Technical Engine transmission upgrade plan.

[jjacob]

Well I have been putting together a plan to improve my 1969 500L. I am in the USA. I have been reviewing information on this as well as other forums. I am looking for some feedback on my plan from the forum.

I have talked to an acquaintance of mine who is one of the three big suppliers of 500 bits and pieces in the USA. He has used 126 engines and transmissions here in the USA in his warehouses.

First let me describe the intended use of this car. It currently has a stock 499cc engine and transmission that runs very nice and smooth. I would like to get more horsepower and torque to make the car more enjoyable to drive up hills, in traffic, and be able to maintain 65 mph (105 kph). I need syncromesh in the transmission in order for my wife to be able to drive it. I am not looking for a screamer, we will be staying to under 5000 rpm. Torque is more important than ultimate horsepower. I am not looking to spend huge amounts of money. I am capable of doing all of the work (except machining) myself.

My acquaintance with the Fiat spares business does not think I need to use a 126 engine as a base, even though he has engines to sell me. He says to just use my current engine (110F) as the basis for the upgrade, and buy a used 126 transmission from him. He says to swap over the bellhousing and axles, and bore the block and clearance the cylinders for the crankshaft.

Here is the plan: Using my current 110F engine as the base.
Cylinders/Pistons - 79.5mm
Camshaft - mild, 30/70?
Cylinder head - mild port and polish, 34mm intake valve, stock exhaust.
Carburetor - unknown at this time but must be reasonable in cost. Still researching this, lots to chose from.
Ignition: Already upgraded to Pertronix ignition system.

Lots of engine bits and pieces will be replaced in the normal course of a rebuild.

On the Nanni Ricambi site they show separate kits for F/L cars (110F) vs. R/126 (126a)

QUESTION 1: For the F/L 700cc kit they show a steel cylinder support that they do not show for the 650cc kit or the R/126 700cc kit. Is 79.5mm too much for the 110F block? Or am I OK if I use the steel support. Should I limit the bore increase to 650cc?
QUESTION 2: For the F/L 700cc kit they show replacement connecting rods that they do not show for the F/L 650cc kit. Are these necessary for the 700cc overbore or can I use the stock rods?
QUESTION 3: Why are there separate kits for the F/L cars (110F) vs. R/126 (126a)?

Lastly, I would like to end up with a compression ratio of around 8.5 - 9.0/1. With either a 650cc or 700cc engine what is the best method. I am assuming my head to be stock.

Thanking everyone in advance for your input.

John

 

[the hobbler]

Hi John;
I personally would use the '650' engine as your base engine--I have tried to give a more detailed answer, but the system kept shutting down--try me direct for a full answer.

 

[Bambino]

John,

I've been down this road quite recently and the advice I received was to start with the 652cc (126) crankcase and go from there.

The standard 500F/L engine has a 67.4mm bore whereas the 126 has a 77.0mm bore and the 695 conversion a 79.5mm bore. Overboring the 500 crankcase by that much will not leave a lot of supporting metal and will most likely significantly weaken it. Going to 595cc (73.5mm) would probably be OK if you use the reinforcing base plates. All of these modifications use the standard 70mm crankshaft though the pistons used in the 695s are shorter and therefore require longer conrods (130mm).

As an alternative, you could just install a standard 126 engine and transmission. It has enough power to get you around, including hills.

I bored a standard 652 crankcase to take 79.5mm cylinders and fitted a copper head gasket to raise the compression ratio. Like you, I just wanted to modernize what is quite a nice little engine. Mine is very tractable, starts and runs well and is great fun to drive.

Chris

 

[jjacob]

This is somewhat of a USA issue. To get a used 126 engine is going to cost around $600 USD (from the supplier I mentioned), and I will still have to rebuild it $$. Remember there were no 500's imported to the USA after 1961 and never any 126's. So if you want anything you have to pay to have it shipped from Europe. There simply is just not the supply situation that you have in Europe or Australia.
Going back to the Nanni examples, it would seem that I can go 650cc. 700cc may be too much for the 110F engines, hence Nanni supplying a steel reinforcement at that bore size.

John

 

[Bambino]

It is similar in Oz. Any 650cc engine/transmission came out of Polish built Nikis which were never that great to start with. All of my parts were imported from reputable overseas distributors and if I were doing it again, I'd still source parts from o/s.
I guess ultimately you get what you pay for and as my Dad used to say - quality is remembered long after the price is forgotten. However, that doesn't help quell the commentary from our significant others when they see boxes of parts arrive but have no money for food
All I can advise is to think it over and gather as much information as you can prior to making a commitment.
Keep us informed - personally I really enjoy these rebuild threads.
Chris

 

[jjacob]

Two more questions.

Does anyone have any pictures of the steel reinforcement plates installed on an engine? Having a hard time visualizing how they are installed.

Also, why does Nanni show different 650cc kits for the 110F vs. the 126a?

Right now I am leaning towards using my existing 110F engine and building it out to 650cc. This way I do not have to replace the connecting rods. I should be able to get to the type of drivability I am after with this set up.

Of course, nothing is written in stone yet!

Chris, I appreciate your insight. I still have two other cars in the que to repair. A 1977 Alfa Spider and a 1966 Maserati Mistral.

John

 

[jjacob]

Hobbler,

Try posting again (better that everyone can see), or PM me. I have to figure what machining a 110F block out to 650cc would cost versus buying a used 650cc 126 engine. Still working out the best engine at the lowest price.

John

 

[Bambino]

Two more questions.

Does anyone have any pictures of the steel reinforcement plates installed on an engine? Having a hard time visualizing how they are installed.

Also, why does Nanni show different 650cc kits for the 110F vs. the 126a?

Right now I am leaning towards using my existing 110F engine and building it out to 650cc. This way I do not have to replace the connecting rods. I should be able to get to the type of drivability I am after with this set up.

Of course, nothing is written in stone yet!

Chris, I appreciate your insight. I still have two other cars in the que to repair. A 1977 Alfa Spider and a 1966 Maserati Mistral.

John

John,

I think that the 500R had a 73.5mm (594cc) engine as an interim measured prior to the 77mm 652cc 126 engine and that this crankcase could be bored without losing too much metal so the 500R/126 kits will be the same.

Each kit will take in to account which crankcase you have - 110F engines will include the reinforcing plate (it goes between the bases of the cylinders and the top of the crankcase) whereas the later 594/652cc engines do not need it.

The website shows no reinforcing plate for 500F/L bores to 650cc so you may be OK.

One final note, I emailed Nanni repeatedly and never got a response - don't know why - so I ended up buying my parts elsewhere. Maybe they were away or something.

Chris

PS: My other cars are a 1959 Alfa Giulietta Spider Veloce (currently in bits) and a 1970 Alfa 1750GTV. I sold the 1960 356B Porsche a while ago to finance my other projects

 

[Bambino]

A couple of photos for you -

The first two are of a standard 500F crankcase.

The photo of the underside shows the buttress that would be largely removed.

The photo of the top side shows where a 6mm cut would go. It would remove the thick reinforcing ridge around the base of the cylinders.

The last photo is of a spare 652 crankcase bored out to 79.5mm. Plenty of meat left.

Food for thought.

Chris

 

[the hobbler]

Hi John;
I must fully concur with the advice from Chris; it would be much wiser to start with a '650' engine and go from there. In the long run, it will probably work out cheaper both in cash, and peace of mind. Chris has basically answered your original questions the same as I tried to. There are quite a number of companies, both in the UK and in Holland, who can supply the parts and give you 1st class service (try 'Van der Laan Fiat 500 parts)--I have used Leo Van der Laan and had very good service from him. Just fitting the basic '650' engine and gearbox will make a surprising difference (almost 25% more capacity)-I will be around for another week, beforeracing a yacht to St Lucia, so if you need help, try me [email protected]--all the best.

 

[jjacob]

Chris & Tom,

Thank you both for your advice and replies. Chris's pictures give me a much better idea of the crankcase potential issues. I can see that any bore increase over 73.5 mm (600cc) will weaken the case without the steel plates. I will see what my supplier finally quotes me on a rebuildable 126 650cc engine (I have asked him to do so).

I will keep this thread going with updates on my plans.

John

 

[jjacob]

Is there any advantage to me just buying a new 126 block out of Italy (looks like about $200 USD delivered). If I went 695cc I would be replacing the cam, carburetor, cylinders, pistons, and rods anyway. I would swap over from my 110F engine all of the tinware, head, crankshaft, generator, distributor, timing gears, etc, etc.

What do you guys see potentially wrong with this route? What items from the 110F engine would not fit on a 650cc 126a1 block?

Thanks,

John

 

[the hobbler]

Hi John;
If you can get a brand new '126' crankcase for that sort of money, I would say--go for it. Just about everything swaps over, but for looks I would put a alloy rocker cover on it and, essential for cooling, fit an alloy sump (if you are only using the car on the road, a 3.5 litre sump will suffice). Put new (good quality) bearings on the crank and a new clutch. I would also suggest that for the little extra cost, fit a new oil pump. Normal engine build-up, fit all new gaskets and seals--all parts thoroughly cleaned (can you do 'vapour blasting' on your side of the pond?)--if you want a list of parts suppliers, let me know, my e-mail address is on a previous message. Good luck, all the best.

 

[the hobbler]

John;
Just had a thought--look at the 'Lavazza Techno' web-site--they are selling a complete '695' kit for 795 euros (about $1029) plus taxes and carriage. Could be just what you need. Also, although the '500' crank will fit in the '650' crankcase, if your supplier (US or Italy) can come up with a '126', or even better a Fiat 126 BIS crank, they are much stronger.

 

[jjacob]

Tom,

Thanks for the replies. It helps! I saw your previous post on Lavazza I will have to send an email to them in English and Italian to see if they will ship to the USA and what the final cost of their kit would be. They look to have some nice items.
Here is a block in Italy on ebay: http://www.ebay.it/itm/MONOBLOCCO-N...919?pt=Ricambi_automobili&hash=item337d43ceaf

The 126 bis crank looks like it has a much larger counter weight. No modification to put that in a 126a1 block?

By the way, would a Stromberg 125 CD fit the 500 like the HS2 does?

I saw you were at Radbourne Racing. My friend Phil Wicks was a driver and test engineer for them waaay baaaack! He is in Virginia now.

John

 

[Bambino]

Is there any advantage to me just buying a new 126 block out of Italy (looks like about $200 USD delivered). If I went 695cc I would be replacing the cam, carburetor, cylinders, pistons, and rods anyway. I would swap over from my 110F engine all of the tinware, head, crankshaft, generator, distributor, timing gears, etc, etc.

What do you guys see potentially wrong with this route? What items from the 110F engine would not fit on a 650cc 126a1 block?

Thanks,

John

John,

This is what I did. The new 126 crankcase was Italian made and well finished. All of the gasketed surfaces were flat and straight. The image above was a test bore on an old (and stuffed) Niki 650 crankcase (=126). Going from 77.0mm to 79.5mm was no problem.

If you use the steel reinforcing inserts after you rebore the crankcase, I would have thought that they will lift the cylinders thus necessitating a longer stroke crankshaft to deliver the piston to TDC with a reasonable compression ratio - or am I imagining that ??

I used the tinware from the Niki that I bought as I think that the 500F/L tinware is slightly different.

Tom's comments about the alloy sump and cam cover are also well worth considering. Apart from looking nicer, the heat transfer is much better - in reality these engines are oil cooled, not air cooled

If you haven't already, have a look at the 695 rebuild thread - it's a sticky and it shows what I did.

Chris

 

[jjacob]

Chris,

I thought the same as you on the steel plates. That is why I wanted to see a picture of them installed. I have already read your rebuild thread, very well done!

Still working through all of this. I like to do all my mistakes on paper. Much cheaper that way.

John

 

[Bambino]

I like to do all my mistakes on paper. Much cheaper that way.

Ditto

 

[jjacob]

I used the tinware from the Niki that I bought as I think that the 500F/L tinware is slightly different.
Chris

What are the differences between the 110F and 126a1 engine tin ware?

John

 

[the hobbler]

Hi John;
To be perfectly honest, I have never put the 2 sets side by side to check, but I don't think that there is much in it--nothing a gentle bit of tweaking won't sort--did you get my e-mail?