1965 Mk1 road/rally Bitsa, (now supercharged 8 port)

[roger mcnab]

hi
well thanks for that you can learn something new every day keep up the good work
cheers roger mcnab

[Richspec]

Mid term update, well it feels like halfway through the year, an event every weekend in May and two weekends into June before I get a rest!

Yesterday was the Thistle Run, a touring event in aid of various charities with around 200 minis taking part, touring from Newtongrange just south of Edinburgh to Eyemouth harbour.

I felt on the last run out down the motorway that the fuelling was off, its too rich at my cruising revs (approx 4000 / 60 mph) and so on Saturday i went out and ran up and down the main road to fine tune the settings in that particular area, in the evening i worked through the fuelling map making the changes, we're only talking a max of 4% i think. Why the ECU isnt bringing the fuelling into line as it should automatically is something to look at soon.
In other news.. bringing it out of the garage it dropped onto 3 cylinders and using the thermal image camera on my phone i could quickly see exhaust 2 was colder than the others, i popped out the plug to find it was soaking wet, quite oily and had a load of shit on it, like carbon.
ummmm. anyways cleaned up and back in all was good and i was able to go and do the mapping.

Sunday, a boring ass noisy drive up the M74 to Moffat and then a glorious thrash up the A701 past Devils Beef Tub and on to the start venue, despite going really well i though there was a slight misfire at times and immediate thoughts turned to that oily plug.
The run itself went fine but i was feeling that misfire more and more but my passenger never even noticed it! So after a late lunch and another clean of the windscreen i swapped out the fancy platinum plugs for some more standard cr8's and yep. Oily Plug.
The run home was down to Coldstream and then Kelso, Hawick and A7 south, again another blast and the car pulling well but missing on load, and getting worse to me (imagination??)

Today started with pulling the plugs, yep number 2 a little bit oily but not soo bad..compression check, even across all four cylinders, off with the rocker cover to see if anything was amiss and...

33775304_10216632428754158_4452559915357044736_o_Fotor.jpg

so right off priorities are, drain the oil, find the bits!
On the end of the sumplug (fancy high strength MS one) what looks like a tiny circlip??
Sitting on top of No3 rocker post - the roller
down No6? pushrod hole, the remains of the pin.

33836544_10216633090890711_6167029530419527680_o_Fotor.jpg

Now how to fix?? well none of the rockers here are getting reused, they're old, battered and are goin in the bin! None of the 5 port sets would fit (without more rockers being required due to the 'handness' required to fit this 90's 8 Port.) Luckily I've just bought another head and rockers off Rich (to replace this head and rockers which I'd borrowed) so had a look at fitting those, the rockers are identical to what was on, the difference in the rocker post and what rockers are needed. The newer 2012 castings need 6 RH and 2 LH, when viewed from the front, this head looked to need 8 RH. Even luckier i have ANOTHER set of the 2012 rockers on the fancy 70's 8 port using a mix of 5 and 8 port spacer kits to make it work, so i could rob rockers off there as well.
So I've ended up using the new rocker shaft, the older rocker posts, 7 RH rockers and 1 LH and all the rollers sit bang on the valve stems after a bit of trial error with shims
The other difference is that the old rockers used the extended adjusting screw and standard pushrods, the new one ares are shorter and you use longer pushrods. I had a set of the MED steel rods ready to go so I'm using those. So back together by this evening, head tightened down and just doing up the last rocker post nut when the stud snapped of clean at the top. Time for more alcohol and back on it tomorrow night.
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old demons have revisited, with disastrous results. Im on a different head, different cam, complete new rocker set (cant be 100% sure as they all look the same across the different heads and engines) but anyway rocker arm pin failure, roller came out, rocker came down onto top cap, onlt this time it popped off the collets and the valve said hello piston. I was just pootling along back to the workshop after filling up with fuel ahead of tomorrows trip to lauder. the only small mercy is it happened 1/4 mile from the workshop and not 2 hours from home.

[Fanfaniracing]

Very bad news Rich!

What rockers did you use?

[Richspec]

The minispares roller ones. like this
http://minispares.com/product/Classic/E ... o%20search

[GraemeC]

The way those rockers are design they have an inherent weak spot as the pin has a step in it exactly at change from where it is fully supported in the wider side of the arm to where the roller is. The pin is also only a press fit on that one side, so once it has broken the section of pin the roller is sat on can freely walk out of the side of the arm, allowing the roller to drop out. Recipe for failure really.
Later designs had a better pin and pin retention design.

After 'getting away' with the same failure on my 5 port engine (with KAD rockers) I went to the solid 1.4 rockers and haven't looked back.
I was lucky in that I didn't lose collets, the engine actually still ran as the rocker are was still opening and closing the valve but was down on power and sounded a bit tappety - a cursory look saved potential heartache I'm sure!

[Richspec]

Yep, solid type from here on in. This will cost me a shit ton.

[Richspec]

loosened off the rocker last night, removed the springs - as there was no visible valve. Stuck borescope down but cant see much apart from 'damage', we'll pop off the inlet plenum next and look down the inlet throat to see just how bad, 'really bad' can be.

[Richspec]

Found the valve, in four pieces inside the plenum...

I'll shrink the photo down and upload from home tonight.

[Richspec]

287711043_10228727085073007_7737756693118725801_n.jpg

there you go!

[Fanfaniracing]

Outch...

[Richspec]

Pictures speak a thousand words...

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20221009_160157.jpg

[Fanfaniracing]

I saw on YouTube how you took out the valve of the plenum...

It broke my heart!!!

[Richspec]

Quick update ahead of 2024. The supercharged 8 port still hasn't been rebuilt after it dropped the valve, in fact i only removed the engine and box yesterday
All the clutch and gearbox bits have now been cleaned (not too bad at all, just some ally glitter in there) ready to build up as a 5 port with the 1460 i recently purchased off here. I'll jump back to a ida carb with 2d mapping for next year, just so i have it to use as I'm really missing it.
So it'll look again like it did a few years ago.