Thread: Head Gasket Time...

Bugger about the timing gear. I still had to modify my 4 belt 3.9 cover, especially considering my block didn't have the cam retaining plate.







As for the studs, as far as I know (JustinC might be able to confirm) all Rover blocks use the same pattern. There was some discussion in UK forum sites about ARP studs pulling threads out of blocks because they don't engage the same number of threads as the original TTY bolts but I decided to go with them all the same. However, I ran 3 stages of 25/50/75 ft/lbs rather than going to 80 ft/lbs as specified by ARP. 3,000km in to the new engine and it's all OK so far.

As for the valves, I can't advise anything other than if you replace them, be certain that they have been cut to match your seats. My recent experience with replacement parts suggests that everything needs to be checked carefully.

You publish a schedule Hoges, for this work, as I would very much like to come and help, heckle and pass tools as much as I can!

Originally Posted by justinc

All good advice above, the 4.6 also benefits from standard factory cam profile unless substantial other changes are made.

The cam timing needs to be degree checked, as stated, as 4 degrees is a quite substantial amount of adjustment to make up and no surprises the performance is way better.

JC

Well, everything is "out", labelled, cleaned and now for the process of replacing.

Camshaft: I got a standard profile OEM supplier cam (not "genuine") from Karkraft and a new "stiff" chain, chainwheel and sprocket. There appears to be no way to adjust the valve timing even if the cam is degree checked. Am I missing something?

Crane/Crow/Piper etc all recommend a specific routine for running in a cam. My new one has no obvious phosphate coating on the lobes... should I use the CRC engine assembly lube paste and running in oil in the engine (e.g. Penrite 15-40w non friction modified) to bed the cam in. Wondering how the experts do it

Sump Gasket Kit: contains a two small black rubber extrusions just a couple of cm long in the form of a "cross"... plus a set of washers (8) large, 2 small, with what appear to be a seal on the inner surface.. I'm assuming these are for where the bearings are replaced...is this the case? What are the crosses for?

Should I put (say)Loctite 515 on both sides of rubber gaskets (rocker cover /sump) before reinstalling, or are the RAVE instructions re. the Loctite on the sump pan for example where no rubber gasket is used?

Appreciate the advice thanks!

Im quite a fan of MR automotives midrange cam for the 3.9 If you havent already got your bits organised I strongly suggest using them for all your parts

the 3.9s offer no factory way of changing the valve timing on stock gears and chain,

Thanks Dave -PM sent

Originally Posted by Hoges

Ummm not started yet.. flew to Cairns for a week to have some "time" with my new grandson! Should really try and get into it before SWMBO gets back from Cairns!!

Congrats Hoges!

time for an update...

Thanks to Blknight I learned late one Friday evening the value of 6pt impact sockets on a looong bar for moving pesky headbolts AND how to slow cook sausage rolls wrapped in foil on a diesel engine while driving... he can explain it

With a small soldering iron and a bit of luck I rescued my trusty 8yr old digital Pentax from the tool box...so here are some highlights.

With heads, sump pan and front cover removed in that order the following became evident:

one slack chain...

[IMG][/IMG]

Removing the front cover I discovered this "blank" gallery above the oil pressure switch -see 12mm screw in plug : Got me thinking that it might serve as a handy place to mount an electric sender for an oil pressure gauge...

[IMG][/IMG]

Having removed cover, sprocket and timing chain, I got to work on the block and pistons with a plastic pot scrub, Lanotec "Orange" degrease and elbow grease, and finiished off with metho clean rags and then a very light application of singer sewing machine oil...

[IMG][/IMG]


I then turned my attention to the camshaft:
First had to make room to remove it: heat exchangers can be moved forward far enough to allow cam to be removed without damaging bearings etc...there's about 2cm free space to angle cam sufficiently if cam is slightly angled down towards front RHS of engine...

[IMG][/IMG]

Lobe damage most evident...


[IMG][/IMG]

[IMG][/IMG]


Replacement Timing chain and sprocket with "stiff" option chain in place. (red dots from a small vegemite jar of poster paint I "acquired" from my wife's box of teaching aids in 1972 to mark the timing points on my Torana... hate the taste of vegemite anyway) Was a precision fit
with absolutely no slack...took a couple of attempts to slide it into place without upsetting the relative positions of cam and crank ...
[IMG][/IMG]

So, having replaced, re-organised etc and forgotten to pack oil pump with grease, I gave the block one last careful inspection and wipeover with a clean rag /white spirit and put the composite (Elgin) gaskets in place, carefully engaged the heads with the dowels and then installed the ARP head studs with an Allen key and installed the heads.

Then came the heartbreak... These rockers were replaced just 20,000km ago -obtained from a well known reputable indy workshop in Sydney... I hadn't noticed it when I took them off as I simply wrapped the whole assembly in a polythene bag and stored it...

[IMG][/IMG]
Damned if I know when it occurred, I had not found the wayward pad anywhere so I can only guess I was jolly lucky and it somehow disappeared when I changed the oil at some stage. At no time has there been any noticeable zwerf on the magnetic plug...

The lifters were replaced at the same time and are spotless, convex, no circular markings at all so far...which surprised me given the state of the cam lobes.

questions: (1) Are cast iron rockers more reliable than alloy?

(2) .. I note the chap who pens the Range rover world Sth Africa blog spot draws attention to the "B......h" brand of alloy rocker which he demonstrates has been over machined and allows too much oil through and floods the top of the heads thereby (a) reducing oil pressure and (b) setting the scene for future probs with sticking valves due to flooding around the stems...

Recommendations please on replacement rockers?

Time beat me... family commitments dictate my closing up "shop" for a month... so

[IMG][/IMG]

When the heads came back from the machine shop I put a straight edge over the valve tops: there is a considerable height difference with the end 2 on both heads (they're 0.2mm lower). I may need to shim the rocker posts... or get some adjustable push rods... thoughts?

will get back, when I "get back"

cheers

I have a 4.6 v8 I did my head gaskets only 5,000 miles ago but got a constant missfire after four thousand. On investigation I realised the the camshaft was worn out. As the heads were recon items and had been skimmed I didn't know how much had been taken off but with the new cam in place and with standard push rods I found the lifter preload was very high and all over the place. So decided to go for Real Steel adjustable push rods as I had tried shims under the pedestals to no avail!. The adjustable push rods were 5/16 so decided to drill out the guide holes in situ. I experimented with a spare cylinder head to see how to deal with the swarf, there was quite a lot on each. The solution I found was to have a rubber hose long enough (cut to length) to have one end tight up underneath against the hole to be drilled and long enough to be tight up against the opposite head bottom, this formed a tight bend so that when I drilled the guide the swarf would drop into the hose. I carefully released this pipe after each drill and shook out the swarf ready for the next one. At the top there is also a lot of swarf so this was collected, as I drilled, with a powerful vacuum cleaner. Obviously I had also covered every hole with paper towel, inc the long and tiny ones down to where the crank would be. I had cleaned heads prior too and after and still found some swarf in the little gulleys where the vacuum cleaner didnt do its work. So using some wd40 to wash them out and lots of kitchen roll and a pile of cotton buds to minutely go over everything including the four bolt holes which were full of oil and needed cleaning anyway, it was done! I am confident that I got it all, fingers crossed. I measured up the RS adjustables and had two millimeters removed from the ends before putting the push-on round ends (need a press). I have after some experimenting found a piece of wire to 55/thou (as recommended by RS) and have started to install them. I found that from no slack to 55 thou is one full turn and two flats then tighten the lock nut, for some reason I had calculated that it should be one turn and three flats but after tightening the lock nut got 60+ thou so I go one turn and two. RPI recommend 40 thou ie 0.040, its up to you? I have had to make very slight adjustments as I go along but not much. I mark each push rod with prit stick so the flats can be counted and then on the rocker to show I had done that one. Wouldn't want to forget one!!

Asof today 16th Oct 12 I have six pushrods to complete, am also waiting for a stiff chain as the one sent was a floppy. Very interested on how you get on?