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PV, 120 (Amazon), 1800 General Forum for the Volvo PV, 120 and 1800 cars |
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tuning a b18aViews : 21218 Replies : 146Users Viewing This Thread : |
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Nov 15th, 2009, 19:46 | #11 | |
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'68 Ruddspeed tuned 121 |
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Nov 18th, 2009, 00:10 | #12 |
foot in mouth specialist
Last Online: Sep 6th, 2016 22:55
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Location: Dublin, Ireland
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evening gents,
there's been some really useful info posted on this thread and the best modification thread too. thanks for all your knowledge. i've been thinking about the best approach (one at a time), which will allow me to slowly uprate as funds allow. comments, guidance gratefully accepted 1. remove stromberg and fit twin SU carbs with either an all-in-one manifold to start, or separates, if i can find a separate outlet manifold (i'm already in touch with a fellow member for the inlet (thanks Mitch)). run the car for a while. 2. fit a simons exhaust from manifold back. 3. take the head off, skim 2mm and harden exhaust valves and guides. 4. fit 4-2-1 manifold. 5. install D cam and any seals, etc whilst i'm in there.. Bearing in mind this upgrade may take place over a few months.. The questions i have are:- Q1 for task 1, is the std b18a exhaust sufficient with the new carbs and manifolds like this, until i finance a sport exhaust and manifold? Q2 Should 1 and 2 really be done together? Q3 is it even worth fitting a std outlet as an interim measure or do i have to do all the airflow together? i take it i can do task 5 in isolation.. happy motoring.. Gareth |
Nov 18th, 2009, 00:13 | #13 |
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approach?
duplicate
Last edited by redcar; Nov 18th, 2009 at 00:15. Reason: duplicate.. |
Nov 18th, 2009, 08:49 | #14 |
Chief Bodger
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Hi Gareth,
If you are going to pull the head the best performance mods for the engine is porting and polishing the head (will also be the cheapest if you do it yourself). I'm not sure what size the valves are on the B18A but normally it's best to keep the exhaust valve the same size and increase the intake valve size if you are porting and polishing the head as this will help intake flow which is harder to do. Maybe guys with experience with the B18 will know what works. Yeah keep the standard exhaust for now. Once past the manifold there is very little to gain in performance so I wouldn't bother with the simons exhaust. Get a local guy to make you a exhaust with as few bends as possible. Do the cam when you do the head. Also renew the rocker assembly; new pushrods, springs, axle etc. Brass guides for running unleaded as this help dissipate heat away from the valves. Have a read of diy head porting: http://65corvette.nonethewiser.net/t...al/diyport.pdf Last edited by Burdekin; Nov 18th, 2009 at 09:06. |
Nov 18th, 2009, 15:40 | #15 |
Master Member
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Before you start tuning your B18 you should read this article from Phil Singher.
http://vclassics.com/archive/badmotor.htm
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Nov 18th, 2009, 22:50 | #16 | |
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the last thing i want to do is banjax a perfectly good engine.. |
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Nov 19th, 2009, 03:10 | #17 | |
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I would have to respectfully disagree with this. Any modifications to the inlet and exhaust system have to work in concert with each other: there is very little point in fitting a free-flowing manifold, porting and polishing the head, and then bolting it up to a standard exhaust. I know this from experience: before I had the exhaust system built for my car ( see best modifications thread), I was running my four-branch manifold linked to a standard exhaust system. (This was a necessary evil, so that I could drive the car to the exhaust centre.) Top speed with this set-up was an indicated 90 mph. With the system I have now, and NO other mods since ( other than re-adjusting and balancing the carbs) , the car will now run off the clock ( on a private road, of course! I would'nt use the car for pouncing on unsuspecting moderns on the motorway, or anything like that, oh no....). More importantly, with the standard exhaust the engine did not rev anything like as freely through the gears as it does now. Just because the market-leading "sports" exhaust will not achieve this sort of performance, does not mean that no exhaust system modifications are worthwhile. My father's B18 Ruddspeed used to cruise quite happily at 100 and would easily hit 115. I don't believe this relatively mild sixties tune would have achieved this kind of top-end performance with a standard system. There is an awful lot of good advice on this thread, to which I will now add the following: PLAN what you are doing carefully, decide what you want to achieve, then write the "wish list" of parts and labour required to achieve this. If you're on a budget, acquire the parts as and when, and basically spend a year or so "parts-collecting". Meanwhile, enjoy your nice standard Volvo. When you're ready, build your engine to your planned requirements. I can assure you that this approach, whilst requiring patience, is far more likely to yield the results you're after. Some modifications ( like electronic ignition) may be expected to improve the running of a bog-standard engine, but if you're modifying the inlet, exhaust, head, cam etc, then do it all at once, and set your engine up once. Finally, all the very best of luck with it! It is amazing what these old engines can do with the right help.... I should add, that the cheapest and easiest thing to do would be to build the engine to late P1800S spec., or 123GT spec. This would give an immediate, noticeable ( and easily achievable) improvement over the B18 A spec. Might be a good "Stage 1", after you've done all the usual "Stage zero" stuff. Last edited by dilip122S; Nov 19th, 2009 at 03:25. |
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Nov 19th, 2009, 21:48 | #18 |
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If your trying to save cash then you might be interested in some of the following, depending on where you are based:
1. the new "sports cam" and followers that appeared in this ad. http://www.volvoforums.org.uk/showth...ight=followers I know it dates back a bit, but I rang Derek in March or April and nearly bought them. From the posts it looks like no enquiries after that. From memory he was asking less than the price of the followers... which you'll end up buying if fitting a new cam. The only problem was guesing what the cam would do as it wasn't a standard D or K. He thought it was aggressive and specialist from Sweden. Other members might have more idea. For the price (and interest !) it might be worth a go. or a K cam for sale here: http://www.volvoforums.org.uk/showth...&highlight=cam I think I paid Brrokhouse £65 for my D (and a K was the same price). The followers were a hefty price. 2. Why not rebuld another engine while keeping the car on the road. There's a B20 on ebay that might seem a good starting point: http://cgi.ebay.co.uk/ws/eBayISAPI.d...STRK:MESELX:IT or tune another head while keeping the car on the road: http://www.volvoforums.org.uk/showth...&highlight=cam 3. Contacting this ad in the 140 section might give you a cheap Simonz exhaust ??? Can a 140 be made to fit onto a 120 ??? I wouldn't know. http://www.volvoforums.org.uk/showthread.php?t=84411 I paid £125 for my Simonz from Brookhouse as part of a deal while buying other stuff and sounds like you'll be running up a similar length list. e.g. Are you going to be needing a rear hub-puller, cam followers, steel timing gears to replace the fibre, gasket sets ? Draw up the list and give Brookhouse a ring. Make it clear your doing a project and might be back for more. I was pleased with the improvement the Simonz gave for the money / ease. (I'm only a daily driver though !) 4. I suspect the SUs might be high up the list ? This add talks about a spare set.. might be worth a call ? http://www.volvoforums.org.uk/showthread.php?t=84383 Last edited by 1966 122s; Nov 19th, 2009 at 22:27. |
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Nov 19th, 2009, 22:38 | #19 | |
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hi dilip122s this is exactly the route i am thinking of taking.. upgrade to a 122s/123gt/1800 spec, drive it for a while, then see what needs doing after this. as for the budget, well, mortgage, bills, kids take all the paycheck, so dad gets very little time/pocketmoney to play with.. so this may take some time 1966 122s, all good ideas fella, keep them coming. this is turning into a useful thread.. This is helping me form a plan alright. i guess the next step is to start examining the diffrences between my b18a and some of the more sorted motors.. PS. stage zero?!?!?!? Last edited by redcar; Nov 19th, 2009 at 22:57. |
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Nov 20th, 2009, 03:00 | #20 |
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What I call stage zero, sorry. Basically making sure you're starting with a sound engine. Checking piston to bore clearances, valve train etc. Check crank, big ends, etc if feasible. Might include new oil and water pumps, fuel pump, points, condensor, check distributor for play, make sure yr brakes, gearbox, clutch, cooling system etc are all healthy, and so on.
Its really easiest, and most satisfying, to start with the engine out of the car. maybe a good route would be to pick up a second-hand B20 ( best for making serious power) and slowly build it up. There's about a million different ways to skin this particular cat, budget will determine a lot of it. Alternatively, if you're reasonably confident that your engine's healthy, pick up a late B18 D head off a P1800, check it over and fit new valves if necessary, but if the old ones are good, and everything's nice and tight, stick with them! Make sure the head's seating nice and flat, if not get it machined. Fit a D cam kit, a second-hand P1800-type twin-downpipe manifold, and get a set of SU's rebuilt.( you can do this yourself with a kit from Burlen). If funds will allow, go for the 123 ignition. Set it all up ( jetting, ignition etc) as per P1800/ 123GT specs. Get it right, and you'll have a nice reliable, strong engine. As and when the money allows,go for a nice free-flowing exhaust system ( including a 4-2-1 manifold) and overdrive, and you'll see much better top-end performance. Porting work to the head starts to become worthwhile at this point, but you're moving away from standard Volvo spec, and will need to make sure your ignition and carburetion are set up correctly, and this would also be the time to look at a more modern cam spec. If you get this far, your engine will now probably rev up to c.6500 quite easily, so you will want stronger valve springs as well ( and i would seriously recommend an accurate rev-counter!) ( BTW, If I were starting by going down the P1800 spec. route, I would probably begin by giving someone like Brian Gue at Amazonia a ring, and asking if he might have a P1800 head, carbs and both manifolds, suitable for rebuilding....) In many ways, the B18, when correctly built, is a smoother and sweeter engine than the B20. They sound particularly nice with a 4 branch! But if you're seriously chasing big increases in bhp, sooner or later you'll probably be going to a B20. Hope this helps. Last edited by dilip122S; Nov 20th, 2009 at 04:10. |
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