Comp Cams makes a cam that I would like to put in my car (CL70-119-6). The lift is .410 and my question is, will the valves clear the pistons if I break a timing belt?
A 410 lift cam is realy not that big. I run a 520 in my 2.0 and a 620 in my 2.3.
As with any combo your piston hight will be an issue if you have a high compression engine.
Are you using stock hight pistons?
Is your head shaved?
I'm running stock pistons for now. Looking at a set that make 9.1:1 for a little more power (8.5:1 stock..., right?). No plans to shave the head, only port & polish and deck the block if needed. My concern stems from previously broken belts and I don't like the timing cover so it has been removed.
there is no danger of the two coming in contact with each other with flat-tops and that low of lift on the cam...it would take north of 500 lift to get you close..... so no problem
Shaving 30 thou off the head is the easiest and least expensive way to gain the 1/2 point of compression you seek.With this cam you still wont have interference problems but may need an adjustable cam gear to correct the slight change in cam timing.
Perfect, thank you for the info. I'll go ahead and install a .410 Cam and shave .030 off the head. Safe and reliable is what I am looking for. At least this way if the timing belt goes I can do a roadside change and go without needing engine work.
.410 isn't much of a cam upgrade. I never had any problems breaking belts on the 2.3. I would go with at least .450 lift, just don't go wild on the duration. Another good trick is to use an oval port head with a d-port intake. Gives the fuel a waterfall effect. If you are going to all the trouble to port the head, you might want to put the bigger valves in as well, or at least make sure to knock out the shrouding around them.
If you have the head off, to properly set up the valvetrain geometry a solid lift adjuster should be installed to zero lash each lobe. At that point rotate the cam lobe to max lift and see if or how much the valve face protrudes past the deck surface. Account for gasket thickness and piston to block deck clearance, and you will know for sure if you have a clearance issue.Hope this makes some sense. Esslinger has a good tech sheet on cam setup. If you decide on a piston swap, I have a couple new sets of Wisecos and one set of TRW forgings. I'm working on unloading some hoarded parts... just not sure what all is here.
Another way is to set #1 piston to TDC.Next press PLAY DOUGH over the valve reliefs about 1/4 to 3/8 inch thick.Next set the cam so both #1 valves are closed. install head with gasket and tighten to about 10 ft lbs,rotate cam 360 deg.Now pull head back off and using a small thin machinist rule press end into impressions left in the play dough and measure your clearance.