Thread: td5 head gasket

I would think you would have been unlucky to get any serious damage in that scenario.

Good luck
Pete.

I think your going to be ok but Id still get them to check the head for flatness... I have a very nasty suspision (but no proof) that there is a slight risk that the manifold (being cast) may be able to cause the head (being alloy) to distort under some circumstances (hot shutdowns for one). This should, in theory, show up as a deformation to the mating surfaces for the manifold and head and a leaking head gasket that still functions correctly as far as the combustion chamber is concerned.

thanks for the responses, especially to blknight. i always pay atention to your posts!

would a leaking head gasket have any other effects on the engine's running? as i've been reporting rough running (not severe enough to affect drivability, nor seeming like a dead cylinder from poor glow plug) and engine harshness from pretty much just after i bought it.

after reading through RAVE, i think i could remove/refit the head and gasket.

my only questions are regarding getting the engine to TDC for cyl1, the timing pin and the gearbox lock.

how can i get the engine to tdc cyl1? i can see that i could keep giving it shorts jabs with the starter motor till i luck out, but is ther an easier way?

do i need the timing pin and gearbox locking tool? if so, are there substitute parts- ie from sprints, repco, etc, or do i need to buy genuine LR parts for these?

assuming i can do this, i guess i just take the head assembly to a "head" garage to have the surface checked? can i do this with all the bits and bobs still in the head? and then if all is ok, i can then refit with all the new parts that RAVE says.

if more work is needed, i can leave the head, as is, with them i assume?

thanks again.

ps- i've found a brand new, complete head on uk ebay for 1100 pounds plus (i'm guessing until i get a response) another 150-200 pounds shipping. if it turns out my head needs more work, is this a good price vs the price of getting mine done?
the bolts and gaskets are alot cheaper than i've seen them mentioned on here too. are there any aussie sellers of these parts , that are a good price?

you dont need the engine at top dead center to pull the head you just need to make sure that the alignment of the timing gear and the timing chain remains constant relevant to the crank shaft.... do this as indicated in the pic from my raves....

td5time.jpg

if you cant get it to go where you want it by cranking it over on the cam gear bolt (pull the glow plugs first to relieve most of the engines compression) you can cheat a little since so long as you put all the parts back in exactly the same relevent positions your laughing, A paint pen and scribe is your best friend here. paint mark the chain on at least 2 places by marking 2 adjoining links and then paint mark the gear and then when its all dry scribe a line in pointing to each pair of marks. if youve done it right then you wind up with 2 pairs of 2 painted links with a line pointing between them. Providing you dont take any other parts off of the head you now cant go wrong.

before you go taking the head off pull the rocker cover (well duh) then chuck a rag over your rocker gear as you toddle off back to the workshop and make up a wooden block, metal frame or some other contraption that will firmly hold the rocker cover when its upside down. The td5 head is somewhat fragile and IMHO the best way to do any work on it is with it sitting either face down on a planed piece of softwood (pine) with holes bored through it for the injectors and valves to drop into OR upside down sitting on the rocker cover. Since you want to measure the face you have to have it upside down and a stable mount is a good thing. once youve done that pull the head off and without putting it down on anything turn it upside down and place it back on its rocker cover. (an assistant is a good thing here)

If you know a mechanic or engineer who doesnt mind lending you a real straight edge (a ruler wont cut it) and you have a set of feeler gauges you can do the flatness check yourself without taking all the stuff off of the head and once youve done that if your not sure you can then send it off as is to be checked out or if your confident order your new head gasket, dowels (if needed) and head bolts in and put it all back. remember to oil the threads of your head bolts and the underside of the head of the bolt prior to GENTLY lowering the head bolts down into their relevant holes. once youve got that done go get the magic number for the head bolt sequence write it out somewhere obvious and start the tensioning sequence. it helps to have an off sider with a paint pen, the magic number and the torque angle gauge.

Ive found that using a 4 inch extention bar on the strong arm allows for the most control when doing the angle torquing phase of tensioning the bolts if you brace the extention and head of the strong arm as you pull on the strong arm. These bolts get done up to EBT (extra Bloody tight) so as you complete each phase of the angle torquing (your off sider should be marking each bolt as you take the socket off I use an asterix pattern one stroke per phase but dots or face markings work just as well) plan the next one so you dont wind up pulling at an akward angle or slip the socket off damaging the bolt (ask Auke about that) smoothness and accuracy counts, youve been warned.

when you do the flatness check the book says to just do it as a pair of diagonals and across the center... Im a little more pedantic I like to check it diagonaly across the whole block (x2) diagnonally across each combustion chamber(*2) along the length of the head at each edge and the center and across the head at the center of each combustion chamber, each support web and the front and back of the block. then once Ive done all of that I do the same thing to the head.


Best of luck to you, its not all that hard sitting down and making an attack plan then taking a break at the completion of each step to rethink the next one along with attention to all the details will get you through.

If you realy mess it up there are locating holes on the crank and cam. You just turn them till the bolt drops in and bingo all st to TDC.

that is brilliant. thankyou so much. am i right to think that its best to remove the old head bolts while the block is warm? to give me the best shot of not snapping them? or does the block not change at all with heat?

one thing you didnt mention(maybe because its redundant) is the locking the flywheel bit that rave talks of. is this not needed when the head isnt being dismantled, and the markings on the cam gear/chain are all thats needed for re-assembly?

cheers again.

Originally Posted by simonr23

that is brilliant. thankyou so much. am i right to think that its best to remove the old head bolts while the block is warm? to give me the best shot of not snapping them? or does the block not change at all with heat?

one thing you didnt mention(maybe because its redundant) is the locking the flywheel bit that rave talks of. is this not needed when the head isnt being dismantled, and the markings on the cam gear/chain are all thats needed for re-assembly?

cheers again.

As long as you don't turn the motor over then Blknight's pic will do.
You shouldn't need the block to be hot but do replace those expensive bolts.
Locking the flywheel is the crank pin. I didn't need to do that one on mine but I did do the head one as my head was fully stripped down.
The hardest pat is the fear of starting.
If you have to pull the head down then removing the injectors is very evil and you need to put them back in the correct order or reprogam the possitions in the ECU.