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Safe cleaning of TS block for rebuild

4K views 38 replies 10 participants last post by  Dino164 
#1 ·
My engine builder has asked that I clean the block internally but I have some difficulty as the crankshaft has been left in situ (He says that the front pulley nut is very difficult to remove) and I am terrified that debris may go undetected. Is it safe to try and clean the block with the crank in situ? I have masked the crank holes but the two main bearings at the front and rear run very tightly in the block and I wonder if there is a risk to mask these holes. In any case, should not all the holes also be washed out?

I do not have compressed air available. Do I need to buy a compressor?
 
#2 ·
I would not clean a block with the crank in place. Water will get trapped in the bearings.
And yes, it is good custom to blow out water from everywhere with compressed air, following the wash.
 
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#5 · (Edited)
I'd agree with that. Nothing hard about removing the crankshaft pulley other than forgetting it is left hand thread. If an impact wrench won't remove it, apply heat to the pulley bolt.
What's an extra pulley bolt in a rebuild?

As the block is in situ, there has been no machining of the block. Therefore the chances of debris are reduced but a footpump with attachment of a football should be enough to clear any light particles from oilways. I'd still allow the crankshaft to droop or have main bearing shells out (refit caps loosely though) when blowing air through.

Any spirit cleaner should work right the way through to diesel. The cleaning agent shouldn't be that important as long as the oilways were clear originally.

It's nice to have everything absolutely pristine for reassembly but as long as there is no major foreign debris, there should be no issues.
 
#6 ·
Thank you for all the replies.

The complication of the rebuild arose because I wanted to use a spare 50K engine that I had stored in my garage. It seemed logical at the time to recover my Sportpack and swap engines in my garage. Having consulted here first, I had the bottom end checked...lo and behold,....the big ends on the 50K engine needed replacing........so I am resigned to doing all the preparation work for the rebuild at home. I haven't any experience of this and am worried that I might not be able to do a thorough job without sufficient knowledge. Ultimately, if it is possible to successfully clean the block with crank in situ I would prefer it. How best to clean the crank oil-ways and do I need to use a pressure washer? Should I invest in an air compressor?
 
#8 ·
What this shows is you can get different answers.
What I suggested is possible but rxe and brinker both rightly think it is not desirable. They are right. It is not a desirable course of action.

To get the best answer, what state is block in, where is it, what has been done to it and what is going to be done to it?

As you have not done tho sort of thing before, it certainly makes sense to do it textbook style rather than having to be creative. There are less chances for things to go wrong.
 
#9 ·
Agreed.

You could try and clean it by (?) pressurising the oil intake with cleaning fluid. This is hard, you need a pump with cleaning fluid, and an ability to block oil galleries. You also run the considerable risk of whatever crud caused your big ends to fail fouling the mains or a gallery elsewhere. I think the chance of the mains being in perfect order with the big ends shot is slim.

I really don't get the problem with the pulley - with the sump off, locking the engine with timber is easy, and it's just a question of getting an impact gun onto it.

I've got a well equipped garage and have built several engines - I would not even think of attempting this .
 
#12 ·
Seriously, get the pulley off.

Step 1 - put a bit of 4x2 in a crank web and either get an impact gun on it, or swing on it with a big socket.
Step 2 - as step 1, but with heat. Preferably an oxy-propane plumbers torch. A mighty oxy-acetylene blowtorch is even better.
Step 3 - drill the nut, and then split it with a chisel. This will definitely work.

Without getting the pulley off, you can’t change the mains, you can’t clean the mains, you can’t replace the crank front oil seal and I suspect you may have fun getting a cambelt on.
 
#13 ·
I followed the steps 1) and 2) but they failed so I tried a local machine shop but the bolt chewed off their socket and so I tried Alfaworkshop and Jamie confirmed step 3) as being the only solution....now armed with a new crank bolt could anyone suggest how I might apply the prerequisite 340-378 NM on a left hand thread?!
 
#16 ·
Left hand thread means it will tend to tighten in service anyway.

John figures other may criticise his method but I think I can hold my hand up and say I've probably greatly under-tightened quite a few.
I'm happy to say not a single one has come off, slackened' allowed movement and caused wear or produced strange noises.

Maybe it's just as well these electric impact wrenches are getting ever cheaper and better. I should get one of the Milwaukee Fuel brushless ones. I think they are the best right now even if the De Walt batteries seem to be the most reliable.
 
#17 · (Edited)
I tend to agree that for crank bolts the specific torque value doesn't matter a great deal, so long as it's very bloody tight. I mean this to apply only to the pulley bolt, it does matter quite a lot with any other bolt associated with the crankshaft.

IMO pulley bolts are generally so big that it would be quite difficult to overtighten the bolt to the point of causing an issue, unless you were unusually strong or used a very long lever. Same for driveshaft / hub nuts, IMO.

Over the years I've come across quite a few pulley nuts (and driveshaft nuts) that were exteremely difficult to undo, the torque needed being far in excess of the specified tightening torque. This isn't because they had been previously overtightened, but due to oxidation of the threads and under the bolt head creating a great deal of 'stiction' (and one of the reasons why an anti seize compound is a good idea, other than lubricating the thread and head underside during tightening). I've also come across a few which were frighteningly easy to undo...

Not useful for you in this case, but 'cracking' the bolt free would probably have been fairly easy if it were a right hand thread. Our Saab 95 had a very tight crank bolt, I just couldn't shift it no matter what I tried, until I came across the 'starter motor method'. This involves disabling the ignition (important!), placing a socket and breaker bar on the bolt head, supporting the end of the bar on an immovable object (in this case a large block of wood placed on the ground, mostly to optimise leverage angle of the bar), then momentarily turning the motor over with the starter motor. This applies a huge torque to the pulley bolt, and unless it is virtually 'welded' on with rust, should 'crack' it free.

Worked for the Saab, but it WON'T work with the TS due to the left hand thread (you'd just be overtightening it more...).

Regards,
John.
 
#22 ·
Dropped, from how high?

IMO, a cracked crankshaft is extremely unlikely to be caused by an insult such as being dropped. Modern crankshafts are tough things, and not brittle. I'd be far more concerned with checking for any surface damage at the point(s) where the crank hit the ground. Having said that, it can never hurt to check for cracks, but even with a crank that had been dropped from a significant height I'd be surprised to find any (at least in a crank that had never been used at high rpm for extended periods, but then I don't think any crack is likely to be the result of having been dropped).

If a crack develops in a crankshaft, it is much more likely to be the result of a manufacturing fault or metal fatigue associated with harmonic torsional flexure at high rpm for extended periods, i.e. an extended period (or repeated extended periods) at an rpm at which a self reinforcing torsional harmonic resonance exists. All crankshafts torsionally twist elastically in some degree, and suffer from harmonic resonances at certain rpm where this twisting is worse. A given crank may not be significantly affected (damaged) by it (harmonic oscillations) if the rpm points at which it occurs is never a stable rpm (i.e. if the engine speed is increasing or decreasing through that rpm point and never spending an extended period of time AT that rpm).

Generally, the longer a crankshaft is the more likely it is to torsionally flex to an undesirable and damaging degree, and to do so at lower rpm. This is at least one reason why long cranks are avoided in modern purpose built racing engines (e.g. straight 6 cylinder engines have long cranks and are not suited to high rpm operation, i.e. over 6000rpm or at most 8000rpm for a very good one). Straight 4s, V8s, and V6s all have shorter cranks (than straight 6s, or V12s), and all else being equal their cranks are much stiffer, and torsionally 'resonate' less and at higher rpm, so are far more suitable for high rpm.

Regards,
John.
 
#24 ·
It dropped from about a metre.
Dropped, from how high? Surely the CPS timing gear would be damaged?

IMO, a cracked crankshaft is extremely unlikely to be caused by an insult such as being dropped. Modern crankshafts are tough things, and not brittle. I'd be far more concerned with checking for any surface damage at the point(s) where the crank hit the ground. Having said that, it can never hurt to check for cracks, but even with a crank that had been dropped from a significant height I'd be surprised to find any (at least in a crank that had never been used at high rpm for extended periods, but then I don't think any crack is likely to be the result of having been dropped).

If a crack develops in a crankshaft, it is much more likely to be the result of a manufacturing fault or metal fatigue associated with harmonic torsional flexure at high rpm for extended periods, i.e. an extended period (or repeated extended periods) at an rpm at which a self reinforcing torsional harmonic resonance exists. All crankshafts torsionally twist elastically in some degree, and suffer from harmonic resonances at certain rpm where this twisting is worse. A given crank may not be significantly affected (damaged) by it (harmonic oscillations) if the rpm points at which it occurs is never a stable rpm (i.e. if the engine speed is increasing or decreasing through that rpm point and never spending an extended period of time AT that rpm).

Generally, the longer a crankshaft is the more likely it is to torsionally flex to an undesirable and damaging degree, and to do so at lower rpm. This is at least one reason why long cranks are avoided in modern purpose built racing engines (e.g. straight 6 cylinder engines have long cranks and are not suited to high rpm operation, i.e. over 6000rpm or at most 8000rpm for a very good one). Straight 4s, V8s, and V6s all have shorter cranks (than straight 6s, or V12s), and all else being equal their cranks are much stiffer, and torsionally 'resonate' less and at higher rpm, so are far more suitable for high rpm.

Regards,
John.
 
#37 ·
Slightly oscillate?
Fit it into engine block and mark the high spots with paint/tippex/crayon whilst rotating the crankshaft.

Remove and reshape the high point with a copper hammer. It doesn't need to be perfect. It just needs to run in front of the crankshaft sensor.

You cannot buy the toothed wheel; it is part of the crankshaft and fitted exactly to give very precise position/angle information of the crankshaft.
 
#38 ·
It doesn't need to be perfect.

and fitted exactly to give very precise position/angle information of the crankshaft.
Which might sound contradictory, but (at the risk of putting words in his mouth) Fruity is saying that a slight wobble won't affect the rotational / angular position of the sensor cog, and it is the rotational position of the cog re the crankshaft which needs to be "very precise". A slight wobble wouldn't affect this. The teeth on the cog would still need to pass close enough to the tip of the sensor probe (without touching it...).

I haven't yet had my TS engine apart enough to have seen this cog (or the sensor associated with it), but would tend to agree that (what I think) Fruity is saying would be correct.

I still think it is very unlikely that the crankshaft drop would have cracked the shaft, or bent it. Also, if the crank hit the ground 'cog first' then the cog would have absorbed some of the impact, making it even less likely.

Regards,
John.
 
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