C1J build.

[Markey Mark (BD)]

After an interest from MFaulks (Martin) into seeing what could be done to the C1J engine i offered to drop an engine round to him so he could have alook, throw some ideas about and then put them into practise.

The ideas that were coming out look bloody amazing and am quite interested to see what he can do.
I'll be suppling Martin with whatever he needs, with what he's going to do to it i'll leave that to him to explain as he know's exactly what he's doing to it. Lets just say its different!

Once its all done it'll be slotting into this so we'll see how it goes!

Will keep updated with all the progress on it, sure Martin will do more than me as he'll be doing the machining work.

[Spooky]

An almost 1600cc C1J by any chance ...

[Markey Mark (BD)]

An almost 1600cc C1J by any chance ...

Well that looks like the crank going in it now!

Its still going to be using the original head though but worked on alot, think Martin has got a plan in mind to replace exhaust valves and rocker ratio.

[BluntyR5GTT]

this sounds like a great project and increase in displacement has got to be good

[Matt Cole]

Now this is interesting! At last some good engine development chat!! Lets get this thread going and forget the ****ty other depressing thread!

[rs250nut]

Your still stuck with a 25mm venturi though

[JRP]

Yay my old campus getting really treated

[Markey Mark (BD)]

Your still stuck with a 25mm venturi though

May not be going with that, but saying that Stuart Clark and Santi Gianni seem to produce the power with it is situ (without the Nitrous)

Everything is going to be flow checked to see where exactly the restriction is, Martin may have changed the idea but the exhaust valves are going to be replaced with identical size valves to the inlet.

[Alastair]

Everything is going to be flow checked to see where exactly the restriction is, Martin may have changed the idea but the exhaust valves are going to be replaced with identical size valves to the inlet.

Why change the exhaust valves? You should get better power gains by concentrating on the inlet valve size, or are you doing both?

What crank are you using to stroke it to 1600? Sounds like a good project - good luck mate

[Markey Mark (BD)]

Why change the exhaust valves? You should get better power gains by concentrating on the inlet valve size, or are you doing both?

I'll let Martin answer that one but simple answer is he recon's inlet valve and port looks good enough, the exhaust side needs the most work doing to it.

Got to remember it needs to get out just as well as getting into the chamber.

[Rob@Backyardracing]

Going to be a great thread this... nice to see some progress of tuning the C1j...

Looking forward to the results of this too, fitting larger exhuast valves is somthing im looking at doing with this project.. https://www.rtoc.org/boards/showthread.php?t=11503

[TrixNFlix]

Good luck guys, look forward to seeing some interesting results and information.

[Andrew Cooke]

best be careful that the improved exhaust flow isn't from the manifold back into the chamber

[Rob@Backyardracing]

Bring on the custom cams, lagg and lenghty runners..

[Andrew Cooke]

Bring on the custom cams, lagg and lenghty runners..

cams? you've been gone too long

[Rob@Backyardracing]

cams? you've been gone too long

what we still one cam racing these days..

[MFaulks]

Hi chaps, sorry for getting to this late, now understand the cryptic messages from Clee

Yes, going to look at various options, but firstly cut up the head and gather as much physical info first. Then play with ports and flow test a number of configurations.

The basic head layout is very compact and much smaller than most of the heads I work on, so will be an interesting aside.

Exhaust configuration is particularly poor, low position in the head, large relative surface area to volume, close proximity to the inlet ports - especially cylinder 1 and 4. Recessed valve, likely to reduce heat soak into the inlet, and scavenge over TDC, especially with the very long con-rod. Stroker crank, is a nice way of reducing this ratio, and making it more tolerant of long duration cams.

Focus of the project is to try stuff, suck it and see - quite literally in some ways, and have some fun with it.

Have some ideas for combustion chamber modifications and really need to look at the valve arrangement too. Inlet side I think can be made to flow really well and so focus will be to reduce heat soak from the exhaust side of the chamber, reduce tendency for on-set of det, and then squeeze hard

[Chris Hebden]

Before reading the thread i thought that this was going to be a Markey Mark step by step C1J build thread! How wrong i was................................... looking forward to seeing the results mate

[MFaulks]

Hi all, well sorry for the long gap... finishing other projects, some material searching: valves etc, and longer stroke crank - thanks Ilker your support has been tremendous.. all has added up with a blown laptop to a lay off, but things have been happening, so here goes:

Thanks guys for all the bits, you will see now they are being used.. and abused!

Firstly I cut up a scrap head donated by Mark to see what we have to play with, not much in places. But if there wasn't a challenge what's the point. As you will see it had been cosmetically ported at some stage, I say cosmetic because it’s the bit the untrained eye sees but of little overall effect. Real critical points especially for choke flow speak for themselves in the following. Other areas of concern is I found hairline cracks in the casting around the seat inserts starting at the water jacket casting seams and propagating in... can't be seen normally until the head is leaking...

Lots I have probably forgotten and I will bring more points as we go. Have generally decided to do 2 stages of tune this one, and another project later, reasons will become apparent. Any questions thoughts or plain abuse, just shout in don’t be afraid!

Second set of photos shows some seat inserts I have mashed in, and some straight cuts and a couple of angles. No flow work at this stage, just playing around as looks see and what can go in and what will be a problem. Once I've blended, shaped into throats and ports etc I will again cut these ports on the saw. Down to 3 cylinders at the moment, soon to be 2... those 2 will go into flow experiments.

I have hunted around for valves, and the combination I currently have are some nice 214 SST with inlay, 35.7mm inlet nice shape, or 37mm Rimflow – std is 34mm. Remember, all being equal, the potential increase in flow is proportional to the square of the radius. Not sure how well the Rimflow will work in this head, actually old technology now, but soon to play and find out. Sure like the additional diameter, masking will need to be balanced, but there is some room to the gasket fire ring that can be had. Exhaust side, have selected a nice 32mm diameter valve, and std is 28.9.

[MFaulks]

Sorry this is going to be a bit bitty as I throw the stuff up, but first up will be the inserts just in, and first rough cuts. Inlets bored to 33.3mm including the cut through port so you can see what's going on, but this is just a starting point, not a final number. Biggest valve has left a good throat; insert size could do with being increased so that a nice top cut can be made. Short side all critical area will blend in, and the insert will be blended round into the port as well. Currently this is a parallel bore as I mentioned currently. On the biggest valve, have also run down a straight clean up cut and this has worked nicely, will make porting work much more consistent. Exhaust bored through at 26.4, but loads more needs to come out of that, but the water jacket is real close, and hence will open out and cut on the saw to see if there is any ally left on the short turn. When I throw up the original port cut-through photos you will see why. Lots to do yet

[Matt Cole]

Brilliant this and i dont even have a C1J!!! Everyone states the carb is a mess, but its the head thats a disgrace. Keep at it matey.

[MFaulks]

more pics as above description

[MFaulks]

last pics post before some more words...

[MFaulks]

Here goes on the scrap head sections, as can be seen some mod work had been done, but nothing that likely would have yield any additional power. in fact with the std size valve the throat area has lost all it's properties with a parallel bore, to make that work well again it would need blending at the insert and a larger valve. Gets back to the age old thing of coeff of discharge...

As to valve sizes, to go back to Alastair's question, yes inlets need increasing for VE, and higher rpm capability - time/area integral ratio balanced against port velocity, but with forced induction on a 2v there are always compromise. The main issue with this head is the heat retention, inefficient exhaust port damming up heat (hot gasses get more viscous, not less viscous with increased temperature - more port wall gas-flow frictional shearing, and surface separation - Reynolds numbers), additional pumping loss, causing early break into detonation limiting overall max boost. Installing a much larger exhaust valve closer to 90% to inlet if possible offsets this if the port can be made to flow and expel the heat to the turbo, which is where it needs to be. Problem on this head there really isn't so much meat to play with. I had wanted to offset the valve back, simply to put it further back in the port, can be done but loads of work and this will go into stage II. There are some other benefits to doing that too . I would like to see how this goes first.

Pic salad as follows:

[MFaulks]

final important pics of cut sections:

[rs250nut]

Nice work Martin, I cant believe how much the inlet port narrows towards the throat area. Would this have been done for any particular reason? How would it affect gas speed

[MFaulks]

Hi, thanks for the support chaps

I think you are looking at the exhaust ports, in the immediately above set of photos, the inlet port is far right only, and set above that, inlet port is the last 3 photos.

The inlet is a capable port, and evident in that the engine does perform, however more can be gained, and this is the aim. The exhaust port is a significant restriction on power potential; however, as I have found on other Renault motors of similar generation, the hardware has been developed to the limit of the intended power level and no more. So suitable and sufficient engineering, but leaving in some cases limited further scope.

I will be looking into port velocities, and velocity profile in the ports, but this has to be coupled with where the power / torque curve is going to be moved and keeping good swirl / tumble in the cylinder for efficient combustion. All very well getting the air in, but wet flow and poor mixture homogeneous properties will kill the performance. Wet flow at low lift will be interesting on this port (gas speeds could be low depending final rpm this is tweaked for) and may looking at making it shear to throw it off the port floor.

Will also be interesting to see whether it is worth sacrificing SSR flow and early separation, if sufficient lift and rapid acceleration can be achieved with the valve to allow the port to be straightening and gain LSR flow. The combustion chamber shape and masking will start playing into this.

But at the end of the day, the engine will need to pull higher rpm with increased mass flow with suitable VE etc to increase torque, as capacity increase capability is very limited.

Obviously this is my take on it, and as always I could be off in the wrong direction, but this adds to the fun!

[Sparkie]

the engine will need to pull higher rpm

be careful with the high revs on the c1j engine. you will wear the liners out very quickly. no oil spray - flick only. Also if you increase the valve spring poundage you wear the cam follower/cam lobe out too.

[MFaulks]

Thanks yes, good point, but this motor is aimed at 1/4mile bashing mostly. So to some degree consumable items, unless the liners are made as specials, but long way from that as need to get some decent ponies from it first, and may even only complete one run before a big oily pile is left on the deck.. I have a lovely twin scroll IHI Titanium turbo to sling at it

[Sparkie]

shouldn't be a problem to get the engine to last 1500 revolutions.

[Markey Mark (BD)]

The works looking good mate, i didn't realise how big the valves were till i spoke to you at Ace Cafe!
If more heads are needed got few more here!

[rs250nut]

Just looking at this area, got to be room for improvement

[gtmatt]

some amazing work there martin keep it up

[Wallace]

As someone who knows naff all...............this is just the sort of thing that makes for an interesting project to read about- shall enjoy your progress...

Best of luck

[MFaulks]

shouldn't be a problem to get the engine to last 1500 revolutions.

Seriously though, I don't think this is going to be too serious an issue. The bottom end assembly will be lightened and fully balanced. The exact selection of piston remains to be chosen, but the BMW mini in forged form would certainly be heading in the right direction and a nice light assembly. Further, modern ring package and better oil control, pin height is about right, and I think I will be able to sleeve the small end for a floating pin. Liner is going to be the issue, as the minimum mini bore is around 77mm from memory, may be a tad larger. Ilker is sending me some 1600 C2J pistons, and I'll look at those and see if they'll do what we need, certainly as a starter.

The rods will get ARP fasteners, and be balanced.

As for the top end, the rocker shaft will be stiffened to reduce flex and ensure we can get rapid valve opening, and achieve full lift. I have selected single groove collet valves, and have matched to 7deg locks and some nice very light Titanium top spring caps. So will be reducing masses wherever I can - valve and spring cap masses especially. So this will assist in keeping spring poundage down, and will also convert to Iski twin interference springs to further control spring damping and onset of valve bounce. As I get further into these details I'll post up, but A series mini technology has provided the race valves and Titanium caps.

As to bore oiling, I think it will be a case of seeing what is needed. I have milled main saddles to insert oil squirters on Fiat 8V twin cam turbo conversions, but I must admit I can't say I really know if it works or not, moreover what degree really. There should be loads of oil mist (hope), and with a light ring tension package will see where we get. Obviously not going to get everything right, and you pays your money and makes your choice... my main concern about oil sprays is that you then need to control the additional oil loading on the rings, and any addition oil past top ring is going to lead to detonation very rapidly. In my opinion ring package selection is going to be critical for both aspects.

This motor will probably get pulled a few times, and so we can look at wear signs and under crown oil bake, and judge temps and whether oil spray cooling or cylinder wall oiling is going to be a problem. I am new to this engine, so almost certainly get things wrong and find out by mistake, so I do really appreciate all comments and heads-up. I'm not claiming originality here, as I'm sure much of this has been done before, I really don't know, so my blind ignorance could be a bonus or an Achilles heel. Hopefully be fun watching it either way. Intension is to use it in anger, and have some fun and share all along the ride

[MFaulks]

Just looking at this area, got to be room for improvement

Hi Jon yes lots of room, short side radius (SSR) is going to be important, port area as you mentioned etc. When I set about on the bench will see, the only other aspect in the equation is the long port and charge density loss through water jacket heating and proximity to the exhaust port, and 1 and 4 are worse off for this as there is an exhaust port either side of the inlet. So don't really want to increase the internal surface area of the port more than necessary. Bit like the old Yank iron V8's where the two outer cylinders typically would run less duration and lift on some circle track cams.

Life is nothing else than compromise, ceramic coatings would be nice... but not really street motor technology or pocket project funding..

[i l k e r]

- thanks Ilker your support has been tremendous...

don't mention it my friend, I'm glad i could help

nice to see that the game is on and as said earlier in the pm I have high hopes about this project

good luck

ilker

[MFaulks]

don't mention it my friend, I'm glad i could help

nice to see that the game is on and as said earlier in the pm I have high hopes about this project

good luck

ilker

come in Ilker, your time is out when are you going to get my cranks and pistonies shipped mate? Daz project is waiting chop chop, cheers mate

[i l k e r]

come in Ilker, your time is out when are you going to get my cranks and pistonies shipped mate? Daz project is waiting chop chop, cheers mate

well after 2 hours journey and a few dead ends and road blocks due to road repairs I managed to find FedEx's office yesterday, by the time I found the place they were closed

I'm planning another journey on Tuesday

fingers and toes crossed mate

[MFaulks]

Cheers mate, sounds like one of my trips Thanks for the efforts!

[Woznaldo]

Any updates Martin/Mark?

[MFaulks]

Well... been rather busy trying to get other stuff done, but good news is that I have a C3J crank here thanks to Ilker, big thanks there chap So I had better pull my finger out

[Woznaldo]

No pressure Martin, it's just a very interesting thread.

[i l k e r]

Well... been rather busy trying to get other stuff done, but good news is that I have a C3J crank here thanks to Ilker, big thanks there chap So I had better pull my finger out

finally

I hope everything is as you'd wanted mate.

any problems, just let me know

[MFaulks]

Ouch!! Just got the bill for the shipping from FedEx - 609 quid!!!!

[clee]

YOU WHAT !!!
Mate, you really need to stop! now !

[SCHWARTZ]

was that on a gold ****ing boat?

[Bigfoot]

would have been cheaper to go get it yourself thats crazy money for delivery

[Markey Mark (BD)]

Ouch!! Just got the bill for the shipping from FedEx - 609 quid!!!!

How much!!!!!

[Matt Cole]

Wooh. Thats insane!!! I think it should be £69!