How to do a 4.0L cam swap w/o pulling the head - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep Wrangler Forums > TJ Wrangler Technical Forum > How to do a 4.0L cam swap w/o pulling the head

ANOTHER Rockridge4wd Creation!! Spare Tire Carrier Delete ROCKRIDGE4WD Introduces a NEW Jeep Wrangler JK *led* tail Engo winches available at www.rockridge4wd.com! Free shipp

Reply
Unread 05-23-2011, 10:16 PM   #1
TJJP77
Registered User
2002 TJ Wrangler 
 
Join Date: Sep 2005
Location: Somewhere, MI
Posts: 1,810
How to do a 4.0L cam swap w/o pulling the head

OK....here we go...cam removal without pulling the head or the lifters!

I know what you are thinking - it isn't possible, right? Wrong!

Why would you want to do this? First of all, pulling the head is a huge PITA...second of all, my engine only has 12,300 miles on it, and I'm not worried about mixing the cam and lifters as conventional wisdom would have you believe. I've put new lifters on old cams with no issues, so to me the reverse should be true as well - especially if the miles are low.

I'm going to skip some basic steps, so this first picture is just after I removed the fan, fan shroud and radiator. I also had the valve cover off at this point as well.



In this next photo, I lifted the entire grille shell with the condenser attached to it and set it aside. Needless to say, I already had the A/C discharged, so it was fairly easy to just unbolt the lines at the connector block and plug them up.



Naturally the next couple of steps were easy too - they involved removing the belt and the tensioner. I then pulled the crank damper and set it aside.

This picture shows what I did next - I removed all of the rocker arms and spark plugs and pushed them into a cardboard "thing" I made to keep them organized and in order from front to back.



So now we arrive at the point where I'm pretty well committed - no turning back now. Timing cover coming off...



Removing the cam sprocket and chain was the next step and a cinch, so no picture...however, with the sprocket out of the way we now have access to the main oil gallery. Here's a shot of me pointing at the hole and "special tool" I had to use to get it out. It's a square drive, but it's not 1/4" or 3/8", so we made do with what we had.



So here's where it gets tricky - I'm ready to insert the dowel into the oil gallery/rifle bore, but the 3/8" dowel I bought (as recommended by the guy who told me about this trick) was way too big. We ended up using a 5/16" dowel and even that was a snug fit.

The guy who told me about this trick also told me that all you needed to do was rotate the cam and push the dowel in under each lifter as the cam lifted it.....ummm, yeah...not so much. I'm not sure if he was intending to support the lifters via the chamfer cut into the lifter body that allows oil to feed into the center of the lifter. We tried an even smaller dowel (I want to say 1/4") but it pushed right in with no resistance, so I wasn't getting a warm fuzzy feeling about supporting the lifters via the chamfer.

The safer play was getting the lifter up high enough to slide the dowel underneath of the lifter foot, so there was no way for it to fall into the oil pan with the cam out. Here's what it looks like with the dowel all the way in:



It took a lot to arrive at this point - I won't lie. We had to manually (and carefully!) lift each lifter up out of it's bore with a small hook fabricated from some welding wire. It's not easy, but you can engage the inside groove cut into the lifter that the circlip snaps into. Google a hydraulic lifter exploded view if you can't visualize what I'm saying since I can't think of another way to describe it.

When lifting the lifters up, you have to be really careful - if you lift too high, the lifter can come out of it's bore and flop over on it's side....we actually has this happen to us on the 3rd or 4th lifter from the front, and somehow my buddy helping me managed to tip it back upright and get it back in it's bore - don't ask me how he did it through that tiny pushrod hole, but he's my hero!

So now we arrive at the moment of truth - sliding the cam out and praying that we don't hear the sound of lifters falling into the pan!

In this picture you'll also see the clever cam "handle" fabricated by the guy who has done this before. it really helps to stabilize the long (and heavy!) cam as you slide it out:



In this next shot, the cam is almost all the way out:



We decided to take a shot down the cam bore so you can see that the lifters are all clear of the cam:



Pretty cool that you can see all the way to the back of the block - look Ma! No lifters!

The good news was that other than the OPDA drive gear in the cam, there was no unusual lobe wear of any kind on the cam...so, the logical extension of that is that the lifters should be fine too. Heck, with 12,300 miles on it, one would hope so!

So, now it was time to put the new cam in. I lubed up the journals with some lubriplate since they get direct feed pressurized oil, so I wasn't worried about stress on these surfaces.

A few weeks before I decided to embark on this project, I stumbled across a cam lube from the same company that makes the ZDDP additive. They have all sorts of pictures and charts on their website comparing their product against other cam lubes that seemed pretty convincing, so I decided to give it a whirl.

The upside is that this stuff is nice and thick, so it definitely stays in place, unlike some of the other lubes that are more like a thick gear oil:



So, now the cam is in and I've installed the thrust plate to make sure it isn't going anywhere when I slide the dowel out:



Now it was time to slide the dowel back out - note that I had the pushrods sitting in their respective lifters so I could watch each one drop as the dowel slid out:



Note the height of the pushrods towards the front vs. the ones at the rear....

As you do this, you'll hear each lifter drop down onto the cam - a satisfying "click" lets you know all is going well.

So from here on out, there are no pics - it's pretty much just put everything back that you tore off to get this far. Some tips along the way:

- Don't guess about how tight stuff should be - use a good torque wrench and follow the specs in the manual.

- Remember to put some thread sealant on the gallery plug before installing it

- Use RTV at the joint where the block meets the oil pan to ensure the front cover seals properly

- Make sure to install a new OPDA gear to mesh with your new cam - don't want to ruin all that work!

- Put some break-in concentrate in the oil to ensure the cam breaks in properly

- After buttoning everything up, adding coolant etc - get ready to fire the engine up - you're almost done!

- Fire the engine up and try to keep it above 2000 RPM for 20 minutes or so. Have an assistant listen for any noises and look for leaks

After the break in, make sure all your fluid levels are OK and enjoy your freshly repaired Jeep. Chances are you will have a code for cam/crank sync (P0016) - ideally you need to have access to a DRBIII service tool to properly set the cam/crank variance and initiate the relearn procedure. A dealer can do this for you, for a fee of course.

Next steps: sometime in the next few weeks I'm going to have the A/C recharged and I'll pop the OPDA out again to see how things are looking...I'm keeping my fingers crossed!

__________________
Chris
'02 Sahara
'06 Rubicon Unlimited
Sienna Jeep Club: Member #15
TJJP77 is offline   Reply With Quote Quick reply to this message
Unread 05-23-2011, 10:29 PM   #2
5-90
Registered User
1988 XJ Cherokee 
 
Join Date: Sep 2006
Location: San Jose, CA, Hammerspace
Posts: 5,344
Sounds about like what I'd try to do - but rather than using welding wire, I've got a long-shaft cabinet screwdriver that I bent a small hook into the end of as a "llifter puller" - been using it for years. I think it's long enough to reach through the head down the pushrod bores. (I think AMC missed their bet on not making the pushrod bores big enough to get tappets out through - it wouldn't have been that much more work, and I can't really see the coolant jacket being big enough to get punctured by about a 1-1/8" bore there. But, I haven't tried it yet.)

Using new tappets on an old cam isn't a problem - but using old tappets on a new cam very well can be! I've known a few cams to get worn beyond use in short order from using old tappets on them (or from mixing tappets & lobes,) so I'd appreciate it if you were to report back in three to six months on how your cam held up with the used tappets on it... Say, November or December?
__________________
"recon" (sic - reckon)(tm) "hihgly"(tm) "seceed"(tm)
"Outback AIDS - Alcohol-Induced Dizzy Spells"
5-90 is offline   Reply With Quote Quick reply to this message
Unread 05-23-2011, 10:36 PM   #3
TJJP77
Registered User
2002 TJ Wrangler 
 
Join Date: Sep 2005
Location: Somewhere, MI
Posts: 1,810
Quote:
Originally Posted by 5-90 View Post
Sounds about like what I'd try to do - but rather than using welding wire, I've got a long-shaft cabinet screwdriver that I bent a small hook into the end of as a "llifter puller" - been using it for years. I think it's long enough to reach through the head down the pushrod bores. (I think AMC missed their bet on not making the pushrod bores big enough to get tappets out through - it wouldn't have been that much more work, and I can't really see the coolant jacket being big enough to get punctured by about a 1-1/8" bore there. But, I haven't tried it yet.)

Using new tappets on an old cam isn't a problem - but using old tappets on a new cam very well can be! I've known a few cams to get worn beyond use in short order from using old tappets on them (or from mixing tappets & lobes,) so I'd appreciate it if you were to report back in three to six months on how your cam held up with the used tappets on it... Say, November or December?
The AMC heads used to have big enough voids to pull the lifters, but for some unexplainable reason they made the holes smaller!

As far as reporting back in, sure - the issue is though that I have no way of actually getting a good look at any of the lifters or lobes, so it'll be hard to give an objective opinion. Let's just say the the guy who explained this trick to me has hundreds of engine hours on a 4.0L with the same set of lifters riding on dozens of different cams (and each cam had enough run time to show any issues) with no ill effects. He was the one who conviced me that with only 12K miles on my engine I should just go for it and not worry about it.
__________________
Chris
'02 Sahara
'06 Rubicon Unlimited
Sienna Jeep Club: Member #15
TJJP77 is offline   Reply With Quote Quick reply to this message
Unread 05-23-2011, 11:18 PM   #4
justanotherjpr
Registered User
 
Join Date: Nov 2007
Posts: 6,337
Thanks for posting this! May I ask why you changed the cam?
__________________
Quote:
Originally Posted by Motorcharge View Post
So do you actually hear your thoughts in your head or is it just sort of a dull roar before you smash your face into your keyboard and just submit whatever dumb **** ended up on the page?
justanotherjpr is offline   Reply With Quote Quick reply to this message
Unread 05-23-2011, 11:39 PM   #5
Tinga
Registered User
2002 TJ Wrangler 
 
Join Date: Mar 2010
Location: Oregon
Posts: 1,330
Quote:
Originally Posted by justanotherjpr View Post
Thanks for posting this! May I ask why you changed the cam?
I have the same question. The cam/litters are like......peanut butter and jelly. If you need to replace the cam... And not the litters.. Something seems off.
After market springs wearing on the cam lobes? How did you figure you needed a new cam?
__________________
Girls like STROKIN too!
[COLOR="Magenta"]http://www.jeepforum.com/forum/f153/1971-jeepster-commando-1380633/[/COLOR]
Tinga is offline   Reply With Quote Quick reply to this message
Unread 05-23-2011, 11:56 PM   #6
DallastheJeeper
Senior Member
 
DallastheJeeper's Avatar
2006 LJ Wrangler 
 
Join Date: Jun 2010
Location: Viroqua, Wisconsin
Posts: 687
Why a new cam at 12k?
__________________
__________________
|^^^^^^^^^^^^^^^\ ||__
|.......PBR BEER TRUCK.... ||""\_____\
|____________________/||__/----|
|(@)(@)"""""""""""|(@) (@)***|(@)

#5-06 Salvage Rebuild LJ
Metalcloak Bumper, Overline fenders and Corner guards.
3.5" Sus Lift
1'' Body lift and engine lift

#4-98 TJ Sahara RIP :(
#3-42 GPW Project. Currently on hold Sand blasted the body and it was held together by screen and bondo so new Tub needed
#2-88 Comanche Currently getting a frame off rebuild and a 4bt.
#1-1994 Power Wheels Wrangler
DallastheJeeper is offline   Reply With Quote Quick reply to this message
Unread 05-24-2011, 12:28 AM   #7
Jtrux
Registered User
2006 LJ Wrangler 
 
Join Date: Jan 2009
Location: TX
Posts: 531
You mentioned no unusual wear on the cam...soooo why a new one?
__________________
Woogity boogity
Jtrux is offline   Reply With Quote Quick reply to this message
Unread 05-24-2011, 01:46 AM   #8
5-90
Registered User
1988 XJ Cherokee 
 
Join Date: Sep 2006
Location: San Jose, CA, Hammerspace
Posts: 5,344
Quote:
Originally Posted by TJJP77 View Post
The AMC heads used to have big enough voids to pull the lifters, but for some unexplainable reason they made the holes smaller!

As far as reporting back in, sure - the issue is though that I have no way of actually getting a good look at any of the lifters or lobes, so it'll be hard to give an objective opinion. Let's just say the the guy who explained this trick to me has hundreds of engine hours on a 4.0L with the same set of lifters riding on dozens of different cams (and each cam had enough run time to show any issues) with no ill effects. He was the one who conviced me that with only 12K miles on my engine I should just go for it and not worry about it.
Hm. Interesting. I've done postmortem FA on engines that have had tappets mixed, or had used tappets on a new cam, and the cam lobes had failed in short order.

AMC also used to have side access plates (as well as most other inline sixes, for that matter) for tappet access - you'd remove the valve cover to pull the pushrods, then pull the side plate to remove the tappets. Problem solved.

The only conceivable reason I could thing of to delete the side plates would be to support a cross-draught head (most inlines are side-draught,) but that would be complemented by a pushrod bore large enough to pass a tappet (most are just under 1.000" - so 1.125" should be plenty.)
__________________
"recon" (sic - reckon)(tm) "hihgly"(tm) "seceed"(tm)
"Outback AIDS - Alcohol-Induced Dizzy Spells"
5-90 is offline   Reply With Quote Quick reply to this message
Unread 05-24-2011, 04:53 AM   #9
TJJP77
Registered User
2002 TJ Wrangler 
 
Join Date: Sep 2005
Location: Somewhere, MI
Posts: 1,810
Quote:
Originally Posted by justanotherjpr View Post
Thanks for posting this! May I ask why you changed the cam?
Quote:
Originally Posted by DallastheJeeper View Post
Why a new cam at 12k?
Go read the main OPDA thread. The gear on the cam that drives the Oil Pump Drive Assembly (OPDA) can become worn by a faulty driven gear on the OPDA. Once the outer hardened layer of the gear on the cam is compromised, the gear wears fairly rapidly.

Quote:
Originally Posted by Jtrux View Post
You mentioned no unusual wear on the cam...soooo why a new one?
If you re-read that, I said no unusual wear other than the gear on the cam. All the lobes were showing a normal, expected polished spot where the cam and lifter mated.
__________________
Chris
'02 Sahara
'06 Rubicon Unlimited
Sienna Jeep Club: Member #15
TJJP77 is offline   Reply With Quote Quick reply to this message
Unread 05-24-2011, 05:06 AM   #10
TJJP77
Registered User
2002 TJ Wrangler 
 
Join Date: Sep 2005
Location: Somewhere, MI
Posts: 1,810
Quote:
Originally Posted by 5-90 View Post
Hm. Interesting. I've done postmortem FA on engines that have had tappets mixed, or had used tappets on a new cam, and the cam lobes had failed in short order.

AMC also used to have side access plates (as well as most other inline sixes, for that matter) for tappet access - you'd remove the valve cover to pull the pushrods, then pull the side plate to remove the tappets. Problem solved.

The only conceivable reason I could thing of to delete the side plates would be to support a cross-draught head (most inlines are side-draught,) but that would be complemented by a pushrod bore large enough to pass a tappet (most are just under 1.000" - so 1.125" should be plenty.)
I'm not talking about the old side covers that allowed access to the tappets so they could be replaced/adjusted on solid-tappet motors. The old 4.2L (and possibly early 4.0L engines) used to have some larger pushrod voids when viewed from top view of the head. I'm not sure what year they changed this or if it came in with the 4.0L. Also, I don't think every void was large enough to pull each lifter straight up - you may have had to push certain lifters over to another space to lift them up - kinda like a Ford FE big block.

Back to the cam/lifter mating issue: I'm sure engines with high-performance valve springs (i.e. not our engines) probably would be a much higher risk of unusual wear. The guys I spoke to have literally several lifetimes worth of engine testing, teardown, inspection and evaluation experience and have personally run new cams on old lifters while performing a specific wear tests for hundreds of engine hours. They even joked and said I'd collapse a piston skirt from normal high-mileage wear/clearance before the cam/lifters would fail from wear.
__________________
Chris
'02 Sahara
'06 Rubicon Unlimited
Sienna Jeep Club: Member #15
TJJP77 is offline   Reply With Quote Quick reply to this message
Unread 05-24-2011, 01:16 PM   #11
Robert J. yates
Registered User
1998 TJ Wrangler 
 
Join Date: Jan 2003
Location: mars
Posts: 3,011
Nice trick... although why you didn't bump up to a performance cam, springs and lifters while you were in there is beyond me. A cam swap is about the only way to actually improve HP and TQ in a late model 4.0.
__________________
Quote:
Originally Posted by samgm2 View Post
And yes, I am an exceptional scientist and engineer.
Robert J. yates is offline   Reply With Quote Quick reply to this message
Unread 05-24-2011, 02:19 PM   #12
chris142
Registered User
2002 TJ Wrangler 
 
Join Date: Jul 2010
Location: Apple Valley,Ca
Posts: 2,754
Will be interesting to see how long the new cam lives with used lifters. Every book out there tells you to replace the lifters when installing a new cam or the old lifters will eat the new cam.

You may not think that 12k is much for the cam and lifters but they are considered broken in to each other after 20 minutes of run time.

Keep us posted on how it does.
chris142 is offline   Reply With Quote Quick reply to this message
Unread 05-24-2011, 06:47 PM   #13
TJJP77
Registered User
2002 TJ Wrangler 
 
Join Date: Sep 2005
Location: Somewhere, MI
Posts: 1,810
Quote:
Originally Posted by Robert J. yates View Post
Nice trick... although why you didn't bump up to a performance cam, springs and lifters while you were in there is beyond me. A cam swap is about the only way to actually improve HP and TQ in a late model 4.0.
Here's why:

Every cam I found, even the mild ones called for high performance springs (along with machining the head to ensure correct installed height). They also called for new valves with single-groove valve keepers. All of that of course means removing the head and increasing the cost of the repair substantially.

It also seems that most (but not all) of the aftermarket cams use the older cam retention system with a button and spring. My front cover does not have the locating "bump" on the inside of the cover, so I would have had to source a new one to make it work - more cost.

Depending on the cam, it may have even required new injectors to take advantage of the change - even more cost.

The bottom line is that I was perfectly happy with the power my stock 4.0L makes and I have around $350 into this repair. That's a win-win in my book.
__________________
Chris
'02 Sahara
'06 Rubicon Unlimited
Sienna Jeep Club: Member #15
TJJP77 is offline   Reply With Quote Quick reply to this message
Unread 05-24-2011, 06:53 PM   #14
TJJP77
Registered User
2002 TJ Wrangler 
 
Join Date: Sep 2005
Location: Somewhere, MI
Posts: 1,810
Quote:
Originally Posted by chris142 View Post
Will be interesting to see how long the new cam lives with used lifters. Every book out there tells you to replace the lifters when installing a new cam or the old lifters will eat the new cam.

You may not think that 12k is much for the cam and lifters but they are considered broken in to each other after 20 minutes of run time.

Keep us posted on how it does.
I appreciate the concern, but I'll say it again: several knowledgeable people I spoke to who do engine build-up, testing, tear down and evaluation told me they have re-used lifters on new cams and put hundreds of hours on the engines (well beyond your stated break in time) with no ill unusual wear or damage.

Post script: I saw these same guys today when I returned a tool I borrowed and told them about the wear concerns brought up here on the forum - they literally laughed about all the worry and hand wringing!
__________________
Chris
'02 Sahara
'06 Rubicon Unlimited
Sienna Jeep Club: Member #15
TJJP77 is offline   Reply With Quote Quick reply to this message
Unread 05-24-2011, 06:55 PM   #15
grogie
M-F: Cell Block #4533
 
grogie's Avatar
2006 TJ Wrangler 
 
Join Date: Nov 2005
Location: Indy
Posts: 7,396
I'd never attempt this on my own, but very cool!
__________________

Red Jeep Club #345
2006 TJ Sport
2004 KJ Limited
2013 Off-Road Trailer

grogie is offline   Reply With Quote Quick reply to this message
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.
Note: All free e-mails have been banned due to mis-use. (Yahoo, Gmail, Hotmail, etc.)
Don't have a non-free e-mail address? Click here for a solution: Manual Account Creation
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.


Thread Tools


Suggested Threads





Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.