1592, 1608 or 1995 for my 124 Special T - my 1st post

Road-race engines and ancillaries - general discussion
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Lee67
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1592, 1608 or 1995 for my 124 Special T - my 1st post

Post by Lee67 » Wed Jan 14, 2015 6:58 pm

Hi all,

This is my 1st post since joining and I'm in need of some guidance in putting together an engine for my 124 Special T saloon.

I've recently bought the car, it's taxed, MOT'd and very solid with the exception of the paint and has done just over 33,000 miles from new!!!

So currently it has a good low mileage 1592 twin cam in it, all standard. With the car but not fitted came a waffle manifold and a correct pair of 40IDF Webers and I also have the required cam driven distributor and exhaust cam/cam box to suit.

Also I have amassed a collection of engines and parts roughly as follows:

2 x good 1995cc blocks/cranks/rods/pistons (standard flat top pistons)
1 x good complete 1608cc engine, I have stripped this and all bores are good, crank is good, cams are good etc. It's fitted with the 4.5mm domed pistons.
1 x complete 1438 engine, unknown condition
1 x Strada 105TC cylinder head with the 43.5mm inlet valves (this has been mildly ported/polished in keeping with GC's recommendations within the tuning manual)
Various cams, all standard Fiat and used but good, narrow lobe 1608 (inlet/exhaust), narrow lobe 1438 (inlet/exhaust), 1608 exhaust cams with distributor drive and 1995 wide lobe (inlet/exhaust).

So, what's the best combination for the best power/torque? I realise that none of the above is going to give me earth shattering performance but what I'm trying to achieve is the best results from what parts I have.

As I see it I have 3 options:

Keep the 1592, add Webers, 105TC head and 1608 exhaust cam/distributor etc.
Assemble the 1608 and add the above parts
Assemble one of the 1995's and add the above parts.

Initially I was keen to keep the original low mileage 1592 "as is" and build one of my spare engines, therefore still having the untouched original engine to go back in the car at a later date to conserve originality but if it's the best unit to use then so be it!

I have heard that the 1995 is not necessarily the best option due to the taller block and increased weight?. What are the advantages/disadvantages to the 1608 over the 1592? Can the 1608 80mm domed pistons be fitted to the 1592 block to increase compression ratio?

Your thoughts please...

I look forward to any advice received from you guys.

Thanks
Lee
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miro-1980
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Re: 1592, 1608 or 1995 for my 124 Special T - my 1st post

Post by miro-1980 » Sun Jan 18, 2015 12:08 am

Hi Lee,

Quite an interesting project. I really like all 124 series and the 124 special T is among my favorites !

As regards what engine to use / build for this car there I believe are two questions:

Question 1. How will you use this car ?
It is to be a car for sports ( rally /race/ track day) or as a purely recreational ride.

You basically have two options : keep is as close to original as possible or modify certain key components. Without answering yourself the first question you will not know neither the reasons nor purposed of any modifications.

I had a long line of Fiat family cars with variety of engines ( 0,6; 0,65; 0,75; 1.0; 1.3; 1,5; 1, 6 both cc versions- 1.8 and 2.0.) I liked them all.
Each of them had advantages and disadvantages depending on a car model and the intended use of the car.

Question 2 is technical / financial. There are few technical modifications which are technically not possible but an unlimited number of modifications which are indeed very costly. Significant part of the costs come from the fact these parts are becoming rare.
So if you define your options , make sure that parts you already have ( especially blocks and heads ) are in good condition fit for building a new engine.
You also have to take into account that while many parts are interchangeable not every part will necessarily ( or easily) fit the rest of your components ( i.e - the gearbox) . But even if they will fit they be grossly mismatched. A gearbox used in 1300 may not necessarily work well with a 2.0. You have to take into account that if you put a 150 bhp engine into a body /chassis designed for a 60 bhp engine you are asking fr trouble. Not to mention such things as brakes , suspension , weight distribution to mention just a few.

Indeed you can put a 2.0 into a 124 special T , but this means you need to modify the rest of the components accordingly. It is a lot of work , poses many technical issues small bt very important technical issues.

So before you go too far decide what do you want to do with this car. Note that of you decide this will be "civilian' car changing it later to a rally car will involve almost complete rebuilding of the whole car (definitely stripping it to the bare chassis, reinforcement welding, etc.)

So the answer to the first question is an absolute must before going any further.

Please share with us some picture of this very nice car ! I have seen one recently on a classic rally In Austria and was amazed again buy the looks of 124 special T.

Rgds

Miro

condition of blocks and heads for these engines ? Do you have gearboxes and bells fr them ?

Lee67
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Re: 1592, 1608 or 1995 for my 124 Special T - my 1st post

Post by Lee67 » Sun Jan 18, 2015 8:47 pm

Hi Miro

Thanks for the advice and comments, I've posted a few pics in the readers cars section just now.

It will be used solely as a road car, I am just aiming to get the most power from it using the spare parts that I already have in stock or that are readily available cheaply. The engines and associated parts that i have available are all in good useable condition and I don't need to worry about building it conform to any regulations for motorsport etc.

So I am free to do what I want to with it - as long as it will not cost too much!

Regards
Lee
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miro-1980
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Re: 1592, 1608 or 1995 for my 124 Special T - my 1st post

Post by miro-1980 » Sun Jan 18, 2015 9:09 pm

Lee ,

In this case my suggestion would be : go for the 1608 cc. The "square" 80x80 arrangement with mild modifications will should give you 120-130 bhp on twin 40 IDF Webers and a respectable 150 Nm of torque.

Note: Do check if the 16908 will fit under the bonnet. and remember it is also somewhat heavier than the 1200 / 1400 engine of 124

This DOHC will also last and give you little trouble. So for the least amount of money you will get a reliable engine with plenty of torque and power as well as very nice engine characteristics. Nice low power and great response to throttle.

Just remember not to fiddle with the camshafts too much (do not go too sharp). Remember the sharper you go the less low power you get. I would actually consider a standard one , but this you need to check with Guy.

I had a 125 special with this engine and only 100 bhp and it was really great .

Just make sure you use something else than the 124 gearbox. Use either a 125 box or 131 box. Actually the 125 box would be my first choice.

Note: I have no idea if the 125 or 131box will fit the 124 chassis without modifications, but most likely some modifications either to tunnel and or length of the main shaft will be required.

Also check if a 131 box will fit the 1608 engine ( it probably will though may require a special 1608 bell.)

Have fun, it is a very nice project !

And keep us posted as you make progress.

Rgds

Miro
www.131abarth.pl
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TomLouwrier
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Re: 1592, 1608 or 1995 for my 124 Special T - my 1st post

Post by TomLouwrier » Mon Jan 19, 2015 9:41 am

Hi Lee,

Nice car, you are very fortunate to find one in that condition!

I mostly agree with Miro on the characteristics of the 1608 engine and the 2L lumps will be more of a hassle to fit as they are taller.
However... I myself have one of those 1608's in my BS1 and I find it quite hard to get parts for it. In fact so much that I've been thinking of getting a 1800 from a damaged US Spider.
So from that angle the 1592 might be the more practical option.

As far as I know the 105TC is reversed port (since taken from a FWD car), did you think of that?

regards
Tom
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Lee67
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Re: 1592, 1608 or 1995 for my 124 Special T - my 1st post

Post by Lee67 » Mon Jan 19, 2015 8:47 pm

Hi Tom

Thanks for the info, I will give some thought to the lack of spares situation for the 1608. Do you (or anyone else) know whether 1608 80mm pistons can be fitted to the 1592 block?

Also, 105TC head is ok, it's not reverse flow although it is in a FWD car - thanks for the warning though!

Rgds
Lee
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TomLouwrier
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Re: 1592, 1608 or 1995 for my 124 Special T - my 1st post

Post by TomLouwrier » Tue Jan 20, 2015 7:23 am

hi Lee,

Did a bit of reading up last night. You're right, that head is still pre-reversion. Check!

Can't advise on the pistons, but I know that the ones from the 125-series block are not interchangeable although both are 80mm. The 1438 has pressed pins, the 1608 floating ones.
And there are the other dimensions; position of the pin, compression height etc. I would be very careful before spending serious money and/or time.

Guy will know.

regards
Tom
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