Tom,
I read that too; Dave Carroll is a god on the Birds list (builds nice stuff
for VG's) so I didn't respond although I was tempted to but I pretty much
stick to fact answers over there. It's an interesting topic and we all
respect a point of view a little better round here - heck my opinion is
bound to be a bit different to others on the list.
Well all I can say is that we dropped something in a race engine in practice
once and had to go with a brand new set of rings etc. This was late '70s and
we were using Nismo comp rings (crap rings but sponsors paid $$$ for them),
run them in like Dave said (like we had no time to do the old fashioned way)
and the rings lasted around 40 minutes. Damn oil blown back everywhere so
bad that you couldn't see anything behind you, Nismo compression rings were
great so you didn't lose power but the oil rings were shockers and when they
let go they did it in style. Basically they were totally stuffed and a waist
of time and considerable effort. We replaced them again (same Nismo crap
rings), nothing else was touched and ran them in just by driving sort of
normally (varying revs an load stuff) and the engine then gave good hp for
~30 hrs (~2000 mls) which was the scheduled tear down.
Street engines are a bit different, long idle times, wot bursts, overrun and
hours vs. distance travelled is quite different, so I'd be recommending that
you stick to the long proven method.
In his defence though, ring technology has improved out of sight since then,
I'd say molly rings are as run in as they are ever going to be in 1hr or so
(15 seconds?) but big end bearings are supposedly a different, then again
how many Datto engines do you hear of dropping a big end - I've only done
one in 30 years (in a 2nd hand engine at that).
I've never used ATF when assembling an engine, most Japanese engine
manufacturers recommend dry fit for rings anyway, but I have always used a
breaking in lube with molly rings (as recommended by Hastings).
So, may be he does have a point if you are using the good modern stuff.
regards
Terry
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED]]On Behalf Of Tom Richardson
Sent: Tuesday, 27 March 2001 10:18
To: [EMAIL PROTECTED]
Subject: Running in L series engines
List,
What is the general consensus about running L series engines in? David
Carrol from Experimental Engineering in the USA recently posted this
comment, here is it below for the benefit of those not on the Bluebirds
list.
What do the list members do to run engines in-this?
I'll be doing a hone & re-ring in a couple of weeks, so I was just curious
:)
Thanks,
- Tom
>From: "David Carroll" <[EMAIL PROTECTED]>
>To: "bluebirds list" <[EMAIL PROTECTED]>
>Subject: Re: A new way to clean your motor - LONG
>Date: Sun, 25 Mar 2001 17:08:25 -0800
>
>List,
>The ATF in the oil trick for de-sludging has been used since the '50s. I
>have used one quart of ATF in place of a quart of oil in L series engines
>for a few hundred miles to de-gunk them just prior to rebuilding with very
>good results. The thing you have to be careful about is plugging the oil
>filter up with all the sludge and deposits that the ATF breaks loose. If
>the
>filter plugs up while you've got ATF (or diesel) in there the oil filter
>bypass will open and all the crap that's in the oil will go through the
>bearings, wiping them out in a matter of seconds. I would only use half a
>quart of ATF if you are not about to rebuild the motor. That way things
>will
>clean up much slower and the risk of plugging the filter will be lessened.
>I
>would NOT use straight ATF to break in an engine. It's viscosity is not
>high
>enough to prevent bearing damage and it does not lubricate cylinder walls
>or
>cams very well. In the '70s and '80s the Nissan-approved method (and the
>method still used by most race engine builders) on L series engines was to
>lube the piston rings and cylinder walls with ATF and assemble everything
>else with Hilton's Hyper Lube or similar. Start the engine. Run it 'till
>the
>ATF all burns out (a couple minutes). Then pull the plugs, squirt about 3-4
>table spoons of ATF into each cylinder, and start it again. When the ATF
>burns out the second time the rings are seated and the engine is ready to
>run or race. The idea here was that ATF is a far inferior cylinder wall
>lube
>so putting it on the rings kept some of the motor oil away and there was
>far
>more friction between the rings and cylinder walls. This made the rings
>seat
>in just a few minutes. All current Nissan engines and all Nissan-factory
>rebuilds are now assembled with the rings and cylinder walls DRY. They have
>only a light vegetable oil coating to prevent rust in storage. It is said
>that the rings are fully seated in the first 15 seconds the engine is run.
>I
>don't doubt it! I adopted this method of assembly about eight years ago and
>it has worked very well. Other than seating the rings no break-in period is
>required with L series engines. Once the rings are seated, go race it. If
>the cams have been replaced, SOHC VGs should be run at no less than 3000rpm
>for the first ten minutes. This is because they use off-center, flat-tappet
>cam followers that have to spin in their bores as the cam turns. Until they
>have worn in a little idling the engine may let them stick in place which
>flattens the cam lobe very quickly. L series have no such problem though
>most L series cam manufacturers include instructions for a SBC which does
>require a cam break-in. All the BS about not revving the hell out of an
>engine for a few thousand miles and such are just that: BS. Think about it,
>a typical road racing season is about 2000 miles. If you couldn't run an
>engine hard for 3000 miles you'd have to break it in for a year and a half!
>;-) Serious racers rebuild either once or twice per season, depending on
>their budget. Hell, Top Fuelers rebuild after seven seconds under load!
>(Including burnout) :-)
>David Carroll
>Experimental Engineering
>Seattle Washington USA
>
> >>>> I seem to recall reading somewhere that Mondello ( a well known and
>respected engine building company ) runs their engine with pure ATF for a
>few minutes for initial break in.
>
>
>
>
>
>
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