New Cam with Head Gasket Change?

Levi

Well-known member
Jul 27, 2004
559
26
Cheyenne, WY
I'm getting ready for my first head gasket change @172k. I have low power and cylinders #1 and #3 only have 80 psi compression. I have the kit and heads ready to go but have been reading and wondering if it is a mistake not to put in a new cam while everything is apart. Do the cams really wear that bad in these trucks? I'm trying to be cheap because of my current situation but don't want to cheap out if it's a stupid mistake. I was looking at a 4.6 cam if I do it. Any trouble with this? I searched and came up with mixed opinions.
 

squirt

Well-known member
Nov 13, 2008
824
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Los Angeles
Measure your lift for wear, and see if it's out of spec before you start the job. If not, I'd leave it. Some cams do wear (including my own), but I'd skip it if you're not seeing any indication of a problem. You can spend that money on the things that will go wrong or break.
 

p m

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Apr 19, 2004
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Stu - seriously?

There's a big difference between a head gasket job and that with the cam.
With a fresh pair of heads and all gaskets at hand, one can start and finish the HG job in a day.

To replace the camshaft, you'll need to remove the radiator, harmonic balancer/crankshaft pulley, and front cover (for which you may have to remove the oil pan, for which ...). As you're in it, you might as well replace the oil pump and water pump. If the oil pan is off, you might as well replace the rod bearings.

I wanted to do the "full job" at 250kmi, but my camshaft and related gear arrived about a month later than expected - by which time I buttoned everything up.
In process, I found that all rod bearings showed bronze - but none of rod journals were worn out enough to warrant anything but bearing replacement. The camshaft lobes were down from their nominal height, but none were flat, and none exhibited any abnormal wear pattern. That is on a SoCal engine that may have only seen ~100 cold starts in its life, so YMMV.

Decide for yourself; a cam replacement will likely double your down time, and you need to be sure you know how to break in a camshaft.
 

p m

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Don't forget the lifters!!
That, too - and pushrods.
I've been told by an authority that I should never, repeat never, use new lifters with an old cam.
About four of mine had abnormal wear or pitting, so I replaced them with new.
I've been then told that I'll wipe out the cam in a day. It's still there, 25kmi later. Same goes for rod bearings.
 

BackInA88

Well-known member
Dec 6, 2007
392
1
Troy, Michigan
That, too - and pushrods.
I've been told by an authority that I should never, repeat never, use new lifters with an old cam.
About four of mine had abnormal wear or pitting, so I replaced them with new.
I've been then told that I'll wipe out the cam in a day. It's still there, 25kmi later. Same goes for rod bearings.

I always heard don't ever use OLD lifters on a new cam.
I have used new lifters on an old cam and haven't had a problem either.
 

PhD_Polymath

Well-known member
Feb 6, 2015
104
1
Slightly west of Boston
If there is no wear on the cam, I would probably leave it. I have had three brand new camshafts wipe on me (flattened lobe(s)). There are a few things to keep in mind if you decide to replace.

1.) New cams require new lifters (at least). New pushrods would also be nice, but I haven't seen huge problems with reusing pushrods, as long as they are not warped. Roll the rods on a flat surface to check them for bends. Also, it is best to put the pushrods back with the same lifter and rocker arm, as they wear together. This wear pattern is probably not the same as the lifter and cam lobe, but unique nonetheless.

2.) For the love of all that is holy, make sure a new cam and lifters are broken in properly. Absolutely smother the cam and lifters in the most tenacious cam lube money can buy during assembly. Gibbs racing makes a superb assembly lube for this. It is the same lube Mark at D&D provides with his camshafts (he is the original "performance" camshaft supplier for Rover V8s in the U.S.A., and takes Buick Crower cams and modifies them to work with Rover timing sets, etc.).

3.) Add a bottle of ZDDP camshaft break-in additive to your oil for the break in (and if you are like me, every oil change). ZDDP is zinc dialkyl dithiophosphate. This compound is an anti-wear additive that provides a "cushion" at the interface of metal parts like the lifter face and cam lobe contact point and prevents your engine destroying itself in spectacular fashion immediately upon start up with a new cam. Note: Rotella T used to have a sufficient amount of ZDDP, but like most other oils, has lowered the amount to comply with emissions regulations. Some fancy racing oils have good amounts of ZDDP, but I would pick something like Brad Penn 30W break-in oil (or something equivalent) and add the ZDDP additive to that.

4.) Do not let the engine crank and crank before starting the first time with a new cam. This also means do not turn the engine more than necessary during assembly, as you will just be wiping off the break-in lube from the cam with the lifters. This will result in metal-on-metal wear and is akin to throwing money in the toilet.

5.) Upon starting the engine the first time, IMMEDIATELY! bring the engine to around 2000 RPM. Slowly fluctuate the revs from 2000-3000 RPM, stopping for a few seconds at 250 RPM increments or so. Do this for no less than 30 minutes (some say 20 is okay, but why not just keep it going for 30, like so many experienced engine builders recommend?). Keep an eye on the temperature with an OBD2 scanner if possible and have someone else watch for leaks and top off coolant while you keep the RPMs up. The reason the engine has to be revved like this is because, in addition to the oiling of the cam and lifters from the oil galleries that supply the rockers from the shafts and the lifter bores, the cam also receives oil slung from the crankshaft. If the engine drops below 1500 RPMs during this initial break-in, a fair amount of oiling is being missed out on and the results can be a flattened lobe in that first 20-30 minutes. If for some reason, the engine has to be shut down due to temperature, leaks, etc., just shut it off and take care of the issue. Once restarted, pick up where you left off. Also, do not just tie the throttle at one high RPM. The RPMs must be varied in the 2000-3000 range during the break-in.

6.) Once the cam and lifters are broken-in, let the engine cool off and change the oil and filter. I always use non-synthetic oil and would certainly recommend sticking with dino oil. At least during the break-in you don't want to use synthetics. Be sure to throw in a bottle of ZDDP additive.

7.) After 500 miles, change the oil again. After this change, you can go to a standard 3000 mile oil change interval if you want. Keep using either an oil formulated with sufficient ZDDP or adding a bottle of ZDDP additive each time.

Notes: I know some people get away with not following these directions and have no problems. I consider them lucky. The cost of a new cam going south on you can mean a complete engine overhaul, as the metal from flattened cam lobes can ruin your bearings, along with crankshaft and connecting rod journals. Yes, you may get lucky and it all gets caught by the oil filter. Maybe you will not. For just a few more dollars, you can lower your risk for such a costly outcome. Also, I know oil is a source of great contention. My advise is to use non-synthetic with a ZDDP additive. For the break-in, if you do not do the rev thing, you are playing with fire. I don't personally know anyone who has gotten away with this. I have, however, seen many cases of 15 minute old engines destroyed by just letting them idle along upon starting. New engines are not bothered by this, as they have roller valve trains or overhead cams.

Good luck either way you go and I hope you have the engine sorted and back to being full of character soon!
 

Levi

Well-known member
Jul 27, 2004
559
26
Cheyenne, WY
Thanks for the replies! I didn't realize the can of worms this would open as far as while you're that far into it you may as well... I figured on lifters, gears, and a chain but didn't think beyond that. At what point would one be better off just pulling the engine and doing a rebuild? I think for now I'm going to plan on checking it for wear and just doing the head gaskets. I will be pressed for time on needing to get it going.

The info above about breaking in the cam is great, you should put it in the tech section.
 

p m

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Levi,

measure the cam lobes, and inspect the lifters for wear pattern. That'll get you started.
BTW, the slack of the timing chain on a 4.2 from a 95 Classic with 250kmi is easily a quarter of an inch, if pulled off to the side between the sprockets. You may do well just by replacing the chain and sprockets, and maybe oil pump as well.
 

fishEH

Well-known member
Jan 26, 2009
6,927
201
Lake Villa, IL
Where's the best place to get quality parts for a D1. Last time I got an AllMakes timing sproket the keyway had slag in it that prevented it from fitting.
 

rovercanus

Well-known member
Apr 24, 2004
9,643
244
I had the same problem. I just contacted Lucky8 and they sent a suitable replacement.

I would talk to Tillery. He can probably get you what you need. If not, I have been ordering from LRDirect out of England. Even with shipping the prices can be very favorable and I get my stuff in a week or less.
 

PhD_Polymath

Well-known member
Feb 6, 2015
104
1
Slightly west of Boston
I would talk to Tillery. He can probably get you what you need. If not, I have been ordering from LRDirect out of England. Even with shipping the prices can be very favorable and I get my stuff in a week or less.

I had no issues with the one Lucky8 sent as a replacement. I assume there are some bad apples in the bunch of cam gears from AllMakes. I buy parts from a variety of known good vendors (Will Tillery, P.T. Schram, Lucky8, etc.). With a Rover habit, it's nice to know there are some good "dealers" out there to hook me up with a fix when I need it. :smilelol:
 

Levi

Well-known member
Jul 27, 2004
559
26
Cheyenne, WY
With the exception of a stripped head bolt and screwing around with that the teardown went really good. Then I noticed the head gaskets looked fine. Cleaned things up a little and the liner on cylinder #5 is down 7mm. F!!! Not sure what I'm going to do now. Weird since my low compression was in #1 and #3.

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jymmiejamz

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Dec 5, 2004
6,008
361
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Los Angeles, Ca
If someone needs a cam, I have a brand new 4.0 one that I bought from Will. I ended up only using the lifters I bought at the same time. You definitely need new lifters with a new cam. New lifters on an old cam is okay, but it is better to do both.

To the OP, I would investigate why you have such low compression. If you had a ring problem it would be a waste of time and money to do the heads.