Algy
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Posts posted by Algy
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Thanks Pete, the heavy ones look the same as the ones on the 1600 engine and mate's MK2 2ltr so matches what you say (thought the my 1600 ones may have been swaped at some point). They may be specials as the engine was breathed on (by a tuner working to Vizards spec) in 1971, according to the bits of history I have with the car (but no mension of rockers, just ballancing, flowing, raised compression 10:1 large inlet valves and manifold matching and tube exhaust manifold). Hence the spare head and inlet manifold being used to go unleaded and reduce the comp ratio to 9.5:1 to sope with modern fuel, but keep some of the performance.
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Hi I thought I would saw you this link
https://www.youtube.com/watch?v=rKwmk1RYHpk
I had some of my apprentices break down some firlter and do the checks shown, it proved he was spot on and the Mann filters came out on top.
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Don't use Hammerite paints they crack and are not oil resistant. I have to say I do give the whole plate a light coat (after spraying the area outside the contact area) as to my thinking it is going to move less than the paper gasket and give some protection at the edge.
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No it is Gypsy Major (Tiger Moth) engine paint (had a choice of green or gray). Don't ask, the story is too long as to how I get hold of some of bits I use, other than to say that I do a bit of work on the side on vintage aircraft :-)
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Thanks Pete, I was aware but alway good to have it confirmed.
I am still a bit puzzeled by the rockers being of lighter construction than the ones that come off the spare head, yet of lighter construction, any ideas?
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The cylinder head has now been matched to the exhaust manifold and inlet manifold. The exhaust a smooth match and the inlet with a small even step (as recommended by a tuning friend).
I need to flow the carb side of the inlet manifold and then vapour clean it before making up the cooling union for the rear, as I don't have a heater and the original has damaged, thankfully the threads in the manifold are good.
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The block has been ultrasonic cleaned and then rebored +0.020", then painted and a few bits added (core plugs and oil way plugs).
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They are one of these places were you spend £50 for a ham sandwich. They use it for making those weird foggy disserts, you know the things all art and no real substance (like the TV master chief stuff). The owner is mad on cars though and offered me a thermos full, which was an offer I had to try. My workshop looked like something from a “Carry On” horror move though, with fog us to knee height.
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Just fitted mine but I cheat.
I heated the ring in boiling water and cool the flywheel with liquid nitrogen (obtained from a restaurant), the ring dropped on with no need to press or hammer.
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I have replaced the ring gear as the flywheel is going to be skimmed and the crank reground 0.010” undersize and the whole lot including pistons and rods balanced. It had seen better days! As I intend to use a pre-engage starter motor I chamfered the inner edge of the ring gear to allow it to fit flush when fitted in the back to front from normal (not strictly needed). The ring was heated in boiling water and the flywheel chilled with liquid nitrogen, the ring dropped on with no need to press or hammer. So now ready to be refaced and balanced.
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I cleaned and checked the rear crank seal housing on a surface plate and gave it a couple of passes on some 400 grit wet and dry to take of the corrosion, before replacing the seal.
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The timing cover was badly distorted and the spare had the chain tensioner mounting missing. I looked around for rivets from the normal sources and couldn’t find them so made my own.
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Here is a photo showing how much the inlet manifold needed to be dressed back to match the head. Well not a full match but so it has a small lip equally all the way around of 0.75mm as this is actually better than a full match. I will flow the duct later.
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Well the Bond Special rebuild continues and now I come closer to actually putting bits of engine together. I decided to keep the original engine cylinder head and inlet manifold to one side (very high compression ratio not conducive to road use) and have a spare 2ltr head converted to lead free and port it. So far I have matched its inlet manifold to it and now ready to send it away to have hardened seats and porting.
So I looked at the rocker shafts of both to see which one was most usable, not expecting to see any difference, but again this Bond Special through up the unexpected.
As you will see from the photo the rocker on the left (Bond) is of a lighter construction and has a larger oil hole in the top. It doesn’t look like it has been modified from a standard one but is a good chunk lighter. The engine numbers between the head donor and the bond are only 50 different so I doubt it was something Triumph did as an update (but I could be wrong).
Anyway the Bond rockers will go onto a new shaft, as they are the least worn (the other one looks like it was lubricated with sand!).
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If you do turn the ring gear around you will need to chanfer the inner edge for it to fit up against the flywheel flang or it will have a gap of around 10-15thou.
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It is worth noting that if fitting a pre-engaged starter to a engine with has a starter ring for a bendix, the teeth are flat on the side the pinion is trying to engage from, so this is a consideration if converting to pre-engaged starter or planning to in the future.
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Thanks for all the advice, have opted for a Mk2 cam. Just now whether to use the stage 2 head as adverised in the club shop or just match my spare head and fit hard seats.
Can anyone tell me what the stage 2 head spec is as there is no info on the shop page!
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Here is a picture of the Marlin.
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1 hour ago, Pete Lewis said:
algy why not link to your linkedin photos ??
Pete
Not a great one for taking photos. I only ever bother if I think it would be of use to my learners or if I think it might help someone else. Don’t think many would be interested in the rebuild of an obscure car, there would be more interest, in the work I do for my customers but that is not for me to post.
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Oh ShaunW, I am not doing modern engines down by any means. I was just making the point that we had to fettle the old engines ore because they didn’t have the ablity to self tune, as the points and plugs burned or the carb went out of adjustment, we would hear it (or see fuel consumption go up). Now the engine has the ability to self regulate and compensate to a very high degree, until it can’t compensate any more. As a trained metallurgist I have seen the changes in the quality of materials used and the precision of the CNC machining has produced components to very consistent tolerances.
I do have to disagree with you though on one point and that is although the engines will in theory be able to be repaired, the chance of that happening in 50 years time I consider to be very slim for the following reasons: The replacement sleeves and pistons along with the sensors and fuel monitoring systems will probably not be available, as the manufactures are using built in obsolescence to try to force new car sales (so not producing as many interchangeable parts).
Yes most of our classics will have had at least a part engine rebuild if not a full rebore and regrind at 200K. In the day we had the head off just about every other year (due to the inability for the engine management system to control carbon build up, poorer quality lubricants, the poorer tolerances of manufacture as well as rate of wear). Modern engines operate in a much more optimum environment, due to the improvements in technology and the use of ECU compensating for the operating environment.
The biggest killer of cars, I see when visiting the garages that my apprentices work at, is ECU faults, making the cars uneconomical to repair (unlike the body work of the 80’s). Yes some modern classics may be kept alive but only by farsighted people collecting donor cars now.
I suppose it is the same with aircraft; second world war aircraft can be kept flying as the reserve factor on the airframe was so high, yet modern fighter aircraft have fewer failures and if they do can still fly but have a finite fatigue life. They are both great in different ways and I would be happy to fly both the same way as I am happy to drive old and new cars.
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On 12/11/2017 at 2:45 AM, ShaunW said:
I'm confident the v8 jaguar engine in my contemporary car will last at least as well. Better materials, better design, better consumables from day one.
It's too easy to get a rosy glow about these old cars but the truth is they were budget cars based on dated engineering even when new. It's only weekly maintenance, multiple rebores, rebuilds and skims that's kept them going.
I'm not committing heresy here, just pointing out that they're not inherently special or better just because they're old, and new doesn't always mean worse.
There is two big difference between modern engines and classics. The faults with modern engines are hidden by a computer compensating, secondly the engines are built with very little reserve factor so once clapped they are scrap.
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As I said before I a trying to keep the car as close to the original spec as possible. This is not a new special being made from an old car it is an old special that was built from scratch for Bond and subsequently modified by Bond before being registered in 1967.
If it were a modified car, I would have no hesitation in just changing the engine, possibly to a later Mk2 2ltr (I have one) and the head ports are better designed to start with, but to modify the block would not be reversible. It is also not just as easy as drilling out and tapping; you need to counter bore slightly as well and drill the head.
I am very happy to modify my spare Mk1 head, as that is reversible.
The original head is a close match to David Vizard’s recommended modifications for fast road, from what I can see, the valve seats are cut with three angles and the valve heads have been rounded. That said four exhaust valve seats have been without valves and although the head face has been protected by grease the seats have been exposed and rusted (hence the thinking to convert to unleaded).
From the advice given so far, I think I will go with the Mk2 cam and lightly modify my spare head to unleaded and larger inlet with three angle seat and light porting. The bottom end will be check balanced and built with new shells as the crank is in good order. Hopefully that will give me an engine that would be close to the original spec / performance and flexibility to drive in modern traffic.
Thanks to all for the advice so far.
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Thanks John.
Yes all at the same volume as measured with an accurate pipette. Without the head gasket to measure the thickness I am just going from the chamber volume for the calculation. I must say I would prefer to be at the 9.5:1 ratio and as I have a spare vitesse 2ltr Mk1 head, was considering relieving the head around the valves (in the same way as this head has been done) and having it lightly skimmed to get back to 9.5:1.
I had also thought, if I was to do that to the replacement head, that I could go for larger inlet valves at the same time.
I would still have the original head, should I ever sell the car.
I can hear you ask why worry when it is a special? Well it is a special –special, it is one of six commissioned by Bond, so trying to keep it as original as possible.
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I would weld a nut onto the stud close to the casting, then I would heat the whole exhaust flange and then shock cool the studs (being careful not to shock cool the casting). Use a deep reach socket with a “T” handle so there isn’t a side load, to undo the studs. Just make sure you remove any coating off the nuts first and use a large nut so you can get a good welded joint.
From my experiance the roller stud tools these are great for fitting studs but unless you get a good one they are generally not that effective at extracting studs in the state that yours are in on the flange.
Bond Engine Rebuild
in Engine
Posted
Now here is a different problem. The manifold from the original cylinder head didn’t have the union on the end for pipe work but the head did have the brass adaptor coming out of the back of the head, yet there was never a heater in the car (no place to put one and open); The spare head came from a car that didn’t have a heater and had a damaged single outlet from the manifold and the hole in the head blanked off.
Here is the twist, the notes that came with the car (dated 2 Sep 1970, so after engine tuning carried out) says “Due to head temperature appearing high, yet coolant gauge showing normal, I have fitted a double ended outlet to the inlet manifold, retained by banjo bolt from the normal GT6 outlet. It has been machined out of brass and has a 1/8” hole in the branch leading to the rear of the head and full bore to the pipe leading to the pump. This is in an attempt to reduce the chance of airlocks in the head. This appears to have worked and reduced pinking during hard acceleration.”
So obviously I can’t buy one of these and would have to make it (not too much of a problem), but has anyone else heard of airlocks in the heads of cars without heaters?
I have looked through all the box of bits that came with the car and can’t find the item but that is not a surprise considering the engine was partly stripped in 1975 after the crash and so has probably been filed under B1N.
I look forward to you knowledgeable Straight Six Triumph fixers passing on your knowledge.