Can I replace a camshaft without pulling the head?

#1

Brother’s DD has a terible oil leak. I traced it to the camseal, but once in there I found the cam had a very deep grove worn into it. As I suspected the new seal did nothing to stop the leak.

Can I raise or lower the motor to get the cam out the front, I know guys have got rocker shafts out the front without pulling the head.

My initial plan was to rebuild my spare head and just swap heads, but the machine shop called today telling me that the spare head is cracked in two places. This is plan B just to get him back on the road.

#2

Never thought about it, but don’t suppose why not.

I think you’d have to remove both rocker shafts to get all the rockers out of the way, and of course take apart the timing belt, etc. to get the front end free, but if you get everything else out, you should be able to find the angle such that you could work it out the front over (or under) the core support.

Be a crapload of work, though.

Do you know the clean way to get the rocker shafts out? You’d have to do one side (intake or exhaust) at a time, rotate the engine to get as many of them free as you can, and pick a spot where the rocker shaft can fit through the holes in the cam gear. Note the position, then note the rockers that are up on the lobe.

Temporarily rotate the engine to get the offending rockers off the lobe, then slide the rockers front or back along the shaft (you removed the clips early on) to “park” the problem rockers in the neutral zone between intake and exhaust. Then re-position engine rotation back to original spot so that you now have no cam pressure on any of the 6 rockers.

Once you have done that, you can work the rocker shaft out.

Next, you get to do the other side.

I think you’ll need to mark both positions (intake and exhaust ‘home’ positions) on the crank pulley so you can find them again when it comes to reinstallation. I think I’d go for pulling the head though, now that I’ve typed all this out, it sounds like you could get stuck and not be able to reassemble correctly.

#3

[quote=“ctbimmer” post=74635]Never thought about it, but don’t suppose why not.

I think you’d have to remove both rocker shafts to get all the rockers out of the way, and of course take apart the timing belt, etc. to get the front end free, but if you get everything else out, you should be able to find the angle such that you could work it out the front over (or under) the core support.

Be a crapload of work, though.

Do you know the clean way to get the rocker shafts out? You’d have to do one side (intake or exhaust) at a time, rotate the engine to get as many of them free as you can, and pick a spot where the rocker shaft can fit through the holes in the cam gear. Note the position, then note the rockers that are up on the lobe.

Temporarily rotate the engine to get the offending rockers off the lobe, then slide the rockers front or back along the shaft (you removed the clips early on) to “park” the problem rockers in the neutral zone between intake and exhaust. Then re-position engine rotation back to original spot so that you now have no cam pressure on any of the 6 rockers.

Once you have done that, you can work the rocker shaft out.

Next, you get to do the other side.

I think you’ll need to mark both positions (intake and exhaust ‘home’ positions) on the crank pulley so you can find them again when it comes to reinstallation. I think I’d go for pulling the head though, now that I’ve typed all this out, it sounds like you could get stuck and not be able to reassemble correctly.[/quote]

I’ve disassembled several heads but always on a bench, and yes when you type it all out I’ll just pull the head.

Anyone got a spare head casting laying around they’d sell?

#4

A couple stout fellows can clean and jerk the head off of the block with the manifolds still on. This makes for a darn easy head R/R.

Or save yourself a crapload of hassle by simply pulling off the piece that retains the front cam seal, replace the seal and also the o’ring that goes on that piece, and then put it back together. Just because there’s a groove near the end of the cam doesn’t mean the groove is causing the leak.

The o-ring is easy to pinch. Using some RPV goobage instead of an o-ring is not crazy.

Put some RPV goobage under the rubber stoppers under the valve cover gasket, then goobage under the gasket itself. Goobage is your friend.

#5

[quote=“Ranger” post=74637]A couple stout fellows can clean and jerk the head off of the block with the manifolds still on. This makes for a darn easy head R/R.

Or save yourself a crapload of hassle by simply pulling off the piece that retains the front cam seal, replace the seal and also the o’ring that goes on that piece, and then put it back together. Just because there’s a groove near the end of the cam doesn’t mean the groove is causing the leak.

The o-ring is easy to pinch. Using some RPV goobage instead of an o-ring is not crazy.

Put some RPV goobage under the rubber stoppers under the valve cover gasket, then goobage under the gasket itself. Goobage is your friend.[/quote]

I’ve pulled several heads so I know the process. I’d never pull one then just slap it back on without sending it to the machine shop though. I’m trying to avoid my brother’s car being down for a few weeks, that’s why I took my spare to get rebuit ahead of time. Sucks it was cracked.

I already replaced the seal and oring. I was told vasoliine is king when it comes to orings, and a little oil on top of that makes the camseal slide in nice and easy. I’ve only ripped the oring once, and that was before vasoline.

I also replaced all 4 rocker shaft plugs, and yes a bit of rtv was used. This isn’t really a small groove, this cam probably has 275k miles on it.

#6

Greg, remove seal and its carrier. Remove seal from carrier. Replace seal with new. Don not drive new seal fully flush into carrier so that seal touches non-groove on cam.

Did i miss somethong here?

RP

#7

[quote=“Patton” post=74639]Greg, remove seal and its carrier. Remove seal from carrier. Replace seal with new. Don not drive new seal fully flush into carrier so that seal touches non-groove on cam.

Did i miss somethong here?

RP[/quote]

Tried that. They’re really isn’t much room to get the seal to ride in a differnt location. The old seal was pressed all the way in. We pushed the new seal in just enough that I was comfortable that it wouldn’t work it’s way back out. Probably moving it 1/8" or a bit more…

Still leaking.

#8

Oh well. When the car is parked,cardboard under the engine works well too.

RP

#9

Well, if you drill a couple holes in the firewall you can push the rocker arm retaining shafts out pretty easily. That would make the cam change easy enough that you’d spend more time drilling the holes and removing the radiator then actually working on the head.

#10

[quote=“Patton” post=74643]Oh well. When the car is parked,cardboard under the engine works well too.

RP[/quote]

It doesn’t leak when it is parked, but almost immediately after start up it starts dripping one or two good drops a second.

It’s a street car with full interior.

#11

[quote=“87isMan” post=74652][quote=“Patton” post=74643]Oh well. When the car is parked,cardboard under the engine works well too.

RP[/quote]

It doesn’t leak when it is parked, but almost immediately after start up it starts dripping one or two good drops a second.

It’s a street car with full interior.[/quote]
You can still bonk the rocker arm retaining shafts forward. You have to use some dowels or drifts. A variety of lengths of 3/8" socket extensions will work. Start with short ones but make them longer as the shaft comes further forward.

#12

Many of the PRO3 guys have drilled both the firewall, and the radiator support to facilitate the removal of the shafts in car. There seems to be a few broken rockers in the pits each year that many guys have it down pretty pat. I myself had to do it once, but it was luckily one of the end ones…

#13

With some quality help we changed a #5 on a hot motor going out the front in about 40 minutes. No need to punch thru firewall. Refer to my first post.

#14

Wasn’t the camshaft!! The oil was leaking through the oil pressure sensor into the harness and was being piped through the harness up to where it goes across the upper timing cover. The outer case of the harness was broken there. Worst ghost oil leak ever!!