Hi.
I recently acquired a 1997 Brava 1,4 12valve with cam failure (one lobe had 5mm ground off, giving almost no valve lift). I bought a cam kit and started what I thought was an easy job (looked that way...).However, when I was trying to fasten the new cam, the treads in the head (for 4 of the cam fastening bolts) gave way even before the cam came in contact with the head, leaving me with no other option than to get new thread inserts. I didn't have this possibility in my garage, so I had to dismantle the head and have it delivered to an engine workshop close to me. (which also meant having the head milled, so it got a bit expensive). Now, everyting seemed to be good. The cam was fastened with the right torque and everything was lined up by the markings. The car started, and the revving sequence was performed to adjust the new cam to the engine.

However, after this was finished, I let the throttle down to idle speed and the engine immidiately died and would not start again. The following day, the engine started up and sounded quite good, but when it started heating up, it got worse and I had to keep it on high revs to avoid it stalling. :bang: It also sounds odd, like there's something wrong with the ignition: sounds like it doesn't run on all cylinders when hot, and there's a "bopping sound in the exhaust. (but only when hot)

It seems like it has no problems running when cold, but as soon as the engine temperature rises, something goes wrong. Has anybode got an idea about what this could be?

I am having similar with mine after a cam swap except i have no pressure on 3 cylinders and the bopping sound when truned over (won't Start). I was wondering if you have 'lapped' or 'ground' the valves since re fitting the cam? Have you pressure tested the cylinders also - I would be interested to see if the cylinder where the cam was worn has any pressure.

I am going to take my head off and completely re-condition the head to see if that does the trick.

If you have solved let me know how.

Cheers

David

dvewls said:

I am having similar with mine after a cam swap except i have no pressure on 3 cylinders and the bopping sound when truned over (won't Start). I was wondering if you have 'lapped' or 'ground' the valves since re fitting the cam? Have you pressure tested the cylinders also - I would be interested to see if the cylinder where the cam was worn has any pressure.

I am going to take my head off and completely re-condition the head to see if that does the trick.

If you have solved let me know how.

Cheers

David

Click to expand...

Hi David.
I'm sorry to say, I still haven't figured it out. BUT: I've learned one thing! NEVER EVER CHANGE CAMS ON THESE ENGINES WITHOUT USING TIMING TOOL KIT! If the cam belt's one tooth off, you'll probably bend at least one valve... You may try to set the new cam at exactly the same position as the old one, but the problem is that you can adjust the cam wheel at least one tooth back or forwards once loosening the bolt, which means you can never be shure you've got it right. Buy a timing kit for Fiat 1,4 12valve (if that's what you have). I got mine from a British supplier called Bennett's. It's made by Laser Tools and the item number is 3470. (There are other suppliers and brands out there, so check out shipping costs on each to find what's cheapest. The Laser Tools kit 3470 has a camshaft locking tool which is to be placed where cam cap number 2 (seen from the cam wheel) is.

You need to lock the cam and the crankshaft at exactly the right position, then loosen the cam wheel and place it as far clockwise as possible. Then you're ready to mount the cam belt. When the cam belt is on, you must pull the cam wheel anti-clockwise to tighten the belt while fastening the bolt to secure it in that position. (this is a MUST!)

I'm now checking out some other possibilities for my problem. TDC sensor being one of them (placed on the rear side of the engine, behind the crank shaft). I'll get back to you on the outcome and why I'm looking at this specific point...

Atle

I have had the same problem for half a year.

I ordered new camshaft and followers half year earlier.
I made the cam swap, no success, there was no compression in one cylinder.

Now, after a half a year, I took the camshaft and followers to a specialist, who told me the cam was bent and one of the follower was allegedly larger by 1mm. That is why they would not let the valve to close properly, so there would not be compression.

The specialist ground and hardened the camshaft polished the followers, and here we go, it worked. He told me it was not sure the company which I ordered from sent wrong cam, probably the lot of trying and reassembly caused the camshaft to be bent.

Check the sizes of your cylinderhead and tappets, there is a pdf to tell you the correct sizes, its name is fiat bravo/brava service manual vol1.pdf

Wish you the best

After the snow melted, I'm now eager to get this thing going again. I found a thread on a non-fiat forum about similar problems as I've had. The suggestion was to change the temperature sensor for the coolant. This, alegedly gives the ECU a signal that the temperature's up and so to lower the amount of gasoline injected... I've now purchased this sensor and will try it oiut during the weekend. I'll post an update once I see what happens....

Long time, being fed up with this problem, I have changed just about everything in the engine bay with no luck... I changed the Lambda sensor, and the engine ran for langer before dying, and that's the closest I've gotten to solve the problem. Last time I tried to start it up, the fuel pump was dead... I'll try to change it for å pump from a Punto 1.1 and see how it goes. Maybe the pump was the problem all along? (hopefully)