Technical Frankenengine/engine build questions...

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Technical Frankenengine/engine build questions...

Tom126

Member
Joined
Jan 8, 2021
Messages
36
Hello Fiat forum,

I hope you don't mind me posting here, it seems like the most right place to post considering the engine (please do move it if I got it wrong)

I have a 126 with a 1.1 SPI 8 v and Van Aaken turbo kit set at about 0.4 bar (engine stripped and rebuilt with low CR pistons in another thread if you want to see)

It's a lot of fun, but I guess with this sickness, we want to keep going and see what else we can do. I also know that the bearings were in tolerance and clean enough but also old, I did t replace them because I thought this rebuild day would come.

I'd like a spot more power and an adventure in the workshop, without going tjet!

I can feel an engine build in my future. I could just get another 1.1 8v and get it really nice and swap it in, but that's a bit boring, especially as there's 1.2 and 1.4 blocks about.

Unfortunately that's pretty much the end of my knowledge on my options. I know there's a few combinations of heads and bottom ends which will work, but that's about it.

I'd like to stick with the turbo kit, which means (I guess), I'll need to stick to 8v head for the manifold.

I also guess it's much easier for me to stick with SPI because I can likely(?) pop the new hardware in, corresponding ECU and use my existing loom.

My ideal would be something like 1.4 8v with the turbo on, I am pretty sure there's a few of these 1.4 engines about but they look like they have the MPI setup.

Appreciate that this is quite an airy set of questions but I assure you I've come this far and I mean to take you up on your advice for the next build! It's a 'what would you do in my situation' question (binning the 126 not acceptable).

Thanks
 

bugsymike

Well-known member
Joined
Jul 2, 2022
Messages
1,480
Location
Torbay
Hello Fiat forum,

I hope you don't mind me posting here, it seems like the most right place to post considering the engine (please do move it if I got it wrong)

I have a 126 with a 1.1 SPI 8 v and Van Aaken turbo kit set at about 0.4 bar (engine stripped and rebuilt with low CR pistons in another thread if you want to see)

It's a lot of fun, but I guess with this sickness, we want to keep going and see what else we can do. I also know that the bearings were in tolerance and clean enough but also old, I did t replace them because I thought this rebuild day would come.

I'd like a spot more power and an adventure in the workshop, without going tjet!

I can feel an engine build in my future. I could just get another 1.1 8v and get it really nice and swap it in, but that's a bit boring, especially as there's 1.2 and 1.4 blocks about.

Unfortunately that's pretty much the end of my knowledge on my options. I know there's a few combinations of heads and bottom ends which will work, but that's about it.

I'd like to stick with the turbo kit, which means (I guess), I'll need to stick to 8v head for the manifold.

I also guess it's much easier for me to stick with SPI because I can likely(?) pop the new hardware in, corresponding ECU and use my existing loom.

My ideal would be something like 1.4 8v with the turbo on, I am pretty sure there's a few of these 1.4 engines about but they look like they have the MPI setup.

Appreciate that this is quite an airy set of questions but I assure you I've come this far and I mean to take you up on your advice for the next build! It's a 'what would you do in my situation' question (binning the 126 not acceptable).

Thanks
Don't know anything specific in your case, but it sounds like the sort of fun I used to have with cheap Fords many years ago as an apprentice on a limited budget.
Glad to hear about the low compression pistons when using boost. Some time ago I rebuilt the engine on a Tickford 2.8 Ford Mk2 Capri (the owner told me it was was then in the 1990s one of the last 100 still around) at the time the engine had been rebuilt several times by other garages???, compressions were all around 180psi apart from the blown pistons!! I was able to obtain a set of Mahle ? pistons that gave 150psi this resulted in the owner being able to use full boost, something he hadn't been able to do since he bought it, even with the use of Octane boosters etc. due to the five star petrol it was designed for being no longer available, so greatly improved his performance overall.;)
 

Kruno

New member
Joined
May 1, 2020
Messages
22
I would use a T-JET bottom end - increased block strength, forged crank and rods, floating pins, increased deck height (0.8mm) for more above ring land material on the piston, internal circulation of coolant changed for better cooling around the cylinder head (still need to see on my own how it works with the 8V gasket and 8V cylinder head but should work)

You can see what compression ratio You would want to achieve and select pistons/deck height from there.

One oil return from the cylinder head needs to be blocked off, crankshaft sensor arrangement needs to be modified, combination of pulley and auxiliaries needs to be sorted out to work, crankshaft bolts are M9 on the T-JET so flywheel needs enlargement of holes and maybe some more stuff I forgot to mention but nothing too complicated.

With stock T-JET pistons at 19.6cc volume and for example head at 20cc at deck height 0.3mm on a 0.4mm head gasket it would be around 9:1 so it should be fine at some decent boost if the management is up to task.

On the photo is mine in the test fitment stage.
 

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Tom126

Member
Joined
Jan 8, 2021
Messages
36
Thank you, that's exactly the kind of information I'm after. Thank you! The increased strength is certainly appealing...

Cheers, I'd be interested to hear more on this.
 
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