First, can someone tell me what the differences are between these three?
Second, has anyone ever made a duplicate of these but of dimensionally thicker metal?
Like so many others, mine had cracks (both sides) in the past that were in turn welded up. The welds appear to have held but whenever it was last done, the engine has since shifted about 3/8" of an inch back mostly on the passenger side (LHD car) making for a distorted bracket in that area and messy interface with the rubber mount. I’ll let it go for now as too many other items are calling for my attention, but I do want to start investigating a long term fix if possible. Also, this car is so early (670236) that the engine has no provision for threaded bosses to attach reinforcement gussets to like the later ones had. So I’m thinking to compensate by fabricating a new horseshoe bracket but of thicker steel. Has this been done before? It looks like there’s room excepting for the lower radiator hose clearance. That could be close. As for the bolt holes, I’d countersink all in order to compensate for the increased thickness. My employer is a railroad so there’s no shortage of scrap steel plate lying about.
Any thoughts here or something I may be overlooking?
Mine was cracked at the lower right timing cover bolt hole, the crack running upwards about maybe an inch and a half as I recall. I opened up the crack on both sides with a cutting wheel in a die grinder so it was like a double vee groove. Then filled both sides with MIG weld, so I got full penetration weld all along both sides. It has not cracked since.
So rather than make a new piece, I would first be sure you have good repair welds.
Here are pictures of my set-up. As one can see, there’s nowhere to attach any reinforcement struts on the block. Welds are still good but the passenger side (LHD) has some distortion of the horseshoe near the rubber motor mount. Almost looks like someone took a pinch bar to this area and muscled things to fit? Like I wrote previously, I can live with this for now but long term I’ll want to try and improve upon this. The horseshoe measures some 0.0160" in thickness or, about 5/32". Down the road, I’m thinking of fabricating an exact replacement but of 1/4" thickness and am wondering what others might think of this. Again, I’d countersink holes as appropriate so original length bolts could be re-used.
Mine measures about 0.165", presumably the same as yours, so they didn’t change the thickness when they added the struts.
You appear to have scooping cuts at the top where the bends are formed, where mine does not. Is yours a C2408 or is it a C2408/1, do you know?
Making a thicker version certainly makes sense; I wonder why the factory didn’t do that, but maybe they saw different failure modes and thought the struts were better. And they added those extra side mounting holes in the block because the same block was used in Mark VII which had side mounts.
Another option is to weld on some horizontal strengthening bars at the bottom where the cracks started.
I don’t think you need to countersink as a 1/16" increase in thickness won’t make much difference on bolt engagement if the bolts go into the block about 1/2", but they are UNF thread so longer bolts are easily found.
I see you have a non-original distributor and water pump.
“Distributor” is actually a Vertex magneto from way back.
Per the SPC, the horseshoe on mine is C2408.
I’m thinking what’s referred to as a “scooping cut” is actually a bend in the bracket along with the angle in which the picture is taken. I’ll consider welding a reinforcement(s) but to do it in situ so close to the magneto (and I do electrically ground it when doing any welding) might not be such a good idea (demagnetization?). Probably best to remove it and make a note on tooth engagement before doing so.
Anyway, what really bothered me most was how the horseshoe/ motor mount interface in the last picture shifted so far aft. I hadn’t seen that before on other cars I’ve worked on.
Given that .165 inch is 4.191mm and we can’t get UK guage steel in Australia and given they were obviously to weak to start with the ones we had lazer cut would have been 5mm thick giving that extra bit of strength.
We had also made the brackets as some restos had later blocks fitted anyway.
I notice picture of mount has rectangular plate on RH side the original spacers were actually I believe under the mount and same shape as bottom plate of mount.
earthing point is usually on the LH side
terry
Those spacer plates under the RH mount were on RHD cars only.
Earth strap is on the opposite side from the steering box, in this case LHD.
Chris, it may become clear why its shifted when you get the radiator out.
September 26th. Boy, did I go off on tangents with this car since the last post. Anyway, I’m revisiting this as I’ve finally removed the old horseshoe. The welded repairs led to warpage of the plate which no one bothered to address afterwards. Second, no one bothered to smooth out the weld beads in those areas where a bolt passes through the plate – making for a poor contact surface. And third, all of the plate holes were drilled out to 7/16" (0.4375"). A pretty good recipe for lateral movement. I’ll deal with it, but what I first need to know is this:
What are the original bolt sizes that secure this plate to the timing cover? I have two that are 5/16", one that is 3/8" and two that are 7/16". I suspect the two largest (7/16") ones were originally 3/8" – is this correct? I’ve pored over my parts catalog but am finding no definitive answer.
Hi Chrstopher I have the same one on my engine the bolts are at the mechanic shop, he will be at my shop next week bring me a E type to paint, I will ask him to bring the bolts with him I have the plate here with me.
Kevin
Looking at a '52 Mark VII block I have here, there are two sizes of bolts into the timing cover and block. The upper bolts are 5/16", but the three lowest on the right side and two lowest on the left side are 3/8".
The studs on the rectangular rubber mounts are 5/16".
The struts and bolts through the plate and into the sides of the block, which I have as shown in my pictures above, but you don’t have, are 7/16".
Now the question is, what size were these studs on the earliest blocks?
And why only 4, not 5, and no nuts?
There is a 3/8" nut listed, but seems to be only on later blocks?
Rob, thanks for turning a critical eye this way. It certainly muddies the picture. Plate A of the parts catalog shows un-numbered bolts securing the horseshoe to the timing cover. But plate C shows studs (with a hex section in their centers instead of separate spacers) and not bolts. Which is correct? My car came with spacers (and they’re of different thicknesses) and bolts. Also, the back side of the horseshoe shows indentations from the spacers – and not hex-shaped ones if the studs had been used. I have no idea why only four studs are listed for this plate instead of five as well.
Perhaps another early '120 owner will have something to contribute on this at some point.
It’s beginning to look like another example of rapidly evolving changes in the XK engine in the first year or two, and the parts catalogue writers not keeping up with every little change.
Ultimately you want to end up with the horseshoe plate parallel to the front face of the block, and the holes for rubber mounts centered over the holes in the chassis mounts. Whether it’s with bolts and spacer sleeves, or double ended hex studs and nuts, or double ended round studs with sleeves and nuts may depend on which timing cover you have.
It looks like you have a motley collection of bolts, so we should assume some of them are not correct.
First off, how is your rear trans mount? Reasonably centered on it’s holes in the chassis shelf?
Measure the offset from the rear face of the horseshoe plate to the centers of the holes in it for the rubber mount.
Can you stretch a string or wire across your front chassis mounting hole centers?
Then get a measurement or two from the string to the front face of the block.
That should equal the total of the horseshoe plate offset plus the timing cover thickness plus the sleeve spacer.
Magnetos are tops in my book. Everything else takes second place. I have an old mag on my Sunbeam Model 9 (a 600cc thumper) and years back I used to curse the starting ritual to no end until having sent it off to be rebuilt. It’s never failed to put out a fat blue spark with an audible snapping sound ever since. I later learned in A&P school of magnetos continued usage to the present day due to their reliability. It’s too bad they aren’t seen as often on cars like ours anymore. They’re a quality item though pricey compared to the alternatives.
A chrome plated horseshoe? You need to keep and polish that as a reminder of the days when it used to be so very cheap to have that sort of thing done. When did the expense of it all change? The '70s? I’m guessing that here in California it might have been around then. Anyway, thanks for sharing this Kevin. Except for the very ends, your holes are all marked as taking 3/8" bolts. I’m thinking now that the earliest engines started with three 3/8" bolts and two 5/16" bolts (or studs?), then went to all 3/8" bolts like yours (assuming a later engine than mine: W1495-8) and finally those rubber bobbins secured through brackets at each side of the block. I’ll leave it to the judges and book writers to parse that one out.
At this point, I just want a set up that won’t shake itself to pieces.
