Georgia Fiero Club Forum

All Things Fiero => General Fiero Discussion => Topic started by: GTRS Fiero on October 09, 2017, 05:05:55 pm

Title: 2.5L vs 2.8L
Post by: GTRS Fiero on October 09, 2017, 05:05:55 pm
Were the later-year 2.5L setups more advanced than the 2.8?  The 2.5 got DIS, a better computer, and I believe a belt tensioner.

It seems that the heads were also improved.
Title: Re: 2.5L vs 2.8L
Post by: TopNotch on October 09, 2017, 06:16:49 pm
They also got roller lifters. But they didn't get multi-point injection.
Title: Re: 2.5L vs 2.8L
Post by: GTRS Fiero on October 09, 2017, 06:45:47 pm
Lifters vs rockers?
Title: Re: 2.5L vs 2.8L
Post by: TopNotch on October 09, 2017, 08:23:09 pm
Lifters. A stock duke has normal stamped rockers.
Title: Re: 2.5L vs 2.8L
Post by: GTRS Fiero on October 09, 2017, 09:49:02 pm
What is the difference between lifters and rockers?
Title: Re: 2.5L vs 2.8L
Post by: TopNotch on October 09, 2017, 10:26:44 pm
What is the difference between lifters and rockers?
The cam shaft pushes the lifter, which pushes the push rod, which pushes the rocker, which pushes the valve.
(And the foot bone's connected to the ankle bone...)
Title: Re: 2.5L vs 2.8L
Post by: GTRS Fiero on October 09, 2017, 10:31:50 pm
(Light bulb)  Thanks.

So hear the word of the--um, TopNotch.

It would seem that we could eliminate one of those things.

So, the 2.5 got roller lifters, but not roller rockers?
Title: Re: 2.5L vs 2.8L
Post by: TopNotch on October 09, 2017, 10:39:03 pm
So, the 2.5 got roller lifters, but not roller rockers?

85 and later 2.5's have roller lifters. 84's and all years of 2.8's have flat lifters. Neither have roller rockers (but mine does).
Title: Re: 2.5L vs 2.8L
Post by: GTRS Fiero on October 10, 2017, 06:15:16 pm
Any benefit to roller lifters on the 2.8?
Title: Re: 2.5L vs 2.8L
Post by: TopNotch on October 10, 2017, 06:28:52 pm
When you go to roller lifters, you need guides to keep them from turning. Later incarnations of the 60-degree V6 have the guides, but I don't know if they could be used on a 2.8 or early 90's 3.4 (which also has flat lifters). The oiling for the lifters probably wouldn't work for roller lifters either.
But if you somehow could use them, the benefit would be less friction.
Title: Re: 2.5L vs 2.8L
Post by: GTRS Fiero on October 10, 2017, 06:29:53 pm
Would they be noisy, like roller rockers?
Title: Re: 2.5L vs 2.8L
Post by: TopNotch on October 10, 2017, 09:52:07 pm
My only experience with roller rockers is on my duke. Dukes have noisy valve trains to begin with, so I don't know if the roller rockers are noisier.
Title: Re: 2.5L vs 2.8L
Post by: GTRS Fiero on December 15, 2018, 02:44:14 am
Do the plugs from the V6 work in the L4, and vise versa?  Just a plug, right?  One of my plugs broke, so I replaced all 6 (different brand).  The remaining 5 plugs are all new, barely used.  I don't know why they wouldn't work in an L4, but you can buy a single plug for the L4, or a single plug for the V6.  It seems to me that plugs come in boxes of 8.  I never thought of plugs as being inherently for a certain number of cylinders.
Title: Re: 2.5L vs 2.8L
Post by: TopNotch on December 15, 2018, 08:49:22 am
I don't think the plugs are the same. I think the duke plugs have a longer threaded section, if I remember correctly. I get plugs for my duke in boxes of 4.