Thread: Preparing TDI block for new head

A carbon steel bottoming tap won't cost you much and it will give you a much better job. The last thing you want to find when the head is on and all the bolts are in, is that you have a tight thread.

Originally Posted by loanrangie

So my new head will arrive tomorrow and its time to prepare the block but have a few Q's -

I removed the drain plug on the lower left of the block so will need to re seal it when i re fit it - can i use stag plumbers sealant ?

Whats the best way to clean the block including the remnants of the old HG ?

I will be cleaning head bolt block threads out with compressed air and maybe an old head bolt with a couple of vertical slots ground into the thread sort of like a poor mans tap ?

Anything else apart from the normal procedures for fitting a head ?

That block drain plug has a crush washer on it so probably doesn't need anything else, but I used a bit of Loctite pipe sealant. Your stag should be OK.
For cleaning the block surface I use a metal paint scraper to remove the remaining gasket, then a few rounds of Scotchbrite scourer pad with thinners or degreaser to get it really clean. Final wipe over with thinners before fitting then new head. I've heard others use acetone.

Old head bolt worked well for me to clean out the threads. Just make sure you blow any coolant/oil/crap out of them first or they can hydraulic. I screw the cleaning bolt in a few threads by hand then give it a gentle run in/out with cordless screwdriver or similar. Follow that with a good squirt of WD40 or degreaser and compressed air to make sure any dislodged rubbish is removed.

Make sure you lube under the bolt flanges as well as the threads when fitting them.

Steve

Mine came apart pretty clean in the first place.
I scraped remnants of the old gasket with careful use of a razor blade. Wiped it down with scotch-brite and a microfiber cloth. Used a vacuum cleaner and compressed air to rid final remnants from holes.

After clean out, visually check threads are clear and blind holes empty. New bolts, oil them. Run the new bolts in by hand to check for tight threads. Shouldn't need a tap.

Don't forget about the dowels. Use new bolts to bolt down the rocker assembly. There's a chance you will snap an injector clamp stud so wind the studs out your old head for spares.

Deck is pretty clean but will scrape over to get those last few bits off, scrotchbrite is a good idea.
Taking my time so i have no need to rush it and **** it up.

Originally Posted by loanrangie

Deck is pretty clean but will scrape over to get those last few bits off, scrotchbrite is a good idea.
Taking my time so i have no need to rush it and **** it up.

Tap the threads with a plug tap and clean out with compressed air, you should be able to screw the bolts all the way in with fingers only, lightly oil bolt threads and under bolt head flanges with quality Assembly Lube.
If engine is in a Disco, install the 2 back bolts and hold them above the head surface with pegs (clothes) so as they don't damage the gasket when fitting the head.
The block surface should be spotless and dry as should the head, I always put a smear of Assembly lube on the head surfaces where bolt flange contacts head as well as on the bolts. The plug in the block only needs a bit of Teflon tape, Stag goes hard and will be hard to remove in a few years time.
Don't forget to use Assembly Lube on both ends of pushrods, Valve stem tops and valve lash caps, do yourself a favour and don't use new Land Rover lash caps, they are rubbish, buy a set of Crane Cams Valve Lash caps, also rocker arm pads, good luck and take your time, Regards Frank.
P.S. If the head is fully assembled and you trust whoever put it together to not leak around the valve seats then install. I would spray some WD40 or pour some petrol into the ports and see if the valves are seated correctly first though.
P.P.S. Go here for info on Valve Lash caps and where to get Crane Cams Valve Lash Caps http://www.aulro.com/afvb/technical-...tegrating.html

So today is headjob day , scraped, scotchbrited, scraped again and scotchbrited again the block surface.
Cleaned out the bolt holes and blew them out with compressor to get last bits of coolant and oil out, used old bolts to check all the threads.
Wiped the head block surface again with metho and clean rag and i think we are ready for fitting the head, just need to fit the injector studs and bracket posts and anything else easier to fit while head is on the bench.

What brand of head gasket are you going to use?

put the rocker shaft on loosely first, install the back two head bolts before you put the head in position.

cut 2 pieces of cardboard shorter but wider than the head gasket and grab 4 credit cards (or similar)

put the locating dowes in

tape the cardboard togehter shiney side out

sit the head gasket on the block
sit the cardboard on the head gasket.
guide the lot into place
sit the head on the 4 credit card thick bits of plastic with the plastic at the outside of the dowe l locations
remove the cardboard
remove the 4 credit cards

Watch the front wiring loom if you have preinstalled the thermostat housing