96 850 T, pulling head for valve job, prepare:

futureboycolin · Post by **futureboycolin** » 16 Oct 2013, 06:38

So after some thought, I wanted to ask this:

For my purposes, I won't need to be securing the camshafts to the cam cover, as I'll be installing NA cams on reassembly. Therefore I can leave the camshafts in the head when and them remove them and set them aside, after marking the cam gears, of course. Then when I reassemble, it's just a matter of lining up the bolt outlines on the gears, and the timing marks, right?

Getting the IPD cam timing tool to tweak the timing once the cams are installed. Will let you all know when it's over. Howuch HP gain can I expect from the NA cams without a tune?

JimBee thanks for the info, it helps a lot.

Post by **rspi** » 16 Oct 2013, 08:35

Hey Jim, it may be early for me but I really do not understanding most of what you wrote.

I have pulled several cam covers to remove cams, etc., and have never secured the cams to the top. Not saying you shouldn't, just never have. There is a danger of a cam sticking in the cover and falling out and damaging something in the head but knowing that is usually enough to help you keep that from happening.

When I break the cover loose with the taps, ratchet extensions, I have found that the easiest way to get it loose all the way around is to kinda rock it closed on the parts that are loose. Causes the cover to rock and the cam pressure breaks the cover loose from the rest of the head. I am careful that the cams do not stick in the cover, if one does, I make sure that it doesn't fall out on to the head.

I do NOT see any benefit of marking the cam sprockets other than the mark on it that should already be there to match it to the top cover. Swapping the cams will void any marks you make. Just align the new cams at the rear of the head, install the sprockets true to the cover and install the belt. Personally I would make the car run with the true timing, then set the timing on the marks, then adjust the timing with the NA cams to get the performance gain. That is done with the belt on.

Does the kit from iPd come with a tool to turn the back of the cams?

Post by **rspi** » 16 Oct 2013, 08:38

Oh, from what I have read, I think you see about a 15 HP gain. The big deal is not the HP gain, but the torque curve changes a lot. Puts you HP closer to the lower end of the RPM scale making the car a lot faster off the line.

A 15 HP gain performs like a 40 HP gain.

Post by **erikv11** » 16 Oct 2013, 08:47

futureboycolin wrote:... For my purposes, I won't need to be securing the camshafts to the cam cover, as I'll be installing NA cams on reassembly. Therefore I can leave the camshafts in the head when and them remove them and set them aside, after marking the cam gears, of course. Then when I reassemble, it's just a matter of lining up the bolt outlines on the gears, and the timing marks, right?...

Right.

On reassembly you should first line up the slots parallel to the head surface on the backs of the cams (instructions for this in all of the head tutorials, intake above horizontal exhaust below), then put the gears back on, then confirm that the timing marks are good. Rely heavily on those slots, they will never mess you up, whereas the timing marks on the gears can be wrong if the cam gears happen to go on wrong for some reason.

The cams are stamped I and E on the back end, so you don't have to mark that but you can.

The danger of not securing the cams is not in having them fall out and hit the head. It is in cracking the thin slots in the head where the cam guides sit. You want the cams to be pulled up into the cover at all times, to make sure they are not sticking in the slots in the head. That's the whole point.

There is very little HP gain from swapping cams, the main point is it allows more cam adjustment to move the power band around relative to the RPMs. Sort of like the NA throttle plate modification - seems faster, and can be more fun to drive.

futureboycolin · Post by **futureboycolin** » 16 Oct 2013, 12:14

But if I do leave the camshafts in the head when I draw up the cam cover, as long as I keep it straight, what's the risk? I will most likely have help lifting the cam cover straight up off the head.

Post by **erikv11** » 16 Oct 2013, 20:17

Wonder if I'm getting trolled now lol ... the risk has been stated several times now

, you run the risk of hairline cracks in the head, at the cam retainer slots. It is actually not even the end of the world if you do crack them, but it's better to not break stuff.

The reason to draw the cover up straight, is to pull the cams up straight with it. That's the whole point. If they don't come up straight, the valve springs will push them up unevenly and you can crack the head.

When you get the whole thing apart, you can now separate the cover and the cams, leave the cams back on/in the head and go put the cover on the workbench, sure. But you first have to release the cams from their slots, by bringing them, yep, straight up ...

futureboycolin · Post by **futureboycolin** » 16 Oct 2013, 23:24

Not trolling, I appreciate all your help. I'm just nervous about the job, don't have the financial means to go buying cam locking tools, y'know.

Just trying to pin down the easiest way to do this job.

Post by **rspi** » 17 Oct 2013, 11:11

LOL, this thread is dragging on like the one with the "I don't want to do a compression test" thread.

The instructions I provided show that I did the job with little or no special tools. Yes it would have been nice to have a cam locking tool, or a draw down tool, or a cam sprocket locking tool, but the fact of the matter was, I had not worked for a couple of years and had to do my best with what I had. Not doing extra stuff. My daughter who was in college at the time, working 2 part time jobs paid for all of the work (parts, tools, gas, head shop, etc). The only special tool purchased was the torque compass/degree gauge.

As with most time consuming jobs, there is very little danger or chances of getting things wrong. Just take your time and stay sober.

Post by **erikv11** » 17 Oct 2013, 13:49

rspi wrote:...As with most time consuming jobs, there is very little danger or chances of getting things wrong.

Don't mean to be rude but, what are you talking about? I agree this job is straightforward if you have some experience and read up, and OP surely seems up to it, but there are all kinds of chances to mess up a head swap.

He'll be fine and should take his time, but don't be misleading!

futureboycolin · Post by **futureboycolin** » 17 Oct 2013, 21:46

I'm def up to it, and totally understand where Robert is coming from. I have some money now, but it isn't earmarked for the car.

Anyway, the tear down is happening on Monday regardless of what happens, and I have to drive it about 3.5 hours to get to where I'll be doing the work and leaving it. Before then I need to bleed the brakes, possibly change the oil as it still has Seafoam in it, and unplug the fuel injector in cylinder #1 (do I unplug the spark wire too?).

With regard to special tools, I have tons of tools. I don't have any cam locking tools though. The Haynes manual talked about building a cam locker for the rear and using a wire to lock the camshafts to the cover on the front side.