cam shaft swap help

[Rootie524]

translate to n00b talk

[1988GTU]

The motor is interference designed.

[Rootie524]

and why is that?

[1988GTU]

I'd suspect in the not so distance future that one of your valves will probably break or not seal properly.

[Rootie524]

well i feel like such a dumb ass. after i told everyone here there is no way it was a pushrod..guess what..it ended up being a pushrod. i though we were careful when taking the old ones out and putting the new ones in. i did the box thing that is tell you to do in the haynes to keep track of them. and i think two fell through and i told my helper to quick put them back in the right spots. apparently he didnt know the right spots. so thats my fault for not checking his work. im pissed at the same time im happy because apparently the timing was spot on and everything else was installed correctly..so ive seriously been thinking about what is wrong with this car non stop for the last few days. and now i finally know what the issue is so im relieved. we had the exhaust pushrod on the intake valve. so it lifted to much, bent the valves, broke the rocker and it explains all the ticking noise because it had the shorter rod on the exhaust valve so that wasnt getting enough lift. so it explains the sudden accelerations, the bogeyness (if thats a word), and all the clicking sounds.

so i replaced the bent valve with one from another 3100 at a junkyard and the piston has no damage to it. and the pushrod is not bent and the rocker is replaced. so i'd say i lucked out. it sucks that the entire engine had to get ripped apart because of one tiny mistake. this could have been done 4 days ago if it weren't for this. but hey..im learning..its a great learning experience and at this point i know almost all aspects of the 3100 engine and where everything is and how to take it apart. so its not the worst thing ever. knowledge is key.

try not to make fun of me too bad for this. haha. im sure you all were confused as i was explaining what went wrong and insisting it wasnt a rod...oh well...haha

[ForcedFirebird]

Broken rocker and bent valve, but not a bent pushrod? Odd.

[SappySE107]

The crank position via the crank gear will tell you #1 TDC position. So far it sounds like a rocker arm gave out for no reason. Exhaust pushrod on an intake valve, or coilbind are the only 2 reasons I can think of for this to happen, and those springs won't coilbind. If the pushrods are in the right order, the rocker failed on its own.

[Rootie524]

then can someone please explain what is happening. if it doesn't need degreeing, and the timing marks were lined up..what went wrong? i have never been more confused in my life. same with the people helping me. we are stumped.

the only thing i can think of is (which i dont think i got an answer for yet)..can you acheive TDC on another cylinder besides the 1st. like can you reach TDC (with the crankshaft timing sprocket in the correct position) on any other cylinder besides one..or will it only have the timing marks line up when in TDC on the 1st cylinder. because if i had it the timing marks lined up before but was at TDC on say the 3rd cylinder and then i put it all back together..that may have been the problem.

so i dont need to degree and there is 100% no need for a valve adjustment..but put the cam and lifters in the right position and tighten down the rockers accordingly and it will be in sync?

[SappySE107]

Stock timing is fine. There is no reason to degree that cam.

[Rootie524]

ok..so the timing chain and sprockets arent the issue..i had everything lined up just like its supposed to be and i had timing issues. so the degree of my cam needs to be changed. that is the only thing i can think of. the only thing.

if this helps..specs for cam:
valve lift intake: .487
exhaust: .502

duration at .006 tappet lift (intake) 263 (exhaust) 275
valve timing at .050:
Open: Int: 5- BTDC Exh: BBDC
Closed: Int: 37 ABDC Exh: ATDC

thats all pretty much off the comp cam spec sheet that cam with..looks like the grind was originally for WOT-Tech (says so on the sheet)

[95Grand-Am]

Since you used a matching timing set that should be fine, alot of people use the older style like you used as it is a little stronger. When you line up the timing marks use a straight edge, the straight edge should go through the center line of the crank and cam and the marks should line right up with the straight edge. Were you able to recover all of the roller bearing from the rocker?

[Rootie524]

well if thats the case the timing was right. i installed the cam just like the old cam..but this isnt the old cam..so someone told me i may need to have the timing marks off for the timing to be right. he said i may need to degree the cam to account for the bigger lift that it is giving. thats the only thing i can think of. because everything else was right.

at any rate..im pretty sure one of my valves is bent (the one that had the broken rocker) so the heads are coming off now. And while they are off im going to see if someone in the area can port them a bit. and does WOT sell exhaust manifold bolts, because a lot of them are breaking.

at any rate. how should i degree the cam that it will work. because the car did idle..so its close to being in correct timing. but something somewhere is off and im very confused right now haha. ill get the specs for the cam if it will help. it has to work though because the spec sheet says its for a 3100/3400 gm engine..so idk wtf..

[WrathOfSocrus]

If the chain was 99 and the gears are 00, then that is a big problem. With the pushrods out, you should be able to press on the lifter hydraulics a little and get them to move. If not, that is probably ok anyway due to the checkball position. You could tear them apart to be sure but I doubt you broke an internal lifter spring unless the pushrods were in the wrong order.

With the pushrods out, check to see if the plunger comes up against the retaining clip on the lifters. If any of them don't, then it is likely sludged up. It costs nothing but time to tear open the lifters, clean them up, and oil the piston so it slides nice and smooth. The springs aren't massively strong and with enough sludge they will have little to no movement. The few engines I have torn into lately ALL had more than half of the lifters jammed below the retaining clip with no plunger movement. WOT-Tech has a tutorial of the lifters being disassembled for the LS lifter springs http://wot-tech.com/shop/all/tce-ls-.../prod_231.html

I doubt that the lifters have anything to do with the engine trouble but it wouldn't hurt to have them clean while that far in the engine. I drilled a hole in a block of wood and screwed it to another block so I could have something hold the lifter upright and keep it from rolling away while cleaning up its internal components. Also, the piston has a slight amount of clearance to the bore in the lifter and can wedge at an angle when it is part way out. Simply pulling harder doesn't work well, applying even force pulling out while trying to wiggle it back and forth a bit works much better.

all i need to do is get the crank in TDC for 1st cyl and put my cam in with pin facing right and it will all line itself up in perfect timing sync?!

Correct. The crankshaft should be at TDC on the #1 cylinder. The crank doesn't differentiate from compression stroke or exhaust stroke. That is a function of the camshaft. As Brad said, if you installed the cam dot down to the crank dot up it should be fine and the cam dot would be on top after rotating the crank 1 full turn with the chain on. I would also take his advice of turning or cranking the engine BEFORE attempting to start up

[bszopi]

If you originally had the pins lined up, then its not a timing issue. Once you get the cam back in, turn it over 360 degrees (via the crank) and look at the pins. They will be 180 degrees out. Turn it over another 360, and they will be lined up again.

As far as the rocker goes, it could have been anything really. As long as nothing looks damaged, put it back together (except for the timing cover [see above] and rocker covers) and turn it over a couple times and watch all the valves, rockers, etc. If everything looks good, button it up, cross your fingers, and start it up.

[Rootie524]

haha i appreciate all the help! its a great community.

and to answer speculation about my new timing chain/sprocket set..i believe its for a 99 3100sfi. BUT i replaced everything. the sprockets that went with it and the chain. i didnt just replace one sprocket or the sprockets with the stock chain. it's all replaced. i just assume it might be causing a problem because it has less teeth on it. but if i replace everything and it has the chain associated with those sprockets..should it be fine?

because if it could be fine then i honestly have no idea what went wrong or how to fix it. because if someone told me my cam being 180 might be normal based on where my cranks at and that the timing gears are fine..then idk what else could have gone wrong..i mean it broke a rocker!! somethings up. im pretty sure its timing..it has to be. and is everyone positive i dont need to do valves adjustments. i just put on new springs and the vavles went back to the same place after tightening the rocker arms so im guessing a valve adjustment isnt in order. so here i am back at timing. it has to be off and one tooth off on the new sprocket is the equivalent of 2-3 teeth off on the old one.

so right now (this is important that i get confirmed) i have the crankshaft sprocket on and the dont on the gear is facing up like it should be. does this determine that it is in TDC for the first cylinder? right now the cam is out and the valves are up so the crank can be turned as much as it needs to be. i guess its in TDC but it may need to be tunred a few times to get it in TDC for the first cylinder...and even when i get it in TDC for the first cylinder can i just put the cam in the correct way and put the lifters and all that back in and will my valves be lifted accordingly so that it wont hit my pistons. in simpler words..all i need to do is get the crank in TDC for 1st cyl and put my cam in with pin facing right and it will all line itself up in perfect timing sync?!