They look like a nice set of rods and pistons Eric!
They look like a nice set of rods and pistons Eric!
Any engine bay clearance issues with the much taller 2.5 engine?
Will research what the 'slipper' bit means. Didn't realise teh 2.3L has been discontinued.
1970 Mk1 Escort Tarmac Rally Car
i think you will find the slipper pistons have 1 less ring and a smaller skirt than standard.
you will need to run at least ignition management on the engine, even with carbs, so ignition should be fairly easy to tune.
duratec engines also have a knock sensor so this should help with safeguarding the higher compression. if you go too high with the compression you can always go for a thicker head gasket. plenty of places make these or spacer plates for all the turbos out there.
Yes, if anyone has height difference between the 2.0 and the 2.5 that would be good. I believe the 2.3s are approx 25mm taller because I would love to put my 2.0 in and then build a stonkin turbo 2.5 in the future.
Project 1 Mk1 RS2000 replica, now home.
Project 2 Mk1 Escort Turbo Duratec, in the planning stage
OK, don't think I have asked this before.....the 2.5L head is presumably different to the 2.3/2.0 due to different bore spacing but has the same size valves? Bigger ports? How do they flow?
The difference between a 2.5 and a 2.5 block with 2.3 crank is only 76cc so on that account does not seem to be worth it. I guess the benefit comes from fitting larger valves and not having those larger valves as shrouded?
The 2.5/2.3 combo must use some very long rods which will increase the weight and therefore forces on the crank = much less revs. I am possibly thinking about a steel crank anyway which will avoid any issues with reciprocating mass.
Unless somebody can verify/confirm the additional power available from the 2.5/2.3 combo over a straight 2.3 then I think I would stick with 2.3.
1970 Mk1 Escort Tarmac Rally Car
All heads are interchangeable and as far as I am aware the 2.5 engine has the same size valves as the 2.0 and 2.3.
I dont understand where people are putting highport heads on 2.5L or putting 2.5heads on 2.3/2.0block ... surely they re-tooled for the 2.5 engine? changing the bore spacing.
Flying Miata has steel 2.0 cranks out of the mx-5 (NC) for about $400 when I bought mine.
iron crank will rev as well if you balance it, but forged steel for $400.
only problem with revs is things wear out quicker so rebuild time is less.
Roger got 5 seasons of racing mallala reving with peak power at 8300 on E85. and on pull down he said the engine was good to go. Only problem he had was broken keyway and that was caused by under torquing the crank bolt.
double post
Last edited by _PauL_; 12-12-2016 at 15:03. Reason: double post
Fantastic thread, very informative and helpful since i'm currently building a 2.0 duratec to go in my mk1 escort.,
I'll probably have more questions than answers.
if the info i found online is correct there is almost no difference between the 2.0 and 2.3 heads ... just my little contribution :-)
The updated NC maita engines with the good crank will rev on the stock motors to 8500 over here. No need for the keyway, just never undo the bolt as mazda put it there. And if you do buy new washers an religiously clean all the grease and oils (no fingerprints) off everything that isnt the threaded part of the bolt. And torque it to the real spec of 70 ft-lbs + 90°. If you're really worried you can use the ARP bolt torqued to 90ftlbs + 90° (bring your 3/4" drive breaker bar and a big piece of pipe for this, it works out to like 420 ftlbs) and put loctite 680 on the washers, crank snout flat, and pulley.
Yes Ive seen first hand, how hard they are to remove from factory we broke a 1/2in drive (made in china of course ) before we got serious with it.
and found out that the 2.5s 2.3 and 2,0 heads are all interchangeable.
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