red hot exhaust manifold - lt40 2.4 petrol/lpg

Regarding the welding, i have mulled it over at length. Some seem to think silver soldering would be the best option because i could weigh the amount of solder prior to heating up the replacement rod and applying it. Problem with soldering though is that you have to get the rod super red hot first and i dont like the idea of any fractional warping that might occur as a result of the heating.  Arc welding 3 or 4 beads on to the shaft of the rod on both sides in equal positions seems to me the least problematic option although even that might create potential warping. 

The replacement rod i got from portsmouth is out of a 1986/7 mk1 and is so absolutely similar to the old one that it was tempting just to fit it directly but on close inspection you can see some very slight differences in the casting. literally identical in every way though other some slight differences. Even came with old style connecting rod bolts.

Having begun to work on the rod I bent, i can see how it might be possible to relieve it of the 4 thou ovality in the big end. Yes bending it is scary but its bloody tough stuff. We'll try that first, see how we go and if im not happy with the results, then ill weld onto the shaft of the new one. 

Wish it was heavier rather than lighter....then it would have been less problematic to perhaps shave some weight off of the milled pads on the big and little ends. I can literally find not a scrap of info anywhere about anyone adding weight to a light rod anywhere in the vastness of the internet.

My mate reckons that for lycoming engines, they have a 14gram weight difference allowance that they are allowed to run with between con rods but that they always try to match them much closer than that....ie. 1-3 grams difference max.

We are going to set to work on it again this afternoon and ill post updates and perhaps images too if i get my act together.

Here's the remnants of the defect on the bent connecting rod cap after it's been coddled back into some sort of useable shape:

Weighing original rod:

weighing replacement rod:

17 grams less, so we looked at trying to find something that weighed 17 grams to get an idea of how much weld we'd need to add in order to match them. we found a nice fat steel washer that gave us an accurate idea of how much mass to add: 

and proceeded to weld a similar mass evenly distributed between big and little ends:

it aint pretty but it's bang on in terms of weight and balance.

So now I've got both the old and the replacement rods potentially usable and will test them on the crankshaft without installing the piston asap.

unfinished Clearances measured in 0.() mm:

Here is the final bit of the work. We turned a bit of billet to exactly the correct diameter and clamped the con rod up to it with some thin shims inside to aid in the correction.

I'm pretty happy with the results and nervous at the same time. I've had it back on the crank journal and it no longer binds with the bearings in but there is some very mellow polishing on certain points around the new shells which i'm just going to have to chance. 

These are the shells from just before we finalised the big end. These ones bound to the crank journal making it nearly impossible to turn the engine over. The ones that are back on have 75% less scuff than the ones pictured and they allow the crank to turn unhindered. Really they are close as dammit. Will just have to hold my breath....All this shit because I wasn't paying enough attention....

So with the last piston back in place and everything turning as it should, plenty of graphogen on the shells and piston rings, I stuck the nice clean oil pick up assembly back in place and got ready to stick the sump back on before I go on holiday:

The sump is lovely and clean:

Meanwhile the head has had its final loving and is bagged up and back here to be fitted.

So clean you could eat your dinner off it. It's now had a dose of duck oil and wax to preserve it while i faff about painting some of the last bits and pieces.

In order to use the existing shims and not add more time on to the already slow and expensive build we ground a very fractional amount off the end of any of the valves that needed further adjustment since the last time we ground the seats in:

Stem seals back on to the new guides:

some graphite grease and light oil mixture on the stems before installation:

and ready to have the springs compressed and valves installed:

Once its all back together it looks bloody sweet!:

Today I had the engine mounts out of the hole to give them a good going over, a paint and to figure out whether to buy some decent window bonding sealant/adhesive to inject into any loose looking rubber areas. I don't trust them as they are and might as well after this marathon. Single cab pick upflex do a black one for this purpose i think for about 15squid a tube. Might grab that tmrw and figure out how to get it in between the rubber and the metal shroud.

Here are the mounts looking a bit tidier:

It's all so close now. I've stuck the right hand engine mounting arm back on, the water pump, dipstick, clutch kit, the timing belt and the nicely lacquered cover set:

Hopefully the radiator downpipe bracket doesn't get in the way as i lift it in.

Painted and lacquered the cam sprocket but not put it on yet as it has to go on after the head is back on because of the backplate thats fixed the the lump. Also put the fresh exhaust studs back in with a double nut and nipped em up tight with a spanner. Need to get some liquid exhaust gasket and some copper slip before i put the manifolds on:

Cleaned up the old thermostat housing and gave it a lick of wheel trim silver that was laying around. Run out of lacquer. Tough luck:

Cut and slotted some of the old head bolts as dowels for locating the head when it becomes time:

Borrowed my mates clutch locating spindel thing to centralise the friction plate to the flywheel and pressure plate. Dowels on the flywheel, does anyone have any idea what these two are for? They appear to do bugger all:

and finally had a little look to see how much clearance im going to have between valves fully open and top of piston just incase i snap a belt:

I had the nead skimmed to its maximum a while back and the custom pistons have 1.5 mm extra crown height. Valve safe. Even without the gasket depth there is about 0.5 mm clearance just in case of catastrophe. With the head gasket that should come close to 1 mm or perhaps a touch more:

So......Its the manifolds and the engine mounts still to play with and then its ready for the lifting eyes!!! Happy days! 

Having had a look at some earlier postings on here regarding cam sprocket marks in relation to cam lobe/valve positions, i noticed that volition had quoted dreamcatcher as having written this:

Could anyone give me a nod and let me know if this configuration is correct?

Can give you one. Really gonna piss you off if it comes loose or breaks, it's a lot of work to get to it.

Plenty of sites with exploded diagrams where you can get the part number.

Then I'd get on the german ebay etc and see if you can get one.

If you can't get the part then have a go at diy.

The problem for me is no matter what way I look its another 10 days of twiddling my thumbs. I've just tried Pete down in Portsmouth.

Meanwhile still contemplating the DIY job: