4 cyl engine question

[R.White]

I have recently been using a lapping compound called "Timesaver" which is specifically designed for babbitt metal bearings.  It is highly recommended  by steam engine enthusiasts.

 

I have successfuly lapped in four of the five crankshaft main bearings (with a bit of scraping) but have noticed a problem with the centre main.  Somehow, the journal is out of round.  This shows up because  the lapped surface on the journal is a mat finish and part of it remains shiny.  Measurement with Plastigauge shows a variation of about 0.004" which is quite a lot.  I suppose grinding will sort it out?

 

How can a centre main bearing go out of round? Oil starvation?

 

 Wear across the bearing is uneven but this could be corrected and is the least of my worries. 

 

Ray.

Edited April 2, 2017 by R.White (see edit history)

[MikeC5]

Hi Ray,  I thought you had new babbitt bearings poured but I can't imagine how a new line bored bearing could be out of round (except maybe a worn out line bore machine?).  If not a new bearing I would suspect oil starvation or maybe improperly set shims.  Did you have the crank checked for bending?  I think they set it up on v-blocks on the ends and then indicate center bearing. 

[Ron Lawson]

NOTE !! Ray said that the Journal is out of round not the bearing

[cahartley]

Forget the plastigauge.

Assuming the other mains are OK remove shims until you feel a bind, then add a thousandth or two and call it a day.

[R.White]

8 hours ago, MikeC5 said:

Hi Ray,  I thought you had new babbitt bearings poured but I can't imagine how a new line bored bearing could be out of round (except maybe a worn out line bore machine?).  If not a new bearing I would suspect oil starvation or maybe improperly set shims.  Did you have the crank checked for bending?  I think they set it up on v-blocks on the ends and then indicate center bearing. 

 

No Mike, I have not had new babbit  metal.  The other bearings are fine and the replacement shells that brother Bob sent from OZ are a first class fit.  I had noticed that the general wear was fairly even but needed taking up a bit i.e from 0.004 to 0.002.  I wouldn't go any tighter than that on a non pressure fed engine.  It is just the crank centre main journal that is out by about 0.003". 

 

I just wondered how it could have worn like that?  

 

As Baldrick might say..."I have a cunning plan.."  but it is too unorthodox to mention here 

 

Actually, C.A. Hartley....you are probably right.  A more pragmatic approach with these old engines is the best way to go.  

 

 

[Spinneyhill]

Kind of reminds me of my cousin's Triumph Daytona motorbike. It seized up (too hot, too fast?) on a ride from Christchurch to Picton and home to Wellington. He put it on the train and sent it home. Our family happened to go and see that family and Peter was working on it. He was horrified when my father went to work on a bearing journal with carborundum stone to make it round. Peter was studying mechanical engineering and Dad served his apprenticeship in a machine shop and was a marine engineer at sea. It will take a while with a stone but will work!

[R.White]

I think I have established why there was so much clearance in the bearings.  I am not certain, but I think the crankshaft may be bent.

It needs a fair bit of clearance to rotate cleanly without any trace of binding. 

 

Ray.

[Taylormade]

Ouch!  I hope you're wrong, you just can't seem to get a break with your motor.

[MikeC5]

Journal...  yes.  I missed that.  It may be possible to have the crank straightened.  I had to have that done before (on a different make).

[R.White]

...I have a 12 ton press?..;

[MikeC5]

https://www.youtube.com/watch?v=Qtb2KWB1Ulc

 

I suspect that's how it is done.  Support the ends and then carefully push in the opposite direction of the bend though it must take a calibrated touch to not make things worse.

Edited April 6, 2017 by MikeC5 (see edit history)

[R.White]

That is my worry. It may just end up worse or cracked and besides, it's not as simple as I first thought.  The crank must have been running like this for a long time and has almost worn itself round again! There is only a small area of excess clearance so I am thinking I should leave it alone.  I didn't notice any vibration before so it will probably be O.K. so long as there is no binding.   

 

I just like to get things right - but I am beginning to loose enthusiasm for the car and I'm fast running out of cash!

 

Ray.

[cahartley]

I'm trying to wrap my head around how the crankshaft could have gotten bent.

As stout as they are and with considerable bearing surface I really don't get it....... 

[R.White]

Ah yes, you might well ask.  You will remember I had concerns that a con rod may be bent?  At some time, this engine has suffered trauma and possibly a seizure.  When the block was being rebored a small piece of piston ring was found deeply embedded in a cylinder wall. Further investigation by testing showed a crack which necessitated a cylinder liner be fitted. Also, the white metal in two of the main bearing shells had broken up and they had to be replaced.  I can't be certain but it had crossed my mind that trauma may have knocked the crank out of true. 

It is probably not connected, but at some time this car has been involved in an accident.  It has been repaired but the frame is still a bit out of true so the hood doesn't quite fit.   The studs on one of the rear hubs are bent.  I imagine an impact to the front cross member could have transmitted shock to the crankshaft sufficient to cause it to bend by a couple of thou...

 

Ray.

 

 

[cahartley]

19 hours ago, R.White said:

I am beginning to loose enthusiasm for the car

 

I can empathize with you.

I have identical feelings about a '65 Mustang....... 

[R.White]

2 hours ago, cahartley said:

 

I can empathize with you.

I have identical feelings about a '65 Mustang....... 

 

'65 Mustang?  That's been my dream car since I was 8 years old!

 

Do a swap?

 

No, didn't think so.!

[MikeC5]

There are other things that can bend a crank.  It is well known in the Ford Model T community that lugging the engine excessively can break a crank.  Perhaps a stouter crank may bend a little under severe lugging.  My experience was with a 'modern' engine that was suffering severe pre-ignition (knocking due to insufficient octane).  At the time I had no appreciation of how destructive knocking could be...  It finally blew a head gasket.  When I tore it down I found scoring in one cylinder (corresponding to HG failure location).  Further tear down revealed top piston ring on all pistons broken into several pieces and a bent crank.  Lesson learned!  I imagine the latter scenario is very unlikely on a low compression engine running modern fuel.  If the center journal is only showing 0.003" runout with indicator, I would probably just go with it although I suspect if you can find someone who has the proper equipment and has done this before, it looks like only an hour of labor should do it.  Don't give up yet Ray....

Edited April 8, 2017 by MikeC5 (see edit history)

[cahartley]

20 hours ago, R.White said:

 

'65 Mustang?  That's been my dream car since I was 8 years old!

 

Do a swap?

 

 

In the words of Jack Benny when asked by a thief "Your money or your life?">>> "I'm thinking it over"....... 

[R.White]

8 hours ago, MikeC5 said:

  If the center journal is only showing 0.003" runout with indicator, I would probably just go with it although I suspect if you can find someone who has the proper equipment and has done this before, it looks like only an hour of labor should do it.  Don't give up yet Ray....

 

Thanks guys.

 

It all comes down to cost, Mike.  As I mentioned, the engine has obviously been run like this for a long time as the crank centre main has almost worn itself round again.  I only noticed the problem because it seemed strange that the bearing seemed to have been "picking up".  I resolved that problem by using "Timesaver" lapping compound that is specifically designed for use with babbitt bearings (because it doesn't contain stuff like emery or ground glass and eventually goes to nothing)  but the out of alignment issue then came to light.  The problem is that the crank would need to be ground after being straightened because all the other bearings would possibly then be out. New babbitt metal and line boring would then be needed and that's expensive work here.

I simply don't have the cash to throw at it now because all the other problems have drained the budget.

 

So long as there is no binding, I think I will go with it and hope for the best.  As I say, it wasn't causing a problem with vibration before so I am gambling on it being O.K. now.

 

Ray.

Edited April 8, 2017 by R.White (see edit history)

[Taylormade]

I know exactly where you're coming from on this issue.  As I restore my 32 Dodge Brothers, I keep running into problems that require the decision - do I go with it or try to fix it.  My transmission gear had a tooth missing and I had to decide whether to replace it or go with what had worked when I owned the car back in the sixties.  I'm assuming it was chipped back when I owned it and drove it daily 1965 to 1967.  It was put away in 1970 and not run again.  I probably could have kept it the way it was, but that nagging worry at the back of your mind is really annoying, and I finally tore down the transmission and replaced it.  Since yours is not a daily driver, I suspect that that your solution of leaving it as is will work out just fine.  But I do know that nagging feeling and I sympathize, believe me!.

[R.White]

Thanks.  I also had to replace a gear in my transmission.  The problem was that the cog in question wobbled on the input shaft.  I tried to build up the sliding surface with silver solder but no matter what I did, including heating it in the oven, it just wouldn't take. A replacement gear from Myers proved a better sliding fit.  I also replaced all the bearings and bushings in the transmission - including the pilot bush in the end of the clutch shaft which was a pig of a job.  I would normally have used the tried and tested hydraulic removal procedure but the oil hole in the end where the oil would normally go made that impossible.  For anyone doing this the best way to get the bush out is to tap a thread into it and screw in a long bolt.  The bush can then be extracted using the method of your choice.  Not having a large enough tap, let alone suitable bolt, I resorted to reaming out the bronze bush.  I fitted sealed bearings throughout including one to the flywheel for a specific reason.  It would seem that there is no provision for lubrication of this bearing which surprised me.

 

One amusing episode with my gearbox was when I discovered that the gear cluster could move alarmingly back and forth on the counter shaft!  Someone had left out a thrush washer - which I found languishing at the bottom of the box.  It fell out when I turned the gearbox over.!  A number of bolts had been sheered off presumably through over tightening while other bolts were missing altogether.  I have replace all bolts with correct new ones.  I also made all my own gaskets including cork seals and ensured correct end  clearances.

 

I have replaced the clutch and the throwout bearing.  The original clutch plates (there are 4 of them) had worn down to the rivets.  Interestingly, the original plates had the friction material riveted with open ended, or tubular rivets.  As I do not possess the correct equipment  to splay over both ends of the rivets at the same time, I assumed that the replacement clutch plates would come correctly riveted.  I was therefore alarmed to find that the replacements were riveted using cap rivets.  The problem with this is that there is very little friction material above the rivet heads thus a much reduced life expectancy for the clutch.  If I had wanted a cheap job I wouldn't have paid £300 for someone to do what I could have done myself. Ah well.

 

For anyone rebuilding one of these clutches, they will need a suitable press.  Also required is a  tool for compressing the central spring and removing the split rings. I made my own extractor tool from a piece of thick wall tubing of 2" diameter with suitable cut outs that allowed me to remove the rings easily. 

[MikeC5]

I hear you Ray.  It is a slippery slope....  It's not like just slapping in a new set of bearing shells.  I'm sure it will be fine as-is.  Previous owners or mechanics can really leave a mess for us.

[R.White]

Yes Mike you are probably having your own journey of discovery.  As I may have mentioned, my problem is that in the past I would have left any tricky engineering to my Dad who was in a completely different league. When I was a lad I recall him doing quite a trade in converting babbitted con rods to shell bearings and among his effects I even discovered a handy tool for straightening con rods.  Of course he was what we would call "old school" having learned his trade on our sort of car when they were still a common sight on the roads.  I sometimes regret not following my Dad in my choice of career but despite his many achievements and accolades  he was not what you might call happy with his lot so perhaps I should count my blessings.

 

On another point; the flywheel on our cars is exceptionally heavy so perhaps it irons out any small irregularities. With my car, the pins on the flywheel have developed ridges and as they are available I can understand the temptation to replace them.  However,  I have read reports of flywheels being cracked in the process so I chose to adopt a different approach.  The pins need to be smooth enough for the plates to move back and forth as they engage and disengage so I decided to file down the ridges and smooth out the surface with strips of emery cloth.  Fortunately, I still have the anti rattle springs which will be refitted between the pins and the clutch.  I am hopeful this time consuming work will assist with gear changing.

 

It puzzled me for a while as to how the gearbox would be reunited with the engine as there are no splines.  What I think you need to do is fit the clutch to the flywheel when the engine is held in position (not forgetting the anti rattle springs).  There is a small taper on the end of the clutch shaft that helps it into the pilot bearing in the centre of the flywheel  -  and then the spigot on the gearbox mates with the bushed open end of the clutch shaft when you have the gearbox in position.  The only tricky part seems to be handling the large cradle type engine mounting which is in two sections on my car and seems particularly clumsy as a design.

Edited April 8, 2017 by R.White (see edit history)