Forum for competition engine enthusiasts. RIP Guy Croft 09/11/2020 - This forum will continue both as a source of information and as a memorial to Guy.
Piero wrote:I was hoping to keep things simple. so with this in mind
and as I already own twin 40s and twin 45s webers, I intend to go for carbs. oppting for the 45s.
I have gathered a few other items, ie a 130 arbath head, with short inlet manifold. will be porting and flowing the head and valves/seats.
hopeing to buy forged pistons from guy.
will have crank/flywheel/clutch balanced.
And I had thought about maybe rally type cams but have not decided yet.
could do with some help on this one (cam choice)
ps am having a 4-2-1 system made.
Piero
With all this, I think you should end up with a very interesting engine, capable of breathing good fire.
If you want to increase the capacity then why not fit a different crank? Cranks are available that will take the engine out to 2.2L.
I know that this will make the engine even less 'revvy' than it already is, but apart from that know very little about these conversions, anyone care to comment?
Its not that I have to go to max bore size, it is just my attempt to learn what you guys have learnt over the years that you have been doing this.
I am trying to find an easy way to increse my engines output without having somthing I dont like at the end of it.
increased bore size seemed easy, and would give me extra power.
I have explored this avenue and am happy to move on knowing what I now know.
Almost having settled on the following- standard bore, strada 130 gas flowed head, balanced bottem end, lightened flywheel, weber 45s, beta exh cam mounted distributor, and rally gravel cams. What would be suitable primary and secondary lenghts and bore sizes for a 4-2-1 exhaust manifold, :?:
I have heard rumors of the existence of stroker cranks, for bringing a 2 liter engine up to 2.2 liters, but have not heard of anyone other than Abarth doing so. As I recall, Abarth built a 2.2 liter engine for the Lancia 037 Rally, towards the end of the cars competitive days. I do not know how well these engines performed or if they were reliable. I have also heard that these cranks are extremely expensive, costing more than a complete new prepped 2 liter engine.
Tom McGaffigan
Thanks Tom,
But I have sort of settled on a 2 litre now.
Had a lot to decide before the car went to Simpsom race exhausts, as I had to work out my primary and secondry lengths for them, so needed to go one way or the other with the big bore thing.
As said, I have taken the easy and cheap opption, and am staying with the 2l.
One thing that would be good to know, is how close I have got to getting the exhaust right.
Based on a Fiat twin cam, 2 litre, with big valve head, ported and flowed head and valves, twin 45 webers on a short inlet manifold, rally gravel cams, I have gone for 18in primarys and 18in secondarys.
Primarys ex dia 1 5/8
Secondary ex dia 1 7/8
Tailpipe/exhaust 2 1/8.
any one care to coment please
What happens to heat dissapation?
How long do you want this engine to last you between rebuilds?
You can RE-sleve the block if you want to keep it after your boreout to max???
- Thanks Guy, that is what I did.
You can bore it out to 86max, and 85 as others have stated.
How can you check the walls for depth, these are Italian mass produced blocks made for 120HP or so. Well that is what the engineers designed the engines for output.
So every time you add HP you increase the chance of .... BOOM!
You can stroke it out going to Gozzoli.
Do you have 2500GBP for a forged stroker crank?
Perhaps he has the gasket you will need!!!
Will the head gasket hold?
Pistons OK, but what is holding your pistons to that crank - Rods and Rod bolts.
Guy has mentioned not to go stock/ stock modified on my earlier post.
A lot of people go for these hot engines and can't do anything with them in terms of getting power to the ground and could get themselves ...... hurt.
Please let us know how it runs when you get done, how you intend to use the car, and which options you took once you get it sorted.
I have dual 42 dcnf s also!
My Scorpion is getting reenforced with a lot of Monte Hospital stuff in progress before I even put cash into that engine.
On the street your Tires, Brakes and the lines leading to them are perhaps more important than the other aspects.
I wish you the best, glad we are all bouncing ideas off of each other.
A previous post was about this BoreOut issue on my Zagato for which Guy gave me some really great advise as well as you guys!
Paul.
Twincam was over engineered for a production engine, and has a super strong bottom end. Engine can take all the power you engineer into if it is done properly. When you compare this engine built from 1966 with its competitors of the day, it was a work of art !! Production engine was actually detuned in a sense especially 2.0 ltr with an economy carb[emission] fitted.