Technical 100+bhp in 128

Currently reading:
Technical 100+bhp in 128

tarmac terrorist

New member
Joined
Oct 24, 2004
Messages
29
Points
11
Location
plymouth/devon
hi guys

i've got a 128 4 door saloon which i plan to take to track days, at present its a 1300 with an twin choke webber carb, however as i crave speed does anyone know of a engine transplant which would get me upwards of 100 bhp.

would a 1600 from a 91 tipo dgtsx go

have considered the strada 130tc lump but don't know if it'll fit. :devil:

i'n not worried about having to fabricate parts or mounts so
any help would be greatly appreciated :slayer:

also can i fit 15" wheels
 
Last edited:
Well the obvious one is the UnoTurbo.... about 105hp

another is a 1.6 16v twin cam from a brava/bravo.... they are around 103hp but with loads of torque too

these both will mate up to your gearbox and will fit (pretty much) straight in

I have fitted a twin cam 2000 to my X19, so it should be able to fit in a 128, though I dont think this would do much good for the handling.....

My dad has put a TC turbo 2000 in the front of an UNO.....tight squeeze.... and once again very heavy over the front wheels.

it is easy enough to get around 100hp using cam/carb/compression and some close tolerances inside..... My 1500 x19 has 99 rear wheel hp, and still uses the standard intake/exhaust manifolds....

or theres the 1.6 crank in a 1.5block...... still fits straight in to your engine bay.

lots of options, limited only by the size of your wallet. (and maybe what class you want to run in)

SteveC
 
thanks mate.

i'm after as much power as is sensible in a front wheel drive car. it's gonna be a project so i'll have to save up and do it over time. i have heard about people using a 1.5 from a strada and with the correct parts and tolerences getting 120-130 brake. bit sceptical but may look into it a bit more. is the brava/bravo lump injected if so could i take off the injection unit and fit twin 40's either down or side draught or how much work would it be to convert the wiring and other bits.
 
well i've managed to get my hands on a 85 X1/9 1500cc :) so i think an engine swap and suspension swap is on the cards now :D would like to know if i can just do a straight swap cuz it's got a five speed box :confused:any help much appreciated.
 
ok so i've now got a 1500 x1/9 engine to which i'm gonna fit 1300 head ultimate road cam+15hp(piper) webber twin 40 dcnf's

does anyone know where i can get a inlet manifold and full racing exhaust inc manifold

also what sort of power output am i looking at (hopefully 120 brake)
 
1500cc is a good starting point.....

I wrote (quite a long) article (that started off as a quotation on a race engine build up) that I've posted on several other forums, about how to build up a good sohc engine.

If you need a new camshaft, I have a good selection of Pittatore cams (made for Alquati).

I would go with the 1.5 head and rebore the engine to take some pistons from a 1.3.... read the article and maybe you will agree.
####################################################
X/19 or 128 engine build

A Regata 85S (Aust spec1986 leaded) is rated @ 84hp/87 lb ft. It runs a 32/34 DMTR carburettor with 22/24 venturis, probably a 10/54 54/10 camshaft, 4 into 2 into 1 large exhaust pipe, has the same valve sizes 36in/33ex and combustion chamber shape as a 1500 X19 (Aust spec). The Regata engine has small valve reliefs machined into the piston crown, giving it a static compression ratio (by calculation) of 9.8:1.

An X19 1500 (Aust spec 1980 leaded) uses a 32 DATRA carburettor with 22/22 venturis, a 10/54 54/10 camshaft, 36in/33ex valves, the same combustion chamber shape and volume but achieves only 9.2:1 compression due to the relatively large valve relief pockets cast into the piston crown, its output is quoted @ 80hp/87 lb. ft.

An X19 1500 (European spec 1979 leaded) uses a 34DATRA carburettor with 23/26 venturis, a 24/68 64/28 camshaft, 36in/33ex valves, the same pistons (large cast relief) the same combustion chamber shape and volume and quotes 85hp/87 lb. ft.

An X19 1300 (European spec 1976 leaded) quotes 75hp/74.5 lb. ft. with a 32 DATRA carburettor with 22/22 venturis, 24/68 64/28 camshaft, 36in/31.5ex valves, 9.2:1 compression by using pistons with small valve reliefs machined out of the piston crown which has the tiniest of domes, yet the combustion chamber shape and volume as the 1500 engines (Euro & Aust spec)

By comparison the std (Aust spec) 1300 claims 73hp/74.5 lb. ft. but with a different camshaft (12/52 52/12) and a 4 into 1 (ex USA) exhaust system. (Someone is fibbing!) All X19 figures are from genuine owners or workshop specification manuals printed by Fiat!

So what’s the point of all this you may ask? Well with a little math we can compare and calculate some compression ratios using a mix of standard components.

For a standard Aust spec 1500 X19 (1499cc) 86.4mm bore and 63.9mm stroke
Cylinder volume = Pi x ( R squared) x stroke
= 3.1428571 x (43.2 x 43.2) x 63.9
= 374.7943 cc per cylinder (swept volume)
Head gasket volume = 7.443cc (approx 1.5mm thick crushed) 1.65mm new ASTADUR type
Volume in head = 34cc (nominal)
Volume in valve reliefs = 4.25cc (cast relief-nominal)
Total @ BDC = 420.4773cc
Total @ TDC = 45.683cc
Compression ratio = 9.20:1

For a standard Regata 1500 85S (Aust spec)
Cylinder volume = 374.7943cc
Head gasket volume = 7.433 (same type of head gasket as X19 1500)
Volume in head = 34cc (nominal)
Volume of valve relief = 1cc (machined out otherwise flat topped piston)
Total @ BDC = 417.2273cc
Total @ TDC = 42.433cc
Compression ratio = 9.83:1

For a standard X19 1300 (86.0 bore x 55.5 stroke =1290cc)
Cylinder volume = 322.518cc
Head gasket volume = 4.757cc (0.8mm crushed 87 internal diameter)
Volume in head = 34cc (nominal)
Volume of valve relief = 0.55cc (machined valve relief less small dome)
Total @ BDC = 361.825cc
Total @ TDC = 39.307cc
Compression ratio = 9.20:1

So with 1300 type pistons in a 1500
Using a thin re-torque type head gasket (0.8mm crushed)
Bored to 87.0mm with standard stroke 63.9mm (1520cc)

Cylinder volume = 380.00 per cylinder
Head gasket volume = 4.757cc
Volume of reliefs = 0.55cc
Volume in head = 34.5cc (allowing for normalising volumes)
Total @ BDC = 419.807cc
Total @ TDC = 39.807cc
Compression ratio = 10.546:1

The crank could be offset ground on the big end journals to marginally increase the stroke to 64.0mm. This would raise the C/R to 10.65:1 and the displacement to 1522cc. This is done to ensure that the piston, when dwelling at TDC, is level with the block surface (promoting better quench) The block /head mating surface would then only need to be gently (0.05mm) surfaced to ensure square and surface finish integrity.

The combustion chamber could also be welded then re-machined. A small change (2.5cc) in the volume of the combustion chamber gives us 11.2:1 C/R. (With 87mm bore x 64mm stroke, 1300 pistons and a thin head gasket)

From this I hope you can see how important it is to normalise / equalise all the head volumes.



1500 X19 and Regata blocks are to my knowledge exactly alike, with the exception of one drilling and tapping for the installation of the oil pressure transducer for the scaled gauge. I don’t propose to drill and tap this as I recommend mechanical type capillary gauges for monitoring all engine functions. At around $150 each they are cheap insurance, you will need Oil Temperature, Oil Pressure, Water Temperature and a voltmeter is a good idea. (Not an ammeter)

1500 and 1300 use different head securing hardware. 1500’s use 10 stretch type bolts, (M10 x1.25) together with an ASTADUR non-re-torque type head-gasket. These bolts should be discarded after 2 – 3 uses. My recommendation would be to change to 1300 type hardware. A 1300 SOHC uses 5 studs, nuts and washers and 5 bolts (M12 x1.25) Then I would use the (1300 X19 type) re-torque head gasket – several good brands are available.

Fiat SOHC engines generally don’t need line boring or bend crankshafts or con-rods. The engine spun easily on disassembly. If the crank journals measure up O.K. it could be used as is, (with a good clean) or else they need to be reground under-size. The crank should always have its core-plugs removed to clean the internal passages. Replacing these plugs is fiddly but necessary, and for high speed applications, I would recommend the replacement of the cup type core-plugs with Allen head type grub screws, after suitably threading the crank. The crank could also be ‘wedged’ and mirror polished. It should be dowelled to a suitable flywheel and secured with 12.9 grade Allen head cap screws and the assembly should be balanced.

The con-rods should be crack-tested, then hand finished. They should then be re-sized at the big end, have new gudgeon pin bushes fitted and reamed to the gudgeon pin. The assemblies should then be balanced (end for end) and finally shot peened. The con-rod bolts and nuts should also replaced.

Now all this is simply following good engineering practice. Replace stressed components of unknown history, check all others. Assembly line components/hardware that are known to fail in extreme service should be addressed immediately, or else you risk poverty. I don’t think any of this is going overboard, it is really only the basics if you want some reliability with your performance and visa-versa. We could go to the point of Nitriding/Tuftriding the crank/rods, but that would add possibly $1000 to the total for no horsepower increase.

The brand of pistons I prefer to use are Kolben Schmidt. (Mahle) These are made in Germany and are the best quality (off the shelf) I have yet found, and they are the lightest. I would also recommend the installation of gapless rings, these can give considerable performance improvements over conventional rings, but the bores need to be finished appropriately. Preferably a head plate that duplicates the stresses caused by the torque of the head hardware, would need to be manufactured.

With standard rings after run-in, generally I’ve been able to achieve 3 – 4% cylinder leakage using K/S or Mahle piston-ring sets. (Chrome top ring) After 2 seasons at Wanneroo (the local race track) with open carburettors (no air-cleaners) an engine usually sees 6 – 8% cylinder leakage. My research tells me that ‘gapless type moly faced rings’, with the right type of bore finish, will return 1 – 2 % after run – in and at worst 3 - 4% after 2 seasons! This directly relates to real horsepower and can’t be overlooked. It may not sound like much, but remember that only 1/3 of the heat energy developed by each cylinder is actually going to push the piston down. So if 8% of the cylinder pressure is leaking away, you are theoretically losing 24% of the recoverable flywheel horsepower from that cylinder!

Whilst on the piston area, the gudgeon pins should be taper bored internally to reduce their weight. Surprisingly you can make considerable weight savings and all this directly relates to con-rod and con-rod bolt stresses and also to crankshaft counter weighting, once again small gains but worthwhile.

####################################################

this was too long and I had to make it two posts

SteveC
 
part two...

The main caps and their hardware need little more than thorough cleaning and chasing of all threads, internal and external. Then correctly torqued and Loctited have always given trouble free service in 1300’s all the way up to 9000rpm.

The X19 sump is finned alloy and has a removable steel baffle plate. I would recommend the fabrication and installation of a windage/baffle plate. A new oil pump, and oil pump drive gear are recommended. I would also HEAVILY recommend the installation of an oil cooler, with an in line thermostat, and the pick-up, which comes from a sandwich block, mounted behind the oil filter. An ACCUSUMP would also be a consideration. Following these recommendations I feel that the oiling system would be adequate for mild competition use.

Engine bearings that are usually forgotten in SOHC and DOHC engines are for the Auxiliary Shaft.
These are full circle bearings that are supplied Ex-Fiat as a semi-finished bearing, meaning that you have to line-bore and ream up a blind hole. I sourced in Italy a company that makes these as a finished full circular bearing and have these available in standard and 10 thou under-size. These should be renewed, as excessive clearance here will adversely affect oil pressure everywhere else.

There are also the front/rear crankshaft seals and the cam/aux seals. I recommend using the best quality seals available. (Silicone or Viton) They do cost more but they handle higher temperatures and circumferential speeds than Neoprene rubber or Poly-acrylic rubber, which tend to go hard with age and temperature.

Finally on the bottom end are the flywheel, clutch assembly and the front crankshaft pulley. The brand of clutches I prefer is Fitchel and Sachs (F&S). The front pulley should be a 1300 type as it is lighter and is a slightly smaller diameter, which will slow the alternator/water-pump down. It should also be accurately indexed for TDC, BDC and for as many degrees in-between as possible.

Basic short-block preparation is certainly important for reliability and durability, but when you talk about improving the output of an engine, you primarily consider the path of the intake / exhaust gases as they dynamically cycle through the cylinder head. The Regata 1500 and X19 1500 heads are basically the same. To develop its potential in horsepower and torque this engine needs the benefit of separated inlet runners. The entire length of the inlet tract needs to be very smooth and have an even taper all the way to the back of the valve, so the cylinder head and manifold need to be considered as a single unit at this point.

Both DCNF and IDF type manifolds available. My preference would be for the DCNF type manifold, because of its much straighter ports, the IDF manifold tends to twist two of the ports quite badly. I also believe that downdraft configuration carburettors are preferable to side-drafts, for the increased torque and quicker throttle response offered by the down drafts. 40 DCNF carburettors use a maximum of 36mm venturis, which is the same size as our inlet valve!

Consistent with the improvements in the carburetion and the related increase in fuel demand, a suitable electric fuel pump will need to be mounted in the engine bay. It needs to have a capacity of at least 1.5 litres per minute. The pick-up in the tank should also be relocated to a lower position, a quality fuel filter with a replaceable/cleanable strainer is recommended, as is a fuel pressure regulator. The fuel pump position on the cylinder block will need a blanking plate. This can incorporate a fitting for additional engine breathing a point often overlooked in basic preparation.

Next to be considered are cylinder head modifications. I propose using standard sized valves. Larger valves would be nice but the additional cost of oversized valves, the valve seats and having them installed is not justified by the expected gains. Realistically more can be gained by reworking of the original valves and valves seats and match porting the cylinder head to the inlet/exhaust manifolds. 1300 and 1500 use the same valve seats/ throat sizes. The intake/exhaust valve seats can be throated out by several mm. Std throat size is only 30 - 30.2 mm intake and 26.75 - 26.95mm exhaust. Improvements can also be made to the back of the intake valve heads for flow. They should also be made as light as possible, as this has a measurable effect on the valve trains maximum RPM. Valve shim thickness should be kept to the minimum, as this also greatly influences weight. The valves can be seated very close to their periphery, effectively a bigger valve. There is plenty of scope for improvement in flow through the head, by hand finishing the intake / exhaust ports and the combustion chamber. I use German made TRW valves and valve spring sets

An improved camshaft is mandatory for real horsepower gains. A decision on which cam to use would have to be made before commencing work on the engine, as just about everything works around this component. The extent of the porting work, which carburettors are used, exhaust modifications and the final compression ratio, all need to be taken into consideration.

Hand in hand with the camshaft is a Vernier adjustable cam pulley, as it enables us to accurately phase the camshaft to the crankshaft. It’s essential to phase the cam / crank accurately.

Next to be considered is the exhaust system. If extractors are to be used, they will really need to be custom made and designed to suit the C/R, cam timing, inlet manifolding and expected rev range for optimum results. A suitable muffler of at least 2 ¼” I.D. will be necessary. I would also recommend wrapping of the extractor tubes with heat retaining wrap.

Finally, the ignition system, the standard points type ignition is not suitable for performance use. The Regata 85S uses a Marelli Plex 201 ignition system, with no vacuum advance, for the European market. It differs from the conventional point type, in that the coil trigger is provided by a four-pole reluctor (this is integral with the distributor shaft) which sweeps past a fixed stator pole. (this is mounted where you would expect the points to be) As the reluctor rotates and passes the stator, a magnetic pulse is created, breaking the coil primary circuit (low tension) via a transistorised electronic module thus generating the (high tension) voltage in the secondary winding.

This system has no electronic control over the timing of the spark but it does deliver the spark consistently and reliably. It works 100 % or not at all. The 2 components that fail, usually heat related, are the stator and lead, and the electronic control module. I feel this is the best system to use, providing 28 degrees of centrifugal advance, usually set @ 10 degrees BTDC, giving 38 – 40 degrees of total advance.

Ignition leads should be spiral wound stainless steel cored, as these minimise a phenomenon called Inductance. As an electrical pulse moves along a wire, it can induce a secondary (though considerably smaller) pulse in a second wire that is close by. This can cause cross firing leading to serious engine damage. The leads should always be separated from each other by at least 15mm, separators should be made by passing the leads through non-conductive plastic card

SteveC
 
And to answer some of your other questions...

I have built several X19 1500 engines that dynoed at around the 110 to 115 rear wheel horsepower, conservatively thats about 135 at the crank, so it is very possible....

best ever result I've had was 118RWHP with 45/85 cam, larger valves, twin 40dcnf's, custom extractors.... was a rocketship to drive, remember standard they are 85 at the crank! (1500)

X19 box wont fit your 128 for several reasons...

inner CV's are very different, and would require specially made axles to make this work (which I can supply)

shifter input is at the wrong "end".... 128 is rearwards, x19's the shifter pookes out the front....

clutch on 1500 is larger, as is the flywheel, and the ring gear is different to a 1300 also.... different starter motor too.

I have done several conversions though, as you can use all the internals from the five speed (and a couple of the casing extensions) and fit them all into the 4 speed casing. Requires a mix and match with the crown wheel and pinion, but both the 5 and four speeds have the same final drive ratio (13/53) so the pinion from the 5 gets used on the four speed ring gear, as long as they are both in good condition, I haven't run into any problems doing this.

This way leaves the axles as standard 128, you get to use your 1300 flywheel and starter too....

The innards of the five speed are a bit more fragile (especially the diff casing) than a four speed anyway, ratios are basically the same 1 to 4, and you would hardly ever use 5th in racing.

You would be well advised to find a shorter (12/53) ring/pinion from a 128 wagon anyway..... or even shorter is better (11/53) but these are specialised parts and fetch good $$. (I paid about 300us$ in 1982 for my crown wheel and pinion from FAZA in california) as it transforms the car on the track.

SteveC
 
well you certainly seem to know your fiats mate and all that info is great dont think i'll be going to some of the extremes mentioned but will certainly keep it all in mind. hope i can bother you for help in the future if i get stuck, also do you know where i can get an inlet manifold for the dcnf's as i've not been able to source one as of yet.

thanks again for your help mate
 
I don't think any of the above is "extreme" .... remember you want 100hp (I assume at the wheels) which means you want to effectively double the output of the car (about 50 wheel hp with a std 1300, 75hp at crank).

I can't help you with a manifold, but perhaps you could try PBS in the USA. Only problem with these manifolds is that they cast one to do both X19 and 128 applications.... which makes the manifold incorrect for both applications.... tilting the carbs away from vertical.

Other than that I would say watch Ebay... I have seen them come up from time to time....or perhaps post a wanted ad on another forum (like mirafiori.com)

Unless you know someone in Italy, and your prepared to pay for a new Alquati one (big $$)

I have an Alquati manifold, but that's staying on my 128 4 door sedan. :)
I sold my spare to a guy in the states....so they mast not be too easy to find over there either (he had a PBS one but wanted the carbs vertical)

another thing you should give serious consideration to is strengthening the front end of your 128.... with doubling the HP in the chassis, it tends to crack them up a fair bit, which doesn't help the handling at all.... How do I know all this, I've been racing and rallying Fiats (mostly 128's) since I was 17, and I'm now nearly 40..... :)

SteveC
 
I've managed to source someone who can supply a mangoletsi one but its 120 pounds plus vat plus postage so thats nearly 160 total. what would you recomend for strengthening the front end up. the cars been stood for a couple of years so am gonna have to strip it right down andstart fron the ground up. also it.s gonna be street legal.
 
Hi there, only just noticed this thread! I'm a student but live in Totnes - just up the road from you. I've got two 128 3Ps sat on my drive - one is about to be scrapped, the other i spent the summer fitting with a modded strada 1500 engine and uprated suspension with the aim of going track days for a bit of fun! My modded car has a blown head gasket at the mo but should be back on the road soon. I've got loads of 128 bits that i need to lose so let me know if there is anything you need. Would be good to meet up when we get them running!
Mike
 
sweet. have you got many spares as i've not long started on this project and need bits still. am looking for anything performance wise as i'm gonna be doing track days too. trying to get an inlet manifold for some dcnf carbs but not much joy. it's good to meet someone local for a change
 
Strengthening the front of a 128.... where do I start!

Firstly, the main problem that causes the demise of the 128 chassis, is often the front left corner where the sway bar attaches to the body. Directly above is the battery, and over the years, fumes and spillage drip down into the corner and rot it away. If you want this car to handle properly, first you need to make sure this point is good.

You will need access to a MIG welder too (or better yet a TIG)

Essentially you need to encircle the entire engine bay with sheet metal, along the chassis rails both side, and across the front (under the radiator) and also try to triangulate the corners where the chassis rails meet the firewall.

If you look closely there will probably already be a few cracks....

remove the front wheels, and look around where the tie rod end passes under the chassis rail/firewall junction.... they crack here too.... simply plate over this, gusseting the corner, but allowing just enough clearance for the tie rod end at full bump.

If you dont plate it up, I can guarentee you that it WILL crack, I'll put money on it even.... and I'm not a betting man generally

The reason you need to plate under the radiator, is that the front x member support will try to tear its way out of the body if left standard., and it ties the two sides together.

A strut brace at the front is a good idea too....

you may think this also sounds "extreme", but if you want to race a 128, it's one of the things you have to do.

I can get more detailed if you get serious.....

SteveC
 
mjaz101 said:
I've got two 128 3Ps sat on my drive - one is about to be scrapped, the other i spent the summer fitting with a modded strada 1500 engine and uprated suspension with the aim of going track days for a bit of fun!

Mike, don't scrap the red 128! Put it on eBay or in Practical Classics as a restoration project. Soemone will give you at least a couple of hundred for it. Glad to hear the blue car is almost sorted!
 
well after reading decembers issue of retro cars where they ran a feature on a company called bogg brothers i have decided to use 2000 Yamaha R1 1000cc motorbike carburretors which rarely go out of tune and produce more power than the webber DCNF's i was originally going to use. other than that nothing new to report. (y)
 
Steve C said:
Mike, don't scrap the red 128! Put it on eBay or in Practical Classics as a restoration project. Soemone will give you at least a couple of hundred for it. Glad to hear the blue car is almost sorted!

Ha ha, well unfortunately the red 128 is about to bite the dust. My Dad wants his garage back so the blue car has to come out where the red car has been hiding. I've had it on ebay and tried to give it away on the FMC site but there is just no interest. The car really is a basket case so i'm going to salvage all i can for the future and get the remaining rust made into a washing machine. I really don't want to do it but i have to be realistic about the situation. Oh well!!

I'll be back in Devon on tuesday removing the red car and starting the head gasket job on the blue car. oh i looking forward to this!
 
Most simple is to put in a 1.6 8v from TIPO or etc...
1.6 16V WiLL NOT FIT WITHOUT MAJOR MODIFICATIONS..

Also all that you need with 8V is to replace FLYWHEEL with one from the 1.1l

A GOOD job without much trouble....

+ 4 carbs 40 DCOE, 4-1 Extractrors exhaust, camshaft... cca 135HP
torque 175Nm
 
Back
Top