8V Rebuild Woes

[James Cornell 10]

I had a persistent oil leak after a HG failure and replacement so I came to the conclusion that it would be worth my time to fully rebuild the engine and have piece of mind that my 205 would be sound for some time to come.

 

So I got a replacement bottom end (as I'm sure the block was warped) and reused my head and internals to complete the rebuild. No corners were cut and everything was done by the book (new rings, bearings, seals, gaskets, skimmed head, measured block, everything deep cleaned etc.

 

When I put the engine back I fired it up and it did the typical 205 start (up to 1500 revs and settle back down) but then stopped running. I started if 6 or 7 times and it was the same every time so I left the battery on charge and came back later that day.

 

When I came to start it there was just a clunk and nothing (like it was seized) so after boosting the battery to no effect I decided the statter may have died and was locked in gear so I removed the inlet manifold and coolant can out of the two holes that do not have a stud in at the bottom of the inlet, then I looked in the no 4 inlet and there was coolant above the valve.

 

Even with the inlet removed and the plugs out and starter removed I could not turn the engine by hand so I assumed that something had gone massively wrong. I removed the head and the head was fine and turned freely by hand and the Pistons and liners looked freshly machined. Now I am very confused and the only thing I can see that may be an issue is that no 4 liner is a little higher than the rest.

 

Could this be water in the piston and aqua lock?

 

I am really not sure what has happened but I am worried that this will be a complete rebuild again, but when the engine ran it sounded absolutely lovely and gave me no reason to this there were any issues.

 

So confused...and fed up ????

[James Cornell 10]

Well after some stripping down I just decided to drop the engine out again, it seemed pointless trying to keep it in the bay.

 

After stripping it down to its bare arse it appears that piston 2 (if the flywheel is 1) had something wrong with the big end bearing because the cap would not come off and I had to drift the con rod down with a punch to get it free.

 

very strange and the other caps came straight off with no issue. I will now put them all back in and see how freely it turns, the crank can be freely turned with one finger so I am happy that is sound.

[James Cornell 10]

Still can't beloved the car is completely stripped down again ????

[erbs 42 1 Cars]

did you replace the main and big end bearings?, did you measure with a micrometer before you reassembled?

 

also did you check the pump was clean and working ok?

 

also did you put enough oil in?

 

Basically what did you do to the engine?

Edited January 13, 2015 by erbs

[Tom Fenton 1,526]

Assemble all the rods onto the crank but leave all the caps loose.

Nip them up one at a time, it should still be possible to turn it over by hand. Then slacken that one off do the next etc.

 

Not wanting to teach you to suck eggs, the caps are matched to each rod and also only fit properly one way round.

 

Also for the sake of £30 I would 100% recommend you buy an engine stand, makes working on it far far easier compared to grovelling about on the floor.

[James Cornell 10]

ERBS - the engine has been built with new big end and main bearings (including thrust washers) and the crank ground to accept .30 bearings.

 

I put 5ltr into the engine for the initial startup but the entire engine was also built with a good layer of graphogen on all of the moving components so I would be surprised if it was oil starvation as it only ran for 5 seconds at a time

Edited January 13, 2015 by James Cornell

[James Cornell 10]

Tom - you're absolutely correct and I believe that this issue may have been caused by the big end cap either being the wrong way around for the rod or possibly the bearing Shell being slightly out of kilter when I knipped it up.

 

I will rebuild the bottom end and see if it tightens up on that piston, if it does then I will scrap the piston and use one of my spares.

 

I would have bought an engine stand but in all honesty I was expecting to be running it in at the moment...not rebuilding it again ????

[opticaltrigger 52]

Hi James,

I agree with Tom's train of thought on this.

The cause of this must be fully understood and methodicaly worked through before you do your rebuilding.

 

What do the big end journals and the shells look like.Can you get some close well focused shots of them up for us to look at.

 

All the best

O.T.

[pug_ham 242 3 Cars]

The bearing cap is a possibility but in my experience (when I first rebuilt an engine & fitted the caps the wrong way round), it wouldn't turn with a 2ft breaker bar on the crank bolt but if you've just got one wrong then it might just be tight.

 

g

[pug_ham 242 3 Cars]

I remembered this after my last reply but haven't had chance to post since.

 

To make things easy & obvious, the conrods & bearing caps had matching paint marks across the faces that lined up & matched each rod on my engine & the other piston & rods I have downstairs on the non locating bearing tab side.

 

g

[James Cornell 10]

That is a good shout ad I will make sure I mark them up before assembly. I expect the new gaskets etc to arrive today/tomorrow so I can start work soon...

[James Cornell 10]

I have rebuilt the bottom end but it was very strange. I mic'ed up the crank journals and they were round and the bearings are brand new but when I put the bearing caps on the correct way (bearing cut out on opposite sides) piston 1&3 big end caps would not go in without persuasion and when they were on the crank went stiff.

 

I have kept the caps on the rods to ensure they are the correct pairs bit I thought I would try swapping the caps on 1&3 to see if somehow I had managed to mix them up but it made no difference.

 

However when I spun the big end caps around 180 degrees on 1&3 the crank movement was perfect! So now I have 2&4 with the bearing cut out on the opposite side and 1&3 with the cut out on the same side.

 

I have torqued everything up and put the cylinder head and gearbox on and everything is still perfect so I need to get hold of an engine hoist some time this week and put it back...let's hope we're ok this time ????

[Anthony 1,000]

That doesn't sound at all right - the big end caps should all be the same way around.

[dcc 855]

don't bother putting the engine back in the car - it sounds like something is fudged.

[James Cornell 10]

It is all built...just awaiting the hoist to get it in.

 

If it goes wrong I will just put an GTi6 engine in, it has been more bother than it is worth rebuilding this 8v...

[James Cornell 10]

I suppose I could run it up to temp and see if the cap will go on tr correct way afterwards, at least that would only involve me dropping the sump off with the car on ramps

[welshpug 1,627]

I wouldnt bother putting it in till its assembled properly.

[James Cornell 10]

It makes no sense, why would the cap not seat when the crank has been machined and the bearings replaced?

 

I didn't think it would have too much impact it the bearings are the other way around as there a not holes/groves to line up...or am I missing something more important?

[welshpug 1,627]

if it has spun a bearing previously theres a chance the cap & rod are damaged.

 

the tabs locate the ebaring, if its in the wrong way it can move if it picks up.

[dcc 855]

I would get your crank and rods checked, if you cba with that then I would be looking for new rods and crank before putting it back in.

[James Cornell 10]

Ok I will have to take it apart again then...I can't believe this is just dragging on for so long. This will be the 3rd rebuild...it even has the gearbox on ATM

[welshpug 1,627]

You're not alone, me and DCC built up an 8v twice to find a cracked block just as we were fitting the gearbox ready toi drop it in.

 

bonus of them being fresh builds it only took 45 minutes to strip them apart totally!

[James Cornell 10]

Yes, just a little expensive when you need a new HG and bolts every time...

[welshpug 1,627]

you don't need bolts every time, just gasket.

[James Cornell 10]

I thought they were stretch bolts and needed replacing once they had been torqued down?