Race Engine Forum UK

No, but someone stripping his engine here will soon be able to tell you,

G

I see you have the flywheel off already. That's slightly out of sequence. No matter.

When removing the fw it is good practice to mark the relative position of the fw to crank before removing. it can go in one of two positions. If you don't mark them (eg: with white paint) you've lost the original balanced position. In saying this I assume that the crank-fw pair are balanced together at the factory. That would be good practice but whether mfrs bother I cannot say, except that the crank and fw will certainly have been separately balanced. Of course we will be contemplating fw regrind and maybe lighten and post-balancing will be essential. Nothing about an engine is more dangerous than an out-of-balance crank assembly. If you were not carrying out any mods then marking pre-removal must be considered essential and that is true of all engines (and propshafts too FWIW). I am always nervous about crank-fw balance and always recommend it on rebuilds.

Ordinarily I would take the head off with camboxes on it, two reasons:

1. You can see the position of the valves relative to each other so no risk of valve clash undoing the camboxes. Your method is Ok assuming the belt is in the right place ie: cam timing is right before you start
2. There is a lot of oil in the camboxes and it spills everywhere (buckets tend to fall out too..)

So I would have cut the cambelt (because we always discard it) and undo the head bolts in the same sequence as tightening them up, see att. Then I would set the head (complete) aside - upside down so the valves don't get bent - on a tray to catch all the oil.

So - from where you are:

Remove the head. It's heavy and may require a bit of persuasion at the corners with a pry bar. Take off the old head gasket and take out the two gasket locating dowels and put them in a bag with say, the coolant drain plug.

Unbolt the oil pump and put in on a tray to drain. Take off the distributor on the block - or in this case the blank plug and remove the 'driven gear' (as it is correctly called) with a magnet or a piece of wood tapped into the spline. You may need to rock the aux d/s pulley to free it. Put it with the pump.

Now we are looking at a bare crankcase assembly. Re-attach the flywheel (just spanner-tight) with two bolts. Turn the crankcase over so the big ends are visible. use some Scotchbrite to clean the carbon off the tops of the bores. This will make getting the pistons out much easier. Wipe clean

Turn the crank to tdc 1&4 and using a 15mm 3/8 drive socket and long T bar slacken and remove the big end nuts on rods 2&3 (nearest to you). There is no problem mixing up rod nuts but it is important to examine them and the face of the rod (on which they sit) after removal. On the side of the rods adjacent the crankpin (big end journal) the rods are stamped with numbers 1-4 (by cylinder obviously). Big ends are paired to respective rods and must not be mixed up. The numbers are on the ex side on the original engine. Remove the big end caps. Some bearings will fall out of position, but either way mark them eg: 2 U (upper) and L (lower). Take a look at the bearings and see how much damage there is. When stripping down observation is awfully important. Use a piece of copper pipe slipped over rod bolts to ease each piston assembly out of the bore. Don't use any steel object against the upper rod half - it can easily score it irreparably.

Turn the crank 180 deg and do the other two. The pistons tend to fall out of the bores after the rings have come free - make sure you catch them. Naturally you should turn the cankcase to what I'd call an 'advantegous' position to do this - upside down is asking for trouble. Always position a job in an advantageous position. Put all the rods and pistons together in a box. On no account separate the rods and pistons. That comes later.

With pistons out it's time to remove front pulley, housings and auxiliary driveshaft (aux d/s as I call it..) Often I find it unnecessary to lock the fw when I'm using battery or air-powered nut guns but in case you need to, screw a bellhousing bolt or any available fine thread M12 (fully home, ie: right in) into the end of the block and use a decent sized adjustable spanner as a restraining strap - one end of it bolted right through the fw with an M8 bolt and the other bearing against the bellshousing bolt. The engine rotates clockwise viewed from cank front pulley end so make sure the locking device (so to speak) is fitted the right way round.

The front pulley will have either a bolt or a nut holding it in place and a nut gun as described earlier is by far the best way to remove either. If it's a bolt it has an anticlockwise (reverse) thread and to undo it you have to turn it clockwise. The nut is turned the conventional way to release ie: anticlockwise. If the nut gun won't free it off there is good chance Loctite has been (incorrectly) used on the thread and a long T bar with 1/2" drive will be needed. Before really bearing on the T bar makde sure your holding device is secure - you don't want to rip any threads out. I actually use a main bearing cap bolt with an old gudgeon pin fitted on it to bolt to the end of the block. That way the bolt has some preload in it (stretch) and that makes it a stronger holding device. And watch you don't end up with the engine on the floor - get someone to restrain it if need be. Sure, I could make a special fw holding tool, but I'm British, if I don't have to stop and do that - I never will. All engine builders have different little tricks for holding fw..

The front pulley is keyed onto the crank and should come off easily enough. If it needs a bit of persuasion tap it with your dead-blow mallet. Behind it is the cambelt drive pulley and they can often be tight. You need to lever it gently with a small pry-bar like the one shown below if it's tight, first on one side then the other. Of course I have pullers too, but I have never had to use one for this.

Take off the fw now because we need to get to the crank rear seal housing. Photos below (I trust) adequately cover removal of aux d/s pulley and crank front and rear housings. Go as far as removing the aux d/s as shown.

Leave the crank in and the tensioner in place for now. Ideally - provided I am not too slow for you - I want you to strip according to my instructions.


I have no idea of your budget on this, my job is to tell you how to strip and we'll keep most of the unit until the decision about rebuild is made. But - you won't be able to save many gaskets and all the seals should be junked as a matter of routine. I junk the lot - but then I have huge stocks of them all - and suggest you do the same.


Tip!

Don't waste too much time now trying to 'inspect' - or measure - things that are covered in oil/carbon. Cleaning comes after everything is stripped and inspection follows that. Learn what you can as you strip - look for signs of unusual damage or things out of place - but otherwise just got on with the strip.



I want to see photos of one of your pistons & rods and all the big-end bearings. The latter esp so that I can comment on wear patterns.


GC

Note: Photos displayed: I have not taken them specially and the order in which they appear may be out of sequence or show ops that are out of place according to the article. But I hope they will paint an adequate picture nonetheless.

Excellent reading Guy....

My block is cleaned , however I am still unsure what to do with the wear ridge at the top of the cylinders. I am working to a tight budget and am trying to avoid going to rebore & larger pistons. I understand ridge dodger top rings are no longer available ?

My cylinder head is stripped and cleaned, and appears intact without any issues. It will get a skim in the next few days all being well.


I hope my posts here are within keeping with the theme of original thread, and go more or less hand in hand with with the work Alan is currently doing.

To keep the budget low is the name of the game for me personally, so any advice will be gratefully received.


Regards

Ivan

I will cover this in due course but it is no 5 minute job to do far less write up.


G

Hi Guy.
As you use an impact tool to remove the head bolts, is it correct to assume that they do dot need to be released slowly (i.e. 1/4 turn at a time) going round each bolt in sequence?
My wondering is in relation to minimising the possibility of any head warpage (which may not be relevant but I have to ask).

My intention is to strip the engine specifically per your guidance, I will get some more done tomorrow night an post details thereafter.
Alan.

All my heads get refaced so it's immaterial whether they warp during strip or not. As a matter of course we will cover the key decisions of budget/ops so if you wish to err on the side of caution undo them with a T bar. I would not go as far as undoing them progressively, but stick to the 1-10 sequence.

G

Hi Guy.
I continued the strip-down this evening, removing the head first.
It came off very easily (just lifted off). One of the chambers is covered in a light corrosion, but it dosent look to be too difficult to remove: I then got out the Scotch Brite and cleaned the carbon deposits of the top of the cylinders: There is no obvious wear on the top of the cylinder, I am not sure where the scratches came from though or they effect the performance: Moving underneath, I removed the oil pump: Not sure what the purpose of this pipe is (is it a standard item?), possibly to guide the oil back to the sump. What is the eccentric cam on the end of the oil pump drive shaft for?
Pistons 2 and 3 out followed by 1 and 4.
Good practice or not, I reassembled the caps and bearings after removing the piston to keep all together in an orderly fashion. Each piston has been previously engraved with its number: The crank journals all seem to be in excellent order, and the wear on the bearings looks minimal: More fun tomorrow eve.
Alan.

Guy, I proceeded with removing the aux drive pulley and shaft.
These both came of with ease.

Thankfully you mentioned about the bolt on the crank bolt being Left Hand thread, otherwise the outcome might not have been pretty.
I used the nut gun and it was really easy.
I didnt even have to hold the the crank pulley, the rapid torque/impact just spun it off.
Its small but still has 590 NM of torque. I cannot recommend one of these highly enough for working on old cars:
My pulley system is not standard:

Here is a montage of the rod bearings (cleaned using a decent solvent spray) hopefully the image is clear enough to make out the wear pattern.
The lower bearings are shown as the bottom ones under the picture.

I will hold off on the crank removal until you offer further instructions.
Regards,
Alan.

Next:

TOOLS:
1. A dial gauge - also known as dial-type-indicator DTI - with a magnetic base (mag base DTI on short) is an essential tool needed now - and I recommend Mitutoyo measuring equipment above all_other_makes. I recommend digital NOT analogue (clock face type) for engine building because it is more accurate and far quicker. Plus you can't ever make a mistake with the reading.
2. Long T bar or impact wrench & sockets 19mm and 16mm 1/2" drive
3. Small and large screwdrivers
4. Marker pen!

Before taking out the crank (assuming all the housings are off) use a dial gauge with magnetic base to check the end float. See photo. The crank is levered (quite firmly) one way and the other with a screwdriver or pry bar. The OE spec on end float - which is the free movement a crank MUST have to allow oil film between the vital thrust washers and the crank flange - is 0.002" - 0.012". The trouble with end float is that if you aren't careful you can end up in a situation where - on rebuild - it's too loose or too tight and you don't know why. So check it now.


If your float is within limits undo all the main bearing cap bolts - and again - nut gun fine for this but wrap a cloth around the socket (which will need to be a balck 'impact' socket because ordinary chrome vanadium sockets can shatter at these big sizes under high applied 'undoing' power, 1 x 16mm hex at the front near the oil pump and 9 x 19mm hex on the 2 liter unit).

The main bearing caps (see photos) should carry the same numerical code as the block and the front cap (which has two different bolt sizes) cannot be fitted in any other position, whilst the others can easily be mixed up especially the wide center main cap (where the bending load on the crank is highest) which looks as if it should be the one at the FW end of the block where the thrust washers are located. It carries a wider bearing than the other 4 caps too.

Keep every bearing with it's caps. Lift the crank off carefully and try not to dislodge the thrust washers. If they fall out make sure you note which one it is. Usually the rear thrust brg is more worn than the front because it carries all the thrust load when the clutch is depressed (a very good reason for taking your foot OFF the clutch when driving by the way..).
Remove all the main bearings and record positions and bearings with the marker pen. When the crank is out wipe the item dry and next we'll inspect and measure it but in the interim have a very careful look at the crank webs and see if you can find a machined flat region (known as a 'flat') with a number like +.03 stamped on it. We will confirm by measurement of the journal with accurately calibrated micrometers but check anyway because it will indicate the use of an 'odd' factory journal size on crankpin or main for which unique bearings were fitted by Fiat and which have never been available in the aftermarket.

You will probably find a bush pressed into the FW end of the crank although it may have come off with (and be in ) the FW.
FWD (front wheel drive) engines generally have this - rather than the bearing that RWD units generally have to support their longer gearbox input shaft. The item is there, in this FWD case, purely (and importantly) to center the FW on the crank.

GC time taken: 20 minutes

Incidentally - for the benefit of readers whose technical English is not great I am tending to mark important technical terms and phrases with 'inverted commas'. I try to be correct about language and all readers should try and adopt the terminology I use because it helps so much if we all have a common system

More later, your feedback when you're ready.

GC

Some notes re your progress to date.

Hello Guy,

As you generally saying: Model Post!
It is a great help to have these pictures with detailed technical explanation as it help talking about the same things.

Thanks again,

Daniel

Hi Guy.
Finally got back to this.
I removed the oil seal carriers on either end of the block:
And checked the end float using my favorite leaver. (I placed a ½ inch drive extension into one of the holes on the outer part of the block, and using a parallel to protect the crank, levered the crank fully one direction and set the dial gauge to zero (not digital but I am happy with using this one), then the other way and measured the result. Exactly 0.4mm or .0157”, so outside the tolerance you specified. (Picture taken before I removed the rest of the bearing caps). I expected to see bearings fully round rather than just a half circle on either side:




Here is a montage of the cleaned crank main bearings:

There is some wear marks on the journals, but nothing I can feel so most likely very slight. Now that all of the internals are out, the block needs a good clean to get the crud out from the innards, any suggestions? Is a caustic soda bath too strong?
As the thrust bearings are out of spec, will these have to be replaced with new (are they available?).
Alan.

No cleaning yet!

Used cranks always exhibit some marking especially with trimetal bearings. Soft bearings allow minute debris to embed and this cuts the crank. Naturally the extent of marking of the crank (tiny grooves around the journal is quite usual) depends on the quality of oil, change frequency, cleanliness of build etc etc.

The big end float may well be some wear. We can deal with this in due course, perhaps with oversize thrust washers but later on when we build up we'll try new std ones first and try to get inside the 4-12thou" limit. Thrust washers - yes, naturally I - for example - stock all these kinds of things. Check the condition of the crank thrust faces with your finger. No groove or evidence of wear - we hope. When they wear you get a distinct groove, and it's usually on the outer end face of the crank thrust region where the clutch load is applied.

Your response please to:

When the crank is out wipe the item dry and next we'll inspect and measure it but in the interim have a very careful look at the crank webs and see if you can find a machined flat region (known as a 'flat') with a number like +.03 stamped on it. We will confirm by measurement of the journal with accurately calibrated micrometers but check anyway because it will indicate the use of an 'odd' factory journal size on crankpin or main for which unique bearings were fitted by Fiat and which have never been available in the aftermarket.

You will probably find a bush pressed into the FW end of the crank although it may have come off with (and be in ) the FW.
FWD (front wheel drive) engines generally have this - rather than the bearing that RWD units generally have to support their longer gearbox input shaft. The item is there, in this FWD case, purely (and importantly) to center the FW on the crank.

Tip!

Make sure you print off everything I write and mark it off as you proceed.


Might as well do some prelim inspection of the crank right now.

No point prepping a 'dud' (unserviceable) crank. Now put the crank between centres on on Vee blocks on front and rear seal journals and rotate it with a dial gauge on the centre main. What you see in the photo - 0.04mm runout - is close to the limit of 'bow' (bent-ness) we want. Also check the FW mating flange for true as shown. We would always dress this face with a fine carborundun stone as part of the routing prep and it is quite normal to have a bit of bow there - but we want it pretty flat. The cast iron flywheel is very weak in bending and we don't want to generate a 'stress raiser' there, it can overstress the centre region of the FW and cause it to crack.

Tools required:
Vee blocks
Dial gauge 0-10thou"
Straight edge (piece of flat ground steel bar)
Feeler gauge with 0.0015" min thickness

GC Time:
40 minutes - 1 hour

Next - full crank measurement and head/oil pump strip.


GC

Hi Guy.
I got to check the crank for run-out, and its reading 0.025mm, so within your 0.04mm tolerance.
The FW mating surface on the crank is pretty flat, a .05mm feeler gauge won’t fit under a parallel.
I gave the surface a quick rub with a honing stone first to ensure no burrs were sticking up. A little more time would probably clean the entire surface.

The thrust bearing faces on the crank are smooth and appear to be in good condition.

I have been unable to locate a machined flat with and numbers stamped on it.

With regard to the FW to crank mounting, there is no bushing to be seen.
Only the bolts were holding the FW in place. I don’t have the FWD gearbox for this and I will be running a RWD box at any rate. If needs be I can turn a bushing to fit.
Alan.

Guy,
These are the measurements from the crankshaft journals:
Front to rear
Main
No.1 52.984
No.2 52.979
No.3 52.979
No.4 52.979
No.5 52.985

Big End
No.1 50.795
No.2 50.796
No.3 50.795
No.4 50.795

Regards,
Alan.