JMT240KGTR

Guys, Misplaced the tool I had to remove this annoying little thing, this weekend I'm put another g'box in and need to replace it. I read a while back this can be done with grease, a driver and hammer? If anyone can help would be great, thanks.

Hi, Copy of one of my earlier posts regarding this topic, cheers. The L24 block can be overbored out to L28 specs, but thats about max. As for C/R, should up it to around mid-high 9's, ie 9.5-9.7:1. This will give an increased capacity of 2.6litre but what I like about this modification is you're keeping the short stroke, therefore the engine will rev harder. I've helped build a motor once that didn't go the usual route of retaining the 240bore size and throwing in L28 rods and crank, this also gives 2.6 specs. Rather we did what you intend doing and that is using a L28 bore with 240rods/crank, again 2.6 litres. We felt this engine had more power than the "popular conversion", we put this extra power down to bigger bore and higher revs (shorter stroke). Many V8s go down this route when talking "stroker vs non stroker", higher revs etc etc. It all depends on the end package and how you extract the most from it ie cam, valves, reducing weight, pulleys, ignition, g'box, diff ratio. Mind you we also shaved the head .050", C/R was quite high, don't know what, it was never measured. Bear in mind I'm not saying this conversion would be better on the race circuit than a fully worked L28 ie L31 triple carbs, big cam etc etc! Here's what we done; N42 L28 block (86mm bore) N42 head shaved .050" (bigger valves than E31) L24 9mm rods and crank Flat top pistons 240 SU carbs (modified needles and jets) Camshaft provided by w'shop (not sure on specs) 280ZX elec distributor & coil Electric fan 3 row radiator Extractors 2.5 inch exhaust C110 5 speed R180 3.9 open differential This motor was fitted in a C110 Skyline, wish it was in a Z, the Z's handling would have loved it. Evidently was involved in a smash a few years back and is gone! Anyhow it was a quick car, and no, you won't have piston height problems, changing the pistons don't affect height only con-rods and cranks on these motors. James __________________ L Series Sixes; can't beat 'em!

Mr Camouflage, Rather than search for a P90 head I'd go with the R30 version E88 head; the design is similar if not identical to the P90 in swirl and combustion chamber characterisitics but the E88 has a much smaller comb chamber than the P90; P90 cc's 53+, E88 39cc's (thats what I measured mine at anyway) and yes it does have the larger 42mm inlet valves, not the 44mm valves you'd find on N42/P90 etc. The difference in valve size isn't noticeable on the street, but if you're a full on race car and need every cubic inch of air you can get into the engine, then get the 44mm valves to suit. After fitting my ex R30 E88efi head last weekend I've upped the C/R to around 9.7:1, but I also shaved the head .030". The car is pretty quick and nimble now. Cheers

Good stuff Nick. Any pics of it or strictly confidential for now? :classic:

Yeah thanks for the replies guys, any info on these is great. 36cc & 41cc hey? Interesting stuff. Well just this morning I cc'd a couple of chambers and they measured between 38-40cc (I re-measured them several times to be sure). Pretty sure this head hasn't been shaved either, height is very close if not exact to the standard. I'll be taking it to the shop this morning and getting .030" shaved. Given the figures between 36-41cc and .030" shave I'm looking around the 9.4-10.2:1 comp, which is good for me! Thanks for the feedback fellas, if any further info on these heads can be provided would be good. Nick what I meant when I referred to this head as similar to the P90 was the closed chamber design, unlike the N42 it has a "heart shaped/peanut shaped chamber" as many would refer to them as. How is that 240K going, finished the GTR replica? James

Thought I'd see if someone can provide some info on the above. Have an Australian spec E88 head off an L24E Skyline, very similar in design to a P90 although chamber is much smaller, comes with 42mm in & 35 ex valves. Anyone know the CC's of these heads? I have posted a pic in my gallery, (still waiting approval) but if I don't need to get it measured and have spec's available it'd be great, at least I'd know roughly what kind of C/R I'd get on an L28. I've used the "calculator" from the Sydney Datsun Club to give me an estimate but they've got 44.7cc, same as an N42. They must be referring to the earlier E88 versions. Thanks.

Just wondering if anyone has or where can I get one from? It'd be a good reference rather than looking through the shop manual and flicking through 80-100 pages worth of info. Stuff like bearings, pistons, rings, rocker, springs, valve guides, sizes etc etc, the whole lot. If anyone can help thanks, James

Cheers, thanks mate. By the way, go Man Utd!:classic:

Thanks Alan. You're a good man! And a knowledgeable one! :classic: