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Triumph TR6 - Air manifold

I am slowly working through my (ever expanding!) list of winter projects, and started sand blasting the exhaust manifold. It seems to be coming up quite nicely, but I wondered about the air injection manifold (my car is a '75). I am tempted to remove it to clean up (and sort out some bent injector tubes - I hadn't realised how far into the head they extend as I removed the manifold...), but if I break it, replacements seem to be unavailable. Assuming I break it (I usually do...) If I plug the holes in the manifold, would I just need to remove the air pump and associated piping? Is there any issue with the timing? I know that all of the emissions type stuff works as a system, but I suspect that the EGR valve can stay where it is?

On the timing front, do I need a strobe light? I assume that once I get the car back together (sometime in 2009 at the rate I am adding jobs!) I will need to set the timing?

Thanks, as always, for any advice
Alistair
Alistair

Alistair,
My recommendation is to leave the air injector pipes in situ. Do not remove them if you want to keep them intact. It is very easy to snap or twist off the tubes or round off the fittings. If you are sandblasting the assembly, it should clean up well. Put some high temp paint on it to keep it looking nice. Otherwise the judicious use of an oxy/acetylene torch to heat things up will help alot. FYI - A propane torch won't generate enough heat to be reliably effective.

If you want to 'detox' your engine that's a different ballgame. Then remove all of the associated components - air pump, hoses, etc. You can leave the EGR in place, or remove it and plug the hole.

Your timing shouldn't be affected by removing any of this. Although each engine is a little different and may benefit from some 'tweaking'.

The old shadetree tricks for setting the timing without a timing light are (who says the marks are accurate anyway?):

1. Connect a vacuum gauge to the intake manifold. Start the engine and adjust the timing to get the greatest vacuum at idle.

2. Adjust the timing by 'ear'. Turn the distributor to get the fastest, smooth idle.

3. Set a glass of water (half full) on the engine. Adjust the timing for the smoothest running (least amount of water ripple).

I have to admit never having done #3 (that advice came from an old time mechanic I trust - one of the few!) as 1 and 2 have always worked for me. Nowadays I still use 1 or 2 and check it with an adjustable timing light. It's much easier to duplicate the timing later using a light.

Good luck,
Tom

Tom Sotomayor

To initially set the timing, I position cylinder #1 at about 5-8 BTDC. Pull #1 spark plug lead and insert a spark plug. Loosen the distributor so it'll move and turn the ignition on. Ground the plugs threads on the block and turn the dizzy until you get a spark. Tighten the dizzy and you've timed your motor.

Once it's running, it's always good to hit it with a timing light.

hope this helps,
Tim

Tim Brand

Hello,

I own a '75 without any injector. But as far I remember I removed injectors in my '73 B-GT( my '75 TR6 do not have them) wihout any problem and plugged the whole stuff. The EGR with could be left in place as I am certain it is all stuck with carbon, but all the associated spagettis could be remove and holes plug. I removed EGR on my TR6 for esthetic purpose only. As for that year timing is suppose to be 4ATDC, I did not follow that and settle timing to 8BTDC dynamic as written in Hayes:"adjust advance just before pinking".

Cheers,

JGC
J. G. Catford

Okay, add removing the air pump etc. to my to-do list...

I had decided to leave the manifold alone, but when I went to straighten the injector tubes as best I could I noticed that the air injection manifold was rusted through in a few places, and so it is coming off. Well, I want it off - some of the fittings are seized solid - I have no means to heat it so any ideas how to get the fittings out? They seem to be made from a rather soft metal, judging by the roundness I achieved in a very short time.

Thanks for the advice and suggestions.
Alistair
Alistair

Hello,

The best is to heat them, but as it is not possible for you. Drill it and use an extractor, but it is more a risky business...

cheers,

JGC
J. G. Catford

At this point it is better to take it in to machine shop / repair facility and pay to have it removed. It shouldn't be very expensive. Drilling and using 'easy-outs' (extractors) will likely end up with a broken easy-out stuck in the hole. This will cost a lot more to remove since they are made of hardened steel.

Tom

Tom Sotomayor

Alistair,

try a propane torch giving it about 5-10 minutes of heat on the first tube nut, dowse that portion of the manifold and nut with cold water... the shrinking effect will not be enough to crack the manifold but may be enough to release the nut.... I agree with Tom that an oxy-acetylene torch is a more effective way to go but when that's unavailable this may work. I did this a few years back and custom built a new injection rail and had to turn new tube nuts on the lathe..5/8 hex stock turned down for1/2-20 nf threads, bored to 1/4" for the tube as I recall. I went to this trouble so that I would not be hassled for the collector plate status by the DMV.

Very cool that you are into it this far... we're rootin for you!

Rob
Rob Gibbs

Be very very carefull heating cast iron (CI) and then cooling it rapidly. It will cause the CI to become VERY brittle. End result is it may not crack today but will be prone to it in the future. The safest bet is to heat the CI and let it cool very slowly. Pros use a heat treat oven and let the temp drop slowly over 10-12 hours or so. The rest of us resort to placing it in a bed of hot sand or borax (20 Mule Team). Done properly it will still be too hot to touch for a couple of hours or more.

Tom
Tom Sotomayor

Thanks for all the help and encouragement, guys!

Foolish chap that I am, I decided to have a crack at the air rail fittings without heat, and managed to get 3 out - the other 3 broke off flush with the manifold. I went out today to find left handed drills, but couldn't see them anywhere. I am tempted to drill the holes a bit oversize and tap the holes - I've never done that before and this is all about learning, right? Any special taps needed for cast iron? The brass plugs I bought on ebay advertised as being for the TR6 air rail holes turned out to be too small anyway, so I am stuck looking for an alternative. This leaves me wondering whether I would be better off (financially and time-wise) looking for a replacement manifold. What happens to all the cast iron manifolds when people buy tubular manifolds? There must be a stockpile somewhere...


As ever, thanks in advance for advice, opinions, thoughts...
Alistalr
Alistair

Alistair,

My two cents advice, do not attempt to drill oversize. The best is to drill, heat and use an extractor to remove it. To find a proper plug will not be difficult, it is just a matter patince to find the right size.

Cheers,

JGC
J. G. Catford

I think the stock threads on the air rail are 7/16-20. That's considered a 'limited standard' so won't be laying around in just any hardware store, though some do carry them.

If my memory is correct and it is 7/16, you could drill and tap for 1/2-13 or 1/2-20 and put in a bolt. But that would be a bit of a bodge. Preferably drill and tap for 1/4 NPT (National Pipe Thread). The 1/4 refers to the inside diameter of the pipe when they were originally made from cast iron. So it's going to be significantly larger on the outside diameter than 1/4". This causes a lot of confusion with those unfamiliar with pipe! NPT is a tapered, self sealing thread. The tap drill is 7/16 (how convenient!). Use the dark, sulpher containing cutting and tapping fluid. You can get it the same place you buy the tap. You'll also want a proper tap handle. Don't be tempted to use a couple of wrenches or vice grips, you'll be unhappy with the results.

If you've not done any tapping before (especially pipe threads) there are a few tricks to keep from messing up or breaking the tap:

1. Drill the hole straight, to the proper size and deep enough. In this case you can probably drill straight through.
2. Clean out all of the chips and debris.
3. Coat the tap and the hole with cutting fluid.
4. Start the tap in the hole square (not angled to any side).
5. Turn CW about 1/2 to 1 turn then back off (CCW) at least a 1/4 turn to break any chips you're cutting.
6. Don't force it - it is easy to break a tap!
7. Since it's a tapered thread, check your fit with the plug BEFORE you think you're done. It's easy to go too deep as well as not deep enough.

Good luck,
Tom

Tom Sotomayor

This thread was discussed between 28/11/2006 and 06/12/2006

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