timbo Posted November 11, 2005 Share Posted November 11, 2005 As an interim measure I'm going to fit the std 2.0 pistons into in replacement of the low compression 2.3 in the stock engine. (i have a set I can get my hands on for next to nowt) Does anybody know what compression this raises the 2.3? 12.1??? If so this creates 2 immediate problems: cranking compression and ignition timing in regard to high possibility of detonation. What do I require in terms of headgasket thickness to meet what the norm is in terms of a reasonable compression? What depth should the pistons be pocketed to (inlet & exhaust) for the std 2.3 cam (fixed timing) The engine is new unrun. The 2.0L pistons have a little use on them.. Would you suggest changing rings? Ps. I'll fit forged pistons at a later date when I go in pursuit of mega power. anxiously waiting for my new 2.3 SV Link to comment Share on other sites More sharing options...
Jason Plato Posted November 11, 2005 Share Posted November 11, 2005 you need to chat with Rob Walker . Mail me off line for his details the "low compression" 2.3 pitons are not actually that low @ 10.5 as I recall ..... Link to comment Share on other sites More sharing options...
timbo Posted November 11, 2005 Author Share Posted November 11, 2005 YHM anxiously waiting for my new 2.3 SV Link to comment Share on other sites More sharing options...
Rob Walker Posted November 11, 2005 Share Posted November 11, 2005 Why not stick with the stock 2.3 pistons? I recently measured both the stock combustion chamber volumes and the stock dish topped pistons and std head gasket and the compression ration was 10.3 to 1. Whilst I apprectiate that this is less than ideal for full balls out power it is never the less usable and I can see no reason why they must be junked as a matter of course. I have not had the opertunatey to do any valve piston clearances as yet but recon with sensible cams and not too much lift at TDC the pistons will be ok without machining. Link to comment Share on other sites More sharing options...
timbo Posted November 11, 2005 Author Share Posted November 11, 2005 Cheers Rob. I have no problems running the std pistons and std cam at this stage as it is just a stop gap before undertaking major work at a much later stage? I must measure the CR when I take the head off tommorrow. Do you know the max valve lift for the stock cams at TDC on the 2.3? As I'll be using the std cams without verniers at this stage the lift at TDC will be fixed as per factory settings. As such there will be no issue of valve to piston contact. Though I would be a little concerned of running the engine on a very low compression ratio with non forced induction. I'm fitting roller barrels on 75mm trumpets (came cheap) so my main issue is the emerald map. I haven't time to start spending a large amount of time on mapping as the kit arrives in Mrch and I'm for France in late June. So essentially I need a good ignition map as a base... the fueling I can tweek map with the wide range lambda. anxiously waiting for my new 2.3 SV Link to comment Share on other sites More sharing options...
timbo Posted November 11, 2005 Author Share Posted November 11, 2005 So essentially at this stage the decision on piston/cams is very much based on my access to a suitable emerald map. Ideally if somone has an emerald map for a 2.3 on stock pistons and stock cams using the stock cam timing it'll make my mapping a hell of alot easier as the base ignition map will be fairly close. anxiously waiting for my new 2.3 SV Link to comment Share on other sites More sharing options...
Dobuy Posted November 11, 2005 Share Posted November 11, 2005 Hi Timbo, I would seriously doubt you will have any problems with piston clearance using the 2.0 pistons with 2.3 cams. I am pretty sure the 2.3 cams are softer than the standard 2.0, so you will not need any pocketing. This is really only required with the uprated cams, like those supplied for the 226bhp 2.0 Raceline engine. Also I would think your rings will be fine, allegedly they are pretty good quality as standard. Anyway you asked for the numbers, this is what I found for the 2.3 from the Ford manual: Journal Diameter (in.) 0.9830 Cam Lift - Intake (in.) 0.3110 Cam Lift - Exhaust (in.) 0.2913 Angle of Seat 45° 00' - 45° 30' Intake Valve Lift (in. @ Zero Lash) 0.311 Exh Valve Lift (in. @ Zero Lash) 0.291 Compression Ratio Nominal 9.7 to 1 Duratec SV, built in Dubai Link to comment Share on other sites More sharing options...
timbo Posted November 11, 2005 Author Share Posted November 11, 2005 I believe I am correct in saying that the stock 2.3 has two variants on the basis of CR determined by piston variation. Figures of 9.7 or 10.6 have been bantered about .. the question is which CR I have. Can anyone exapnd on this? If the CR of my engine is mid 10's I see very little reason to start changing pistons at this stage considering my future plans. Thanks Dobuy... 0.311" of lift on inlet (311 thou) = 7.87 mm lift 0.2913" of lift on exhaust = (291 thou) = 7.39 mm lift Thats not alot of lift for a cam. anxiously waiting for my new 2.3 SV Link to comment Share on other sites More sharing options...
Dobuy Posted November 11, 2005 Share Posted November 11, 2005 AFAIK these figures are from the Ranger 2.3 engine Duratec SV, built in Dubai Link to comment Share on other sites More sharing options...
Dobuy Posted November 12, 2005 Share Posted November 12, 2005 Timbo, I am not sure if you are aware, but the gudgeon pins are a bit of a pain to remove and refit. You may need someone to do it for you as they ideally require a small jig so that you can press the pin out. Heat may also be required, I have never done this, Raceline have always done it for me. After market pistons have circlips, so are easy. Duratec SV, built in Dubai Link to comment Share on other sites More sharing options...
I.Mupferit Posted November 12, 2005 Share Posted November 12, 2005 Pete McEwen told me we wouldn't need to pocket the 2 L pistons if I used the standard 2.3 cams in my engine but with some decent cams then, yes, you do. His view is that the standard 2.3 cams are ok for use in a truck where you need plenty of low down pulling power but pretty naff for use in any car with sporting aspirations. Hence I had mine changed on Peters recommendations. Brent 2.3 DURATEC SV Reassuringly Expensive R 417.39 😬 Link to comment Share on other sites More sharing options...
Dobuy Posted November 12, 2005 Share Posted November 12, 2005 I reckon that if you want a cheap upgrade, put the 2.0 pistons and cam in the 2.3, as the both of these are a bit more performance oreinetated than the 2.3 Ranger engines. Duratec SV, built in Dubai Link to comment Share on other sites More sharing options...
timbo Posted November 12, 2005 Author Share Posted November 12, 2005 Depending on what CR I get today I'll decide whether to put the std unpocketed 2.0L pistons in. What max lift on the std 2.0L cam? Also, more importantly lift at TDC? What I am trying to achieve is to see what a near std 2.3 engine is capable of on a tiny budget before I start throwing lots of cash at it ... which is cast in stone at a later date. Assuming that 2.0L pistons and std 2.0L cams are readily available as most people immediately dump them when specing their engines the costs are incredibly low. Yes Dobuy... I am aware the pins are press fit on the std pistons. As you say.. abit of a bugger but I have access to the neccessary equipment. anxiously waiting for my new 2.3 SV Link to comment Share on other sites More sharing options...
timbo Posted November 13, 2005 Author Share Posted November 13, 2005 Have stripped the engine. FIRST POINT:: found a piece of shaved metal the size of a good pencil sharpening lying in No.1 cylinder *eek* Pistons are Mahle & have the mark 44/35 stamped on the face. They have a 6mm flat edge round the piston face with what looks like a 3-4mm sunken flat bottom dish. Before I start CR measurements does anyone know off hand if these are the 9.7 or the 10.5/6 pistons? I'm stuck in 2 minds. I have access to a set of very cheap low mileage std 2.0L flat top pistons (say £50). To press swop the pistons across onto the rod will be roughly £50. So thats £100. At some stage I will definetly go forged so am I better spending the money now on the forged? For the forged Omega pistons fittment do I have to reem the std rod small end? The std 2.0L cam has 1mm more lift than the 2.3L std cam on the inlet. However, if I fit the std 2.0L cam I'll have to reshim hence at this stage I'll stick with the 2.3 std cam. So thats a false economy. anxiously waiting for my new 2.3 SV Link to comment Share on other sites More sharing options...
AMMO Posted November 13, 2005 Share Posted November 13, 2005 Timbo Personally I would ditch the stock pistons and cams. The flat top 2 litre pistons are not that expensive and a set of cams will make the engine go really well. You could also do a bit of porting while you are at it. Sticking to stock components and having to do work at a a later stage is false economy in my opinion. AMMO Link to comment Share on other sites More sharing options...
timbo Posted November 13, 2005 Author Share Posted November 13, 2005 Yes AMMO.. I'll eventually be going down that route.. but part of the fun I see in owning a 7 is always working at it. I'm starting simple but will no doubt end up putting alot of money into it in pursuit of mega power. However at the moment I'm going to see what a near stock 2.3 is capable of with a more suitable CR. If c. 200bhp is attainable for a 'near' stock 2.3 surely that starts to bring these engines back into the realms of affordability... Try getting 200 on a K from a near stock engine!! anxiously waiting for my new 2.3 SV Link to comment Share on other sites More sharing options...
Dobuy Posted November 13, 2005 Share Posted November 13, 2005 Not sure you will have to re-shim, as the base circle should be the same, just the lift is different. Of course I am just thinking out loud, I could well be wrong Duratec SV, built in Dubai Link to comment Share on other sites More sharing options...
Jason Plato Posted November 13, 2005 Share Posted November 13, 2005 At some stage I will definetly go forged so am I better spending the money now on the forged? no brainer I reckon ontop of all the costs of swopping to 2 l pistons and the inherant risks of re press fitting the pins , you also have to cost in the consumables for stripping the bottom end again.... if the cams are same base circle, then you shouldnt need to reshim. Link to comment Share on other sites More sharing options...
Dobuy Posted November 14, 2005 Share Posted November 14, 2005 And these rods ain't exactly expensive here and pistons here Duratec SV, built in Dubai Link to comment Share on other sites More sharing options...
timbo Posted November 27, 2005 Author Share Posted November 27, 2005 An update on trial fitting 2.0L a std piston into the 2.3L. The result is a 12.08:1 CR! The combustion chamber volume, deck volume & headgasket volume through my measurements was 51cc with the std pistons fitted. The std 2.3 -ive chambered pistons added an extra 14cc volume which lowers the compression to 9.7, exactly as per manufacturer specifications. Working the calculations back against the 2.0L std engine 51cc gives a CR of 10.7:1 using 83.1 stroke. The extra 10.9mm stroke in the 2.3 over the 2.0L accounts for the additional compression. The piston height at TDC in the bore is identical for both 2.3 & 2.0L. As such the 2.0L cams in the 2.3 will prevent no problems using the std 2.0L pistons. However... I've a big concern. 12.1 is a hell of a CR for a std cast piston. I'll speak to Alan @ Scholar on Monday as they fitted 2 of the pistons the wrong way... maybe forged is the best route. (I know you told me so 😬) anxiously waiting for my new 2.3 SV Link to comment Share on other sites More sharing options...
Dobuy Posted November 27, 2005 Share Posted November 27, 2005 maybe forged is the best route. (I know you told me so) I think it was definately worth trying, as someone once said: To all the conformists in the world, thanks for nothing. Suprised that the CR is that high, I think Peter @ Raceline tried it, don't know what result he got though. Edited by - Dobuy on 27 Nov 2005 10:56:31 Link to comment Share on other sites More sharing options...
timbo Posted November 27, 2005 Author Share Posted November 27, 2005 Yeh... it seems to be that different people are banding about different figures... strange one! All I can say is that my engine, which had the balancer shaft on the frt timing cover, with the std 2.0L piston fitted is 12.1. anxiously waiting for my new 2.3 SV Link to comment Share on other sites More sharing options...
I.Mupferit Posted November 27, 2005 Share Posted November 27, 2005 Peter has, indeed, fitted the 2 L pistons to a 2.3. Why not give him a call and ask his opinion, he is a very approachable bloke. Brent 2.3 DURATEC SV Reassuringly Expensive R 417.39 😬 Link to comment Share on other sites More sharing options...
timbo Posted November 27, 2005 Author Share Posted November 27, 2005 Will do Brent anxiously waiting for my new 2.3 SV Link to comment Share on other sites More sharing options...
snitcher Posted November 27, 2005 Share Posted November 27, 2005 speak to Alan @ Scholar on Monday as they fitted 2 of the pistons the wrong way I know a couple of other people that has happened to. Be sure to check everything in minute detail. Link to comment Share on other sites More sharing options...
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