Camshaft removal 4.6

[Thunderchief]

I'm at present doing a budget engine build on a gems 4.6 to go in my SD 1 which has languished in the shed since 2002. I've stripped the engine, but the cam doesn't want to come out without brute force. I removed the retaining plate, but the cam isn't playing the game, it looks like there's a white metal semi circle thrust type bearing on the lower half of the bearings which was retained by the plate. What do I do to pull the cam without damaging anything?

Thanks in anticipation.

[garrycol]

With the timing gear and valve gear etc removed the cam should just pull out.

[stevieturbo]

you've stripped the engine...how far ?

You do not mention you have removed the cam followers/lifters ?

[Thunderchief]

All the lifters are out, timing chain pulley off. I've removed cams from 3.5s in the past with no problems, so this is a bit of a mystery. I was given this engine, it was stored in a building which caught fire, some of the external bits partially melted, top of plenum, rocker covers, alternator etc, but nothing around the lower half of the engine, timing cover etc. The cam turns fairly easily, but it's a bit stiff. I'm wondering whether the cam bearings may have partially melted, I think the melting point of white metal is around 250 centigrade iirc.

Thanks for the replies chaps.

[stevieturbo]

Can you get a visual down the valley ?

Does it move fore/aft at all ?

[Thunderchief]

Problem solved. the front bearing had indeed partially melted in the fire, a few hefty whacks with a drift against the side of one of the cam lobes had it out, the front bearing came out with the cam. Thanks again folks.

[stevieturbo]

If it's got hot enough to do that....are you considering using the block ? Or is it for scrap ?

I'd be very concerned about its integrity and whether it's straight anymore

[Thunderchief]

Hi Stevie. Only the very front edge of the front bearing had melted and run down behind the retaining plate, all the other cam bearings look fine, the crank and pistons rotated as you would expect and the crank journals look good, the main and big end shells also look surprisingly good, there was still plenty of oil between the crank and the shells on disassembly. I'll go over it all thoroughly, check the decks with a straight edge and torch, blank off the waterways and pressure test the block, if anything seems remotely sketchy, then it's scrap. Plan B would be to hang around until I can find a useable 4.0 at the right price, then use the 4.6 crank and rods with the 4.0 pistons.

Cheers, Andy.

[stevieturbo]

Years ago I bought a used 4.6 allegedly all running well.

Bought it, all looked ok, turned over fine etc....so I rebuilt with new bearings, quick hone etc. Just a simple refresh, nothing fancy.

But damn when I bolted the crank in it needed a 2ft breaker bar to turn the crank over !! lol The block looked ok, but the main tunnel was nowhere near straight. The block itself was twisted. How that even happened I've no idea, as visually it all looked nice. I can only assume it had a massive overheat or something. But was effectively scrap.

Luckily back then brand new 4.6's were still available so I got a complete new short motor instead.

Just have yours checked for stuff like that before spending much money on it.

[Thunderchief]

Stevie, thanks for the tip, I'll check it, it was free to me so financially I'm up whatever. Because it was in a building which caught fire, it got hot, but I would think that it would have had fairly even heating, no massive hot spots like if it was running and overheating and as it wasn't running, no dynamic loads on it while it was hot. But that's being optimistic, lol, I'll check, check and check again. cheers.

[garrycol]

Bought it, all looked ok, turned over fine etc....so I rebuilt with new bearings, quick hone etc. Just a simple refresh, nothing fancy.

But damn when I bolted the crank in it needed a 2ft breaker bar to turn the crank over !!

If it turned over OK before the build and not after the build then there was an issue during the build (wrong size bearings maybe) not the block. If there was a problem with the block it would not have turned over before the rebuild.

[stevieturbo]

Bought it, all looked ok, turned over fine etc....so I rebuilt with new bearings, quick hone etc. Just a simple refresh, nothing fancy.

But damn when I bolted the crank in it needed a 2ft breaker bar to turn the crank over !!

If it turned over OK before the build and not after the build then there was an issue during the build (wrong size bearings maybe) not the block. If there was a problem with the block it would not have turned over before the rebuild.

Nope. It was simply that the engine had been running for thousands of miles in that state and bearings etc were all worn.

Even after running it myself despite how tight it was as I just decided f**k it, I'll run it anyway and see what happens, upon disassembley it was much freer...albeit with now worn bearings. And when running found a hairline cracked liner...which was likely the cause of the original problems in the first place.

[Mc Tool]

I would have thought that the fact that only the front cam bearing had melted would suggest the block did not get overheated evenly . And if the top of the motor ,rocker cover and manifold also melted I would be reluctant to spend money on it . They are cheap enough , better off getting another . Cooked aluminium can soften ,twist and bow .
You would have to check main and cam bore alignment ,deck the block ,plane the heads and then still have to hope it doesnt start pulling threads when you start torquing things up.