58 Cad - No compression

[Dr.Feelgood]

Hi all,
The 365ci in the 58 has no compression. I have the rocker arm torqued to the specified 35ftlb, the valve gears are aligned correctly, It has new rings and lifters and all the rods are the same length. When I loosen the rocker arm, it gets great compression! I heard that its possible when I soaked the new lifters in oil, the oil got inside and is not letting them compress?
Any thoughts or advice is appreciated!

[travlinman]

I'm not familuar? with a 365, but Everybody I know pre soaks the lifters in oil and it's never caused a problem. If it has adjustable rocker arms, just tighten Them until it stops clacking. If They are non adjustable, maybe the new lifters are too tall. Some Caddy and Chevy lifters are the same on the outside, but the preload/travel inside is different. Just throwing shit out there till Somebody that knows something comes along. Good luck.

[Dr.Feelgood]

Thank you, Thats what my neighbor said too, the lifters could be different inside, they didnt look adjustable to me though. Then again Ive never changed lifters before...

[Dickey]

They aren't adjustable per se, just hydraulic. Their springed pushrod dimple moves around until oil pressure keeps it ridgid. How do the old lifters compare to the new ones when placed side by side?

[Dr.Feelgood]

I threw out the old ones 3 months ago, but as I recall, they were the same inside and out. Ive cleaned the oil out and re installed them, still little to no compression. I'm looking into the possibility of rocker shims.

[travlinman]

Shimming Them will work as a band aid. You can not tell how much the plunger travels by looking at it. Only way is with a dial indicator. The Chevy vrs Caddys travel if I remember was around .050. Since You didn't pull the heads, used the same pushrods, the same cam, only difference has to be the lifter plunger travel. These just aren't going down far enough. On the hot rods We were always changing the push rod length. In this case, shorter ones. If Your on compression stroke, both valves closed, and the pushrod is bottomed out in the lifter holding the valves open, what else can it do but leak?

[A.Sharpe]

The rockers should be adjustable. Tighten the rockers with the pushrods in the down position one at a time( you will have to turn the engine for each rocker) leave it slightly loose. (You should be able to rattle the rocker slightly) The engin should start .(Its gonna rattle and run rough) One at a time tighten the rockers until they are quiet. Now one at a time loosen the rocker until it rattles then retighten until it is quiet. I could be wrong but I think the 35lb torq is for the rocker stud to head torq. Just a note your gonna take an oil bath.

[A.Sharpe]

Here's a link that might help.

http://www.centuryperformance.com/adjusting-valve-lash-spg-149.html

[Dr.Feelgood]

Thanks, I'll look into that! and yea, I took an unintentional oil bath yesterday... dripped all down the freshlypainted engine...

[Dickey]

The rockers should be adjustable. Tighten the rockers with the pushrods in the down position one at a time( you will have to turn the engine for each rocker) leave it slightly loose. (You should be able to rattle the rocker slightly) The engin should start .(Its gonna rattle and run rough) One at a time tighten the rockers until they are quiet. Now one at a time loosen the rocker until it rattles then retighten until it is quiet. I could be wrong but I think the 35lb torq is for the rocker stud to head torq. Just a note your gonna take an oil bath.

Out of curiousity how would you go about adjusting these individually?




Arguably, this is a 390 and I haven't actually worked on a 365, but I'm pretty sure the family is similar in regards to the valve train configuration. The issue at hand is either the plunger in the lifter as stated or the pushrods are not correct. Dr, you need to measure one of them to know what length they are. They should be 9.600".

Incidentally, you have now learned why older gear heads tend to keep a bunch of old, seemingly useless parts around on their shelves in the garage. Never throw out old parts until you're finished with whatever it went to. All of us learn this lesson in the manner that you have described, hehe.


edit - from your first post I gathered that you had all new rings, lifters and pushrods which you confirmed were the same length. I just realized in later posts there was an assumption that you kept the original pushrods. Which is correct? If you're using the same pushrods as you had, your issue is that someone sold you the wrong lifters. Not a big deal, just order a correct set from a company that specializes in old Caddy parts.

[Dr.Feelgood]

Correct Dickey, 331, 365 and 390 all look like your picture, I assumed by tightening individually meant to adjust each one until its just tight enough at exhaust stroke right?

and Yes, I kept the original rods, they are all same size, none were bent. we had thought they were the wrong lifters too but when I took them apart, as I recall they were exact... spring tension inside the lifter could be off I suppose. I dunno...

[Dickey]

Which is what I was getting at. So far as I could tell when I was digging around in my engine, all of the rockers reside on the same shaft so they cannot be adjusted invididually without using shim caps of some kind on the tops of the valves themselves.

I suspect, though I do not wish to speak for them, what others have done in this thread is assume that the 365 family of Cadillac engines is like the SBC and BBC engine families (among others) where by each rocker resides on its own perch and can be adjusted individually by tightening the nut that holds it to the perch.

Like this:



In your particular case, since you haven't held the new lifters next to the old lifters, making a determination from memory as to whether or not one is a few thousandths of an inch different from the other is not feasible.

Upon further consideration, how worn are your valve springs? A simple spring tension check should let you know if they are within spec. I only ask on the off chance that your springs are so badly worn that they cannot override the last several thousandths or so of static tension in the lifters themselves. If it is a simple tension issue, you can temporarily correct the trouble by shimming the springs (not the rockers) from the head to compress them a bit more. That is not a permanent solution by any stretch of the word, just a diagnostic technique to avoid purchasing parts without knowing what the problem really is.

[travlinman]

By any chance did You have the heads reworked?

[Dickey]

By any chance did You have the heads reworked?

Oooh, good catch. I hadn't considered that.

[A.Sharpe]

Ok I stand corrected. Once a year I get to screw up I just didn't want to do it this early in the year.