How can one put a hydraulic cam in a 74 block that came with a mechanical cam? Can it be done? Just change the bearings or what? Thanks in advance!

-A. Lewis

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1972 Dart Swinger, 225cid

This has been discussed several times as I recall. The gist of it is that the hydraulic cam will fit and work in an earlier block. You have to swap out the entire valve train, including cam, lifters, rocker shaft, rocker arms and push rods. Since the oil for the lifters is supplied through the rocker shaft and push rods you have to be certain that sufficient oil is making its way through the entire system.

I'm sure there is a lot more detail and things to watch for in previous posts. Do a search and see what you can find.

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David Kight
'62 Valiant Signet, White
'98 Dodge Dakota
'06 Jeep Liberty

Growing older is unavoidable but growing up is strictly optional.

Make sure you also keep the bolts for the Hydro rocker shaft.
Frank

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Scrapple: Because a mind is a terrible thing to waste.
73 Duster - Race Car
66 Dart Wagon - DD
178" FED
82 D150
All Slant powered

hello dakight and other sages- have never had a hydraulic cam sl6. currently have the last non hydraulic sl6 in my 80 plymouth. only inconvenience ive had with all my sl6s is the need to occassionally adjust the valve lash. is the hydraulic cam sl6 a desirable improvement. if so why? only benefit i can think of is eliminating valve lash adjustments. since they were made apparently 81-87 there must have been some benefit. uncle moe told me only main reason was to cut manufacturing costs. thanks. bob f

Hey Bob. I personally wouldn't make that change. I agree that the only advantage is the elimination of the need to do periodic lash adjustments and in doing so you give up a broad choice of performance profiles. Something to be said for doing the lash adjustments is that it gets you under the hood where you're more likely to look other things over and perhaps do a better job of maintaining your ride.

I was just trying to answer the question without the terse "go look it up" answer that is frequently tossed out in the forums.

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David Kight
'62 Valiant Signet, White
'98 Dodge Dakota
'06 Jeep Liberty

Growing older is unavoidable but growing up is strictly optional.

The change was made primarily to help with emissions compliance by eliminating cylinder-to-cylinder variation inherent in solid-lifter setups. It probably also reduced engine assembly time and eased vehicle pre-delivery inspection and subsequent service at a time when engine bays were growing ever more crowded especially in the region over the valve cover.

Unless I were faced with a difficult-access situation, I would not change from solid to hydraulic. The factory hydraulic cam is a very tame/weak grind, and the options in better grinds are very, very limited. Of course a good cam grinder can make up whatever you want, but most of the experimentation and development in the slant-6 community has been for solid-lifter cams.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Thanks for the replies. Which cam bearings do you use?

-a. Lewis

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1972 Dart Swinger, 225cid

Should just be the regular ones don't know there is anything other than the regular ones.

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Part of Tyrde-Browne Racing

I think the only difference now is, if the camshaft rear journal isn't grooved, you will need to use a grooved bearing in the rear block journal.

-D.Idiot

The cam bearings are different, between the solid lifter engines and the hydraulic lifter engines. The number 1,2,and 3 cam bearings are wider in the solid lifter engine. The number 1 cam bearing in the hydro engine is grooved ( I have no idea why), where the solid motor bearing there is no groove. As strange as it seems, there is no difference in the #4 bearing, between the two motors. The additional oiling required for the hydo valve train, is supplied by a groove in the cam journal, itself. I do not have a hydro block to look at, to see how the bearing fit in the block. I do not have a hydro cam to see how wide the bearing journals, are. I am inclined to "GUESS", use the correct bearings for the block.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

ok sorry dont mean to hyjack this thread but can i put a solid cam in hydro engine???

That's much easier...change cam, lifters and valve train and get it back on the road...


Charlie, It'll be a while , but I have a hydro motor on a stand waiting for disection, measurement, and reconditioning, when I pull it apart I'll post the results of bearings and changes, since this seems to be an occassionally hot topic.

Thanks,

-D.idiot

That will be good. I have both sets of cam bearings "in stock", so I did a comparison, of them. I have seen a NEW hydro cam, but it has been awhile, so the only thing I remember for sure, that is different, is the groove in the rear cam journal. As for a hydro block, I have never been inside one of those.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

The biggest problem with the SL6 hydraulic set-up (or most Mopar Hydro set-ups) is the non-adjustable, stamped steel rocker arms.

When you have no rocker arm adjustment, you have to take extra time and "care" to make sure all the valve stem heights are the same.
From there, you need to check the hydro lifter "pre-load" when the rocker arm shaft / assembly is installed.

When running Mopar V-8 with the hydro lifters, I would use the mechanical (adjustable) rocker arms and set the hydro lifter's preload on each hydro lifter.
This can not be done on the SL6 because of the way the stamped rocker arm delivers oil to the hollow pushrod, that runs down and oils the hydro lifter, the adjustable (mechanical) SL6 rocker arm has no way to do that.
(There is no oil gallery down at the lifter bank, unlike the V-8 set-up)

So yes, if set-up correctly, the hydraulic SL6 can save you some lash adjustment time but for me, the extra "up-front" set-up time is more work then the occasional lash adjustment time.
DD

thanks for the info guys!

-A. Lewis

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1972 Dart Swinger, 225cid