Cam gear swap

[Zaffer]

I did a search and couldn't really find anything this specific, but if anyone knows, don't hesitate to correct me.

I was just looking to see if anyone had the figures as to how much the timing is off when one accidentally swaps the intake and exhaust cam gears. I know they are usually marked, but mine aren't. Just wanted to know for future reference.

Thanks!

[bradartigue]

Depends on the gear but you'll be all out of whack I believe. You'd be overlapping when you should be durationing

When properly installed #4 E&I (or S&A as they are stamped on the wheels) cam lobes will point up at TDC.

[Ramzi]

About 15 years ago we sold a HP prep head (including 40/80 cams but no pulleys) to a fellow in the Southwest. He had it installed by a 'trained' and experienced Fiat mechanic. After installation the customer called and complained that the car would hardly run, backfired, wouldn't hold idle and that his mechanic felt that the valves were improperly adjusted. We did not feel that the head could have possibly shipped with valves that were not adjusted that, but sent him a full set of shims and a tool to re-adjust the clearances anyway. A day later ... no improvement.

So our mechanic who had been working on Fiats since he was a kid, took his personal FI Spider and swapped the intake and exhaust pulleys... and his car ran incredibly poorly too... even to the point of backfire which in an FI car is a great way to damage your AFM. We called the customer, asked the mechanic to check how he installed the pulleys and sure enough they he had reversed them. Sadly, he never even sent back our tool & shims.

Here is a photo of how the cam pulley alignment hole align to the pointers in relation to the cam shaft alining dowel hole (located just above the bolt which holds the pulley to the cam shaft) at TDC



Here is the link to the photo which shows both pulleys and their appropriate aliment.

http://i1015.photobucket.com/albums/af2 ... rsOK69.jpg


Hope that helps

Ramzi
Auto Ricambi, LLC

[azruss]

Here are the exhaust (on the left) and intake (on the right) pulleys. what matters is looking at the relationship of the hole with the cam pin. The bottom picture show the pulley location when timed. They are really aligned, it is the camera angle that makes the exhaust look like it is one cog off. Look at the location of the camshaft pin and see if it matches yours at TDC, If your pulleys are switched, the difference should be obvious