If you were in the market for an engine rebuild and you had these option which would you go for:
Standard OEM short block, std rods and pistons. Reasonably priced. ~300bhp (Still have old block left as spare)
New OEM short block with uprated rods, pistons. 60% more than stock. ~320bhp run more boost than std but perhaps more conservative than if sleeved (Still have old block left as spare)
Refurbed sleeved block with uprated rods, pistons. Costs approx twice std after the old block it returned. ~340bhp
Do it once do it right, darton sleeves, lower comp pistons and stronger rods. You know it makes sense in the long run, doing it cheap does not work. I only put a 2nd hand gearbox in my car so I at least could still use it till it was fixed properly
I would keep the stock block. It IS better then using sleeves. The stock MMC bores are good for enough power. You will need the correct compatible pistons though.
Keep your cylinder head, get a new bottom end, new low comp pistons and bearings and call it a day. Maybe get a set of valves and an uprated oilpump (but these rarely fail unless over revved).
I would keep the stock block. It IS better then using sleeves. The stock MMC bores are good for enough power. You will need the correct compatible pistons though.
This seems a pretty tempting option, although I’d be a little worried that if something goes wrong I’m back at square one. Why do you recon that its better than going with the sleeved block?
Does this mean your gay supercharger was the cause of bad things ?
Don’t think so, the car’s lost a lot of oil and hence something’s gone wrong as a result of the low pressure. Not sure on detail yet, but from initial diagnosis its got good compression across all cylinders and it idles ok. So I’ve got fingers crossed that if the options above are taken its my choice rather than it being forced on me. Main thing we need to work out is where the oil went.
Th stock MMC liners where chosen for a reason. They are better at coping with heat and are stiffer then ali/iron liners. The bore to bore spacing if I recall correctly is only 5.5mm and iron liners where not good enough. Wear is also much better.
The only reason you would want to change the stock MMC liners is if you don’t use the correct pistons(the liners will get damaged). People are now moving away from sleeving and just buying a brand new short block and build that. You can also use the stock con rods if you want to save some money since they are good enough for most applications.
What is the power limit of the stock rods then? I am considering trying the drop in pistons option to keep down costs as it saves pulling the engine (mines not broken).
I was looking at the fitting guide for the Mahle pistons and it suggests filing the rings to fit?
I’ve not got much cash as I’ve just bought a new house but I would like stronger pistons.
Any advice will help
Stock rods are good for over 350bhp(the reason you would want to change them is for balancing reasons / lightening).
Please be careful with the drop in pistons on your current block. You need to measure it up to make sure they are within the correct tolerances for the Mahle pistons.
The ideal would be to get a new bottom end and build that(you should get 400hp easy with it built correctly) but if yours is still within spec a set of drop in pistons would be very economical and reliable.
Ultimately reliability has a lot to do with having a correct tune. I know people running about 320bhp on the stock engine unopened (on MR2s)with a rotrex setup. I also know others who have failed engines with much less power.
Take a look on spyderchat.com (search for the rotrex threads here) newcelica.org and monkeytuner for some reading on the pros and cons. Should keep you entertained for some time and get a few other opinions
I do look at all those sites, but sometimes the advice is a bit OTT and very American
As my engine is still in good health I wanted to get the pistons sorted cheaply myself, my reasoning means this will only cost me gaskets pistons and my time. I just can’t afford a new block the moment
Why don’t you just keep the power at 280 ish for now then? Thats already plenty in an Exige. What I would suggest people with superchargers do is buy a J&S safeguard. This can save your engine in case of bad fuel or bad mapping.
it retards knock. Im not sure how sensitive to knock the stock ecu is. The J&S can be setup to your liking with one or more knock sensors and sensitivity to retard knock thus saving your engine in case of knock
Ok overdue for an update. The bearings on number 1 cylinder have gone. Completely broken up hence the knocking. All the others are also in a bad way and have some movement. Lesson to all, check your oil very regularly when on track. Head appears to have been spared. So now need to make my mind up on what to do.
Narrowed it down to two option
1: New internals. Pistons liners rods and have a new crank knife edged and balanced
2: same but go with the Monkey Wrench 2L stroked kit.
Then I’m getting a bit paranoid about what it’s costing and want to be very sure it doesn’t happen again. Dry sump?
Car already had the moroso baffled sump and an accusump and this has still happened. Oil was checked before leaving home the day before and topped up to the marks. Still don’t know where it all went as there is good compression in all cylinders and we haven’t found any leaks. Wondering if it might have burnt off in the sump as things started to fail. Assuming the smoke then went through the breather that would explain the amount of sooty deposit in the inlet pipes.
