Engine Problem ! Help ! Advise

[J.C944TurboMan]

The engine on my 944 T has been making a knocking sound for the last 10 miles or so . I feared the worst and laid it up and did a sorn ! I thought it was time to bite the bullet and have a look at the bottom end , so set about some extreme D.I.Y after having been qouted £2500 to have the shelfs replaced and stuff ! Ouch !! After two days of removing parts I finally got the engine sump off ! I am not to clued up on engine wear or rebuild , So don't know what to look for really just having a go . I can not see anything obvious or see anything broken as such ! Only thing that stands out is on piston 2 the conrod moves a lot side to side on the crank ! Could this be the knocking I have been hearing ? I took the bottom part of the conrod and removed the conrod from the crank , it seems to have excessive wear on one side , to the point that the shelf is rubbing against the crank if you know what I mean ? I am no expert but fear the worst and that I may need an engine rebuild or a replacement engine ? Please can anyone help and advise what to do with the engine next ? Thank you

If anyone has a late M44/52 late engine for the right money I might be tempted to replace this tied ( 220 156000mile M44/52 lump)

Once again thank you.

 

[homesea]

That looks like why the engine was knocking. Check the other 3 and the crank for wear. If you replace all shells and bolts all should be well.

As you have got to that stage it's worth pulling pistons and checking rings and bores for wear and also the little ends.

I've seen a lot worse on running engines, looks like you just got them in time!

 

[J.C944TurboMan]

So is the side to side movement on the crank due to the shells ? I thought the conrod was worn on the side to the point were the shell is rubbing against the side of the crank ?

Am I right to say if the pistons have to come out then the hole engine must be removed from the car to allow the complete crank to be removed ?
At this stage might as well go for a complete rebuild !

Instead of througing go money at this engine I would rather purchase a M44/52 250bhp lump if any one knows of such ????

Regards J.C

 

[J.C944TurboMan]

This picture explains my concerns of uneven wear on each side of the conrod click on thumbnail to enlarge and I have circled areas .

Thanks best regards J.C

 

[JamesO]

The engine does not need to come out to take the pistons out but the head needs to come off.
If the crank moves backwards and forwards too much then the engine will need to come out IIRC .1mm to .4mm. Its in the workshop manual somewhere.

You can measure the wear to the current shells with plastigauge. I would do as advised, put new shells in as you you have it apart far enough. Put the car back together just enough to run it and see if it still knocks at worst you've spent £80 on bearings (less than a full tank of fuel costs) at best you've fixed it.

 

[DivineE]

Will this not have made a pretty feature of the soft alusil walls if the piston has been moving at an angle? Also why only one bearing so worn? Could it be a slightly bent rod? Questions I'd be asking before I took the time to put it all together again. If you've got this far I think it would be worth removing the head and looking down the bores.

When you say you might as well change the engine for a 250 block can I assume you have a 220 turbo? If so there is no difference. The only thing you might have different if your 220 is an early one is better rods than the 250 block, other than that they are identical. The only difference made specifically for the power increase was a larger hot side on the turbo. So far as I know.

 

[JamesO]

Surely checking its in spec first is a better bet.

 

[J.C944TurboMan]

Thanks for your advise James

The crank does not move side to side , it is the conrod that moves side to side excessively on the crank , so were the two nuts are that hold the conrod to the crank , you can move it side to side with your hand about 2-3mm , now the other ones barely move 1mm if that .
It might be the big end bearings knocking so doing the shells might be of no prevail and trust me this is not a small job ! So i was just seeing it anyone had previous experience and could steer me in the right direction .

Best regards J.C

 

[JamesO]

THe conrods will move side to side at the top thats normal, there is a 3mm approx gap either side of the end of the top of the rod.
I have one on my fireplace in fact here is a picture of the underside of a piston

Big end bearings are what you have out, little end is shown in the top pic, main bearing is an engine out job.
As I said I would check the crank fit new shells and nuts (only lubricate the bearing surface not the back of the shell), torque it correctly, put the bare minumum of parts on the car so it will start and see how it sounds once the oil is warm.

Heres another of a healthy shell and 968 con rod apprx 100k, sorry my phone has no flash so pics very grainy.

 

[TURBOSRACER]

Hi i have got a m44/52 250 complete engine for sale, its on pistonheads
porsche parts page 12 at the moment its done 158k loads of service history
a few small oil leaks pulled very well but not been on the road for a year but
i do run it regular.

 

[J.C944TurboMan]

Cheer I will have a look thanks

 

[peanut]

it might have been a help to ask before you took the thing apart to be honest.Its quite possible the knocking noise was in the top part of the engine or even somewhere else.

Make sure that you do not mix any of the conrod caps up as they are matched to each conrod. They should be marked 1,2,3,& 4 but don't count on it. Use a indelible marker to number them . Also a good idea to mark the back of the bearing shells with a marker so they do not get mixed up inadvertently

You can remove and replace all the big end bearing shells without removing either the cyclinder head or the engine from the car. You can also replace most of the main bearings shells also without removing the crank from the block.

The bearing in your picture is not particularly worn, certainly not enough to cause a knocking noise. If it was you would be seeing a pure copper colour showing through the this skin of aluminium. This is how they are designed.

Now that you have got this far you have a decision to make.
1. Bolt it all back together and take it to an engineer to assess or
2. Replace all the the big end shells and some of the main bearings and hope that cures the knocking problem. or
3. Strip and completly rebuild the whole engine and hope that that will cure the knocking noise. or
4. Buy and fit another engine without knowing if a)the problem with your is something cheap and simple to fix.b) there may be something wrong with the replacement engine.
If you decide to do option 2 you can pm me and I'll try to advise you how to do it by phone and email.

 

[J.C944TurboMan]

Thanks Peanut I really appreciate all your input , I am at my witts end and a masive cross roads of what to do next !!! I do know quite a bit about engines but never been to envolve in engine rebuilds , just mainly done head gaskets and general servicing . I do know the diffrence between top end noise and lower end noise and I would say 99% This is a lower end knock !

I have over the 2 years I've owned my 944T spent so much £££££ on the car that I will never recoup ! Now the hart is damaged I might as well count my losses and let it go , As I feel they are now getting older and more and more demanding !

I have seen on ebay a 944T that looks better than mine unmolested selling for £3.500 if I am not carefull I will end up throughing another 2-3K at mine and again money down the drain !!!

I think we try and achieve the impossible !

Regards J.C []

 

[peanut]

no worries JC. We are all on here just to share our thoughts & experiences with fellow 944 owners and help each other any way we can. Where abouts are you ? maybe there is someone near that can offer some help ?
I used to rebuild all my own engines once upon a time but my back restricts me now . I have replaced the shells in dozens of engines over many years without removing the head . I am sure you can do the same in a 944 . You might not be able to replace the front and rear crank bearings and seals obviously but I'm pretty sure you can renew all the big end bearing shells and at least the centre thrust bearings which would definitely give you another 5 years or 25,000 miles motoring .

If you then find that one of the small ends has gone then you'll only have lost the cost of some bearings seals and gaskets etc .

I'll be happy to advise you by phone ,video and email etc .

It would be the cheapest option by far and at least you would have a working engine for the time being whilst you decide whether or not to sell it and buy another car or run yours into the ground for a couple of years. It will owe you nothing then.

 

[peanut]

wow that sure is a nice garage [&o] Whereabouts are you in the UK ?

Theres bound to be someone nearby that can drink ya beer, eat ya hotdogs, and generally give you some support []

 

[zcacogp]

A pretty car. Too good to lose.

It sounds as if you are in a smidge deeper than you you are comfortable with. (Nothing to be ashamed of - we've all been there, and it's a good way to learn a lot in a hurry.) You need to find someone who can look at your engine and tell you, with some experience, what the problem is.

Can you take the shells and photos down to a local indie, and ask their opinion? Possibly with a few cans of beer, on a quiet Friday afternoon? Ask nicely, be patient, make it clear you are an enthusiast and value their opinion?

Of course, if there is a knowledgeable forum member nearby who can drop in (for some beer-drinking, hotdog-eating etc) then that would be a good option as well.

You are in a situation where you need advice, and if you get the right advice you will probably be able to fix the car for not much money. BUT it may prove quite expensive to not fix it, if you see what I mean.

Come on chaps. Anyone in the area of Mr J.C944turboman who can drop by and help? Or suggest a good, friendly indie in the vicinity of North Manchester who is willing to be forthcoming for a four-pack of stella? (I'm serious.)


Oli.