Dipped in green glass

[That Man]

Quoted from Nick Moore

Followers in, followers out. I bought a set of Rimmers 'uprated' followers (I know, I know). They're advertised as harder and lighter, and given the frequency of camshaft or follower failures, I wanted to give the engine its best chance at a long life. The followers are about 32g, very thin-walled and tuftrided. They look the business, anyway.

However, when I lubed them up and popped them into the block, they were very tight. Some needed drifting into their bores! That seemed wrong, so I pulled out the camshaft and drifted the followers out again. The culprit seems to be the nitride coating. I'll sand them slightly with wet and dry and try to get them sliding easily. I do not want them seizing on startup. And yes, I do have the proper cam lube to protect the lobes.

The chances are is they have gone oval, this can easily happen when machining a cast component as i believe the cam followers are, do you have a micrometer? according to the book the new tappet to bore clearances are only 0.0013" to 0.002" so not much room for any distortion. I also doubt they have been nitride hardened more likely tuffrided, as only a few alloy steels (and titanium) can be nitrided. AFAIK only Newman do nitrided followers. Neither of these processes should cause the followers to grow in size, but again may have caused distortion  

[Nick Moore]

Hey Man,
Thanks for the info about the bore clearances. You may have a point about the lifters being distorted. I spent about three hours yesterday working on their sides with 240 grit emery paper. The black coating is off and the lifters move much more freely. I'm happy that none will seize now. Only the sides were polished - I'll let the cam lobes polish the bases, as I didn't want to compromise the hardening.

I don't have a micrometer so haven't been able to check for distortion. Your suggestion makes sense though. Once their sides were polished, some lifters slid in their bores easily. Others were more reluctant. Swapping lifters around showed that the problem was the lifters, not the bores. A troublesome lifter would jam in every bore, a freely moving lifter would move easily in every bore. It felt as though the troublesome lifters were flared - the first half always slides in easily, and then they would tighten up. Ovaling (sp?) of the thin walls would produce the same behaviour though.

Interestingly, the lifter bores are stepped. The first section is quite loose and the lower portion much tighter. Presumably that's so that oil can seep between the upper bore wall and lifter body, while the portion of the lifter nearest the camshaft isn't free enough to wobble around. Clever old Triumph.

I'm not going to send them back. All the lifters move easily now they've been polished, although the troublesome ones still get stiff once past their operating range. And if I did send them back, can you imagine someone at Rimmers sitting down with emery paper and a micrometer and checking that the replacements were round? Nah, they'd use sling another set in the post and let me check. I'm in Australia, so don't fancy a game of parcel to-and-fro!

[Nick Moore]

OK, after typing the last post, I went back to the garage and had a think. Refitting the camshaft showed that eight followers do indeed move smoothly as they follow the cam lobes. That means they'll be able to rotate and not wear prematurely. The other four, though, don't move freely at the bottom of their travel, even after more polishing (I'm gonna steal Mr Chatterton's crown at this rate). One jammed so hard I had to drive it up from underneath!

A trawl back through the forum showed that camshaft witchery is a recurring problem: Sorry , link no longer available Just because the camshaft and followers all come from Rimmers, doesn't mean that they're designed to complement each other 🙁  I think I'll take Andy Thompson's advice and order a set of followers from Wishbone Classics.

This must be the longest engine rebuild in history - everything needs measuring, polishing or trial assembling!

[Nick Moore]

Aaaarrrrgh!

This afternoon's job was trial-assembling the bottom end so I could see where the sump needs modifying for the longer stroke crankshaft. It's never that simple though, is it?

When I rotated the crank, I could detect some stiffness at one point. Feeling the movement of the pistons as they went through their cycles showed that the problem was in cylinder 3 - the skirt of #3 piston is grazing the crankshaft's counterbalance at the bottom of its stroke. A borescope confirmed the problem - see the crappy photo. I painted the suspect section of skirt and sure enough, a patch of paint was wiped off by the crank. So, I guess the piston will need a chunk of its skirt scalloped. The alternative, machining the crankshaft's counterweight, isn't a good idea as the bottom end has already been balanced.

While I could grind a bit of the piston skirt away with my Dremel, Terry can sort this one. I do not want to think of my grinding handiwork going up and down 6000 times a minute     

FFS... oval tappets, mis-matched rods, oversized valves, colliding pistons... I don't remember building engines being this hard? 🙁

[Nick Moore]

The offending crankshaft counterweight:

[oil_on_the_carpet]

Quoted from Nick Moore

The offending crankshaft counterweight:

Ah yes, the 'quality' of the castings!

I'm taking a disc sander to my NOS one and dressing down all that flash before getting it hardened.

[GT6MK3]

Ouch!

Nick, from memory that was a NOS crank?  I wonder if it would have fouled stock pistons?   You're having a rough trot!

Hoping to spend a couple of hours 2morrow measuring up your scooby plate if that help ease the pain.

C.

[Nick Moore]

The crank was a reground one from Greg Tunstall. It's not the problem, it's the piston skirt. And to be fair, we were warned that there could be a problem, which is why I checked. While I could skim the counterweight to give it clearance, the crank's already been balanced. The easiest solution will be to nibble a bit out of the piston skirt. Not too much though, as it's the skirts that stop the pistons rocking and knocking. The skirt on that side of the piston should be pushing away from the bore wall on the firing stroke, so it shouldn't be a problem to take off a small amount. And it will be small, only about 5mm long by 2mm high. I'll double check today that the rest of the piston skirts are clear of the crank by at least a mm, but I think they're OK. Terry is not happy btw, I think he wants to fit the pistons somewhere without adequate clearance.

If you can program a CAD machine with the specs of that Rocky cover, I know Greg Tunstall would be interested in a couple.

[Nick Moore]

Mr Sump meets Mr Hammer. Now we have a GT6 sump that can accommodate a 2.5's longer stroke crankshaft 😎

The red paint is Glyptal. I'd read that it was a good idea, but having seen how easily it flaked off, it's going to be removed.

[Nick Jones]

Blimey..... do they need to be that big?  Seem to remember a dainty little dent sufficed for a 1300 Herald sump on a 1500..... and it did most of it by itself on first start-up  

Nick

[Nick Moore]

The bottom of the rods dip nearly 3.5cm below the bottom of the block. I may have been a bit generous, but figured that a large gentle dip was better than sharper small ones. The sump's now away getting powder coated. The inside of the sump will be left bare this time, as the more I read about painting the inside of an engine, the less I liked the idea.

Last night's job was working on the oil pump's oil ways with a Dremel. The internal passages had sharp bends and lots of casting flash. I figure that rounding off corners and removing obstructions could only improve oil flow. I also smoothed off the pump's baseplate with fine sandpaper.

[Nick Moore]

The head's finished! It's been skimmed to reduce the combustion chambers to 42cc. With a 76.2mm bore and 1mm thick head gasket, that should make for a CR of about 10.5:1. It has hardened exhaust valve seats - the exhaust valve diameters were reduced 1mm to make it easier to fit the seats - bronze phosphor valve guides, valve stem oil seals and Jaguar valve springs.

We haven't done any porting yet. Trial fitting the PI manifolds showed that they don't match the inlet ports very well. There are two ways to tackle that. One is to open out the inlet tracts slightly, the other is to modify the inlet manifolds. The PI manifolds will be modified to fit EFI injectors, and may need cutting and rewelding to lower their profile and fit the fuel rail under the bonnet. That'll give me the chance to change their shape where they meet the inlet ports. I won't make any decisions on this bit in a hurry...

[GT6MK3]

Nick

Have you run that number through here?

http://www.csgnetwork.com/compcalc.html

I'm certain you'll need to angle them down.  Pretty sure I know who can help there...

C.

[andy thompson]

Run the piston flush with the top of the block and it will run 10.4 - will need good ignition control to prevent pinking

[Nick Jones]

That O ring is a pointless object...... won't do any harm I suppose, but don't expect it to seal the guide either!

Nick

[Nick Moore]

Nick - The oil seals have been rattling around in my parts collection since the late nineties (I was planning to fit a 2.5PI to my Herald coupe) so I figured I should use them! Can't hurt, anyway.
Andy - yep, the ignition and injection will be controlled by Microsquirt. The pistons come up flush with the top of the block. That's where most of the CR increase comes from - the head needed very little skimming.
Craig - yes, the manifolds will almost certainly need angling down. I'd like to have the extractor primaries fitted before doing that though.

The pistons are getting their skirts modified to clear the crank. Although only #3 is fouling, #4 is damned close as well. Terry will modify all six to be the same weight. He warned me that they will be fine but may not look pretty I also dropped the rods off, and Terry took one look and showed me that the die marks for the heavier one are different. So whoever built the motor in the Triumph factory used five rods from one batch and one from another. Maybe he ran out. A little bit of industrial archeology there.

Just waiting for rings now so that we can close up the patient. Turns out they're 1.3mm wide, which is an odd size, so we have to wait for the supplier

[GT6MK3]

I've got a spare set of rods here if you need em.

[69vitesse]

Quoted from Nick Moore

I also dropped the rods off, and Terry took one look and showed me that the die marks for the heavier one are different. So whoever built the motor in the Triumph factory used five rods from one batch and one from another. Maybe he ran out. A little bit of industrial archeology there.

See thread in main bit, I found the same, a pulled set of 2.5 rods that were as fitted at the factory, but clearly from two distinct production batches.
QC seems to have gone out the door at Triumph once BL got into its stride.

[Nick Moore]

A few more steps forward. Rimmers sent four more hardened cam followers to replace the four oval ones. These ones are a different design, taller with thicker walls and a drilling to let out the oil. They're heavier too, at 47g each. But the main thing is, they aren't oval! I've decided that I'll use these hardened followers, and check the condition of the cam lobes from time to time. With fairly soft valve springs and a fairly mild camshaft, I'm hopeful that the bits won't eat each other.

Thank you Mr Rimmer!

I finally got around to installing the windscreen wiper motor. So far on this rebuild I've used a colour wiring diagram I found on the net, and it's been easy to follow. But today I found that if you connect the wiper switch as shown on the diagram, there will be a 'pop' from the fuse box and no wiping 🙁  The four wires should be connected to the switch in the opposite order. Now it works, and even parks.

Terry my engine machinist recommended an oil bypass because I'm running roller rockers. The experts here don't like that idea, so I've decided to try the engine without a bypass, and if the front rockers are receiving oil I won't fit a bypass. Anyway, to try and help the stock oiling system I've drilled out the head's oil ways slightly to 13/64", which matches the drilling in the Harland Sharp pedestal. Because it will still only receive pulses of oil when the camshaft turns, the widened drippings shouldn't starve the bottom of the engine. I think...

[Nick Moore]

Quoted from Nick Moore

Because it will still only receive pulses of oil when the camshaft turns, the widened drippings shouldn't starve the bottom of the engine. I think...

Autocorrect strikes again - drillings, not drippings. I am trying hard to avoid drippings.

[Nick Moore]

After several months' leave earlier in the year (mostly spent in the garage) I'm back at work full time. In the geology business, that means weeks away at a time in mining camps, followed by a few days home again. Great for the wallet but it's meant that the GT6 has sat idle 🤔

Anyway I've just had the garage rewired for 15A power for my welder, and started welding the chassis rails where they'd been modified to fit the W58 gearbox. I'll hold off posting photos until my welds have been prettied up. The engine and gearbox have been bolted together for the first time to check that the custom bellhousing fitted the alloy TR6 back plate, and the input shaft tip fitted into the modified spigot bearing. Thankfully, everything went together without drama bar filing a few holes in the alloy plate slightly.

It'll probably be the next break in July before I can trial-fit the engine and gearbox in the car for the first time and start work on the gearbox mounts.

[Nick Moore]

After making great progress during a work stand-down at the beginning of the year, my GT6 has been languishing in the garage while I've been away geologising. A few things have happened though. My piston skirts are being machined to clear the crank webs, and Grant Rings made a set of chromed 60 thou rings for me. Andy Thompson's sending over his old GTT43 camshaft and lifters, which is a real boost - thanks Andy! And I've ordered a 77mm bore head gasket from Wishbone Classics - my car has a 76mm bore, and while standard gaskets should fit, there's enough slop around the head studs that even slight misalignment would leave a portion of the fire rings hanging in the combustion chamber. That would be Bad. With any luck, I should be able to get the engine bolted together once and for all in a couple of weeks... finally.

I had a thought the other day, while staring at the engine sitting on the garage floor. If I wanted sequential injection at a later date, could I use the camshaft's fuel pump lobe as a cam sensor trigger? I know people have used cut-down distributors, but that's a lot of leftover hardware bolted to the side of the engine for the sake of one sensor. (Besides, I like my little Canleys alloy distributor pedestal, machined to take a core plug). I figure that if the fuel pump lobe had a slot cut in it, or most of the lobe were cut away, it would give a strong one-per-revolution signal for a Hall sensor. The sensor could be mounted through a fuel pump blanking plate like the one I've already fitted.

I can think of two complications. Firstly, the sensor would have to be happy in a hot oily environment. And secondly, there's no guarantee that the signal would arrive as number one inlet opened (I think that's what Bainzy said on his Spitfire thread). Megasquirt would have to be able to be told that the signal meant at the camshaft was passing, say number three inlet opening plus 5 degrees, or whatever. Maybe it can be programmed to accept any point on the camshaft, I'll have to check.

In any event, my current Microsquirt can't do six cylinder sequential, so cam sensors will have to wait. Megasquirt Pro (http://www.diyautotune.com/ms3-pro.html), essentially a pre-assembled small case Megasquirt or souped up Microsquirt, can do full sequential, so I'll probably upgrade later. Getting the damned thing built and driving is priority number 1!

And now, back to the garage to make more brmmm brmmm noises 🙂

[Nick Jones]

Somehow missed your earlier post with the W58 pic......

Nice looking bell housing, and the correct Toyota shift housing for the forward position......  Conversion Components?  Or Dellow?  

Nick

[Bainzy]

The moment in which the cam sensor passes doesn't have to be hugely critical. Unlike the crank wheel where the tooth tells the ECU the exact position in degrees that the crank is, all the cam sensor does is tell it what phase you're in (which is one out of a possible two). The idea is to set the cam sensor to activate about 30-40 degrees before the missing tooth on the crank wheel passes the sensor, mainly just because there are a few spots where picking up the signal causes issues. Once you then have phasing correct, you can choose the time to inject in software anywhere from -360 to +360 degrees from TDC.

If you manage to get this to work Nick I'd probably do the same, as like you say its a bit annoying having all that gear still bolted to the engine just for a cam sensor. It'd probably be really straightforward if you were getting a cam ground from new, you could just ask them to replace the fuel pump lobe with a trigger wheel of sorts.

[Nick Moore]

Nick - it's a Conversion Components bellhousing and gearlever adapter. It's actually a TR6 kit, so I have to add a longer hydraulic clutch hose, and shorten the speedo cable. Otherwise it was a straightforward conversion, although a few parts needed minor machining and finishing. I used an alloy TR6 engine backplate, lightened steel TR6 flywheel and CC supplied the clutch.

Bainzy - I'll have a look at where the fuel pump lobe on the camshaft sits when the crank wheel's missing tooth is 30 - 40 degrees away. An alternative is making a trigger on the camwheel and having the sensor pick that up. A bit of Googling shows that there are oil-proof Hall sensors for this sort of thing - a guy Megasquirting his BMW took this route.