Breaking in roller cam -tips? ALDL shorted? (Page 1/1)
cebix OCT 06, 04:24 AM
'85 2.5 duke auto.

About to start my engine tomorrow for the first time, a fresh rebuild. Any tips on doing it properly? Should I set the timing straight at plug #1 with cylinder 1 at TDC or should I advance it a little manually? Should I run it with ALDL shorted or not?

Thanks.
Lou6t4gto OCT 07, 11:43 PM
there is No Breaking in of a roller cam. only flat tappet cams
cebix OCT 08, 01:56 AM
So just run the engine normally from the start?
theogre OCT 08, 02:57 AM
Roller cam and lifters doesn't need much Break in but rest of engine often does.
Basically drive normal first 250 to 500 miles and avoid floor the gas etc.

Hope you use cheaper oil. Anything cheap 5w-30 w/ API rating. (SJ SL etc.) or the Poland/EU equivalent ratings.
Why? Rebuild engines can have problems besides "Breaking in" a motor and may need to dump after 1 to 1000 miles because of coolant leaks, bad whatever leaving metal in the sump, etc.

Set timing as directed by VECI label etc.
You need ALDL A-B shorted so can set base timing on any ECM w/ HEI. W/o that ECM control makes setting timing impossible.

If you install the dist... get #1 plug to be at/close to TDC after compression.
Ever then likely won't start under slower turn the dist one way or the other then set timing as list on VECI label on deck lid.

Warning: Do not crank too long. Starter and everything will heat up fast and you'll need a new starter etc. likely soon. GM spec 30 sec ON max then 2 minutes or more Off.

------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave

[This message has been edited by theogre (edited 10-08-2019).]

cebix OCT 08, 04:09 AM
Thank you. That explains a lot. So you say to break the engine in lightly? A lot of people seem to say to break it in hard with lots of WOT accelerations for those first miles. Is that a racing myth that doesn't apply to passenger engines?
theogre OCT 08, 04:05 PM
Can floor it some but avoid idiot burnouts etc. that many try on first day to few months.
Most vehicle engines are never made to have owner doing burnouts etc right from the factory. Is why nearly all Warranties are voided by Owner Abuse. Most Rebuilt engine more so w/o spending a lot of $€ to get best parts. You likely have most to all stock type parts or "Rebuilt" parts like a Crank w/ under-size main and rod journals or simply reused many stock parts.

That's ignoring 86 and older "Iron Dukes" have weaker head, block and other parts then many others. Later years are better but not much.

And many Fiero can't reach WOT because of pedal and cable problems. Watch the TBI when someone else floors the pedal or use ECM scanner to read Throttle angle/%.
See my Cave, Throttle Cable