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Drool tube Hydraulic Head Question
https://slantsix.org/forum/viewtopic.php?t=55770		 Page 3 of 3
Author:  CNC-Dude [ Mon Jul 14, 2014 9:13 pm ]
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If the valves are longer than stock it would have the same effect as milling the head. Avoid shimming the rocker shaft if at all possible. I tried to grind the shims to a proper half moon shape and still cracked some rocker stands. That's why the rocker shaft on the race engine is mounted with studs. Shorter push rods are the solution but must transfer oil like AMC. You can cut a section out of a pushrod and then tap each end so that you can put in a piece of threaded rod and make your own adjustable pushrod for measuring. The threads don't have to be deep, just enough to hold the threaded rod in place.
There is an adjustable pushrod checking tool for a Slant on eBay right now for sale if that will help solve the mystery.

Also Lou has a good point about interchanging hydraulic and solid lifter valvetrain components. A lot of variables that need to be figured out.
Author:  Dart270 [ Tue Jul 15, 2014 3:49 am ]
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Ah. Must be the valve lengths. Good idea, Seymour!

Lou
Author:  sandy in BC [ Tue Jul 15, 2014 7:49 am ]
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I cant imagine that new pushrods wont fix this......
Author:  DadTruck [ Tue Jul 15, 2014 1:38 pm ]
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solid lifters on a hydraulic camshaft is not a good combination
cams intended for solid lifters have a very slow inital ramp off the heel of the cam, to take up valve lash, the lash allows for thermal growth among the vlave train components.
that is why there is a valve lash associated to a mechanical cam and lifter.

cams intended for hydraulic lifters are zero lash,,full contact all the way around the cam lobe, initial ramp off the heel can be quicker as any thermal growth is automatically countered by the hydraulic lifter.

using mechanical lifters on a cam that does not have lash ramps, is trouble,,, as that is why they put lash rams on mechanical cams..

perhaps the stock D150 cam ramp is so lazy, it may work,, but you are violating a basic design characteristic of a mechanical lifter - cam interface.
Author:  Rick Covalt [ Tue Jul 15, 2014 5:43 pm ]
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Has anyone run a solid lifter head on a hydraulic motor?
Yes we have done this, without any issues. We also ran solid lifters on the hydraulic cam for a good while without any problems. I'm not saying it is ideal or even good for the cam, but it ran perfectly fine for probably a year and a half until the oil pump gear went out.

Rick
Author:  Sam Powell [ Wed Jul 16, 2014 4:32 am ]
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Fifty years ago I put solid lifters on a Pontiac hydraulic cam. It ran like a scalded cat for about 3 months, then the cam was wiped. These lifters were advertized as "OK" solids for a hydraulic cam. Not a good idea.

Sam
Author:  CNC-Dude [ Wed Jul 16, 2014 10:29 am ]
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We built many circle track engines with solid cams in them that had hydraulic lifters because the rules said no solid cams. Valve adjustment was more tedious but no problems were ever noticed.
Author:  Reed [ Wed Jul 16, 2014 10:48 am ]
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The pre-1981 head can absolutely be run on an engine block that was originally built with a hydraulic camshaft. Any slant head can be run on any slant motor. The catch is that you MUST match the valvetrain to the cam installed in the motor and you MUST make sure you use the rearmost rocker arm shaft bolt that matches the head used. See here: http://www.slantsix.org/forum/viewtopic.php?t=46756

For example, the engine in my brother's 1983 Dodge van is a 1976 225 block, a 1972 198 head, and a 1983 hydraulic cam and valvetrain. It runs fine. Very smooth, 21 inches of vacuum at idle.
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