Javelin LRM 957 - a Restoration Project

[David Morris]

Hi Keith,

Thanks for your email. We were using the existing bolts, with new washers, replicating those used previously.

I did try to post a photo, thinking this might be useful, but when I clicked on the 'Insert Image' icon, the result just shows an unintelligible computer message, so I gave up.

David

[Keith Clements]

The image icon is used to include a link to an image that is already stored on the Internet.
To add an image see post in Bradford forum.

[David Morris]

Hi All,

Thanks to Keith's help, I think I might have managed to post the photo of the internal damage to a spare crankcase, caused by the Big End bolt head?

Or maybe not?

For backup, I plan to send the photo to Keith, so perhaps he can insert it? The scuffing can be seen just below the liner.

All the best,

David

[David Morris]

Hi All,

No, it looks as if I have been successful!

Completely chuffed by this success, I have also attached the photos of John Airey's balance pipe test rig, which was great to use at his Swindon Workshop!

All the best,

David

[David Morris]

Hi All,

We pressed forward yesterday with the engine build-up. Vic had kindly been donated some new washers from Nigel Woodford for the big-end bolts that were thinner than the original split type and were internally serrated. These gave slightly less height for the big end bolts when tightened and thus better clearance within the crankcase.

We fitted the baffle plate over the crankshaft and, after making a new sump gasket, fitted the sump. Vic had already fitted the oil pump, after making sure the gauze was clean and the spray nozzle from the pump was clear. The pump we fitted was the latest type, with the adjustable oil pressure cut off and the deepest body.

I may have mentioned this before, but when over at John Airey's Swindon workshop, he had kindly drilled out the oilway that goes from the oil feed pipe to the main oil galleries, via the rear timing case cover. We had noticed that Jowett's had obviously increased the width of the main oil galleries when the block had been back to the factory, as they had fitted the larger brass end plugs to the enlarged oil galleries. We could see that Jowett's had fitted their reconditioning plate to the crankcase, showing that they had reconditioned the engine sometime in the past.

Vic had fitted the bell housing, complete with the new rear oil seal from JCS and we then fitted the flywheel, torquing up the flywheel bolts to the correct value of 75ft/lbs. We oiled and gently inserted the camshaft and push rods. Again, we had selected what seemed to be the best camshaft from the eight blocks that we had in the garage, making sure that we didn't choose one from an engine with hydraulic tappets, as these are different to ones from the later mechanical tappets. Also, we selected a camshaft that was the later vernier type, to aid our later adjustment. This engine really is a 'bittsa' ! Time now to apply some Wellseal to the faces of the crankcase and carefully fit the new head gaskets, also from JCS. These were the later NZ pattern, supplied complete with the small 'O' ring. Vic had sorted out the correct selection of small and large washers for the head bolts, plus the ones for the rocker shaft.

This would be a tense time, as I have experienced previously that horrible sound of a block cracking when tightening down the head studs! We carefully fitted the solder wire under the washers of the top head studs and took everything down to an initial 20ft.lbs., making sure we had fitted the rubber washer under the rocker shaft oil banjo, plus it's larger washer. Slowly we progressed, until we reached the final figure of 37.5ft/lbs. Phew!

Time for some lunch and gather some strength for the next stage of fitting the timing gears. She's getting there!

All the best,

David

[David Morris]

Hi All,

Vic and I pushed ahead with the engine assembly today. We are having to fit our time on the engine around hospital appointments for Vic’s partner Carol and myself. I had my appointment with the cardiac specialist yesterday. I was surprised to learn that my heart artery that was blocked was so tiny! Apparently, all the heart arteries are no wider that the plastic tube inside a ball point pen! No wonder that they get blocked! Perhaps we need a filter fitting somewhere?

Anyway, back to the engine. It was time to set the valves and close-up the front of the engine. We were following the detailed instructions available in the Technical Notes in the Jowett technical Library. Vic had made up the bracket needed to hold my dial gauge positioned firmly up against the end of the push rod for No.1 Inlet valve, after taking up all the slack as instructed by the manual. I had printed out a circular timing chart that I had laminated to keep it stiff and we mounted this on the crankshaft nose, complete with a pointer. Having fitted the flywheel, we set it to the mark for TDC ½ and set the chart to 0 Degrees. Then, as instructed, we backed-off by 35 Degrees and then slowly went clockwise until the flywheel showed the 12 Degree BTDC mark. This agreed with the marking on the timing chart, which gave us some confidence. So, hopefully, the crankshaft was in the right position.

We then moved the camshaft clockwise, checking that the dial gauge was showing that the cam follower was on the heel of the cam and not showing any movement. We had set the indicator to 0. Then, we started to see movement on the pushrod, as indicated on the dial gauge. When this reached 0.014” lift, as instructed, we stopped moving the camshaft and, for safety, put a Tipex line on the camshaft boss. We then assembled the lower cam chain chainwheel, followed by the upper chainwheel onto the camshaft boss. It took a couple of repeats of this whole procedure to find the ‘sweet spot’ where the dowel pin could be inserted into one of the camshaft setting holes without anything moving. We found using the reverse end of a twist drill that was close to the size of the dowel helped to find the ‘best fit’ hole in the camshaft boss.

Having clamped-up the camshaft bolts, remembering the tab plate, we rotated the crankshaft two full turns until the 12 degree point arrived on the flywheel again and we checked the 0.014” lift on the push rod. It all seemed ok! We locked the tabs on the camshaft. Then came the chain, which fortunately had a removable link.

Next was the Rear Timing Cover (RTC). We had checked previously that the RTC was a good fit to the faces on the block and that there were no rough edges to the fixing holes. We fitted a stud to the passenger side fixing hole, instead of the normal bolt and coated the block face with a thin smear of Wellseal. Then came the aluminium gasket and the three Nitrile ‘O’ rings that sit in the new-style aluminium gasket, kindly made by John Airey. I have attached a photo of the new gasket in position. We have found that this new-style gasket helps to solve the major source of oil leaks on the engine. The reason for the stud is that this helps locate the aluminium gasket during assembly, otherwise the whole delicate assembly slides around under the RTC faces. Having applied a smear of Wellseal to the mating face of the RTC, this was then bolted down to the crankcase.
Then we prepared the front cover, which Vic had fitted with a new nose oil seal. The five holes in the Front Cover that align with the RTC were opened out by around 2mm with a suitable twist drill, so there was no tendency to pull the RTC forward out of position. I had cut a new Front Timing Cover gasket and this was coated with Wellseal. All the remaining long bolts were then fitted, but the five that locate into the RTC were only gently tightened to around 15ft/lbs. The lower ones into the sump were also fitted. We had removed the oil filler tube, to gain access to the top RTC stud, and the bolt holding the tube was carefully replaced, keeping hold of the bolt, to make sure it didn’t drop into the sump! Having the tube loose also enabled some fiddling with the crankcase breather pipe and pintle valve.

Next time it will be time to set the valve gaps and the remaining bits and pieces on top of the engine! We might even get to put her back into the car! Wow!

All the best to you all and do enjoy what looks like our summer?

David

[Keith Clements]

if you make the aluminium gasket yourself it is worth checking with engineers' blue that the 3 holes made are as central as they can be to the bottom AND top facing holes. The alignment of the holes is not concentric because of the angles involved . You are also constrained by the amount of meat required to safely hold the O ring in place. Of course THE expert made this one.

[David Morris]

Hi Keith,

Thanks for your email. I asked John Airey for his advice and apparently the Australian JCC advise plugging at least one set of the holes and re-drilling, as the original Jowett assembly didn't get the oil ways in the RTC and the block to align. Hence, once drilled, they can then use a standard gasket. Without this, you have to resort to a degree of 'personification' in the manufacture of the aluminium gasket, plus quite a lot of luck! Fingers crossed!

I suspect the factory used engineers blue and quite a lot of item selection from a pile of RTCs. I know Drummond has found at least five different types of RTC. It's a horrible design and I wish Gerald Palmer had spent a bit longer avoiding that angled joint. A real 'Friday afternoon' job! If he had brought the block faces up to form a decent flat joint and maybe used drilled dowels, together with 'O' rings from the start, we would have engines that were much drier? Jowett's were no strangers to 'O' rings, as they used them on the balance pipe and later on the bottom liner seals and finally, as Wills Rings, on top of the liners.

Many thanks,

David

[David Morris]

Hi All,

No more news at the moment, but I have been thinking....With Javelin and presumably Jupiter engines as well, there is often a big difference between one engine and another. Some are really lively, others are rather flat and unresponsive. What governs this? My thinking at the moment concerns the valve setting that Vic and I did on this engine last week. We religiously followed the instructions in the manual and the Technical Notes and, of course, hope that the result is OK.

But presumably the instructions were written to apply to a fresh engine, with no wear and all pristine? Now, we are having to cope with 65 years of wear on the components, camshaft, tappets, valve train and the valves themselves. Should we be changing the instructions in the light of wear and building-in a modifying allowance? When I was measuring the root and lobe dimensions of various camshafts, to sort the ones that were designed for hydraulic tappets and those later ones for solid tappets, I found wide discrepancies in wear. Should the instructions suggest that we firstly measure the camshaft for wear and perhaps the whole valve train, then apply this to the valve lift specified in the 'book', resulting in a different figure to the 0.014" lift in the original instructions?

Just a thought, but I would be interested in any views?

All the best,

David

[Keith Clements]

Look in JT for a discussion on the work Philip Dingle did on camshafts. Also the results I had when modifying the advance curve of the ignition. Also the work on combustion chamber gas flow and valve seat angles.

Valve timing is critical and since it is not variable it is a compromise to get the best cylinder charge at the normal cruising revs. The aim being to scavenge the exhaust gas and replenish with the correct combustible mixture.

I have fitted various modified camshafts for racing and rallying which required different valve timing set up since they had different profiles. Your presumption that a worn camshaft could benefit from a different set up is probably correct...but better to fit a new camshaft and get rid of the wear in the cam shaft bearing housing.

[David Morris]

Thanks Keith,

Did you need to modify the valve timing setting criteria when using different profile cams? I have looked through my notes and see that I had found at least four different camshafts for the Javelin engine, identified by Jowett part numbers as :- 50662, 54151, J54538 and J54651. I guess the earliest one would have been for the hydraulic tappets? Followed by the first solid tappet one that did not have the vernier peg setting and then the two later iterations, with their J numbers? I suspect there must have been others? Pity the part numbers are not etched on the camshafts, as they are on some components.

Did all these camshafts require the same valve setting of 0.014" lift on No.1 inlet?

As for your suggestion about using a new camshaft, it would be nice, but finances decreed that we are using the best components from the engines we have dismantled. Getting rid of the wear in the camshaft bearing housings would surely involve a big expense, with associated line boring, sourcing an oversize camshaft ( if still available ), or sleeving the housings? We checked the wear in the block and it was within the 0.002" allowed, although as you have mentioned the centre bearing is subject to the most wear. Fingers crossed that she runs well and our efforts are worthwhile. The moment of truth beckons!

All the best,

David

[Keith Clements]

I have fitted various modified camshafts for racing and rallying which required different valve timing set up since they had different profiles

I cannot remember what the differences were however but think the higher lift cam needed an earlier opening. No doubt Google will reveal the answer! Richard Gane has also used many cams so should be able to say. Race engines do pop at low revs caused by the early opening of the inlet valve and greater overlap of inlet and exhaust open. Exhaust pipe and inlet tract tuning also assists in the scavenge at a particular rev range.
https://en.m.wikipedia.org/wiki/Variable_valve_timing but that is about reducing emissions.

[David Morris]

Hi All,

First, thanks to Keith for his reply. We were back on the engine today. First job was to set the tappets, not crucial at this stage to be exact, as we will need to re-adjust when the heads are tightened down, after 20 mins of running ( being hopeful about her starting! ). Like many, I advocate setting the push rod clearances to a point when they just rotate, making sure the tappet is firmly on the heel of the cam.

Then to fit the distributor. I guess this may bring a couple of adverse comments, but I have had success on my Javelin, DCB 246, by fitting a few years ago a new 25D distributor originally profiled for a 1963 MGB. The cam profile looks very similar to the later Jowett's and they are available new at less than £40. It's great to have a distributor that feels fresh and without any 'slop'. We had to cut the two slots in the new driving peg, for the original snap ring. New leads and plug caps followed.

Vic had previously fitted the clutch and the associated release bearing parts, plus the spin-on oil filter and bypass hose, so the next job was to slide the engine into the car. I know that there are two schools of thought, as to whether to fit the gearbox to the engine out of the car, but I favour fitting the gearbox without the engine in place and then slide the engine in later. It is much easier to connect the gearbox without the engine in place and avoids having to twist your hands through that silly little oval access hatch in the front floor. You just have to get everything lined up and perhaps give the crankshaft a bit of a twist, to align the clutch splines.

Anyway, we managed it and I have attached ( hopefully? ) a couple of photos. I had to pack up then, but I know Vic will enjoy making the various pipe connections and filling her with oil. Next time, we should be pressing that starter button! Wow!

All the best,

David

[Keith Clements]

Be careful with the MG distributor, it may have way too much advance for the Jowett and eventually break the block. The max advance should not be more than 25 deg (23 deg is probably the best for the standard Jowett cam and modern petrol) without vacuum and another 10 degrees with vacuum measured on the crank. A strobe with built in adjustment to bring the strobe light back to TDC is ideal to check.
Worn dizzies give too much initial advance, so if set up statically often run poorly at 600 rpm. They may also cause difficult starting if set up on the strobe.

[David Morris]

Thanks Keith,

Assuming she starts when we have her all connected, we will use a strobe light to check TDC, having marked the front pulley. We will follow this by a check on the advance introduced when the vacuum is applied and make sure the figures you quote are not exceeded.

Thanks,

David