Updated: Mar 5
Ever now and then a classic comes through the workshop that doesn’t need chopping to piece’s. This is one of those cars. Super tidy inside outside and underneath. The only thing the owner of this Austin Healey 3000 wanted was repair to a blowing and knocking exhaust system and rear seat belts fitted.
This is a very welcome sight when working under a car. At the end of a day working under this I almost didn’t need to wash my hands.
The exhaust blowing noise was found to be coming from the gap around the exhaust clamp.
We can see from where the carbon has built up inside the silencer (arrowed) that the rear section wasn’t pushed in far enough to stop the gasses from leaking out.
All exhaust mating surfaces were cleaned of the carbon deposits ready for reassembly.
Exhaust is reassembled this time using exhaust paste to insure a gas tight seal.
At this point the rear section was adjusted away from the body as can be seen above in a before and after. It’s not a huge change but it’s enough to stop the tail pipes hitting the rear valence.
Next up is the seat belts. The will be bolted strait to the floor but the will have to be braced.
Hear we can see the rear seating area from underneath. This is where the seat belts will be anchored. There’s not a great deal of room to work but it’s not to much of a problem.
A sheet of 16 gauge steel spanning the width of the rear seat along with the existing floor, rear bulk head flange and 4 very large washers is more than enough to anchor the new rear lap belts.
Exhaust and belts done this one is ready for the road again.
A pleasure to work on I look forward to working on it again.
Not so easy Healey
Some time after the first lot of work on the Healey, the owner returned the car stating that it was using oil and losing power. At first I had hoped an ignition service and new valve stem oil seals would cure the problem, however after inspecting a very smokey crank case breather with very strong smell of petrol it became clear that combustion gasses were passing the piston rings into the block.
Off with its head! At first glance the head gasket looks ok. The problems lay within the bores.
The block is removed separately from the head simply because it's a big heavy engine coming out of a pretty small hole. For safety sake I wanted to make the load on the engine crane as light as possible.
Once the engine was out I could begin to remove the crank and pistons. The nuts holding the main cap in place came off without a problem but the big end bolts were more of a pain. The top of the bolt has a retaining pin that stops it from turning while it's being tightened or undone. Unfortunately those pins had sheered off meaning the bolt was turning at the same time as the nut I was trying to undo. The only thing I could do was cut the nuts off the bolts and replace the whole lot.
It's pretty clear what the problem is hear. The top compression ring has broken up and tried to escape out the side of the bore.
After removing the rest of the pistons I found that all 6 had broken compression rings. It's a miracle this car was able to run at all. Hard to believe but even with all this damage the car was still running quite smoothly. I guess they just don't make cars like they use to.
Big end bearing have significant scoring. Probably picked up fragments of the broken up piston rings. Needless to say they have been replaced with oversize bearings now.
Main cap bearings are much the same.
The sump bares the evidence of an exploded piston ring. Lots of little bits on the bottom of the sump would easily find there way into the crank journals and cause even more damage if not cleaned up.
Nice and clean now ready for refitting.
Combustion chambers show significant carbon deposits. This kind of build up can be caused by a rich fuel mixture but in this case it's due to oil entering the combustion chamber through the damaged piston rings and being burned with the fuel.
Hear we can see a massive amount of carbon build up on the inlet valve. This suggests that not only has oil been leaking past the piston rings but also the valve stem oil seals.
This is what a straight 6 engine looks like when every piece has been stripped off. This little lot stretches the length of the car and a fair portion of it will be replaced or machined before it goes back together.
While the head, block and crank were away at the machine shop I had a few other things to do. The first of which was cleaning the engine bay.
Most of the dirt was just oil and grease which wiped lean without needed any detergents. A good clean and the odd paint touch up and I think it came out pretty well.
Next was the front brakes. The pads were nearly new so no need to replace them but the discs had become scored and pitted and weren't working to the full potential. The discs on the Healey are removed complete with the hub bearings. It might make sense to replace those at this point but there was really nothing wrong with them so it was rebuilt with the same bearings.
Old disc scored and pitted.
New disc nice and clean and most importantly flat. Flat discs vs scored pitted discs obviously offer far more contact surface between the discs and pads and therefore more stopping power.
Front brakes all done. The calliper pistons on the driver side were also freed at this time as they had been sticking.
Rear drums were the same story as the front discs although after fitting the brake shoes must be adjusted to suit the new drums.
Something I had noticed during the initial inspection was that gearbox rear stabiliser bush looked like it had been eaten.
A new polyurethane bush was fitted as a replacement.
One of the exhaust mounts had begun to delaminate and so was replaced with a new one before it gave up completely.
A new fuel pump came next. The old one was getting noisy and the owner didnt want to be stranded on the side of the road when it decides to give up and so a new one was ordered. The new one wasn't a perfect match but it's pretty close. Any parts needed to make the new one fit were taken off the old pump.
Back to the engine side and the all the parts are back from the machine shop. The head has been pressure tested, refaced and had hardened exhaust valve seats fitted allowing for the car to run on unleaded petrol without the use of additives. The original valves have been reused after having all the carbon cleaned off and then being re-cut into the seats and vacume sealed.
The head was also fitted with new bronze valve guides due to the old guides being to badly worn for re-use.
New pistons assembled into the old connecting rods with new gudgion pins and retaining clips. Old pistons ( as seen next to the new) were already +0.30 oversize. Due to the damage caused to the bores by the exploded piston rings it was necessary to rebore the block and fit new +0.60 over sized pistons.
Big end bearings are +0.30 over size to suit the reground crank.
new crank main bearings also at +0.30 oversize.
Hear we can see the new crank main bearing halves in place. The other half is fitted to the main cap which is fitted once the crank is in place. Large amounts of assembly lube is used at this point to insure the crank is properly lubricated for its first start up. The bores are also heavily coated in engine oil before the pistons are fitted.
Hear we can see the pistons going into the bores. This tool compresses the piston rings making it easy to knock the pistons in. It's important at this stage to insure that non of the piston ring closing gaps line up. If they are in line it makes it easier for combustion gasses to escape into the block.
With the crank and pistons now fitted, the end float needs to be checked ( this is the forward-backward motion of the crank) incorrect end float would require a new oversize thrust bearing to be fitted.
The end float on the crank is measured using a dial guage and on this engine should be somewhere between 0.063mm and 0.140mm. Less than that a would not leave room for the crank to expand when the engine is hot. More that that and crank would have to much room to move. In both cases the crank would wear out quickly. In this case how ever the end float is measured at 0.070. No oversize thrust bearing was needed although a new standard size bearing was fitted.
The Healey had already had a clutch kit fitted relatively recently in terms of mileage so all that was fitted was a new friction plate.
There are several clutch alignment tools available but iv always used this method and it's never failed me. A threaded bar into the first motion bearing, a nut holding the friction plate in place and a socket aligning it to the pressure plate is all that is needed.
As with the oil pump, cam, pistons and crank, the cam followers are liberally coated in oil before fitting.
Engine now back in the car seen hear with new water pump, head studs and gasket fitted. Very nice looking engine. Not something you'll see under a modern bonnet.
Once the head is on and fully assembled, the valve clearance is set at 0.12" by inserting a feeler guage between the rocker arm and valve stem and making adjustments on the other side of the arm. The feeler guage should slightly drag between the two surfaces for perfect clearance.
A compression test is done as the final job and shows just over 150 psi on all 6 pistons.
All done at last and back on the road.