Does cylinder head and cam towers have to match? - PeachParts Mercedes-Benz Forum

rgnprof · #1 12-04-2006, 05:43 PM

I just bought a used head - without the cam towers - for my '72 250 (see previous posts) - do the cam towers and heads have to be matched? Can I use the cam towers off my old head with the new head? Or can I buy new cam towers?

Someone has told me that you just can't ever get the cam lined up and installed right when you have mismatched, used cam towers and cylinder heads?

Any thoughts?

Ryan

t walgamuth · #2 12-04-2006, 08:25 PM

i would not think that was so. however if the head has been warped and planed without straightening it first, then a problem can result. then the cam towers might be planed to follow the shape of the planed head.

warped heads should always be straightened before they are planed.

i have changed the heads from under the towers and vice versa, i believe.

tom w

rgnprof · #3 12-04-2006, 09:36 PM

According to the PO (an excellent mechanic friend of mine) - that's exactly what happened. Someone - not him - failed to straighten the head. The head to block side was fine, planed etc. but the top side was not straightened out (I guess you can heat the whole head and then bend it back in line).

When they installed the cam towers, evidently they installed the center two and then measured the end ones gap from tower to head, and then planed down the middle two to match before installing the cam.

I'm not sure what my options are? I contacted the seller and he is going to look for the cam towers and send them along if he can find them...

I doubt that you can just buy new cam towers and fit them to this head and camshaft - can you?

ryan

Tomguy · #4 12-04-2006, 09:40 PM

New cam towers wont do much good (if any) since you'd have to modify them to fit the warped head. This is one reason MB advises against planing heads - a slightly warped head will fit back on the block fine with the right torque sequence. This prevents having to plane the cam towers. Otherwise, you'll have to install this used head onto your block, then check cam tower alignment.

I have reused old cam towers on different heads before. There's no problem with it if everything is still unmolested by a mechanic/machinist that doesn't know anything!

rgnprof · #5 12-04-2006, 09:46 PM

I don't know that the "new" head I just purchased is warped or not - I do know that my current head is shot and needs replaced, but that the middle 2 cam towers currently on the head have been planed to fit this head.

Will they - or can I make the old towers fit the new head (again, i do not the shape of the new head - it is in the mail)? If not, what are my options?

ryan

ctaylor738 · #6 12-04-2006, 10:18 PM

FWIW, the parts book shows the towers available as a set.

rgnprof · #7 12-04-2006, 10:20 PM

Do you think that means they are still available? And would new one's fit an old head and cam?

Ryan

t walgamuth · #8 12-04-2006, 10:35 PM

yes. they should be available. your head may be salvagable too. a skilled machinist should be able to straighten it, i think, and plane it again. so that the bottom is parallel with the top. this will work as long as the thinnest part is thicker than the minimum thickness. it is possible too that the cam towers can be made to work too, but this i am not sure of.

my machinist and i had this discussion before but i cannot remember about the towers.

good luck.

tom w

vox_incognita · #9 12-05-2006, 06:06 AM

IS it a w114?
Yes,they`re available as a set,and thre is a note "up to ...from engine N-r"
http://www.detali.ru/cat/oem_mb2.asp?TP=1&F=114010&M=114%2E920&CT=M&cat=034&SID=01&SGR=001&SGN=01
http://www.detali.ru/cat/oem_mb.asp

ctaylor738 · #10 12-05-2006, 07:36 AM

Who knows? A good dealer parts department will be able to tell you.

I recommend that you call Mike Elias, the manager at Metric Motors in CA. He has been very helpful to me on questions like this. I think that they are www.mercedesengines.net or something like that. Phone number is 800-622-6867.

cth350 · #11 12-05-2006, 08:39 AM

If your towers have been milled, chuck them and get a new or used set.
Benz goes to great lengths to make the cam tower system work, it relies on both surfaces of the head being flat and the towers being true. Heat and over torquing can mess that balance up, so don't over-do things and get the new head milled by somebody that knows what they're doing and you should be OK.

-CTH

PS. If you have the upper surface milled, be prepared to shim the towers to account for the now "longer" chain and also be prepared to replace the 12 little thrusters with thinner or thicker ones to account for the changes.

t walgamuth · #12 12-05-2006, 09:13 AM

Quote:

Originally Posted by ctaylor738

Who knows? A good dealer parts department will be able to tell you.

I recommend that you call Mike Elias, the manager at Metric Motors in CA. He has been very helpful to me on questions like this. I think that they are www.mercedesengines.net or something like that. Phone number is 800-622-6867.

i concurr that mike at metric is very knowledgable and willing to help. i have also bought parts from him that nobody else keeps around like glow plug chamber shims and subtle things like that that are required to do a head or engine job correctly.

if i ever buy a complete unit refurbished it will be from metric because of mike.

tom w

rgnprof · #13 12-08-2006, 08:41 PM

I received my eBay bought cylinder head today - slightly different cast number and it says 280 S/A instead of 250A- which is stamped on mine. But all the passages are the same, everything looks the same except for the cylinders. On mine the cylinders are cupped out a little bit and on the new one I just got the cylinder head is flat around the cylinders/valves resulting in lowered cylinder capacity in cc's.

I called Mike Elias at Metric Motors and he was very helpful. I gave him the casting numbers and he said the heads were interchangeable, but I am wondering at how big a difference this will have on my block. If I am understanding all of this, lowered cylinder capacity means the engine will now be running at higher compression - is that right? Or do I have it backwards? And if so, what are the risks to the old pistons etc.?

The head looks like it is in very good shape - I measured the height in several places all reading about 85 mm - which is what it is from the factory when new. I think I have plenty of stock. There is some corrosion around some water passages between a couple of the cylinders, so I am a little concerned about that.

I still need a set of cam towers (still hoping the eBay seller comes through, but...). Mike had a set for $180 but I sure would like to find a cheaper set - I only paid $50 for the head.

If anyone has a set, let me know. I don't think I can reuse my old ones...

Ryan

t walgamuth · #14 12-08-2006, 10:34 PM

smaller combustion chambers do indeed give higher compression ratio.

you can measure the capacity and calculate the compression ratio. take a measuring device and measure the liquid necessary to fill each combustion chamber with the head upside down and level. if you have flat top pistons that are even with the top of the cylinder it is easy. if the piston tops are not flat it is more tricky. if you have questions i suggest scoping out your facts and reporting back so we can help you sort it out.

good luck

tom w

rgnprof · #15 12-22-2006, 03:19 PM

OK, a quick update. The ebay seller was able to track down the cam towers and the camshaft from the head that I had previously purchased from him and sent them both to me today. So now I have the head and the camshaft and cam towers. Everything seems in very good shape - I don't think the head has been milled - with my micrometer it is measuring about where a new head would measure - approx 84.8 mm.

The camshaft and towers look good - my question is do I use my old camshaft with the new towers? I'm not real sure which parts wear together and should be replaced together. The new head did not come with any of the rocker arms, but did come with all the springs and cam followers/lifters and valves still installed.

I haven't yet pulled the head - I'm still getting around to it - going to check the compression and do a leak down test first.

Ryan