FWIW, there's nothing wrong with adjustable rockers with hydro lifters in an engine block designed for hydraulic lifters. For example, a 273 that originally had mechanical tappets can live quite happliy with hydraulic tappets under its original rockers. They just have to be set to the correct lash to get the right pre-load for whatever type hydraulic lifter is used.

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Thanks for all the insight. It seems quite obvious that the shop that built the motor did something wrong. The only prudent thing to do is pull the cam and lifters and pushrods and replace them with the correct ones. It will be a few weeks before I can tear it down but I'll post the results if anybody cares. Thanks.....