Broken Block :-(

[James Cornell 10]

Hello damirgti

 

Looking at the picture (I realise it is not very clear) where the leak is there is a little raised bit on the block face (which I am assuming is where the head bolt is) and it sounds like what you are suggesting could be a good idea.

 

I will try to loosen/tighten the bolts tomorrow and see if it seals...fingers crossed

[DamirGTI 325]

If it's round the block bolt thread area - first , double check that theres no cracks !! clean the area with scotchbrite pad , wipe off with clean rag soaked in engine degreaser or better spray clean the area with brake cleaner , use an magnifier glass and take an good look around for possible evidence of cracking .

 

Could be crack inside the coolant galleries i.e. block internals caused by the head bolt torque force "pulling" the threads and cracking the surrounding metal area .. the areas on the block around the head bolt threads are most prone to cracking so be aware .

In such case , if there's doubt that the leak manifest from the bolt thread area , avoid additional undoing/re-tightening of entire head bolt assembly and rather that that - leave all the other bolts in place and undo just the one from the leaky area .

If it's cracked the block inside the coolant system you'll find out as soon as you remove the bolt out .. if the leak is not so severe , and the bolt threads are still in good enough state to hold the head bolt torque force smear some RTV sealant on the bolt threads and refit/tighten the bolt back inside (drain the coolant first) . This usually works good on iron blocks , however on aluminium ones XU engined especially - not so sure but you can try if that's the case ...

The main problem is that the OE head bolt torque specs. states quite a bit of torque force for now mostly 25 years old blocks so , apart from possible cracking , chances are that the bolt threads will be fubared so fixing the leak with RTV method will be useless ... certainly wont be the first one with "pulled" bolt threads on a XU engine/block .

 

If the leaking starts from the top block base i.e. accumulating horizontally round the HG line then sliding down the block , and you can't detect any external cracking on the block itself (however it still might be on internal side where you wont be able to see it while the head is on the block) , then try the bolt undoing/re-tightening by 1/4 of a turn in order to reset the head bolt torque force if it's the HG sealing problem which might caused this leakage .

 

Did you spot any "unusual" issues while tightening the head bolts ?

Set the torque wrench to 95Nm and go over all the head bolts per tightening sequence/pattern just to check if any of them is gone loose .. do not further tighten them yet (proper way needs to loosen first and then go re-tightening back), just check if all of them hold 95Nm of torque .

 

D

Edited December 7, 2013 by DamirGTI

[James Cornell 10]

Hello damirgti

 

Thank you for all of the pointers, to try and answer all of your questions as best as possible

 

When I first took the head off the only unusual thing I noticed was that the head bolt on the front of the block nearest the cam vernier was oily on the thread, the rest were fine.

 

With regards to the block I checked it before I replaced the hg and I could not see anything unusual and all of the surfaces looked flat and damage free

 

It is always a possibility that the bolt has "pulled" the block and that would make me very cautious about the loosening and tightening method.

 

On a positive note I decided to take the car out for a drive today and the block seemed to stay dry and after 30 miles or so the coolant reserve is still full so maybe it has sealed...

 

I will do some more miles tomorrow and see, I've just got to sort out the issues with misfiring and kangarooing below 2500rpm which has now manifested its self since the rebuild....there is always something :-)

[DamirGTI 325]

Oily bolt - that's fine/usual , no worries about that one

 

If you haven't spotted any cracks , high or low spots on the block deck prior to assembling the head , seems like it was just the HG needed to "settle down" after rebuild (could've been an blob of oil on that area when you've been lifting/arranging the head to slide down the block dowels/HG .. theres always some oil residue which remains inside the head and once you lift the head up to offer it to the block it sometimes made an droop of oil down until fully seated on the block dowels/HG , couple of engine heating/cooling cycles and that'll burn off and the HG will seal up completely)

But do monitor coolant level few more weeks , and the leak area as well just to be sure .

 

Also , compression test would be good idea .. if it's a bit dicky while driving now after rebuild (though it shouldn't misfire as such) - check the ignition timing , often you need to re-set the timing i.e. add just a few degrees to smooth it up cos now the cam will be a little bit off the crank due to the head skimming thus it'll need ignition timing correction to compensate .

 

D

Edited December 8, 2013 by DamirGTI

[James Cornell 10]

Let's hope it is something as simple as that damirgti, I would love to think I could leave the head non for more than a week :-)

 

With regards to timing is there a way to use a strobing lamp or do you just have to adjust and drive until it is right?

 

The running issue is wired because it idles and starts well (which is wired for a 205) but when you pull off if you use less than 2000rpm the engine dies as soon as you start to let the clutch out and some times you can catch it but if not it dies all together. When driving at anything below 2500rpm and you try to accelerate it cuts, Judders and coughs until it reaches 2500-3000 and then it revs smoothly. It's just like when your rotor arm or ht leads have broken down.

[James Cornell 10]

I tried advancing the ignition a little last night and it has smoothed it out but it is still awful below 2000rpm, I've now changed the dizzy cap, rotor arm, ht leads, spark plugs and it is just awful to drive at low speeds. I did another vaccume pope check today and everything is connected so I just don't know anymore, I'm really losing my faith with it all and I am wondering if I should just rip the whole engine out and replace it...

[mikeyd 13]

is it possible the cam is timed up a tooth or so out?

[James Cornell 10]

I know this is probably a silly question but I timed it up with the dowels locking off the cam and crank, is it still possible to be a tooth out?

[DamirGTI 325]

Anything is possible ... route the belt like so starting from : crank pulley-to-cam pulley (snug without slack) , then back from the crank pulley-to-water pump and lastly slide both ends round the tensioner roller .. so that initially , when fitting the belt , you have belt slack round the tensioner , rather than on the opposite side i.e. in between the crank and cam pulley ...

Time it up an see if the locking pins/dowels slide in as they suppose .

 

Said you've checked air/vacuum leaks round the hoses , how about the bolt which attaches oil filler to the inlet manifold ? this one creates nasty air/vacuum leak ..

Double check all the wiring connections which where disconnected during the HG job as well (dizzy signal cable especially)

 

Do compression test also.. since there was some leakage after HG job and was the last thing which was freshly done on the engine .

 

Is it the same issue while the engine is cold/hot ?

 

D

Edited December 11, 2013 by DamirGTI

[James Cornell 10]

I will take the c belt off tonight as a starting point and refit it just to be sure. With regards to the dizzy signal wire is that the thin cable that goes into the yellow clip below the coil?.

 

I will struggle to do a compression test this week as I will have to borrow a tester from a friend.

 

I will also strobe the flywheel once the cam timing is sorted, does anyone know if the flywheel is marked up or do you have to make you own marks?y light is basic and does not have the advance dial on it

[MikeC 10]

Said you've checked air/vacuum leaks round the hoses , how about the bolt which attaches oil filler to the inlet manifold ? this one creates nasty air/vacuum leak ..

 

This is the one leak i totally overlooked, and once sealed the engine ran far far better far better, which i must say cheers to Miles and Damir who pointed the way for me before

Edited December 11, 2013 by MikeC

[DamirGTI 325]

With regards to the dizzy signal wire is that the thin cable that goes into the yellow clip below the coil?.

 

 

I will also strobe the flywheel once the cam timing is sorted, does anyone know if the flywheel is marked up or do you have to make you own marks?y light is basic and does not have the advance dial on it

 

That's the one - black cable going from the dizzy body to the ignition amplifier , in-between it splits by 3pin connector (black into the yellow ) .

 

Personally i wouldn't bother with timing it up via strobe light , the OE ignition specs will be kinda off these days due to the wear and tear built up inside the engine/engine components , different fuel type and octane grade then years ago etc. ... your best bet to get the timing spot on is doing it "by ear" , go for a spin and gradually advance the dizzy with test drives in between , load the engine in 4-th or 5-th gear by full acc pedal application and listen for engine sound - pinking (it'll sound like shaking an glass jar with few spoons inside) , when you detect pinking stop advancing the dizzy and back it off on retard side a little bit from the start of the pinking spot until it stops pinking and that's it .

Anyways , the flywheel does have marks . One single mark for static and another double for dynamic ignition timing adjustment , also the TDC mark and BTDC mark on the timing plate (though on most of them i've seen just the TDC mark on the timing plate without BTDC one ...)

 

D

[James Cornell 10]

I have advanced it one tooth and it is pinking like mad so that leads me to believe that it was set correctly in the first place, however because it is fairly easy to move the timing a few teeth I will try retarding it by two teeth (one tooth before I changed it) And see if it runs any better...but I am not very hopeful.

 

One other thing to add to the mix is my battery has gone and won't crank the engine without a booster which leads me to suspect that maybe there is a wiring issue because the battery has been on the optimate whilst I have been working on the car. I know it is a long shot but if the voltage is down and the alt can't compensate enough at low revs, maybe that is causing the stuttering when pulling away.

 

I think I will put two wires into the car and feed them into the engine bay so I can connect a multimeter to the battery terminals and watch it whilst driving the car to see if there is a dramatic drop in revs when pulling away, I don't know how finikey the pugs are about voltage but I remember from a Triumph TT600 I had that was a battery eater it was a dog below 6000rpm unless you put a new battery in.

[Tom Fenton 1,525]

Not sure why you are moving the cam timing. Set it correctly with the locking points in the cam sprocket and crank sprocket and thats it. Ignition timing can then be altered by moving the distributor in its slots.

[James Cornell 10]

Hi tom, as discussed earlier in this post I have timed the engine using the locking dowels (several times lol) and I have been having the issue with poor running. A lot of the members have suggested that I may be a tooth out despite timing the car with the cam and crank locked off and as it is not too much effort to move the cam timing it may be worth a shot. I am still confident that the timing was correct in the first place but I have to explore every avenue

Edited December 20, 2013 by James Cornell

[Tom Fenton 1,525]

If locked correctly you cannot get it wrong on the 8v engine.

[James Cornell 10]

I had timed it 3 times to make sure it was right...I suppose I was just clutching at straws

[Anthony 1,000]

As Tom says, if the timing pin holes line up, the cam timing will be correct - blindly moving it a tooth or two out will only further add to the confusion.

[James Cornell 10]

I just wanted to eliminate it as a culprit, you are right in that it can't really be wrong with the two locking dowels in place

 

Has any body ever had very poor running at low revs from a bad battery?

[jackherer 543]

They're very tolerant of low voltages in my experience.

[James Cornell 10]

Well I have taken it out and put it in the optimate this evening so I will see what happens at the weekend when I put the timing back. Maybe it is drawing current from somewhere and that is causing the bad running, I'm sure this little saga is not over yet :-)

[Miles 331 1 Cars]

As said there's loads of other things for poor running, Injectors, Dizzy, Connections and wires to name a few, Timing once set and checked should never change at the belt end

[James Cornell 10]

Well I have moved the cam belt back one tooth and checked that the dowels are locating correctly and took it out for a gentle drive this evening and the ignition is quite retarded and it was awful at low revs again making it hard to pull away but revving cleanly after 2500rpm so I have wound the dizzy back towards the bulk head (I'm pretty sure that is advancing the timing) and I will take her out again tomorrow morning and see if she is a little more civilized.

[James Cornell 10]

Stil no closer, I have retarded it enough to stop the pinking but it is s*it at low rpm and is dropping oil...arrrrggggg!!!!

 

f*** it for a few weeks I am going to just park on some cardboard :-)