AC Owners Club Forum

AC Owners Club Forum => AC Weller Engine => Topic started by: GSouthee on December 02, 2015, 15:34:39

Title: Head gasket,valve timing done, All good at last!
Post by: GSouthee on December 02, 2015, 15:34:39

Hi ya now it seems I have a blown head gasket, getting water into oil I think ( milky substance around oil breathers in last week or so, water loss and bubbles into rad when hot. Checked cylinder pressures and rear 2 are down to around 100/110 psi rest at 135+. Somewhat annoyed as engine only done 18000 since rebuild albeit in 1965.
   
   So ordered head gasket and some other gaskets as needed from Rod Briggs. (Bloody hell they cost more than the engine rebuild back i the day).  got everything undone ready loosened head bolts (noted one side was tightened to around 60 psi while other side was around 45 psi all should be 40 psi, strange).
   
   Just cant get the camshaft stud undone, anyone know if it turns in normal direction or is reverse thread????
   
   
   
   Got to get it done as going to new years parade (hopefully)

Title: Head gasket,valve timing done, All good at last!
Post by: GSouthee on December 03, 2015, 19:44:37

Well got bolt/stud out.  Handbrake on, in gear, wheels chocked, heat applied, hardwood wedge in between head casing and sprocket (Thanks Rod Briggs for that one), then 2 foot tube over spanner once the end was cut off and Hey Presto its off.
   
   Now cant get head to split from block. Got under constant pull from above on hoist with straps, so much so it was almost lift car up. Tapped with wood block and club hammer. Don't want to pry it apart in case damage bock face or head. Now soaked all head studs in wd40 and going to get a paint scraper to try and get between the 2 layers of the old gasket.
   
   Anyone got any good ideas let me know.
   
   Dam never had a head like this and rebuilt loads of V8's in the past.
   
   Still perseverance is good for building spirit.
   
   Cheers

Title: Head gasket,valve timing done, All good at last!
Post by: 3.5 Pints at the Bar on December 04, 2015, 10:06:57

Mine came off after cranking the engine to use the compression (on the unaffected cylinders). If there's still say, 100psi, for some cylinders, that equates to about 500lbs lift concentrated around that cylinder. I also hammered in wooden wedges between the gasket layers.
   
   I've known others who suspended the front of the car, hanging on the cylinder head, which applies about 1400lbs force - but being careful how it is attached to a hoist, so as not to risk cracking/breaking the head.

Title: Head gasket,valve timing done, All good at last!
Post by: GSouthee on December 04, 2015, 13:37:26

Cheers 3.5 pints,
   
   Yep mine is still under pull on hoist, don't want to exert too much pull as when it lets go it may take off.  Going to try the scraper, wood wedges etc. too late for the compression thing as timing pulley off now.
   
   Lets hope for success.
   
   Cheers  G

Title: Head gasket,valve timing done, All good at last!
Post by: GSouthee on December 05, 2015, 11:54:06

Finally got it off, paint scraper, 4 hardwood wedges, 1 hoist, a little heat, lots of profanity, and bruised hand (missed a wedge with the hammer, more profanity).
   
   Head looks ok, little blow hole between rear 2 cylinders (see pic link).
   
   Bit of muck in bottom of water jacket will flush out before all goes back together.
   
   https://www.dropbox.com/s/bipj98o3i2k4kd1/DSCN0856.JPG?dl=0
   
   Cheers  G

Title: Head gasket,valve timing done, All good at last!
Post by: BE774 on December 05, 2015, 12:12:42

Hope it was juat a poor head gasket that failed. You probably know that cylinder liner projection is critical on these engines. Are you brave enough to (attempt to) take the liners out to check the condition of the figure of 8 gaskets at the bottom? Or will you just replace the gasket (assuming liner heights OK) and hope that is the end of it with correct torquing and retorquing of the head?
   
   Hope all goes well. Graham.

Title: Head gasket,valve timing done, All good at last!
Post by: GSouthee on December 05, 2015, 18:09:42

Cheers  Graham.
   
   I'm thinking of just doing the head gasket as engine has been rebuilt 18,000 miles ago, I have checked the heights and all looks ok according the series 2 handbook.
   
   Then incremental torquing upto 40 lbs (10,20,30,40) following the torquing pattern as per handbook. Then get run it up get it hot, cool down re torquing, then 100 miles and do again.  (Dam fussy these AC's)
   
   I am going to Hylomar blue as handbook suggest using Hermatite on gasket.
   
   Have flushed a little muck in water jacket and run around inside it with hoover (old Dyson with a very narrow adapted tube) to clear it right out. Not much in there at all, mainly at the rear 2 cylinders, guess that's down to lack of water flow that far back.  Will possibly investigate drilling and tapping block at rear end and run a water pipe to it to aid flow later in year if gasket works out ok.
   
   Now to get a can of high temp paint for head, and clean up inlet manifolds for when carbs come back.
   
   Cheers  Gary

Title: Head gasket,valve timing done, All good at last!
Post by: GSouthee on December 08, 2015, 16:26:52

Right,
   
   Gasket on,  Head on and after knocking the cam wheel and chain loose accidentally adjusting the cam timing as the chain jumped round, had to re adjust the cam timing and bolt on cam wheel (should have bought a vernier one while all was off), All torqued down in sequence and in incremental tightness, left it all afternoon and re torqued, now to leave over night and re torque in morning.
   
   Then, exhaust back on, clean up rocker cover (must get it polished once I find a local metal polisher, too messy to do myself).
   
   Now wait for carbs and fit.
   
   Cheers  G

Title: Head gasket,valve timing done, All good at last!
Post by: BE774 on December 08, 2015, 16:47:12

Hi Gary, glad it is all going back together again.
   
   Hope you don't mind me saying, but could I suggest that it is better to get the engine thoroughly hot and cooled down again before re-torquing the head nuts? This heat cycling allows the castings, liners and gaskets etc. to settle down. Then repeat after one week and again after one month if the vehicle is used regularly (or maybe one month / 3 months if not used much). Look forward to hearing all is sorted in due course. Graham.

Title: Head gasket,valve timing done, All good at last!
Post by: GSouthee on December 08, 2015, 18:33:54

Hi Graham,
   
   All advice welcome,  I was going to run it up hot and cooled down, once carbs back. Yes it is used regularly so will do the one week and one month as well.
   
   Just hope I've got the valve timing right.  I noted the 1/6 mark but also a FP mark on flywheel not mention of its use in the AC handbook.
   Any ideas.
   
   Cheers  Gary

Title: Head gasket,valve timing done, All good at last!
Post by: BE774 on December 08, 2015, 20:55:57

Not absolutely sure about FP, I think it stands for firing point. All my books are still packed away after moving so cannot check. Does the FP mark's position correspond approximately to the expected ignition timing point? Sorry can't be more helpful. Graham.

Title: Head gasket,valve timing done, All good at last!
Post by: GSouthee on December 09, 2015, 15:54:51

Yep on measuring it is as you say Firing Position/Point.  You would have thought that AC would have mentioned it in the handbook.
   
   Anyway exhaust manifolds back on after a repaint in stove black, had thermostat case machined to take normal 72 degree thermostat and then polished up case, re-fit tomorrow.
   
   All looking good.
   
   Cheers  G

Title: Head gasket,valve timing done, All good at last!
Post by: GSouthee on December 15, 2015, 09:16:40

Dam  thought I would check all the valve gap settings. Anyway decided to turn on the timing wheel nut as it was easy to get to at the same time as being at the top end whilst poking about with feeler gauge.
   
   Guess what this Muppet managed to. No! I slipped and dropped the spanner down the inside the timing chain case. Gulp, swear, sweat. Then next half an hour with one of those long flexi claw things with the plunger that works the claws and a  smallish ring magnet on a length of wire I got it back out.  Phew, thoughts of head back of and another expensive new gasket flashed through my mind.  Wont do that again.
   
   Anyone got a spare starter handle as I have not got one.
   
   Carbs on way back so will be fitting them next.
   
   
   Cheers  G

Title: Head gasket,valve timing done, All good at last!
Post by: GSouthee on December 17, 2015, 17:29:33

Well it seems the valve timing is out, Will get to it tomorrow. Looks like long thin bar for the timing tensioner and move a tooth round on the wheel.

Title: Head gasket,valve timing done, All good at last!
Post by: GSouthee on December 19, 2015, 15:51:45

Ha thought that would be easy but is it, by buggery not.  Has anyone done the valve timing adjustment, does the wheel need to come off onto the resting plate or am I just not getting enough leverage on the tensioner to do on cam?
   
   Will have another go tomorrow.
   
   G

Title: Head gasket,valve timing done, All good at last!
Post by: GSouthee on December 20, 2015, 13:24:55

Well managed to get valve timing wheel round one tooth, but on starting it appears to be still out, had to advance dizzy too much to get running and misting back through carbs indicates inlet still opening too early.  Not sure if another tooth will be too far the other way yet, if it is may have to get the wheel off and drill some adjusting holes in it as per Leo Archibold's book. Got to out this pm so will leave it till tomorrow.
   
   Ho Hum the joys of old AC's.  (Almost had thoughts of taking engine out and slipping in one of my V8's either Rover 3.5 and 5 speed  or Daimler 250 Auto, maybe one day if this engine gives up).
   
   Cheers  G

Title: Head gasket,valve timing done, All good at last!
Post by: GSouthee on December 23, 2015, 09:27:36

Valve timing set eventually, getting good at slipping timing wheel  and chain off now. Got it spot on with some holes drilled in the wheel so as to turn by less degrees than one tooth allows. Fired up easily and spitting gone from carbs, carbs running beautifully.
   
   But and a big but!  there is now a awful deep knocking from down below (in the engine not me). Was not there before head gasket done, sounds like ends, not sure how or why it should happen but get to just over 1200 rpm and its starts to knock away.
   
   Had a word with Steve Gray who suggests dropping sump and checking ends, though he does not understand why it should appear if not there beforehand. So it looks like only option at mo, just put in all fresh oil as well, Dam.
   
   If ends are cooked, I will have to consider options. Rebuild bottom end, if to do that I might as well have modern seals fitted front and rear, possibly have big ends shelled instead of white metaled and have a front damper conversion instead of flywheel damper.  Not sure of costs (but am led to believe an arm and a leg come to mind).
   
   Other option is to fit another type of engine, possibilities inc a Rover V8 (tad too much power), Daimler 2.5 V8 (much more in keeping with early style and less power) or some other straight 6.  I know Rovers very well and would be my obvious choice as have built many in past. But I do like the look of the AC engine and it keep it all original. Just not sure if alleged costs would be viable for a Saloon.
   
   Still it will give me something to think about in the Xmas to New Year gap.
   
   So with the consultant telling my pins in foot won't be out before New Year and now the engine looks like for trip to the New Years parade is out of the window.
   
   Ho Hum.
   
   Cheers  G

Title: Head gasket,valve timing done, All good at last!
Post by: Flyinghorse on December 23, 2015, 10:48:00

I would be surprised if the big end had just suddenly gone what with no miles done,unless you had an oil blockage. Also would your oil pressure not have dropped?
   Did you drop more into the engine than you suspected when your spanner slipped?
   
   Have you retimed it and reset the valve tappets (Can create surprising noise) since all the valve timing issues?
   
   I use a long screwdriver to find the precise knock location.
   
   Its not clear to me from your note if the knocking gets worse above 1200rpm or below? I always thought the big end were worse at low idle.
   Good luck as I had been enjoying this thread with someone wielding the  spanners.

Title: Head gasket,valve timing done, All good at last!
Post by: GSouthee on December 23, 2015, 13:47:17

Hi Flying horse.
   
   No only dropped the spanner once. after that made sure it was stuffed with rag around it.
   
   Oil pressure excellent, I thought I would see a drop but not on this occasion.
   
   Knock only comes in as engine revs climb, don't want to do it too much as may cause further damage.
   
   I am going to check valve timing and gaps again as someone has suggested it may 180degs out, not sure how I would have done that but who knows.
   
   Oh my head hurts.
   
   Cheers  Gary

Title: Head gasket,valve timing done, All good at last!
Post by: 3.5 Pints at the Bar on December 23, 2015, 14:34:24

If you're valve timing is okay, then you might want to check that the distributor isn't over-advancing as the revs pick up. Check the centrifugal weights, etc. Big end trouble seems unlikely.

Title: Head gasket,valve timing done, All good at last!
Post by: GSouthee on December 23, 2015, 16:21:41

Cheers  3.5 pints, will check that as well. I hope it is something basic that i've missed.
   
   Cheers G

Title: Head gasket,valve timing done, All good at last!
Post by: Flyinghorse on December 23, 2015, 17:49:49

You did mention you had advanced the timing previously so pinking/knocking is possible as 3.5pints suggests. May be an easy fix for you.
   I would start from basics and do the tappets/valve clearances first,then set static timing off flywheel/using a light, followed by fine tuning with a strobe.
   
   I don't know the AC 2 litre engine or  saloon but my Bristol 400 (an in period competitor)  also has an advance retard knob in the cabin,and has no vacuum advance--did you set the static  timing with this in the right position(i cant recall what the Bristol manual says) but you will see if retards or advance by pulling the lever.
   
   Good luck -sounds like you need a break!
   
   Graham

Title: Head gasket,valve timing done, All good at last!
Post by: GSouthee on December 24, 2015, 13:21:42

Hi Well went back down garage this am, I went back to basic and first checked the valve timing again and it was a tad out so went round another hole (the ones that I drilled in it to allow tighter timing) on the cam wheel, now right on the nose at timing point. Then ensure the dizzy in the right place, all good within a degree or 2 for start up, Then checked the valve gaps again and blimey so far out it was untrue they were nearer 10 thou not 20 thou some were almost 8 thou. I can only think in all my adjustments that I forgot to re-gap after all the adjustments. Went through each one, marking the top with a dob of typex so I knew where I was up to. Double checked the timing again.
   
   Connect Battery, put rocker cover back on, turn on ignition, turn on battery, lean down press solenoid on starter and, and , and  it started first time. No noise, No rattles, a little fast on tickover so will probably have to reset carbs and ignition timing after xmas.
   
   Let it run up for 15 minutes to get hot, still no prob's.
   
   So moral of the story is do a checklist as you go along, double check every thing, listen to other folk, check again.
   
   So thanks all who gave advice/ideas etc. Now don,t have to think of costly rebuild or retro fit another type of engine (the V8's will have to wait for another project).
   
   Now if the consultant is good to me on new years eve and removes my pins from foot op I shall go the London New Years parade.
   
   Cheers all and a merry xmas.
   
   G

Title: Head gasket,valve timing done, All good at last!
Post by: BE774 on December 24, 2015, 15:30:51

Good news, Gary! Don't forget to re-torque the cylinder head. Have a relaxed Christmas and an even better New Year's parade.

Title: Head gasket,valve timing done, All good at last!
Post by: GSouthee on December 26, 2015, 09:35:22

Cheers,
   
   Have already re-torqued it after running it up hot will do again later in week, and then hopefully give it a run on New Years eve before another re-torque.
   
   Cheers  Gary

Title: Head gasket,valve timing done, All good at last!
Post by: GSouthee on January 02, 2016, 16:33:14

Well went to New year parade and all was well. No running probs. Just re-torqued head, very slight tightening before wrench clicked in. Now leave it alone for a couple of hundred miles before last tighten up.
   
   However will need to get a couple of rocker gaskets as this blue paper type I got from Rod Briggs has come apart now and is currently held in place with a smear of Hylomar.  Does anybody do a cork rocker gasket or is there something better. I thought a smear of vaseline would stop it sticking to the head/rocker cover by no.
   
   Next on list will be doing the leaky front oil seal.
   
   Cheers  all
   
   G

Title: Head gasket,valve timing done, All good at last!
Post by: BE774 on January 02, 2016, 17:22:53

Glad the car behaved itself and you were able to attend the event, Gary.