Distributor Installation/Cam Break-in

[Mark H.]

I've been reading with interest the thread on proper distributor installation. When doing this in the context of an engine rebuild, am I correct that once the engine is fired up for the first time, assuming it is running OK the first order of business is sitting for 20 minutes at 2000RPM to break in the cam, then shut it down, change the oil and filter, and then fine tune the timing?

[Clem Z.]

Re: Distributor Installation/Cam Break-in

very the RPM,2000 to 3000 because the cam get some oil from the throw off from the crank and by verying the RPM the oil will get thrown off differently.make sure you fill the carb float bowls before trying to start the engine so it will fire right away.cranking away to fill the carb bowls is a sure way to grind down a cam lobe.

[Mike M.]

Re: Distributor Installation/Cam Break-in

mark: in addition to clems suggestions, don't forget to coat the cam and lifters and fuel pump rod with a good CAM lubricant such as TRW Cam and assembly lube. mike

[Duke W.]

Re: Distributor Installation/Cam Break-in

I don't think it's necessary to change the oil, but you should change the filter if you used a paste type assembly lube as these contain solids that can plug the filter. By installing the distributor as I described the initial timing should be close enough to do the 2-3K half-hour break-in before fine tuning the timing. During the cam break-in you could also set the total initial plus centrifugal using a dial back timing light.

New OEM engines don't get this kind of break-in, but it's a good idea to do the initial break in this way to ensure that the cam is properly broken in. With an aggressive racing cam, this kind of break-in is absolutely necessary, and it is usually done with light valve springs, then the intended high force/9000 rev valve springs are installed.

Duke

[Ralph E.]

Re: Distributor Installation/Cam Break-in

Are you suggesting if a carb replacement was done, the carb float bowls should be fill before restarting or cam damage could occur.

[Clem Z.]

Re: Distributor Installation/Cam Break-in

only if you are starting with a brand new camshaft/lifters

[Ralph E.]

Re: Distributor Installation/Cam Break-in

Thanks, I'm about to retart for the first time with anew carb and distributor. I already cranked the car to get the oil moving. I'll fire the engine up once I get the distributor static timed.

[Mark H.]

Re: Distributor Installation/Cam Break-in

Thanks - but for the idiots among us - how do I fill the float bowels?

[Clem Z.]

Re: Distributor Installation/Cam Break-in

use a small syringe thru the bowl vents.

[Craig S.]

Re: Distributor Installation/Cam Break-in

In the case of my mechanical street cams on BB's (3963143 grind) I have been breaking in with the inner springs removed for the 30 minute break in, then installing the inners. These are 450lb/in springs, with 120lb seat and 180lb full lift or thereabouts. I am not sure if this is necessary, but it sure doesn't hurt....and lots of cam lube on the lobes....Craig