Tuning 1.2 8v Rebuild/Tuning

[Brooky]

I think your wasting you time getting a c&b 300 cam. Without decent valve springs and engine management you'll never rev high enough to get the power out of it, I hope the bottom end is lightened and properly balanced. A decent inlet manifold or itb's are worth concidering aswell. And good luck with the emissions test if you plan to put it on the road. I'm glad I had a mate as a mor tester when I had my 280 cam

 

[sei16v]

Still think.... Bigger engine!!

As for the charger, i think it is possible, but would need to be a different engine all together...

If the 2.0 16v fits, then im sure a charger could be bolted on a smaller sized engine... Its just the other bits it requires to get it all set up which would cost the cash...

Although on the dub scene, it looks that people only fit uprated injectors, pump, thicker headgasket and map the engine for the added air which is being thrown in...(not sure the engines would last long with that small list of mods)

Sure it would be possible with the 2.0 8v vauxhall engine, as the top end is tiny, so plenty of room to mount a charger and pipework

Tempting myself here lol!

 

[arc]

the problem that scuppered daves supercharged 1242 16v was the crank pulley shearing, knocking the timing out and wrecking the engine.

I think there is enough room to fit an m45 if you move the rad to the other side, and fit it there.

 

[sei16v]

After a little look, the c20ne + charger is very very do-able!!

Hmm 2.0 8v supercharged seicento!! Plus it would be lighter than my 2.0 16v engine, although that was only 70kg over the standard engine and box weight of the sei...

Heres a link of one in a corsa, musics annoying but the work is respectable!!

It will definatly fit, so pick up the parts, get the coffee's on, and il be over in a flash!!

You know you want to!

 

[sei16v]

the problem that scuppered daves supercharged 1242 16v was the crank pulley shearing, knocking the timing out and wrecking the engine.

I think there is enough room to fit an m45 if you move the rad to the other side, and fit it there.

That sounds tasty, any info on it before the engine self destructing?

 

[fingers99]

That sounds tasty, any info on it before the engine self destructing?

It was certainly quick -- a search should throw up the thread (in the Punto section, methinks).

Real issue is why the pulley sheared. My guess is that that kind of charger puts loads on the joint between the pulley and the crank it simply can't take. The pulley will sheer its key, but as the key is only ever there for location (as in, getting it on in the right place) that can't be the issue.

A cure might be to drill and tap the crank to take a larger bolt capable of being tightened to a higher torque setting, but that is engineering at the bleeding edge.

The rods will go at much over 140bhp anyway............

 

[cc1]

I'd drill the crank and fit some dowel pins like you would a flywheel. The Key on the crank is not very strong. Had one go on me when the bolt came slightly loose.

 

[fingers99]

But the point is that the key doesn't need to be. It just says "hey, I'm in the right position, now do the bolt up". I've stripped one while dismantling an engine. If the pulley turns relative to the crank it's because there's not enough force holding it there -- a dowel will either fret or shear, too.

The parasitic losses of non-centrifugal blowers are huge, hence the shock loads on the pulley. I think it's just the wrong way to go.

 

[arc]

That sounds tasty, any info on it before the engine self destructing?

https://www.fiatforum.com/punto/89930-punto-supercharged.html

 

[Todger182]

What were the benefits of the 280 cam Brooky? I've seen a couple of sei rally cars and they look off it with the 300 cam. but they do have itb's with an airbox, and add in to the fact they have a proper ECU.

Springs for a 300 cam are going to be a little difficult to track down but i'm going to have a word with my friend and see if his supplier does different grade springs or even smaller helper springs to fit between.

I've managed to find a spirit level and placed it on my head and the flat surface on the level is showing that the area round cylinder 3 is about 1mm out from the rest.

I think that head is fubar as it only has 1 skim left in it.

Thanks

Edit: oh I do have friends in MOT's

 

[fingers99]

I think that head is fubar as it only has 1 skim left in it.

Skim and thicker Spesso HG? (Fluffy does them.)

If 8v it'll run OK (subject to getting the valve timing right, it'll probably no longer be a safe engine) -- it's a trick some use to increase the CR.

 

[craigb244]

Before I forget, for the pistons do you just press the rod out on the conrod to release the piston? And same again to fit my 8v ones on?

dont bother. they wont fit. Gudigon pins are totally different size im afraid

 

[Todger182]

********, that wasn't something I wanted to hear....

I don't want to use the full 16v pistons as it will plumit the CR through the floor.

This project is starting to feel like a donkey load of ****e.... I don't want to give up but nothing seems like it's going to be worth while at this rate.

I supposed I could have the 8v rods CNC'ed down and balanced.

Thanks

 

[fingers99]

Why not just use 8v pistons and rods? I'd always assumed that was the plot (I think).

An alternative (but you'll loose squish) may be just to deck the block and machine a wee bit off the pistons.

You might be just as well off finding an 8v bottom end, though.

 

[Todger182]

In what way are the pins the wrong size? length or diameter?

I've read that they are interchangeable, so this is going against my knowledge whence my curiosity.

Thanks

 

[fingers99]

Diameter. Folk who want a cheap 1242 turbo get an 8v engine and then pop 16v pistons and rods in.

 

[Todger182]

Great...

Time to rethink this project now then.

The blocks appaear to be the same with all the extras taken off, my complete 8v crank, pistons, fly, and the carrier (I think thats what it's called) would bolt on with my 8v sump etc.

Then I have pretty much a complete 16v bottom end lying around still.

Which way are the pins diameter too small or too big? I'm going to go with too small.

Thanks

 

[craigb244]

Diameter. Folk who want a cheap 1242 turbo get an 8v engine and then pop 16v pistons and rods in.

I wouldnt say its a cheap way to turbo a engine as the pistons are bloody hard to get hold of unless you want to buy a full engine just for a set of pistons but imho its a much more reliable setup then a decompression plate.
My spare engine has just the head machined to lower the compression.

Great...

Time to rethink this project now then.

The blocks appaear to be the same with all the extras taken off, my complete 8v crank, pistons, fly, and the carrier (I think thats what it's called) would bolt on with my 8v sump etc.

Then I have pretty much a complete 16v bottom end lying around still.

Which way are the pins diameter too small or too big? I'm going to go with too small.

Thanks

why not just look for a punto 75 engine. these are already decked. they have a much better lubrication system

 

[Todger182]

I have the p75 nw. But its damaged on the cyliner walls, 1, 2, and 4 can be honed but 3 would need re sleeving as the scoring would still b visible.

Im tempted on just fitting the full 16v pistons but my friend said they will hit the valves due to the valve slots (or whatever they are called, im at work so can't be arsed )being in the wrong place.

Thanks

 

[craigb244]

they do work. the valves will never hit the pistons.

but you really wont want to use 16valve pistons as it will lower your compression a lot. which is the opposite to what you really want to do (unless you want a turbo or super charger)