ludo Posted May 5, 2020 Share Posted May 5, 2020 oversize the pipe, but yes restriction will rob power, Bernouilli knew his stuff 2 Quote Link to comment Share on other sites More sharing options...
Mark (smokey mow) Posted January 4, 2021 Author Share Posted January 4, 2021 This thread is long overdue an update but the truth is that very little progress has been made over the last 6 months. With Covid restrictions in place and the inevitable impact this and furlough have had on many of the local businesses I’ve been using I found it easier to leave it until matters improved. Before things were put on pause one major job that I did compete was a full trial assembly of the car with all the parts. I wanted to do the as a) I had no idea how it went together and b) I had no idea if I had all the bits. Well it’s complete and aside from a couple of small questions along the way most of it seems to be there and fit as if expect. As for the questions well one of the rear trailing arms is half an inch longer than the other, no idea why as the chassis mounts are in the same location so I suspect it’s just lazy welding and the other is that I’m missing most of the coolant hoses from the front of the car so need to figure how this crosses the pedal box. Over the Christmas break I’ve been looking into the Roll hoop, this is only 1” diameter tube so has got to go. A replacement hoop has been drawn up so I’m now at the stage of getting prices for this to be fabricated and fitted. For now just a plywood mockup to show. The other major milestone is that I’ve sourced a suitable engine for the car. I’d originally looked at getting something built as the spec required for this car would be scarce to say the least. By chance I spotted an advert that sparked my interest and after an exchange of emails the deal was done. The engine in question was built by George Bevan for the imp touring car. For those who no their Imps the Bevan Imp raced to victory in 3 years running from 1970-72 in the British saloon car championship at the hands of Bill McGovern. This engine was the spare from that very car and I bought it directly from the Bevan family so can attest it’s provenance. The spec is as good as it gets, 998cc, R23 steel full race cam (9200rpm) ported and polished head with wills rings, lightened rods and balanced crank all of which takes the power from the stock 39bhp to a conservative estimate of 110bhp based on period data. 5 Quote Link to comment Share on other sites More sharing options...
Mark (smokey mow) Posted January 4, 2021 Author Share Posted January 4, 2021 Those who know me well would know that I’m lost without a project on the go so to pass the time over the summer I found something to keep me occupied while not working on the Costin. I’ve always fancied restoring a bike but not having a licence limits my options somewhat if I ever want to ride it. After a bit of searching the Testi Champion ticked the boxes but being Italian they’re few and far between in the U.K. a suitable project was found in Italy and after a few emails I was able to convince the seller to dismantle the bike and post it to me in 3-boxes! Suffice to say that my local postman was less than impressed with this. Against all odds it arrived safely (missing a few nuts and bolts) but all the important bits were there. from this.... to this.... 9 Quote Link to comment Share on other sites More sharing options...
Rory's Dad Posted January 4, 2021 Share Posted January 4, 2021 Lovely!! 1 Quote Link to comment Share on other sites More sharing options...
stephenh Posted January 5, 2021 Share Posted January 5, 2021 Mark, I may be totally out of date here, but doesn't your car driver's licence act as a provisional licence to ride bikes up to a certain small size of engine? Looking at the pictures I'm guessing that the engine capacity of this bike is small to match the tiny front disc brakes and the very narrow section rear tyre? No use me looking at my licence because I passed my bike test many years ago, so it isn't limited to cars. As for the engine for the Costin, I am delighted for you that you dropped on this, absolutely perfect for the job. Very light weight for a car engine as unusually for the period it was all aluminum head and block, and in the form you have found it has excellent power relative to the engine capacity. Well done, and keep us posted on developments. 1 Quote Link to comment Share on other sites More sharing options...
Mark (smokey mow) Posted January 5, 2021 Author Share Posted January 5, 2021 3 hours ago, stephenh said: Mark, I may be totally out of date here, but doesn't your car driver's licence act as a provisional licence to ride bikes up to a certain small size of engine? Looking at the pictures I'm guessing that the engine capacity of this bike is small to match the tiny front disc brakes and the very narrow section rear tyre? No use me looking at my licence because I passed my bike test many years ago, so it isn't limited to cars. As for the engine for the Costin, I am delighted for you that you dropped on this, absolutely perfect for the job. Very light weight for a car engine as unusually for the period it was all aluminum head and block, and in the form you have found it has excellent power relative to the engine capacity. Well done, and keep us posted on developments. Thanks Stephen, you’re quite right the bike is a 50 which means I can already ride it on my OAP licence without needing to do a CBT first. I’m very happy with the engine. there’s a slight historical link as Bill McGovern also drove JW4’s for Johnny Walker on several occasions and also the Costin Walker in 1970 and 71 so it seems quite fitting to be fitting the engine from his touring car. Quote Link to comment Share on other sites More sharing options...
Nic Chase (NICO) - Shropshire & Mid-Wales AO Posted January 5, 2021 Share Posted January 5, 2021 Another top quality restoration Mark. Well done. Loving the work on the Costin. Quote Link to comment Share on other sites More sharing options...
Kevin Pullen Posted January 14, 2021 Share Posted January 14, 2021 Excellent work as usual Mark, I’ve got a full license so if you need a test pilot I’m available Quote Link to comment Share on other sites More sharing options...
Mark (smokey mow) Posted January 26, 2021 Author Share Posted January 26, 2021 Trying to keep up the progress since Christmas I’ve been in talks with a couple of people about both the roll bar fabrication and also a couple of jobs I will need doing in the engine. I’m prioritising pulling together the parts needed for this as the engine gearbox and chassis work are the first three that need to be completed before I can reassemble the car. It’s such a tight fit in the engine bay that I need to fit these first and then assemble everything else around them. the latest job completed is the inlet manifold. I’d made a mock up using SU’s for hen I gas the exhaust fabricated but after some thought and a few conversations with race organisers I’m switching back to Weber’s for ease and simplicity. The car was run with both over the years and series regulations require me to run the car in a period specification so It was a choice between either twin 1-1/2” SU HS4’s or a single Weber Carburetor. When I bought the car it was fitted with the Weber on a crude manifold. This was a prototype but far from ideal and despite the tubes having a reasonable diameter the hose joiners reduces this to little over an inch. This made its way to the bin quite soon after I got the car so it’s time for something better. There was no chance of getting anything off the shelf since the engine orientation is so different to the Hillman imp so I had to start from scratch and given the problems I’m having getting parts made right now and looking to save a bit of money I thought I’d have a go myself. First off we start with a drawing and then onto fabrication. my welding skills are slowly getting better but cosmetically still not perfect, but luckily most were to be dressed smooth any how. Just a coat of paint needed now. 7 Quote Link to comment Share on other sites More sharing options...
Mark (smokey mow) Posted February 6, 2021 Author Share Posted February 6, 2021 All being well the car is booked in to have a new roll bar fitted later next month so before I strip everything down to a bare chassis there’s a few jobs, measurements and photos I need to do as it’ll be a long time before the car is complete again after this. The car is being built with circuit racing in mind and for that I need a 2 litre oil catch tank, which is done thing the car never had in period. There’s absolutely zero room inside the chassis to fit it so the only space left is on the outside. I’m trying to avoid adding any new brackets to the chassis but luckily a suitable space presented its self to the side of the gearbox, I just needed to fabricate a bracket so it could be bolted to the box. incase you’re wondering yes I did spill a whole bottle of marking blue ! 2 1 Quote Link to comment Share on other sites More sharing options...
stephenh Posted February 6, 2021 Share Posted February 6, 2021 I'm quite surprised that you needed a 2 litre catch tank, Mark. It's only a small engine, I would have thought a 1 litre catch tank would have been satisfactory, and acceptable? Quote Link to comment Share on other sites More sharing options...
Mark (smokey mow) Posted February 6, 2021 Author Share Posted February 6, 2021 56 minutes ago, stephenh said: I'm quite surprised that you needed a 2 litre catch tank, Mark. It's only a small engine, I would have thought a 1 litre catch tank would have been satisfactory, and acceptable? I had initially thought the same as you. I've got an invitation to run in Formula Junior and It’s their series regulations that mandates 2 litres as a minimum. Quote Link to comment Share on other sites More sharing options...
Steve holt Posted March 8, 2021 Share Posted March 8, 2021 Hi Mark, This has been a really interesting read as I have just bought a jw4 for restoration. I hope to post some photos of it soon. steve 2 Quote Link to comment Share on other sites More sharing options...
Mark (smokey mow) Posted March 9, 2021 Author Share Posted March 9, 2021 11 hours ago, Steve holt said: Hi Mark, This has been a really interesting read as I have just bought a jw4 for restoration. I hope to post some photos of it soon. steve Hi Steve, thanks for your message. I’d love to hear more about it and please drop me a message at wsccessex@btinternet.com if you want to get in touch. I can probably also help you with parts. if you’re on Facebook a few of us have also recently set up a page for these F4’s. https://www.facebook.com/groups/249327320175050/?ref=share Quote Link to comment Share on other sites More sharing options...
Mark (smokey mow) Posted March 26, 2021 Author Share Posted March 26, 2021 Yesterday and as planned the new roll bar was fitted. the back stay is still yet to be made but the fabricator will be coming back to fit that and also repair a lot of the cracks and damage to the chassis once it’s all been shot blasted which hopefully will be it’s next stop later this month. A big thanks to JMW motorsport for helping to organise this. In case you’re wondering what the internal pyramid structure is, this replicates the crash pylon that Costin originally designed for the car. To my knowledge the Costin Amigo was the only other car to feature such an unusual safety feature. 6 Quote Link to comment Share on other sites More sharing options...
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