Valve compressor tool - PeachParts Mercedes-Benz Forum

lotzagoodstuff · #1 06-06-2008, 10:12 PM

Good afternoon. I am a new 350SL owner, getting ready to do valve seals. I have done many valve seals on domestic OHV engines with the lever style tool, which obviously won't work for the 4.5 OHC engine. I stopped off today and bought the screw down type, but I am wondering if I will have enough clearance to get in there with this tool.

Any input would be greatly appreciated.

Thanks

R. J.

lotzagoodstuff · #2 06-07-2008, 11:29 AM

So I was just looking at the shop manual and was wondering how hard it really is to pull the camshaft out to really get some good access to the valve springs. It appears that there's just bolt that holds the cam sprocket onto the camshaft via a keyway, but I can't tell if it's a tapered or standard shaft.

I know it may be easier to just get the correct valve spring tool, but if I can do a little more dissasembly to gain a lot more access I would be a lot more comfortable doing the valve seals with the cylinder heads in place.

Again, my lack of experience with MBs is probably creating some silly questions, which I apologize for in advance.

Best regards

R. J.

GaryF · #3 06-10-2008, 11:59 AM

I used a sealy spring compressor, the lever type that hooks under the camshaft. It looks very similar to the mercedes recommended tool so its probably the right approach and I had no access problems.
How do you intend stopping the valve dropping into the engine ?

ctaylor738 · #4 06-10-2008, 01:32 PM

You can remove the large bolt and tap the sprocket off, and pull the cam out. Obviously, you need to remove the rocker arms to do this. Will your tool compress the valve springs with the rockers in place?

lotzagoodstuff · #5 06-15-2008, 10:02 PM

Thanks for the reply. I have purchased the hook tool to do the job with the cam and heads in place. I have the adapter to pressurize the cylinders with shop air to hold the valves in place. I am still a little confused about the pulling the rockers and the physical keepers on the valves themselves. I have a crimmy Chilton's manual, but it's not very descriptive.

Any pics or links would be much appreciated.

Thanks

R. J.

lotzagoodstuff · #6 06-16-2008, 01:27 AM

It took me a little while to remember the order of operations, but I did manage to get two cylinders done today without too much drama. I do have to say the old seals didn't look that bad, not really dried/cracked/missing, and I didn't get too much wiggle out of the valves I've looked at so far. Any guess where I may be sucking oil if this doesn't cure the blue cloud behind me? All the plugs burn nicely, it doesn't turn the oil black immediately and it has pretty good power so I don't think the rings are shot. I have already unhooked the vacuum line from the trans to make sure I didn't have a bad modulator sucking ATF into the manifold, but no real change (besides shifting hard).

I really like these cars, they are built really well, I just need to get this one to stop smoking so I can enjoy it.

Any thoughts are appreciated.

Best regards

R. J.

ctaylor738 · #7 06-16-2008, 08:14 AM

You're taking the gamble that the heads don't need guides, and that seals will fix the smoking. There's no test that I know of other than wiggling the stems, which is rather inexact. It's a science experiment - there's really no way to tell how it will turn out until you get the car back on the road.

You can do a dry and wet (add some oil to the cylinder) compression tests to check the rings. My rule has been if the compression improves 30% or more on the wet test, then rings are needed.

lotzagoodstuff · #8 06-22-2008, 12:40 AM

Valve seals were fine, guides weren't that bad, I have a feeling the rings are shot or more likely stuck (car was sitting for some time). It doesn't turn the oil black immediately and I don't have any fuel or combusion effects in the oil itself, so I am going to try some Auto-Rx as I've had good luck with that product loosening stuck things in the past.

I am going to post this separately, but for anybody who's been following this: how hard is it to put in the newer 4.5 SL engine with the K type injection versus the D type? I have a line on a newer engine and trans and I see the K type seems to be more popular/desirable.

Any input is appreciated

Thanks

R. J.

Roncallo · #9 06-22-2008, 07:18 AM

I have the KD 2400. The other one wasn't available 30 years ago when I bought it. I bought it for my Pinto but it ended up working great for MB's. Although I did modify mine by cutting and welding the handle with a 90° bend to to clear an add on after market AC compressor. I see the new one has a handle adjustment for maybe 45° of bend in either direction.

http://www.pbase.com/rmscott/valve_spring_compressor

Lexxani · #10 06-22-2008, 09:30 PM

I just got done messing with my valves, I was getting carbon fouling on cyl's 1 and 7, I pulled the exhaust valve spring from #1 and grabbed my needle nose pliers to pull the stem seal off, and low and behold, the damn guide pulled right out with it (it took NO effort at all, almost as if It was just placed in the hole). Now its time to do my heads . . .I hope this scenerio doesent play out with your vehicle.

Do you know which cyl's your leaking oil?

Have you performed a leak-down test? (I assume you have access to shop air) this would give you a much better idea of if its valves or rings.