engine rebuild

Make it go fast! Kick it up a notch. Post tips in here.
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maytag
Posts: 1789
Joined: Mon Oct 19, 2009 9:22 pm
Your car is a: 1976 124 spider
Location: Rocky Mountains....UTAH! (Not Colorado)

Re: engine rebuild

Post by maytag »

In my opinion, you really need to come up with a budget, and decide what you can do for that budget. And then stick to just that. Otherwise, you'll end-up like mine, creeping WAAAAY beyond the intended scope, and costing too much and taking too much time.

in response to a couple of your questions, and with a small budget "freshen-up / performance increase" in mind:

yes, you can get hi-compression pistons in a standard bore. Hone the cylinders well. Oreilley will have a loaner=hone. typically, these will come with a ring-pack that sits slightly lower on the piston, so you don;t need to worry abut them hitting the ridge. HOWEVER: you'll still need to ream the ridge if its' enough to keep the pistons & rings from sliding into the cylinder. Replacing the pistons will require a rebalance of the assembly, because your bob-weight will have changed.

If the crank has no obvious scoring or burning, Mic it and the bore, or plastigage it. Bearing shells can be had in just about any thickness you could want. CLEAN EVERYTHING REALLY WELL. You can rent a 3000psi pressure washer for $50 and clean your driveway too. :lol:

I see no reason to summarily replace valves and springs. If you don't have bent valves, and the seats look good, lap them, put on new seals and call it good. I understand that these guides rarely fail, bit you could check them.

Cams are a good choice next. well, should I say "Cam". Many people suggest that replacing the intake cam with something with a little more duration and / or lift is a good thing. I think general consensus would be to get a set of adjustable cam gears so you can dial them in.

So rough pricing:

pistons - $400
Balancing - $120
bearings - $150
valve seals - $25
Intake Cam - $200
Cam gears - $300
gasket kit - $150
I'm no Boy-Racer..... but if I can't take every on-ramp at TWICE the posted limit.... I'm a total failure!
fiat218
Posts: 5745
Joined: Fri May 16, 2008 5:06 pm
Your car is a: 1969 124 AS spider

Re: engine rebuild

Post by fiat218 »

i have just learned alot from reading this post , as far as what to get or what not to do in my rebuild
i got dual carbs and this is what i am working with, so what ever makes the car tick with duals is what i plan on doing
Jim
East Grand Forks MN
1970 Fiat Spider BS1 ( FOR SALE
1969 124 AS Spider
2017 Abrath
2018 Alfa Romeo 4c Spider
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engineerted
Posts: 531
Joined: Tue Feb 21, 2006 9:57 pm
Your car is a: 1974 124 spider
Location: Farmington Hills, MI

Re: engine rebuild

Post by engineerted »

Replacing the pistons will require a rebalance of the assembly, because your bob-weight will have changed.
Not exactly correct, as this is an inline 4 cylinder with a 180 degree cranshaft. The crank is internaly ballanced, ie. the counter weights are to balance out the crank pins thus no need for bob-weights ( bob-weighs are used on 90 degree crankshafts, most US v8 engines) I would advise ballancing the rods end to end and make sure the pistons are with in .5 grams of each other.


Ted
Ted
1978 124 Spider, Complete Restoration
1974 Fiat 124 F Production Race car
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maytag
Posts: 1789
Joined: Mon Oct 19, 2009 9:22 pm
Your car is a: 1976 124 spider
Location: Rocky Mountains....UTAH! (Not Colorado)

Re: engine rebuild

Post by maytag »

engineerted wrote:
Replacing the pistons will require a rebalance of the assembly, because your bob-weight will have changed.
Not exactly correct, as this is an inline 4 cylinder with a 180 degree cranshaft. The crank is internaly ballanced, ie. the counter weights are to balance out the crank pins thus no need for bob-weights ( bob-weighs are used on 90 degree crankshafts, most US v8 engines) I would advise ballancing the rods end to end and make sure the pistons are with in .5 grams of each other.


Ted
good point. This is actually the ONLY 180d motor I've ever owned, let alone rebuilt.

For clarification, when you say "balancing rods end to end", you aren;t suggesting making the small end weigh the same as the big end, you're saying make the big ends all weigh alike, and small ends all weigh alike, right?
I don't know how you'd balance 'em end-to-end.
I'm no Boy-Racer..... but if I can't take every on-ramp at TWICE the posted limit.... I'm a total failure!
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engineerted
Posts: 531
Joined: Tue Feb 21, 2006 9:57 pm
Your car is a: 1974 124 spider
Location: Farmington Hills, MI

Re: engine rebuild

Post by engineerted »

http://tinyurl.com/bqtl9d9

This is a good video, if you know that your rods are factory matched set, just weigh them and if they are within a few grams, no need to balance end to end.
Ted
1978 124 Spider, Complete Restoration
1974 Fiat 124 F Production Race car
Daniel

Re: engine rebuild

Post by Daniel »

you're saying make the big ends all weigh alike, and small ends all weigh alike, right?
This is correct ! :mrgreen:
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maytag
Posts: 1789
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Your car is a: 1976 124 spider
Location: Rocky Mountains....UTAH! (Not Colorado)

Re: engine rebuild

Post by maytag »

engineerted wrote:http://tinyurl.com/bqtl9d9

This is a good video, if you know that your rods are factory matched set, just weigh them and if they are within a few grams, no need to balance end to end.
right, so, as I said: you are NOT BALANCING END TO END. That would be impossible to do. You cannot make the big end weigh the same as the small end. :wink:

And for the record: I'm not sure what Fiat's version of "factory matched" was, but most manufacturers use a "binning process", whereby all rods of a certain range fall into one bin, next bin has a slightly higher range, etc etc. So you could conceivably end up with a factory-assembled motor with rods quite different from each other. same goes for length.
I was surprised when I tore into this motor to find these rods VERY close in length. So I first matched the "taller" of the pistons with the "shorter" of the rods, so that what I ended-up with was 4 assemblies as close in length to each other as possible. Then I matched the weight of the pistons to each other (these high quality pistons were already very close, but my previous set which I purchased from our friend "Fiatfactory" were terrible), and then I weight-matched the rods, small ends first.

Theoretically, this thing should rev veeerrry smoothly. :lol:
I'm no Boy-Racer..... but if I can't take every on-ramp at TWICE the posted limit.... I'm a total failure!
Landhawk

Re: engine rebuild

Post by Landhawk »

Have learned quite a bit from this thread and the research I've been doing. Thanks to everyone for the great information!

I found a local shop that has some reasonable prices and plan to use them for cleaning block, honing cylinders, cleaning/glass beading head, valve job... The guy I talked to suggested that I have the head pressure tested, an additional $45 or so, guess I'll do that since it's not that much. I still plan to do as much as possible myself, but will be a much better job for some things with the equipment the shop has.

Got the engine hoist yesterday, so this memorial day weekend will be dedicated to getting the engine out and taken apart as much as possible, plan to take plenty of photos during the process. :>

I'm putting together an excel spreadsheet that will list all of my expenses (with links to the parts where applicable) so I can keep track and post here if anyone wants to see it.
Last edited by Landhawk on Fri May 25, 2012 8:36 am, edited 1 time in total.
Landhawk

Re: engine rebuild

Post by Landhawk »

So, are you saying I should not have the crankshaft grinded and then balanced? Or grinded but not balanced? Or just clean it real well? I understand the part about the rods, but just want to make sure I know what is needed for the crank. Thanks.
maytag wrote:
engineerted wrote:
Replacing the pistons will require a rebalance of the assembly, because your bob-weight will have changed.
Not exactly correct, as this is an inline 4 cylinder with a 180 degree cranshaft. The crank is internaly ballanced, ie. the counter weights are to balance out the crank pins thus no need for bob-weights ( bob-weighs are used on 90 degree crankshafts, most US v8 engines) I would advise ballancing the rods end to end and make sure the pistons are with in .5 grams of each other.


Ted
good point. This is actually the ONLY 180d motor I've ever owned, let alone rebuilt.

For clarification, when you say "balancing rods end to end", you aren;t suggesting making the small end weigh the same as the big end, you're saying make the big ends all weigh alike, and small ends all weigh alike, right?
I don't know how you'd balance 'em end-to-end.
BEEK
Posts: 1833
Joined: Wed Mar 24, 2010 10:45 pm
Your car is a: 1975 Spider
Location: clermont fl

Re: engine rebuild

Post by BEEK »

if the crankshaft bearing surfaces are in good condition, grinding the crank is not only a waste of money , it actually hurts the surface hardness. a stockt non turned crankshaft is much prefered
Automotive Service Technology Instructor (34 year Fiat mechanic)
75 spider
, 6 Lancia Scorpions, 2018 Abarth Spider, 500X wifes, 500L 3 82 Zagatos. 82 spider 34k original miles, 83 pininfarina, 8 fiat spider parts cars
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narfire
Posts: 3959
Joined: Sat Dec 27, 2008 2:14 am
Your car is a: 1980 124 spider
Location: Naramata B.C.

Re: engine rebuild

Post by narfire »

I was told exactly the same thing. After mic'ing the crank and if it is below spec, I believe one can purchase various oversized bearings. Just thinking here but if the crank is out of round.... perhaps another crank might be the way to go. If it is pitted and/or in shite shape, source a good used one.
80 FI spider
72 work in progress
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opus10583
Posts: 861
Joined: Tue May 03, 2011 7:13 am
Your car is a: 1978 CS1
Location: Westchester County, NY

Re: engine rebuild

Post by opus10583 »

Hi,

What's the situation with auxiliary shaft bearings, truly NLA or not?

Which is the block cleaning process which harms these bearings and which does not?

Thanks,
Mark
...Yes; I know what it means: Fabbrica Italiana Automobili Torino.

DOLCETTO: 1978 CS1; 10:1, DMS, 4-2-1...
ANDIAMMO: 2012 500 ABARTH

Acquista il Biglietto; Prendere la Gita! - Hunter S. Thompson
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boogiedude
Posts: 410
Joined: Mon Mar 02, 2009 5:22 am
Your car is a: 1978 spider 1800
Location: Honolulu, HI

Re: engine rebuild

Post by boogiedude »

Autoricambi carries the aux shaft bearings, or at least they did when I built my motor last year.

I believe acid tank is the damaging process
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SLOSpider
Posts: 1140
Joined: Wed Mar 03, 2010 2:10 am
Your car is a: 1973 124 Spider 2.0FI
Location: Lompoc, Ca USA

Re: engine rebuild

Post by SLOSpider »

I hate reading a book only to find out the last pages are missing. So where is the spreadsheet?
What did you do?
1975 124 Spider
1976 Mazda Cosmo http://www.mazdacosmo.com
1989 Chevy k5 Blazer
1967 GT Mustang Fastback
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124JOE
Posts: 3141
Joined: Fri Jun 24, 2011 7:11 pm
Your car is a: 1978 124 fiat spider sport 1800
Location: SO. WI

Re: engine rebuild

Post by 124JOE »

after reading this post i dont recall anyone sugesting more fuel
as jim is tring to run duel 40s,he may starve the engine or fuel

or am i just wrong?
when you do everything correct people arent sure youve done anything at all (futurama)
ul1joe@yahoo.com 124joe@gmail.com
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