Rough Running

[dougbgt6]

The current wisdom is to use new uprated cylinder head nuts and new uprated washers. Not sure about the studs but you have to put them in the right way round. Having said that I've replaced my head gasket twice, not because of leaks, but after major rebuilds. And I have to admit that I reused my old nuts and washers and never replaced studs!  That was 20 years ago when I didn't know better, these days I would use all new stuff.

[jamesdennison]

The current wisdom is to use new uprated cylinder head nuts and new uprated washers. Not sure about the studs but you have to put them in the right way round. Having said that I've replaced my head gasket twice, not because of leaks, but after major rebuilds. And I have to admit that I reused my old nuts and washers and never replaced studs!  That was 20 years ago when I didn't know better, these days I would use all new stuff.

 

New it is then!

[Pete Lewis]

Studs will probably do 3 refits

the use of grinding paste to reseat the valve should be fine , if you have the seats machine cut then get some inserts fitted, they only need inserts on the exhaust .but you can fit them to all

 

you may have the air flow ./throttle plates in a state of ballance but your mixture is rich on one carb

so when you correct the mixture you need to re correct the air flow balance

 

I keep whittering on about soft deformed washers as this is what I keep finding , the original nuts

if sound will be ok ,, look at the parts removed is there any signs of deformation ??

 

 

pete

[jamesdennison]

Valves out.  Just waiting for a couple of tools to arrive and I'll regrind - pic attached - look ok?

 

Lesson learnt - use a stud extractor as a last resort 'cos studs are over a fiver each and the stud extractor damages the threads...

 

Re:"Lead Memory" any advice on cleaning the chamber without affecting this?

 

 

[JohnD]

If you regrind the seats, you will remove all trace of a 'lead memory'.

But you should regrind the seats.

Bite the bullet - steel inserts to the exhausts!

John

 

PS Lead memory is in the valve seats and nowhere else.

[Pete Lewis]

not the 'approved' way to re face the seats but if they are lightly pitted , oil the stem,  apply the paste to the seat.  insert valve  then

 

attach battery drill to the stem and with  steady pressure , much in and outing and constant reversing you will soon get a clean up.

 

dont get the valve pockets below the seat and you want a clean narrow seal , not a wide face grind

 

as for the chamber  its down to wire brush scraper, or any complimentary object to dig the corners 

 

the face can be done with a flat block some wet dry with a squirt of oil .

 

note the studs have a slot in the threads at the block end , this stops any hydraulic effect when fitting the studs as this can blow the block

 

I use a stud box with a chuck grip , can be used on an impact wrench

 

 

 

Pete

[jamesdennison]

I've watched a could of youtube videos showing hand vs drill method.  No rush and not something I'll (hopefully) have to do again so I've bought a thing that looks like a small drain plunger for a couple of quid and will have a go by hand. 

 

It all makes much more sense now everything is in bits.  The valve stems have hard oily deposits on them so first job is to get everything cleaned up.  

 

That pic looks like the stud extractor I used - it left a mark through the threads.  I guess I could have used a die to recut the thread but didn't seem the right thing to do on a head stud.

 

I'll probably spend a week or so on this... 

[Pete Lewis]

easy way to clean the the carbon of valves is again best in a pillar drill or a drill in a bench stand,  

 

insert valve stem in chuck  and with a hard implement, old wood chisel , tile cutter etc  spin the valve in the drill and use tool to machine the crud off

 

quick easy effective.

 

doubt you will get far with you mini sink plunger , if there's any debris stuck to the head it will spin off,  and your fingers will go numb

 

that type of extractor   normally clamps   below the thread and only grip on the shank,  did you enter the stud in as far as it would go ?

[jamesdennison]

After a bit too much elbow grease and not a lot of progress the head is now with a local specialist in Telford for reconditioning and unleaded conversion.

 

No 2 valve seat was very pitted and I know it would have bothered me while driving.

 

I'll post a pic of the results when it comes back.

[Pete Lewis]

Fine that sounds a good plan

If there serious pitting youve done the right thing

or you can spend hours going nowhere

 

pete

[jamesdennison]

Head back from XXXXXX

 

£220 well spent I think.

 

Couple of q's before reassembly -

 

1. There is quite a bit of burnt on deposit on top of the pistons.  Should I leave this?  I can't see a way of getting it off without risking bits falling into the bore so I reckon best left alone?

 

2. I assume I don't use any sealant when refitting the gasket

 

3. Should I degrease the top of the block .... or indeed should I actually put a bit of oil on it?

[Pete Lewis]

Payen or copper fit them dry , they need all the grip they can get, add a smear of sealer around the rocker feed, retoque after 100 miles, and reset the tappets

 

Grease or thick oil aound the bore will trap much of what you scrape off turn the engine over a few times to raise the debris to the top of the bore ,

not utopia but quite effective

 

pete

[Mjit]

To clean the tops of the pistons:

1. Get the worlds supply of blue engineers paper towel and a pot of Vaseline.
2. Get 2 of the pistons to TDC, then back them off a little.
3. Apply the Vaseline (that will dissolve to nothing harmful in the oil when the engine runs) liberally to the tops of the 2 bores near TDC then turn the engine to that TDC.
4. Fill every hole you can see with paper towel.
5. Clean up the pistons at TDC wiping/blowing/vacuuming off the detritus.
6. Yank out each of your paper towel hole fillers in turn and replace with new (the idea being to drag any detritus that may have got caught up and away from the engine).
7. Turn engine away from TDC a bit and wipe away the Vaseline (that should have caught any small bits) with more new paper towel.
8. Rotate the engine till the second pair of pistons are at TDC and repeat.

[jamesdennison]

Started putting together today.  I am a bit worried that I have stripped a thread on a head stud.

 

Torqued in proper sequence to 20 / 40 / 60  lb/ft and seemed ok so I went for 65 which is the recommended torque and I felt no 4 slip a bit.

 

I've left it and going to look again in the morning.  I find it odd that this could happen as I'm using new studs and the correct new nuts.  I've done a fair bit of spannering and you tend to get a feel for the limit of torque.  Didn't feel like I was over stressing at the time.

 

Q - will the gasket be ok or by torquing it down will I need a new one?  

 

If the thread is stripped I plan to helicoil. 

[Pete Lewis]

Its pretty unusual for a 7/16 stud to give problems , as the cars not been run a chance with reusing the gasket is probably  ok and going to work,

hope the block has not disintegrated around the tapped hole

cant advise on helicoil on a head stud never tried that

pete

[jamesdennison]

The nut had failed!  Took it all apart again this morning and it was obvious what had happened.  Fitchetts replaced FOC and and I've left them with the failed nut which I couldn't get off the stud.

 

All back together now and torqued up to 60 lb ft

[Pete Lewis]

Trouble is there's nuts and then there's nuts,

there is not much identification on nuts unlike bolts which have some clear markings to show their specification

glad its a simple fix not a disaster

pete

[jamesdennison]

Not going well folks.

 

compression test - 

 

  1       2      3       4      5     6

150   170  150   70    20   120

 

Tappets were set before test.

 

It's not fully back together yet -

carbs are on but not connected throttle cable so not on full throttle (which I know should be done for comp test)

Exhaust manifold is on but not yet connected

No coolant in there yet

 

... but I wouldn't have thought any of this would make much difference.

 

There was a slightly different noise when testing 4 and 5... bit like putting your finger in a bottle and pulling it out.

 

Only other thing that I've done different is to remove the rocker oil feed kit after reading how bad they are on here.

 

Any ideas?

[Pete Lewis]

If the throttles closed you do get low readings ,, not as low as 20

it was 4 in trouble before you started all this, but now 5 has jooned in with a low and 6 poor

Remove the carbs or jam open and test again

Were all plugs out ??

 

Double check your tappets, even double the 0.010" just make sure theres a gap on the firing strokes

 

did they fit new valve guides ???

Pete

[jamesdennison]

May not have been 20, the scale doesn't start until 50 but well in the "red".

 

I'll remove the carbs and give it another go tomorrow.

 

Yes, all plugs out.  I've shined a torch down the 'plug hole and everything seems to be moving up and down and opening and closing fine..... very shiny in fact as everything is spotlessly clean.

 

Head was fully refurbished.  I don't know whether they fitted new guides, but they're a head specialist and gave me a lot of confidence in their ability.  Had a dozen or so heads on the bench ready for the coming week and a similar number on the shelf ready for collection.  They seem to be the specialist used by all the garages in the local area.

 

Tappets are gapped to 0.010 as per manual - I'll try without carbs first and then widen the gap as you suggest.

 

I'll try dry first then put a squirt of engine oil down the 'hole.

 

Fingers crossed.

[Pete Lewis]

Just going back over this you did have a recess around each bore and used a gasket with a tab at the back

 

if you dont have a recess you dont want a tabbed gasket

Pete

[JohnD]

Earlier this year, I ruined a good block when I torqued in the head studs - and cracked the block, just at the front, right into the water jacket. Instant boat anchor.

I learnt two things from this:

1/ my torque wrench was under reading by 20%.

2/ a lot of people, who I respect as triumpheros, do not torque them in at all! I know it says 60 lbs-ft in the book, but just over hand tight is enough for many.

One - two! - or life's little lessons.

John

 

Ps this was in reply to James' cry of "stripped thread" a page back.

He turned not to hve done so, but I share life's lessons.

[jamesdennison]

Just going back over this you did have a recess around each bore and used a gasket with a tab at the back

 

if you dont have a recess you dont want a tabbed gasket

Pete

 

The gasket does have a tab and so did the one that came off so hopefully not the issue.  Just about to take carb off and try compression test again.

[jamesdennison]

Not going well tonight.

 

Carbs off and I realised that by turning the engine over there would be a flow of petrol so I extended the petrol pipe to catch and drips in a bottle.  It wasn't drips it was a torrent so my garage is a no go area for the evening and my wife is not pleased about the smell.

 

I have a knot in the extended hose, a hose clamp and a stopper (bolt) in the end... and it's all raised up but it isn't enough to stop the flow when the engine is turning over.  I can't see a tap to turn off the flow - is there one?  If not, is there a recommended method to stop the fuel coming out?

 

Anyway, I tested no 4 with carbs off before this stopped play - still reading below 50 with or without oil in the chamber.  I rechecked the tappets before doing anything else, they're still 0.010 and haven't closed up.

[dougbgt6]

Disconnect the fuel line before the pump, there should be a rubber section coming up from under the chassis, clamp or block this and the wife will be happy! From the earlier picture your bores do look recessed so the tabbed gasket is correct. Did you did tighten the head nuts in the right order, as in the manual? This can lead to problems if not done correctly. If you did buy that T shirt, slacken the nuts off and redo in the right order, you should be OK. I know JohnD is a guru and knows many things but I would stick to the manual torque wrench settings for now, until you obtain your own gurus badge. And as Pete says double double check your tappet gaps.