OZDAT :: L18 engine build advice please

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L18 engine build advice please http://www.ozdat.com.au/forum/viewtopic.php?t=3936	Page 4 of 6

Author:	naukkis [ Fri Dec 17, 2004 5:52 am ]
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Unprepped L18 bottom end with full-counterweighted crank will hold up to 9000 rpm, I've newer faced any problems below 8000rpm. There's two problems which need to be fixed, stock flywheel is enormously heavy and will break crank if revved over 8000 rpm, and because crank's rod bearing supply oil lines are cross-drilled, number 2 main bearing will supply oil to 1 and 2 rod bearing and number 4 main bearing supply 3 and 4 rod bearings, there's bad rod bearing oil starvation over 8000rpm. Mainly rod bearing cooling is inefficient and rod bearings will melt if revs are keeped over 8000 long period, eg over 30 seconds or so. Porting those 2 and 4 main bearing oil lines, increasing oil pressure, and making oil supply groove to those main bearing journals will help but there usually still be rod bearing problems if revs are keeped high long periods. Real cure is factory option crank which isn't cross-drilled, or FJ20 which rod oil supply is as good as it can be. Oil grade is also critical, extreme multi-grade synthetic oils, eg 5W-50 lose their characters rapidly when oil temp rises in rods and instant bearing failure can occur, even with poor mineral oil (eg 10W-30) rod bearings will last much longer.

Author:	fr3ak [ Fri Dec 17, 2004 11:51 am ]
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OK! The final engine plan list is: 180BSSS Head- Various work done, double performance valve springs, unknown extent of porting etc, WADE CAM 74' "works copy", adjustable CAM gear Standard bottom end- Polished/ balanced conrods, polished crank (more work to follow), L28 86mm pistons (with dish) 40mm Delorto carbies x2, Match ported to REDLINE manifold, CAI, pod Genie 4-into-1 Extractors, 2.5 inch exhaust Bluebird Dizzy+coil The engine will be 'put together and see what we get' approach. This will stop the whole thing being a big dollar build. Any guesses on the power at the wheels? Thanks to everyone who has helped out with input. Hopefully i'll get many a fun day/ night from the old girl

Author:	Tazholio [ Fri Dec 17, 2004 12:36 pm ]
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eee eff eye

Author:	DattoPimp [ Fri Dec 17, 2004 1:41 pm ]
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Word Taz. My dads 720 ute with L18 revs to 6.5 - 7 grand, and its completly stock. Mind you it doesn't have much after about 6200. 225thous old, not much compression, the usuals. Someone mentioned that the L18 and L20 flywheel stock is 200mm and the truck has a 225mm flywheel. Is the 720 a 'truck'? and what 'trucks' used an L20? And are the flywheels interchangable? as i wanna chuck a bigger clutch on and if there is a simple bolt on bigger flywheel, well that opens up options for stronger clutchs, which is what i'm after.

Author:

proL18 [ Fri Dec 17, 2004 2:49 pm ]

Post subject:

fr3ak wrote:

OK!

The final engine plan list is:

180BSSS Head- Various work done, double performance valve springs, unknown extent of porting etc, WADE CAM 74' "works copy", adjustable CAM gear
Standard bottom end- Polished/ balanced conrods, polished crank (more work to follow), L28 86mm pistons (with dish)
40mm Delorto carbies x2, Match ported to REDLINE manifold, CAI, pod
Genie 4-into-1 Extractors, 2.5 inch exhaust
Bluebird Dizzy+coil

The engine will be 'put together and see what we get' approach. This will stop the whole thing being a big dollar build.

Any guesses on the power at the wheels?

Thanks to everyone who has helped out with input. Hopefully i'll get many a fun day/ night from the old girl

sounds good.

buy a dremel and do the polishing yourself.

Author:

fr3ak [ Fri Dec 17, 2004 2:54 pm ]

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pro240c wrote:

sounds good.

buy a dremel and do the polishing yourself.

Dude

Are you serious? I'll give anything a go if it'll save cash.

Who else has done this? Where's a good place for destructions to DIY?

Author:	Warps [ Fri Dec 17, 2004 3:16 pm ]
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I did it with a pencil grinder and assorted burr tools. There are a couple of key areas on an L series head that respond well to porting. The main one is to unshroud the valves. You'll see as the valve opens, there's a vertical surface next to the valve, whish effectively blocks gas flow around that side of the valve. Opening this up improces flow nicely. Also, just open the ports up slightly and clean them, removing sharp edges, specially from transitions. Don't go crazy and try to make 50mm diameter ports. It won't work The best advice I ever received is to take it steady and do a little in each port at a time, so you try to keep all of the ports identical. Here'sa good general DYI guide to porting. They're working on boat anchors, but the principles are the same for an L series head.

Author:

fr3ak [ Fri Dec 17, 2004 3:23 pm ]

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Warps wrote:

Here'sa good general DYI guide to porting. They're working on boat anchors, but the principles are the same for an L series head.

hehe, i thought pro240c was talking bout polishing the rods and crank!

All of that porting stuff which you suggested has already been done! Lucky me

Thanks anyway

Author:	Warps [ Fri Dec 17, 2004 3:45 pm ]
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Should read the whole post, I guess How about thisthen?

Author:	jdmdatsun510 [ Fri Dec 17, 2004 4:16 pm ]
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Dont use one of those Redline maniflods! they are pretty crappy. The runners aint even straight and tapper in at the middle. Get your hands on a Datrally Maniflod. They are an excellent casting. And it will flow enough air for your intended rpm.

Author:	Tazholio [ Fri Dec 17, 2004 4:22 pm ]
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ahahahhaa @ Datsss73's avatar

Author:	thehelix112 [ Fri Dec 17, 2004 4:22 pm ]
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Warps, AWESOME links!! Glad you didn't read the whole post! Dave

Author:	jdmdatsun510 [ Fri Dec 17, 2004 4:28 pm ]
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<-------Dance fatboy! Dance !

Author:

proL18 [ Fri Dec 17, 2004 5:18 pm ]

Post subject:

fr3ak wrote:

Warps wrote:

hehe, i thought pro240c was talking bout polishing the rods and crank!

i was....

Author:

fr3ak [ Fri Dec 17, 2004 9:39 pm ]

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Datsss73 wrote:

Dont use one of those Redline maniflods! they are pretty crappy.
The runners aint even straight and tapper in at the middle.
Get your hands on a Datrally Maniflod. They are an excellent casting.
And it will flow enough air for your intended rpm.

OK then.

WANTED: Datrally manifold to suit L series 4 cylinder engine. Will consider swapping for Redline Manifold of similar description. Enquire within.

Jokes people. It'll have to do, i don't wanna spend more money unless i really have to. Damn i'm being a tight arse

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