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How "peppy" should a rebuilt redblock feel?

SenseiRice

New member
Joined
Aug 5, 2016
Location
Southern NH
So I got a 93 squirter motor for my 1991 245 (lh3.1 5spd) and I rebuilt it over the winter. This is the first overhaul I've ever done so I made sure to do everything as close to the book as possible. I got 0.005" shaved off the deck and an ipd vx3 cam for the motor. I did not overbore the motor as the bores were still within spec and the ring gap was 0.012" across cylinders 1,2,and 4 while cylinder 3 was 0.0013". I also did not get new cam shims, I checked valve lash with the head off the motor and while it was cold and I didn't write down the exact specs but I recall it being relatively equal across the board and all measurements were close to the lowest spec. (I know it's supposed to be done at operating temp but I had no way to heat it up that much at the time and the spec said it was for a cold engine) Everything else minus the valve guides and valves is new (I did lap the valves), new bearings, new valve springs, new gaskets, and so on. I just got done the break in and took my car out on the highway and it really doesn't feel much faster than my old stock b230f with 286k miles on it. I wasn't expecting a speed machine but I was in 4th at about 95mph with my foot hard on the floor and it really wasn't accelerating. It's running 87 octane gas with a bottle of stp octane booster so I don't know if that has anything to do with it still feeling sluggish or if it's because it still has the 27 year old main fuel pump, fuel filter, and injectors that have never been cleaned; at least as far as I know. It also has a code 2-3-2 in the jetronic computer but the code isn't illuminating the cel and no codes in the ezk. It also has a pretty gnarly exhaust leak because the flange that bolts the downpipe off the header too the rear of the exhaust is warped and rusted pretty badly. The car also has a rougher idle but doesn't feel like a misfire to me, it also has no problems with running and revs just fine. I'm thinking of running a compression test this weekend and maybe a fuel pressure/volume test but I wanted to know if there was anything else I should check? Or maybe I'm just delusional thinking it should be a lot quicker and I should accept my slow brick will never get to 60mph in under 10 seconds without a 16v or turbo.
 
Assuming that the old engine was in decent shape, not puking a ton of blowby aka wasting bangs that could have been pressing down on the pistons...might have picked up 10hp? A bit more squish and more lift of the cam like you installed will do something, but it's nothing earth shattering in a NA engine. Chuck a decent free flowing exhaust on there to replace your trashed one, and you are at a good spot with a solid foundation to add on to later (more compression, bigger valves, boost ect.)
 
Assuming that the old engine was in decent shape, not puking a ton of blowby aka wasting bangs that could have been pressing down on the pistons...might have picked up 10hp? A bit more squish and more lift of the cam like you installed will do something, but it's nothing earth shattering in a NA engine. Chuck a decent free flowing exhaust on there to replace your trashed one, and you are at a good spot with a solid foundation to add on to later (more compression, bigger valves, boost ect.)
I looked down the bore of the old motor with a bore scope and there was still minty crosshatching and no scoring, never tested the compression but it didn't burn much oil so it was in pretty decent shape (burned about a quart and a half every 3000 miles) the only thing original on my exhaust is the header and that's the only thing leaking rn but after the header it's a 2.25in catless straight pipe with a flow master super 10 at the back.
 
I've never known an M cammed engine to feel 'peppy' except for maybe from 1500-3000 rpm. A small zone of peppiness.

Exhaust leak messes with the computer. The code means the computer senses something isn't ok. Take care of the multiple issues and it'll feel better.

A good thing to do is change to LH2.4 and get a cam and chips for the ezk and jetronic. Then you will have peppy.
 
it's NA and it wasn't whooped to begin with. you're not likely to feel much of anything until you put a manly man cam in there
 
You are running a (relatively) low compression 4 cylinder motor. The VX3 likely does a decent job as compared to the stock M cam, but you still don't have enough compression to take full advantage of it. LH3.1 also does a great job of keeping you at stoich (read more efficiency - less power).
 
It would be difficult to duplicate that torque push you get from a turbo with an n/a engine, my Toyota makes 180hp but only 136ft/lbs of torque over 8250rpms with a 4.56 final drive and 6spd manual. It's a relatively quick car but it never really feels the same as when the turbo spools in the 242.
 
Adjustable cam gear and 2.0 pinto timing belt.

Pinto 2L belt isn't really needed until ~ .060in. I should say, I'm pretty sure you can't even stretch a 2L pinto belt on until there's .060in or more off of the head :)
 
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