Cam replacement, hypothetically...

powerband

powerband

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Would it be possible to change out a cam without removing head?

Before I get the more reasonable- "OF COURSE TAKE OFF THE HEAD..." answers ,
work with me:

> Engine is on sturdy rotating stand.

> rockers removed to access lifters (trapped in lifter galleys).

> Balancer, front cover, etc, removed for access.

> Engine is inverted and lifters are coaxed (upside down) to top of block bore travel.

> Cam is removed and replaced.
>
> Engine is turned upright, lifters seat against cam and engine re-assembled.

This would not allow replacement of lifters which is a considered necessary, but I wonder if I missed anything that would prevent the idea.

Powerband
 
8)

You want to replace the lifters because flat tappet lifters are slightly curved outward on bottom. After many miles the bottom wears into a cam and become matched to that cam.

Installing old lifters in wrong hole, or using old lifters on new cam can cause major problems with wear on hte cam lobes.

You can use new lifters on a old cam but I would not use old lifters on a new cam.

I could be wrong but I think it would cause excessive cam wear.

But yes your idea seems sound, assuming no lifters are varnished into the bore and dont want to drop.
 
8) when changing a cam you always change lifters, otherwise you run the extremely high risk of wiping a lobe or two off the new cam, and having to do the job again. do your self a big favor and remove the head.
 
I would pull the head. if you drop even one lifter in the valley you are screwed. also if it is a higher milage or original motor I would guess that there is some varnish on the lifter bores that will keep them from coming out of the block without some help from below. you will also need a means to hold the lifters in place with the motor inverted or else they all dump in the lifter valley area (been there done that not wanting to do it again)

if the motor is going to be out of the car why not pull the head and pan? not even an hours extra work and you can R&R the bottom end too.
 
powerband":1oqu99j7 said:
Would it be possible to change out a cam without removing head?
This would not allow replacement of lifters which is a considered necessary, but I wonder if I missed anything that would prevent the idea.

Powerband
Click to expand...

Okay, Okay I know the lifters should be replaced as I said in my original post... :roll: Here's the poop:

I built a "high performance" (250) head with the best of the Schjeldahl bros' suggestions and a few of my machinist's. To test it I put it on a low miles (@50K) '71 Maverick 170 block with a steel shim HG running 10.5:1 CR (with new HiPO lifters). I ran it for a short time (few hundred miles) in my '61 Comet until satisfied (it worked great as built) and then removed the engine.

My daily driver is a '63 Wagon with the original tired six. For the price of a performance cam alone, it would be a neat experiment to put the "biggest" cam available in the Mav 170 with the built head and see how it performs. It's not worth (for me) to build up the 170 and I don't want to disturb the steel shim head gasket seal and also risk needing additional milling (for flatness) until I decide where the head will wind up.

Any cam suggestions for the Mav170/ HP 10.5:1CR head/ Standard tranny / experiment? :shock:

GARAGE3MOTORSWEB.jpg


Powerband
YEEHA_WEB.jpg
 
falcon60":33b6c776 said:
I like experiments like this. :eek: I'd try this cam if it were me.....

http://www.classicinlines.com/proddetai ... 2DHSP%2D10

Terry
Click to expand...

I am using a 272H Clifford cam in the 250 at @ 10:1 with 1.88 intakes.

I am leaning towards a radical cam trial, maybe someting like this:
http://www.classicinlines.com/proddetai ... 2DHHS%2D09

Anyone worked a 200 with one of the more radical cams like the FSP "CSC-280 (109*) Hydraulic High Intensity Camshaft"?.

Thanks
Powerband 8)
 
in that case....

I would make up some 1/2" or so shorter pushrods (just some cheap rounds stock or similar. Drill the ends to wre them to the rocker shaft so when the motor is inverted they can drop down "a little" as needed. they will prob need a love tap past the varnish. with the pan off it can be done...


I do have a spare metal shim gasket for a 170 IF you were interested..
 
The steel shim gasket for the 144 & 170 isn't worth "protecting" -- there are plenty of them floating around out there. The $20 or so you'd save would be lost in extra labor, and the potential for issues isn't something I'd care to think about.
 
SixFoFalcon":1z6v3zit said:
The steel shim gasket for the 144 & 170 isn't worth "protecting" -- there are plenty of them floating around out there. The $20 or so you'd save would be lost in extra labor, and the potential for issues isn't something I'd care to think about.
Click to expand...

Sorry I not two cleaer talkin :)

I meant I don't want to disturb the seal and head. The Head is milled to the max already, and for proper seal I like a fresh milled surface. The removal/replacement cycle can produce slight inconsistencies that can show up in high compression/ metal shim situations.

YOu're absolutely corresct, I have a number of small bore steel shim gaskets on hand. I only wish the big bore - 200/250 gaskets were so available...

Thanks for all the input, this harebrained idea is still hypothetical so I'm lookin' for the why/why not 's

Powerband 8)

100_2001.jpg
 
Gotcha--I overlooked that in your last post. ;) Seems like a valid concern. I also didn't think about the added cost of the lifters themselves. If they are *that* new, I have to wonder if they are in need of replacement w/ a cam swap.

What kind of rockers are you running? Maybe get some high ratio rockers and see how far that gets you with the existing cam? In the end, you'll at least be able to re-use the rockers on a future build. But you'd also have to do some careful calculation about valve to piston clearances, since you're running such a high compression ratio. Sorry, I'm probably not helping! :roll:

My current dilemma is what to do with a fresh rebuilt head I found. It's a D5 that would kill my CR if I used it as-is. The CCs are about 60cc. Do I have it milled again, or sell it to someone interested in forced induction? Such a pity the machinist couldn't have skimmed it down another .050 or so while they had it. :(
 
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This is from a post that I replied to from about a year ago. It was asking if you could replace lifters without removing the cylinder head. I have changed the cam in my ranchero numerous times (land speed racing) I've done it with the engine in the chassis (remove the bumper etc.) on my back, (no fun) and I've also done it removing the engine. In my opinion it is easier removing the engine. Thats my 2 cents worth, Paul.
Yes you can, I've done it. Pull the engine from the chassis, stand it
up on it's back, remove the oil pan, valve cover and rocker arm, shaft.
Push the lifter up from the bottom just enough to clear the cam, remove
the cam, push the lifters down from the top, using the pushrods.
Install the new lifters from the bottom, reinstall the cam etc. etc.
Hope this helps. Paul
 
rancheroman":q0pksyjy said:
--------------------------------------------------------------------------------
This is from a post that I replied to from about a year ago. It was asking if you could replace lifters without removing the cylinder head. I have changed the cam in my ranchero numerous times (land speed racing) I've done it with the engine in the chassis (remove the bumper etc.) on my back, (no fun) and I've also done it removing the engine. In my opinion it is easier removing the engine. Thats my 2 cents worth, Paul.
Yes you can, I've done it. Pull the engine from the chassis, stand it
up on it's back, remove the oil pan, valve cover and rocker arm, shaft.
Push the lifter up from the bottom just enough to clear the cam, remove
the cam, push the lifters down from the top, using the pushrods.
Install the new lifters from the bottom, reinstall the cam etc. etc.
Hope this helps. Paul
Click to expand...

:shock: Wouldn't ya' know somebody comes up with :

"Been there done that"

But even better - detailed "How To"...

That's great detailed info. I thank you for sharing it. I didn't consider the - "push the lifters down from the top, using the pushrods. Install the new lifters from the bottom," - that's a possible option.

Powerband
GARAGE3MOTORSWEB.jpg
 
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