Technical Cadillac guys, converting a 365/390 to hydraulic roller cam

Guys,

Been doing some investigation on converting a first generation 390 to a hydraulic roller to get away from the dreaded "cam failure" issues many are facing.

Caddys are expensive to build as is, but even more so if you have to do it more than once. My thought has been to use some of the more modern, available, aftermarket parts. Spend the money up front and be done with it.

• I have spoken with Harland Sharp and they will build a set of adjustable rockers.
• The issue is a tool steel or billet core for the early Caddy.
• Bullet Cams says they can do it, but is going to be expensive.
• Comp Cams didn't seem too interested and they told me it would be an 8 month lead time.
• Still calling other cam companies. Isky is next.
• I plan on using an aftermarket Hyd roller lifter out of a Chevrolet. The Cadillacs measure exactly the same as the SBC.
• It will require a custom length pushrod, which will be the cheapest part of the whole deal.
• The small valve spring seat is a concern. It measures 1.200”
• Beehive springs might help to remedy this. Spring pockets can be machined to accept a larger diameter spring, but how big is the question.

Would like to have your input on anything I may be missing. I know Tony at Ross Racing is doing this conversion, so I am sure it's doable.

Thanks,

Root

 

The roller lifters not only have to be the same diameter, but also have to be spaced the correct distance apart as controlled by the bar connecting them. You need to check that before buying anything.

 

Ohhhhhh....good point. See that’s why I love the hamb.

 

The Chevy lifters are the same diameter as the Cadillacs... will the oil passages in the block allow them to interchange?

 

Custom adjustable rockers are nice, but probably not cheap? I few years ago I found that there were still a fair number of Studebaker adjustable rockers around. You put them on the Caddy shafts. You loose a bit of ratio, but that can be recovered when getting the cam ground. Delta did the cam. I also know a few guys that just used adjustable push rods so as not to need dimpled valve covers to clear the adjustable rockers.

 

What about using solid rollers with the oiling hole in them? No experience, other than reading the HAMB

 

If you have an old Chevy lifter laying around, compare it to the Cadillac lifter you have and see if they have any major difference. I don't think oiling will be a major problem if any, but it won't hurt to look at them side by side.

 

Using the Chevy lifter (hydraulic or solid flat tappet) in the Caddy has been the common solution for some time. Just need different push rod length. I have no experience with trying a roller tappet.

 

I don't really have any experience working around roller lifter engines, but now you folks have got me totally bam-boozled. Elcohaulic made a reference to checking for push rod rotation but his post reads like he's describing roller lifters.

Say it ain't so. Tell me I'm not goofy for thinking that there shouldn't be any positive push rod rotation on a roller lifter setup like there would be with a flat tappet cam and lifters. If your roller lifters are rotating and causing the pushrods to also rotate, then you've got some bigger problems ahead of you, right?

 

The Caddy lifter oil holes are exactly where the SBC are.

The adjustable Harlan Sharps run $400-500 depending on if we can get a large enough order.

I have Studebaker rockers but they have a ratio in the 1.4:1 range,where the stock Caddy was roughly 1.6:1. So you buy a hot cam and then by the time you put the Studebaker rockers on it, you are back at stock.

 

I think he was referring to the flat tappet hydraulic cam, to ensure the lifters are spinning in the holes.

 

When I built my Olds 324 I used a cam from Ross with Chev lifters and custom length push rods. Tony had told me that I should use hollow push rods at the ends of the heads and solid in all other places. He said this because using standard hollow push rods everywhere with the Chev lifters would flood the valve train with more oil than is required. Never messed with a Cad but wonder if the Ross rule applies in your case.

 

Schneider says they have the last batch of Cad 365/390 flat tappet blanks

 

Have you talked to Isky or Howard Cams to see if they have any roller lifters that fit? I think the very first thing that needs to be done is to insure you can get a roller lifter that has the correct spacing. If you can't find that, then you won't be able to run a roller cam. I would think that whoever has roller cams for your engine should know where you can find the correct lifters.
Even if you have to run a flat tappet cam, I would get some roller rocker arms and new pushrods. Also new springs and keepers. Little port work on the heads...........

You might post the dimension of what the actual spacing is. Then maybe some Hamber can tell you of another engine that has similar spacing.

 

I have a set of roller lifters for a sbc and an empty Caddy block. I'll experiment this afternoon.

 

An issue you might want consider with Harland Sharpes,is valve cover issues.I have a nasty cad 365 with 390 heads that a friend had built.They went with Adjustable 1.6 rollers ( edited= ) Isky ,which are much less bulky than the HSs, and there is no way they will fit stock covers even with dimples, or my aluminum Hildebrants .They went with spacers and Ford 460 valve covers to clear ,and it runs very strong,but it take away from traditional..

 

Wow, this brings up a couple questions.

Are the 340 Mopar shaft sizes the same?
Harland Sharp says there will be no interference problems. Did they buy a set of HS first?
Could you get specs from your buddy on mods they have made? I am constantly looking for better ideas.

 

Ok, new issue. I tried a set of Howard’s hyd rollers and the spacing it the same, but the Caddy has an overhang in the block that the sbc doesn’t have.

Not sure how tall the OEM rollers are with the valley spider? I’d have to research the heights n all the different mfgs.

 

When GM went to the roller cams in small block Chevy engines they used a bar that has a slot in each end to orient the lifters. Each lifter drops in singularly. Each lifter is flat on the sides. Then the bar with the slots in it slips over the two lifters after they are installed. That type should work for you. Probably cheaper to buy too. The video below is not exactly the same, because the bar has open ends whereas the GM OEM is closed on the ends.

 

What years are we talking for that style of lifter?

 

1987 & up with factory roller cam
(Corvettes & tpi Camaro’s)


Sent from my iPhone using H.A.M.B.

 

Sadly,my buddy has passed away.This motor is pretty serious.If you will notice I edited my first post.They are Isky 1.6.Rockers, 12.5 Venolia pistons ,H- beam Rods ,Heavily reworked 390 heads,welded, ported .2"intake 1.6 exhaust,Solid lift cam,595 lift 262 degrees at 050, 108 lobe center.

 

Something like this?
https://www.summitracing.com/parts/nal-12499225/applications
https://www.hotrod.com/articles/ccrp-0710-chevy-small-block/

 

The retainers you show appear to be for Ford engines. Try something like this.........https://www.jegs.com/i/JEGS+Perform...xtRlkLrFqol6m31oWYfpkpIKFXp0eVqhoC2dMQAvD_BwE

I usually shop Summit, but I think Jegs has some discounts available if you join their mailing list.

You might want to watch this video as it shows the dog bones and the retainer. You would need to find a way to attach the retainer into the Cad. Also shows adding a front cam retainer. Chevy is a little different but some food for thought since I don't know what the older Cad uses to retain the camshaft.

 

You are correct. I grabbed the wrong link. I replaced it with an article from Hot Rod that covers a conversion to a SBC.

The Caddy is just like a SBC, the only difference is the timing chain doesn't share the 3 bolt pattern. A cam button would probably have to be modified.

 

Bump. Still researching.

 

The howards lifter can be relieved for valley pan lip clearance to get them in. That top area is non functional except for the side that has the anti-rotation bars attached. I have some from a SBC that are cut away, probably for weight reduction.

 

I think the OEM GM lifters are the ticket.

 

Do call Jones Cam Designs in NC....

 

This is what the stock 87 up “spider” looks like. It bolts down in the valley and the fingers simply keep pressure on the center of the link plates. I don’t have one here to try but I bet it would be pretty straight forward to adapt to the Cadillac.