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Post by indianajones on Sept 27, 2012 0:50:57 GMT
Sorry, another thread lol Carrying on from the engine conversion thread, I've had a think and I reckon I'll be boring and keep the B series in her (But I haven't ruled out a conversion for another crab down the line). Hopefully I should be getting an 1800 engine (with gear box) on the weekend, but is lacking a head. Of course it's the same as an MGB so won't be hard to get another one. The idea is to rebuild this engine and then once ready (in a couple of years) to do a straight swap into the Wolseley, thus keeping the car on the road. Now I'm thinking let's not just do a rebuild to 'factory spec'....let's get a little bit silly and have some fun. I'm thinking 'S' type/MGB spec. What do you reckon I should/could do? Twin HS6s? (Like Chris) Different cam? Improved head? what sort of things did Downton do? (I've only just found out about this group) mk1-performance-conversions.co.uk/downton_bolt_on_kits.htmmk1-performance-conversions.co.uk/images/dtn_1800_4.jpgwww.dep-o.co.uk/features/b-series/Cheers, Andrew |
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Post by nz3litre on Sept 27, 2012 4:23:45 GMT
Hi Andrew
Somewhere on this discussion board is a shortcut to a very through American sourced 25 odd page article on modding the B series... I printed it off last week but can't find it now! Some one wiser will point you to it I am sure.
Regards John.
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Post by indianajones on Sept 27, 2012 8:03:23 GMT
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Post by nz3litre on Sept 27, 2012 22:45:01 GMT
This thats it.
Cheers John.
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Post by indianajones on Sept 27, 2012 23:47:35 GMT
I have also learnt that if I increase the power output by 20%+ I will need to get it certed.
-Andrew
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Post by Penguin45 on Sept 27, 2012 23:57:29 GMT
HIF44s, my dear old thing. Nothing like a dead MGB to offer cheap performance enhancements. ;D The "S" models were a pair of HS6 carbs. The HIF is supposed to be a more stable carburettor in use, whereas the HS's need constant fettling. Not so sure about that after the last couple of weeks...... On a serious note, the simplest way of unleashing a bit more power is to let the engine breath more easily. Inlet is very simple - free flow air filters are easily available - K&N is probably the best known make. However, you may need to compensate with the needle, as increased airflow leans off the mixture. The HIF44/K&N set up is a well documented one, whereby the needles are changed to AAAs. Then you've got to get the air out again. This becomes a bit specialist, as manifolds are definitely a black art. The LCB MGB one is well known, but is of course aligned for a rear wheel drive car (ie angled to the right from side on, whereas ours needs to go straight down the back. Due to the low survival rate of our cars, this almost certainly means "one-off" specialist manufacture and, therefore, expense. I noted £295 in the link posted HERE. It's a lovely thing, but could I justify it based on 4,000 mikles a year at most? Then there's cams (MGB owners like the 1800 MkIII cam), gas flowing, balancing, lightening. Superchargers......... I find that a little light tweaking has been enough. Chris. |
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Post by Penguin45 on Sept 27, 2012 23:58:57 GMT
Indy, if you can get another 20% out of a B engine, they'll be queueing up for your services.
Chris.
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Post by indianajones on Sept 28, 2012 0:04:15 GMT
Cheers for the post Chris. I wasn't aware of a needle change, as I have a K&N pancake filter on my carb, what would I be looking at needle wise? (HS6) As for LCB manifolds, TCs, cams, polished ports/modded heads etc. Of course none of it can really be 'justified' lol.........but saying that if it's you're only toy (well mine is, at the moment) why not have a little fun with it. Want it to be sweet for those 4000 miles!  Indy, if you can get another 20% out of a B engine, they'll be queueing up for your services. Chris. lol Good info so far, keep it coming -Andrew |
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Post by dave1800 on Sept 28, 2012 1:33:37 GMT
Andrew There is some more information you may find helpful on MGB tuning but you need to set aside an hour to read it as there are no headings and it’s nearly 200 pages long! Google “Stephen Strange MGB Performance Article” as it's a pdf file the url link won't copy here and it exceeds the attachment size for this forum. I would advise that before you do anything you try and work out just how much you are willing to spend and then start pricing what you want to achieve. I think you may have a horrible shock especially if you are not able to do most of it yourself. A few sobering thoughts: the “Which” magazine back around 1971 compared a standard 1800 Mk11, a Wolseley 18/85 Mk11 and an Austin 1800S. They found the standard car the best – the Wolseley power steering was too light to allow full advantage to be taken of the handling and the extra power of the “S” showed up deficiencies in the gear change as there was less low down torque and quite a fuel penalty. (Alexander may disagree). There is an interesting set of articles on the Autospeed website about restoring a Landcrab UTE by Julian Edgar who posts on the Google Groups website. groups.google.com/forum/?fromgroups&hl=en-GB#!forum/austin1800 Here is a link to Section 3 of his article autospeed.com/cms/title_Restoring-the-Ute-Part-3/A_112775/article.htmlThere is lots of fascinating and useful information on Julian's Autospeed site; I think it's well worth a browse - including quite a few articles looking at the 1800 suspension and construction. He concluded that if you seriously want to modify the car then discard the B series engine and go for a more modern lump. Personally I don't like these types of conversions, but if the alternative was the vehicle would be scrapped then I am OK with it. Many years ago I was told by a highly respected mini tuner and racer who towed his cars on a trailer pulled by a Mk11 1800 that "the 1800 B series engine doesn't take kindly to performance tuning unlike the A series. Any attempt really screws up the fuel economy very badly - and it wasn't for want of trying" If you want say an increase to just125BHP you need a camshaft that gives you absolutely nothing under 3,000 rpm - not exactly ideal for everyday driving. And remember if you have more power you need to upgrade the brakes first. BMCs own figures show that even the standard MGB stage of tune increases the specific fuel consumption by anything up to 40%. I believe this is mainly down to the camshaft - Leyland Special Tuning even went as far as specifying the standard Austin 1800 MK11 camshaft for stage1 tuned MGBs (and MGAs) as it gave more power up to 5,400rpm. If I had the time, energy and cash (not necessarily in that order) I would be tempted to try and get the most satisfaction by considering the following when rebuilding the engine: balancing the crank, con rods, flywheel clutch etc to make the engine much smoother and long lasting. improving the gas flow with an 1800S or Downton style exhaust manifold or and an MGB manifold with 1.5” carbs, not the 1.75” used on the “S” leaving the compression ratio at the standard Mk11 (9:1 in the UK) to avoid destructive knock using a programmable ignition eg 123 to ensure the timing could be set exactly right for your particular engine (don’t tell Chris!) Think about polishing the SU needles and using a wide band oxygen sensor to maximise the performance and improve the economy (Google SU needle polishing for more info) A more challenging conversion would be to change the carbs for fuel injection although I don’t think you would gain much from a single point injection and the multipoint is complicated by the siamese inlets which require some clever electronics to overcome the timing / charge robbing issues, but was achieved on the last of the classic Minis. Remember these are just MY thoughts and there are plenty of hot MGBs around and real experts like Peter Burgess who can help you achieve your goals. Good luck! David |
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Post by nz3litre on Sept 28, 2012 1:43:00 GMT
Hi Andrew
Who would question if it;'s 20% more power or not... more like a period mod that you have had for years!
When the Factory rated the C engine from new they imagined another 20 - 25 odd horses that never existed.. whereas with the 3 litre the factory was possibly more accurate.. I could happily do heaps to the C before it reached 20% over factory claims. The right sort of mods will give you more torque I think than outright horses as well.
If you ever need HS6 carbs as fitted to the 3 litre I think I would have some for you.
Cheers John.
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Post by indianajones on Sept 28, 2012 4:30:53 GMT
Thanks for taking the time to make that very well written post David. balancing the crank, con rods, flywheel clutch etc to make the engine much smoother and long lasting. Is this general rebuild stuff? as I was imagining I would need to do such things regardless. Also doing the pistons and bores etc. improving the gas flow with an 1800S or Downton style exhaust manifold or and an MGB manifold with 1.5” carbs, not the 1.75” used on the “S” The exhaust manifold makes sense and isn't a huge/stupid mod so is on the list at this stage. As for the manifold, any MGB one would work right? did the S type use HS8s? I thought they had HS6s? HS8s would be a bit much really? The best advice I have read has come from Paul Walbran, a local MG man here in Auckland, where he says rebuild the engine first and then go from there, you might just find a 'new' spec engine is just what you're after as opposed to pouring tons of money into it. And John, I won't say no to those HS6s if I do need them! Cheers, Andrew |
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Post by dave1800 on Sept 28, 2012 4:59:23 GMT
I was suggesting balancing over and above the "normal" rebuild
I believe the MGB inlet manifold will work, maybe someone can confirm?
Yes the S used HS6 (1.75" throat), the MGB HS4 (1.5" throat). If you used a CR less than the S type which I think would be sensible then 2x1.5" HS4 carbs would be better and possibly easier to source for most of us, but you have an excellent offer in NZ of HS6s. HS8s would screw up the low down power too much.
Extract from Wiki
To determine the throat size from the serial number: If the final number (after one, two or three letters, beginning with H) has 1 digit, multiply this number by 1/8", then add 1". For example, if the serial number is HS6, the final number is 6: 6/8 = 3/4", add 1, total is 1-3/4", etc.
Regards
David
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Post by indianajones on Sept 28, 2012 5:28:10 GMT
It's been a long day it seems as I know that HS6 is 1 3/4, I recall reading how the numbering system works a while back.
On the matter of carb size it's walking that fine line between performance gain and MPG increase, of course one would hope that the MPG would be better on the twin for open road use.
So it's be between HS4 and HS6s it seems
-Andrew
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Post by Penguin45 on Sept 29, 2012 8:33:17 GMT
Always a good discussion when this one come up. It really depends what you want from the vehicle. Mine does virtually no "round town" driving and is mainly used for trips over a reasonable distance; specifically down to Cornwall - a 360 mile run. Twin carburettors are a sensible choice for this kind of use. A single carburettor will be running close to fully open on a fast long distance run, which is not its most efficient use. A pair of carbs will be running partially open, keeping them more "in the zone" and working efficiently, thus decent fuel economy. This was almost incedental to the "enlivening effect" when the accelerator is pressed a little harder than normal........  Combined with a single box straight-through stainless exhaust and a pair of K&N filters with a carburettor needle upgrade it works out quite well. I have created the moderately efficient long distance family cruiser which I wanted. Ultimate power (or speed, come to that) doesn't interest me particularly. Being able to proceed safely and quickly in modern traffic does, and I think I've achieved that. I would point out that last year, I had to use the car for work for 10 days due to the van needing some major repairs. Short hopping round Leeds at low speed on an engine which didn't get fully warmed up dropped the fuel consuption from the 36/38mpg I was getting on the old engine on a run down to about 22mpg......... However, that isn't what the car is set up to do. David - you may not have noticed, but I have set the engine up again from first principles with decent results. Timing and carburation issues have been dealt with and the temperature has dropped to sensible levels. As for the major hikes in power available, I have neither time, inclination or cash available to go that way. I think the engine now puts out around 95bhp instead of the listed 86 and that'll do for me. With a 'Crab major power increases will be wasted anyway if you can't do something about the final drive ratios. On our cars this can only be done with tyre sizes - mine's on 14" wheels instead of the original 13" ones. The transmission case from a 1700 manual "O" series angine has higher gearing and apparently can be adapted to fit. Hmmm - I know where there's an engine kicking about........... Chris. |
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Post by indianajones on Sept 29, 2012 8:39:51 GMT
22mpg isn't bad really given the set-up Twin carbs are certainly looking like a good mod at this stage as I want to use it for more open road trips in the future (after tech etc) -Andrew |
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Combined with a single box straight-through stainless exhaust and a pair of K&N filters with a carburettor needle upgrade it works out quite well. I have created the moderately efficient long distance family cruiser which I wanted.