atl1234

so to make a long story short, i bent some valves after doing a cam swap. not sure if it was due to too long of a push rod, or install error.

so I'm here to show photos and ask questions, so this doesn't happen again.

Im running a jp double roller chain, and not sure about the markings on it.

keep in mind i didn't install the jp chain or sprockets.

so im guessing the "0" marker on the crank sprocket is the marking for TDC, since cylinder 1 and cylinder 6 are at TDC.

Now for the cam sprocket.... which i see has a "0" on it as well.

is it suppose to look like this with the dowel pin at the 9 o'clock position, where the "0" on the cam sprocket is at the 12 o'clock position?

or

is it suppose to look like this with the dowel pin at the 3 o'clock position, where the "0" on the cam sprocket is at the 6 o'clock position?



When i bent the valves, the dowel pin was at the 3 o'clock position.

S_M_I_D_D_Y

Doesnt matter. Engine will run fine either way. If you spin the crank 360* the cam will spin 180* and the dowel will move from 9 to 3 position. As long as the dot on the cam sprocket and the 0 ( as long as the crank sprocket is in the 0 key position also) on the crank sprocket line up your good to to

atl1234

is there anyway to find out if the crank sprocket is keyed on the "0" mark, without taking off the oil pump?

atl1234

if my cam and crank are lined up correctly, then i must have bent my valves with too long of a push rod?

would you agree with that assumption ?

Darth_V8r

iTrader: (4)

Lots of cams require fly cutting the Pistons. Did you measure or calculate for PTV clearance? What are the cam specs? Did you mill the heads or go thinner head gasket or both? Those also reduce PTV clearance.

Did they all bend immediately on first start? Did it happen at WOT?

Did you rotate the engine a few times by wrench before attempting to start it? Did you encounter any serious resistance?

Assuming you used stock lifters, you'd have to miss your pushrod length by .100" to cause lifters to bottom out. Did you measure for pushrod length? Did you upgrade to larger OD pushrods?

Too long pushrods could have caused it but it wouldn't be nearly first thought I had. Unless I knew I had screwed that up. Id start with cam specs, and I'd be thinking about basic valve train control.

atl1234

I'm running a texas speed 228r

here is the link for it:
https://www.texas-speed.com/p-1148-t...-camshaft.aspx

popular cam, very mild

i believe the head has been milled, its a texas speed: PRC stage 1 head

lifters are morel link bar

bent the valves during start up, cylinder 4,6,5,7
those are the pistons that have "little eye brow" marks no them

yes i rotated the motor, and didn't feel any resistance

I'm running texas speed pushrods, started with a 7.300, then moved to a 7.400, and now have settled with a 7.350(after using a measuring tool)

atl1234

and I'm using this head gasket
http://www.ws6project.com/user_stor/...-head-gaskets/

Darth_V8r

iTrader: (4)

Ok. I'm assuming you were aiming for .040 preload? The total plunger travel on morels is .140 IIRC. If the pushrod were long enough to cause the problem, your valves would literally not be closed. During cranking you have no oil pressure, so it wouldn't have been pumped up. The PR would have to be long enough to fully collapse the lifter and still keep the valve open. If you got 7.350 measured and ran 7.400, I don't think that would be too long enough (I know but it works) to cause contact.

The cam should not have caused it I agree. 228r is moderate and guys run bigger cams all the time. I'm sure you didn't screw up the install.

Did you degree the cam by any chance? I had one that was nine degrees advanced.

atl1234

yes that was the preload i was shooting for.

and no i didn't degree the cam

Darth_V8r

iTrader: (4)

Since you're going to have the heads off anyway, here's a few things worth trying just to rule out some stuff so it doesn't happen twice:

1. If you have access to a solid lifter, install it, put some clay on the piston, bolt the head on, adjust the pushrod to zero lash, and rotate the engine 720. Verify your PTV clearance.

2. Texas Speed likely ground the cam themselves, and I doubt it's off, but I'm sure they'd be willing to put it on a cam doctor to validate the measurements.

3. After getting the cam back, degree it. Assuming the cam checks out, if the cam times out off, you'll know that the timing set is off.

It could end up just being the pushrods, but these few checks would rule out the other possibilities, which would either prevent the same thing happening twice or give you more evidence that the pushrod length was all it was.

atl1234

now correct me if I'm wrong, but if it was the pushrod length that caused the valves to make contact with the pistons, then wouldn't all of the pistons have marks on them from the valves making contact.

i only have cylinder 4,6,5,7, have marks on them

Darth_V8r

iTrader: (4)

Most likely yes. That's one reason I leaned away from the pushrod explanation at first. I just don't think they were that much overly long to have done it.

Long time ago, I lost a timing belt on a BMW 2.5, and there were only three eyebrows in the pistons, but I removed the valves and every single valve was bent. You may want to put the valves all in a drill and spin it to make sure.

I really do think you're looking at something with the timing - either the cam or the set is likely off IMO.

atl1234

Just checked the valves with the drill method

they all seem ok, no major wobble, but not perfectly straight

KCS

iTrader: (20)

Degree the cam.

Sales2@Texas-speed

iTrader: (5)

Can you show how the crank sprocket is installed? You will have to remove the pump though to see how it's installed on the crank

atl1234

shot in the dark

anyone know anyone who rents cam degreeing tool?

Sales2@Texas-speed

iTrader: (5)

Are you sure the crank key is in the right spot?

zraffz

iTrader: (1)

You can piece one together for $50.

As far as cam dot at 6 or 12, it doesn't matter. Every other rotation will realign it; have you ever heard any stories about a distributor being 180* out? This is when the crank needs to go one more full rotation to realign the dots. You can't be 180* out on an LS motor because the cam sensor reads each cam revolution and knows precisely where it is.


You should always degree your cam and check PTV clearances at least one one cylinder for each head. I've had .050ish" on the intake and .095ish" on the exhaust and didn't want to fly cut so I tweaked my cam timing 2 degrees to get .060" and .085"... not something many will agree with doing but it will do the trick.

atl1234

crank key is at the 1 o'clock position. i can see it threw the oil pump

atl1234

what is involved in piecing a degreeing tool together? how can i do this?