Mis-shifted, SERIOUS advice needed

1130 Views 14 Replies 7 Participants Last post by Storm88000, Feb 18, 2004

jktriple0

Discussion Starter · Feb 15, 2004

Last night I mis-shifted my SR20, and of course the engine saw high revs. Now it is parked in my garage with a trashed exhaust camshaft, and damage to rocker/roller setup and possibly bent valves.

My problem is that went to remove the camshafts, I performed a 3AM error (meaning a big brain fart) and tried to loosen the bolt on the end of the camshaft with the retainers(caps) for the camshaft off of the engine. So, the camshaft slipped out of where it's supposed to be, with the timing chain and sprockets still in tact. I can't get the sprocket and camshaft back in place because the timing chain is still very tight.

I am trying to remove the timing chain tensioner now so that I can loosen the chain, get it all back in the right spot, so then I can loosen the camshafts the correct way. However, I cannot get the tensioner out. The bolts are off, and nothing is on the studs, but it will NOT come off.

Before I go any farther, I have to solve this problem. However, that is only the beginning to the list of problems:

I do not know whether my valves are bent or not. Will I have to completely remove the head for this, and will that require doing everything that the FSM requires (as far as removing pulleys, draining fluids, taking parts off, etc.), or is there another way to get around it to where that much labor won't be required.

As you can see, I am far from an expert in this, and I am learning as I go (reading JWT tech articles, and my FSM). This car is my main transportation, and the longer it sits the longer I cannot go anywhere.

The car is a '00 Nissan Sentra SE (not the performance package). That means it has the roller/rocker setup. I tried B15Sentra.net, but it was an absolute waste of time. That forum is garbage. Anyways, ANY help at all would be greatly appreciated.

I have pictures if needed.

Thanks in advance. I used the search button but none of the results helped me out with my current situation.

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T4 Primera

· #2 · Feb 15, 2004 (Edited)

Wouldn't a compression test give you an indication of whether the valves are still seating properly? Of course you'd still have to get things somewhat back together first.

First the chain. Try a variation on the wedge method used for holding the chain when installing cams. i.e. slip something down between the two sides of the chain to gently force them apart. You may find that the tensioner pops out of it's hole when you do this. If not, it may still provide enough slack to reposition the cam.

Once you have everything back in place, I would suggest removing the plugs and slowly turning the engine over by hand to see if it binds up anywhere.

If it seems to turn over ok without binding or locking, maybe then you could replace the plugs and wind it over on the starter for a compression test.

Storm88000

· #3 · Feb 15, 2004

jktriple0 said:
My problem is that went to remove the camshafts, I performed a 3AM error (meaning a big brain fart) and tried to loosen the bolt on the end of the camshaft with the retainers(caps) for the camshaft off of the engine.

OMG!

Lesson learned, *DON'T* work on your car (especially something that involving) in the middle of the night when you're tired. Although I don't understand how you could miss that in the first place.... really....

I am trying to remove the timing chain tensioner now so that I can loosen the chain, get it all back in the right spot, so then I can loosen the camshafts the correct way. However, I cannot get the tensioner out. The bolts are off, and nothing is on the studs, but it will NOT come off.

This is just a hunch, but I'd say that when you loosened the cam incorrectly it might have caused the tensioner to stick. Just a wild guess, usually the tensioner pops right out once you get both nuts off, but you have B15 and perhaps that is different from the standard 91-99 SR20DE.

I do not know whether my valves are bent or not.

Exactly how did you miss shift, from what gear to what gear at what speed? I'd bet your valves are ok and you just broke some rockers.

white_91_ser

· #4 · Feb 15, 2004

i had this same thing happen to me one night,did the rockers just spit out on the exhaust side?mine were just laying in the head.2nd,if had cranked it over and opened the intake did it sound like it was back feeding through the intake side as if it were out of time?this is what happened when i over revved the engine,i just loosened up all the caps EXCEPT for the last one by the cam gear on the exhaust side and used a big flathead screwdriver to re-install the spacers and rocker arms back onto the seats.car still runs like a champ,and you bet that i'll never miss a gear again.hope this helps in some way and good luck.

T4 Primera

· #5 · Feb 15, 2004

white_91_ser said:
i had this same thing happen to me one night,did the rockers just spit out on the exhaust side?mine were just laying in the head.

He mentions it's a roller rocker setup in his opening post. I didn't think they could throw out as they're shaft mounted

jktriple0

Discussion Starter · #6 · Feb 15, 2004

Ok. The compression test sounds like a definete course of action. Redlining 3rd, going for 4th, got 2nd instead. Revs shot up in the 8-9000 range b4 clutch was put back in. Two "rollers" from two rocker arms are shot. and the lobes on the exhaust camshaft over those same two rocker arms are badly damaged. (makes sense: lobe comes around to hit the roller and when the lobe comes around and there is half a roller or no roller, things get jacked.) I will try that wedging trick. Thanks guys for replying! Didn't think anyone would.

eric96ser

· #7 · Feb 16, 2004

Use a long flat header screw driver to remove the tensioner. You shouldn't have to really pry on it, because it will pop out. Make sure you have the washers off also. If you don't really know what you are doing, removing the head can be a big mistake. I saw you posted this on the KC mailing list. I would get some help from one of more of the locals before more damage is done.

jktriple0

Discussion Starter · #8 · Feb 16, 2004

Yeah. I think i've decided what to do. I had one of the locals stop by and look at things. We both agreed that I should probably just buy 2 new rocker arms, put em in and try and put things back together and do a compression test. Assuming I can get that intake side cam sprocket back down in there. If I pass the test I buy new exhaust camshaft and roll. If I fail I buy new engine. There are still these little pin like looking things that were a part of the debris, and I have no clue where they came from. I'm thinking those pin things are gonna end up screwin me over. New engine is sounding like the route I have to take.

jktriple0

Discussion Starter · #9 · Feb 16, 2004

Below is the site with the pics. (One of my friends took pictures and he has a Spec just as a sidenote.)

http://gallery.thevboard.com/index.php?album=KCSpec/SR20&dispsize=512&start=0

Yeah take a look at that little shinny pin thing on the table. What is it? Where'd it come from?

T4 Primera

· #10 · Feb 16, 2004 (Edited)

jktriple0 said:
Below is the site with the pics. (One of my friends took pictures and he has a Spec just as a sidenote.)

http://gallery.thevboard.com/index.php?album=KCSpec/SR20&dispsize=512&start=0

Yeah take a look at that little shinny pin thing on the table. What is it? Where'd it come from?

It looks like a needle roller - part of a bearing.

Are the rockers themselves, or possibly the rollers that ride the cam lobes, mounted on needle roller bearings? Could they have come from there?

That's the only place I can think of where they might have come from - the rockers.

Keep them all together - when you find where they came from, you might find out how many there should be - and be able to account for all of them.

T4 Primera

· #11 · Feb 16, 2004

Another thing to watch for - make sure you dont get the little guides and shims sitting inside the springs retainers (on top of the valves) mixed up.

Best of Luck.

jktriple0

Discussion Starter · #12 · Feb 16, 2004

Ok guys. Thanks for all your help. I have decided to let the professionals handle this one. I really don't wanna spend the money, but I need a car, and I don't have time to get into any big engine repairs. I will let you know how the technician's examination goes.

94sentraSER

· #13 · Feb 17, 2004

go with a UKDM red top low port!!!! only 750.00 from Soko! do like me and just say phuck it!!!

99SE-L

· #14 · Feb 18, 2004

From the pictures, you haven't even losen the timing chain yet. You need to pry the tensioner out with a screw driver after you unbolt it. You can just remove the cam gear from the camshaft and take out the camshaft. But to repair your engine, you would need more than just a rocker arm or camshaft replacement. If the exhaust cam and rocker arms broke, that means your valves must definitely be bent since the SR20s are interference engines, if your valves arent timed properly, the pistons will definitely hammer the valves. Since you are having problem doing the cams alone, you made a wise decision letting the pros handle it as doing valves and removing the head is a much tougher job.

Storm88000

· #15 · Feb 18, 2004

99SE-L said:
From the pictures, you haven't even losen the timing chain yet. You need to pry the tensioner out with a screw driver after you unbolt it. .

Or it will 'pop' out. Mine does.

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