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BlownCorona

Specific engine building technical questions

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Hi hopefully more experienced people than me. 

i have a few questions, mainly about what extent i need to go to, around my up coming engine build for the corona. engine is currently a disassembled 18rgeu which had a failed head gasket. 

 

Now i know how to build an engine, have done a couple in the past and even have some formal engine building training. but what i dont know much about is building an engine to make more power than it came from the factory. 

short story is its an old 18rgeu with a supercharger strapped to it. will be running about 8psi, and run by a megasquirt stand alone ecu. 

how far do i need to take things? do i need forged pistons? do i need fancy bearings, do i need flash piston rings, do i need a MLS head gasket (im pretty keen to use one anyway) 

is there anything else i should be doing or need to look for, in order to produce a reliable engine. i don't much care about making the most power i can. but reliability is 100% priority, while still being supercharged. 

id usually just do internet research on this, but theres a million conflicting articles and most originate from someone selling something. 

 

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Without googling too far into it what can you still buy for a 18RG?

They are basically a tractor engine so I doubt it needs much to take 8psi, fresh stock rebuild  would probably do that for 300,000km no prob. Just gap rings for boost/heat I think. If you need to go oversize and can get nice pistons then do that if you have the $$. Even then stock cast ones would probably survive ages on 8 pound if you had to bet on it.

Bottom end is like no prob, oiling systems on these are good, any bearings will be sweet, just obviously get it all measured and machined to whatever is needed and build to factory spec.

If you can still buy a fancy head gasket then do that also over a shitty repco spec one for sure. But even then these things don't generally blow head gaskets unless you cook them and 8psi is pretty gentle.

 

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you can get forged pistons, though would need 1mm over bore. and are spendy. 

can get an MLS gasket from the same outfit in america, kinda spendy, but not all that much more if your buying a gasket anyway. ill probably be buying there full gasket kit anyway as it looks the most complete and well priced. 

they also do flash bearings with some kind of special heat treatment. probably not needed by the sounds. 

forged rods also availible, but since they are rated to 200hp per rod, i aleady assumed this was not required. id be pretty happy with 200hp across the whole motor! 

 

definatly going to be gapping rings for boost, as this is 100% of the reason its only ever ran super low boost 2-3psi. its been over heated a few times, never super super hot. but ill want to get the head checked out and hardness tested as first port of call. 

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Also placing money on a fresh stock engine will be fine.     main thing is to make sure the tune is on point.

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assuming, and your not the first person to suggest i wont really need forged pistons, i dont buy them. 

will standard type piston rings be up to the task, once gaped properly, or do i need to look around for something specific?

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tuning i want to do myself. fucking it up is a concern and did make me wonder if i should buy stronger parts just for insurance on that front, but am interested to hear what you guys think. 

not a 100% tuning noob, but not a pro either. 

i also dont have a dyno in my shed KPR. lucky bastard. :grin:

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you could use it if you weren't at the other end of the country. 

rings should be fine,  usually ring lands on pistons are first thing to go on a cast piston.   stronger parts will still fail if the tune is off.   detonation is like a first year  apprentice jacked up on a 500ml  monster energy, wielding a large hammer in one hand and a gas axe in the other.  shits gonna get fucked up either way.

best advice i can give re tuning, is invest in some kinda of audible knock detection  if you don't have it already.   chuck it on something you don't like,  advance the timing till it pings its nuts off, so you can familiarize with what knock sounds like.      most boosted  engines will want to knock at low rpm under boost, and again at max torque.   avoid it at all costs

most people get caught up on afr,  while it does need to be right.  its not going to nuke your engine as fast as too much ignition advance. 

good fuel, cold iat's and non restrictive exhaust all help the cause also. 

 

 

 

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very good info. certainly keen on knock detection. ive got a knock sensor here that i planning on making some sort of DIY audio knock setup with. just need to look into what parts itll need

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