Bobbed and caged RRC called The "JWH"

[Soren Frimodt]

Cheers guys, I hope you can get a sense of how tiny it is with how huuge those 35"s look  And funny thing is, by making it as narrow as I have, you don't really notice the very short wheel base. Its still 'rectangular' looking instead of the more square-ish look you get from bobbing the ends off a Rangie.

It looks to be closer to completion than it is though. The cam in the old SD1 engine is completely shot, so I'll have to replace that, planning on fitting a 3,9 stock cam for budget. Anyone have any experience of this?

And I still have a lot panels to make and the complete electrical system. But sure, it is progressing nicely  

I don't know when or where the first testdrive/shakedown will be, but sometime in the spring for sure. I'm pretty sure how everything is going to work so its not as critical with a lot of testing as it was with the Single-Seater, there was a lot more 'unknowns' on that

[lo-fi]

Just love the look of this one. Purposeful, utilitarian, and kinda mean looking! 

I can probably help with needles to get the Strombergs set up for the 3.9 cam.  I'm actually running a 3.9, but I'd be willing to bet the difference in fueling required is more to do with the cam than 0.4 litres of displacement. 

I've got a set of the most juicy stock needles I could find, but they still weren't giving quite enough fuel from mid range up, so I ended up rolling my own. Might be perfect on the 3.5 - happy to send for you to try. If not, a few minutes with a bit of wet and dry with the needle spinning fast in the pillar drill does the trick! 

Keep the updates coming

[Soren Frimodt]

Geez lo-fi! Thanks for that man! I intended to find a set of SU's for it, mostly because I have more experience with them and didn't want to spend the time on the Strombergs, but SU's are getting increasingly hard to find in any useful shape within my budget. And I have a set of VERY good looking Strombergs in the attic, so I may very well hold you up on that gracious offer 

The thing with the cam is that the engine actually has quite a lot of blow-by and is in need of complete overhaul. Seeing that it is one of early ones with the big valves and 10,5:1 CR it deserves it and I wouldn't mind spending the money, but just not for this car. This would be much better off with a 3,9 or bigger and some proper BHP's so I'd rather make this run just right enough for me to have fun, and then figure out / build another engine for it. And then store this one for later use, perhaps in the 80" where it would be a right gem with only 1200kgs to push around.

[lo-fi]

That is a nice 3.5 to build up. All the right bits. 

Pop a 3.9+ in, then .  Ping me a PM with some details when you're ready and I'll happily send those needles over. B1FN if I recall correctly. I think measurements of my homebrew ones were in my 109 build thread too, so should be enough to get you going. Going to (twin) turbo this one? 

I certainly can't fault my Strombergs, she starts and runs perfectly hot or cold. Nothing against SU, but like yourself, it's what I had and SU's were not easy to get hold of.

[deep]

I had Strombergs on a 3.9 in my Stage One.  They performed magnificently and really needed very little sorting.  IF you were going to run full throttle for extended periods you might have to look at a slightly larger jet but that's an unlikely scenario?

[Soren Frimodt]

On 31/12/2017 at 5:38 PM, lo-fi said:

Going to (twin) turbo this one? .

Well you're not the first one to ask I can tell you that  But I don't really see it happen for two main reasons: 1st, with V8's its always like you just have the option to go bigger, which in the long run tends to be cheaper and more reliable. 2nd the RV8 isn't exactly known for its ability to sustain good oil pressure, and this would kill the turbo(s) in no time. I could of course go drysump but again this adds to the price and complexity  

22 hours ago, deep said:

IF you were going to run full throttle for extended periods you might have to look at a slightly larger jet but that's an unlikely scenario?

I could very well see this scenario happen  But I was wondering, there are no loose jets per say in the Stromberg are there? I certainly have never seen one  

On to todays update, did get a bit done when I eventually was able to stumble into the garage just before noon  

The subject of today was Ali work on the bed, here's how it panned out:

I absolutely hate this kind of work, so glad to have gotten this much done today

[lo-fi]

I couldn't help but ask  supercharger? Sorry... 

I believe some of the really early carbs did have removable and adjustable jets, so it depends what era they came from. The type fitted to RRC, which seem to be the most common, are a press fit and a bit of a pain to change. I ended up chucking the carb bodies in the lathe and using the tailstock to press the jets in.

There are a couple of different jet sizes, but you'll have the biggest in the V8 versions anyway. I found that mine ran ok on the 3.5 needles but the wideband lambda showed it running quite lean ~3000rpm upwards. I don't like seeing 16:1 under load! 

Happy new year! May it be one of happy, productive invention and tinkering. 

[deep]

1 hour ago, lo-fi said:

I couldn't help but ask  supercharger? Sorry... 

I believe some of the really early carbs did have removable and adjustable jets, so it depends what era they came from. The type fitted to RRC, which seem to be the most common, are a press fit and a bit of a pain to change. I ended up chucking the carb bodies in the lathe and using the tailstock to press the jets in.

There are a couple of different jet sizes, but you'll have the biggest in the V8 versions anyway. I found that mine ran ok on the 3.5 needles but the wideband lambda showed it running quite lean ~3000rpm upwards. I don't like seeing 16:1 under load! 

Happy new year! May it be one of happy, productive invention and tinkering. 

Thanks for the clarification.  As I understood it, the jet regulates mixture wide open, the needle everywhere else.  On my Stage One, the engine was very strong at full throttle, so the jet clearly isn't far off.  With any modified engine being used in anger, you do want to be fairly sure it's not too lean though!

[lo-fi]

I did experiment drilling out the jets a few thou, but found it impossible to get the idle away from being seriously rich with any needle, float and jet height. That was my first failed attempt at fixing the high end mixture before reprofiling the needles. I believe there were different springs you could put in the dashpot too, but I never found any to buy. 

I do like the CD carbs, they're quite fun to play with. Lots of tinkering potential! 

[Soren Frimodt]

Great stuff guys, yeah the general consensus is that the main jet is for full throttle and the needle for the midrange, but I can see that isn't the case with these and SU's. I'm trained as a Motorcycle Mechanic and on all the CV style Carbs I've touched the affore mentioned was the case. But I guess the British Engineers always loved to be different   

[Soren Frimodt]

A bit of an update on the Cam stuff.. Found a video on the Tube of You that explained how you could check if the cam was worn without taking the valley gasket off. Simply mark the pushrods and turn the engine over and check if all pushrods turn at equal speeds, if at all. A very obvious way to check it, I just hadn't thought about it  But as you can see on this video it is quite clear the cam is well worn:

So I continued stripping down and this is as far as I got:

Found a barely used Piper cam on Ebay at a very good price, so going to stuff that in there 

[Bowie69]

Looks lovely and clean I'm there Soren

...and two out of four ain't bad

[Soren Frimodt]

10 minutes ago, Bowie69 said:

Looks lovely and clean I'm there Soren

...and two out of four ain't bad

Yes I'm very surprised about that myself  I have stripped quite a few V8s in my time, and only ever seen one this clean before, and that was a 4,6. Sure I change oil quite regularly, but I haven't owned it for more than like a 20th of its life, so someone else must've taken good care of this engine  

No I suppose not, but they all look quite bad on the lobes, there was also two standing still on the other side. All exhausts though, wonder why that is? Smaller valve, but more heat? surely that shouldn't travel all the way down to the cam lobe. Perhaps just a coincidence? 

[Bowie69]

No, that is a bit odd to be honest.

You would think enough heat would be taken away by the oil and rocker shaft. 

Perhaps the exhaust has a different profile and wears the edges off more quickly than the inlet?

Or maybe some numpty replaced it before and didn't set the lifter preload properly

[elbekko]

13 hours ago, Soren Frimodt said:

Found a barely used Piper cam on Ebay at a very good price, so going to stuff that in there 

Does it come with the tappets (labelled and numbered)?

[Soren Frimodt]

10 hours ago, elbekko said:

Does it come with the tappets (labelled and numbered)?

Nope, and I know what you are referring too, that they wear in together. But after some research I have found plenty of people saying that so long as you fit brand new tappets they shouldn't have a problem wearing in. I have also ordered some proper assembly lube and break-in oil. So chances should be good. But just to make sure I don't get hung up should the Piper cam be a dud, I've also ordered a new std 3,9 cam which I will fit if there's anything wrong. Prices on both are negligible, so won't leave me sleepless. Though of course I hope the Piper cam is good  

Anyways good Her all apart today, and I can happily report that She looks really good on the inside!  Someone has definitely been in there before, as the cam woodruff is ground down a bit and the chain and sprockets are in really good condition. But seeing as the engine is from '72 why shouldn't it have had a cam swap before?

Even the cam bearings are in really good nick, so I'm ready for new parts to arrive! 

There's a wopping 2,7mm difference between this, the most worn lobe and the least worn lobe on the exhausts  

Double springs on the valves, I can't recall the other RV8's I've done had that, is that stock you think?

[dangerous doug]

The pace you work at truest is astonishing. Do you even sleep?! 

 That’s impressive! Good thing your getting a new Cam, You should be ok if you have new tappets. Could I suggest a solid timing gear aswell? That looks like a genuine one with the plastic teeth=poop

 

also, while it’s in bits have you thought about opening up the valve throats? Really easy job, I’ve done some on an engine that’s just been rebuilt and it’s running beautifully apparently

[lo-fi]

That's an ingenious way of checking cam wear, Soren. I'll remember that one! I had an old 3.5 many years ago that had a misfire I could never fix, which turned out to be a cam lobe worn almost round. I wish I had some pictures, but it was sadly before Camera phones 

Valve springs look very similar to the ones on the SD1 heads from that very same engine (many years of festering in the garage later):

 

[Soren Frimodt]

10 hours ago, dangerous doug said:

The pace you work at truest is astonishing. Do you even sleep?

Hahaa yeah I get plenty of sleep, what you see here is only 1,5 hours of Work so nothing major at all  

 Could I suggest a solid timing gear aswell? That looks like a genuine one with the plastic teeth=poop

Remember mate, budget..  I will say though that the general condition of this engine makes me happy, and looking forward to doing it up 'properly' in the future. But with all the blow-by there is now, I see Little pointin exotic parts. 'Polishing a turd springs to mind'  

 

also, while it’s in bits have you thought about opening up the valve throats? Really easy job, I’ve done some on an engine that’s just been rebuilt and it’s running beautifully apparently

You have to enlighten me here mate, what throats?

 

7 hours ago, lo-fi said:

Valve springs look very similar to the ones on the SD1 heads from that very same engine (many years of festering in the garage later)

Yeah I can't recall if its like that on LR V8's,  but those heads sure look like mine

 

[elbekko]

11 hours ago, Soren Frimodt said:

But after some research I have found plenty of people saying that so long as you fit brand new tappets they shouldn't have a problem wearing in

Fair enough, I hope it works out for you I've seen a cam get destroyed within 1000km from mixing up the tappets.

[Soren Frimodt]

45 minutes ago, elbekko said:

Fair enough, I hope it works out for you I've seen a cam get destroyed within 1000km from mixing up the tappets.

Yeah I've heard horror stories about that too, and I'm sure they are true, but I think its only a problem when you mix used tappets. But time will tell I guess  I also need to finish up the fuel system so that it can run for the 20 minutes at around 2000rpm that is required for breaking in the cam, the approx 4,5 liters I can have now won't last long enough at that pace I fear  

[dangerous doug]

The circled bit is the problem area, if you remove a valve and stick your finger in there you’ll feel a sharp lip, smooth that out for free power

 

 

[Soren Frimodt]

Ooh porting is what you meant, well I'm not planning to take the heads off, and even though I could just make sure the valve is closed while I do it, I still believe the risk of damaging the valvestem will be too great compared to the little benefit. I have previously done  a lot of porting, especially on 2-strokes, and can really appreciate the free power aspect of it, but it is quite time consuming.. Besides often times port matching is more relevant and beneficial on these old British 4-strokes in my experience

[dangerous doug]

I was told by v8tuner over here hat all “stage 1” heads are on a RV8 is some of the casting marks removed and opening up the valve throats. They don’t even match the gaskets. He was saying that mod is worth 20bhp ish

I understand you not wanting to take the heads off though. And it’s mandotory that you put them back on with arp head studs lol

 

 

 

[lo-fi]

33 minutes ago, Soren Frimodt said:

Besides often times port matching is more relevant and beneficial on these old British 4-strokes in my experience

In my conversion thread there are some pics of my port matching work on the dual plane carb manifold. Some ports needed quite a shocking amount of work to match the gasket. Interestingly, the 3.9 heads have ports cast with far greater precision and matched the gaskets almost perfectly, including the little notch for the injector. I can't remember if the 3.5 heads are similar in that respect, but might be worth attacking the manifold anyway. I don't have a before and after comparison, but it certainly runs well!

Thanks for the heads up on the porting detail, Doug. Very interesting!