M116 Heads on an M117

[SELfor50]

Here you go folks, an example of M116 heads on an M117.

According to the owner, the M116 manifolds wouldn't fit properly so there's been some custom work done there....
MB Spares have confirmed though, that you should still be able to use any of the V8 merc manifolds to bolt on / interchange. (this confirms who will be doing the work for me)

This car has also had the M116 cams 're-profiled'. Can't remember who by, but the same mob will be doing this for me... But instead of mild, i'm gonna go slightly 'wild'.

From someone who did this 'mod' about 20years ago.. He confirmed that it livened it up a great deal, and for 'bang for buck' while retaining that solid german reliability, it's the way to go!








Not much to see of the heads, but they're M116, early d-jet heads with the mechanical lifters. Best of the bunch apparently.

Thoughts?

 

[WGB]

126 V8 manifolds have those type of joints in their manifolds don't they?

Bill

 

[SELfor50]

Couldn't tell ya... though wouldn't suprise me.

MB Spares said that all v8 manifolds are interchangeable.. maybe someone gave him the 350heads and just grabbed those manifolds off the pile and threw them in?!

I'll confirm with John Green sometime in the next couple days..

 

[oscar]

You can pretty much ignore my last email Cam, I think your first post has answered a lot of my questions. But I noticed he's put the M117 rocker covers back on. (air filter mounts). I suppose don't throw anything away.

 

[Michel]

Couldn't tell ya... though wouldn't suprise me.
MB Spares said that all v8 manifolds are interchangeable.. maybe someone gave him the 350heads and just grabbed those manifolds off the pile and threw them in?!
I'll confirm with John Green sometime in the next couple days..

Cam,

I know you don't want to hear that, but you're barking up the wrong tree.

Too much hassle for hardly any gains...
Rather than this... find a way of producing extra horses quick ... and cheap

 

[Mercules]

Assuming the different heads will give a different compression ratio - what will be the increase??? Does this guy have any before/after dyno runs to backup his claims... I think if i was going to the trouble of swapping heads and cam i would want something to stand on

Cam

 

[SELfor50]

Hmmm... a few people have already suggested that Michel.. But it may not be that much work.
He doesn't have any before / after runs.. But I might ask him to put his beast on the dyno next time i'm back there to show me the difference. As it was done about 20yrs ago, he said he hadn't thought about it till I rang up the other day.

But yeah... I'm not gonna be going completely ahead on this until i'm back from over seas in 6months time.. and even then it won't be unless i've got my full research / figures done.

If the compression ratio is increased though, does that not make better combustion / output etc? (this is something i have no idea about!!)

 

[Mercules]

Hmmm... a few people have already suggested that Michel.. But it may not be that much work.
He doesn't have any before / after runs.. But I might ask him to put his beast on the dyno next time i'm back there to show me the difference. As it was done about 20yrs ago, he said he hadn't thought about it till I rang up the other day.

But yeah... I'm not gonna be going completely ahead on this until i'm back from over seas in 6months time.. and even then it won't be unless i've got my full research / figures done.

If the compression ratio is increased though, does that not make better combustion / output etc? (this is something i have no idea about!!)

Increasing compression ratio, in conjunction with the right fuel and ignition timing, will definately result in more power - turbocharging and supercharging are both ways for atmospericaly forcing your comp ratio higher... nitrous is a chemical method of increasing your comp ratio - but the traditional way is to skim the heads, fit heads with a smaller combustion chambers or pistons with a flat/domed crown.

 

[SELfor50]

Ok... so if the M116 heads have the smaller combustion chamber.. and with a slightly more agressive cam in there and the right tuning. There should be a result of more power yeah?.

 

[SELfor50]

Or would I maybe be better off just skimming my current heads to avoid the hassle of the swap??

 

[B13]

See if you can get a "lend" of a W116 head...

Then dig out one of your spare M117 heads you bought off evil-Bay.

turn both upside down and using a measuring cup and an eye dropper, fill one combustion space with fluid... say cooking oil... until its just about to overflow.

Start with a measuring up of say 250ml... if it takes (say) 125ml to fill a M117 chamber, and only (say) 100ml to fill a M116 chamber, then you are on your way to increasing you compression ratio. You measure the capacity of the combustion space by subtracting the remainder left of the original 250ml....

I believe this is called CC-ing, and engine modifiers use it when modifying heads for performance...

Mercules am I on the right track or not?

Ian.

 

[WGB]

What goes under the heading of 116 and 117 motors is a vast smorgasbord of different motors from 1960's to the 1990's.

Those exhaust manifolds definitely look like 126 items to me and that could mean the heads are M116 off a 350 fitted with 126 manifolds but equally they could be M116 heads off a 420SE fitted with their own manifolds.

Equally M117 motors go from 450 up to 560 models with presumably many different heads/camshaft/ancillaries combinations.

Bill

 

[B13]

Thanks Bill.

To clarify, when Cam talks about a M116 cylinder head he's referring to a D-jet one as fitted to a 280SE 3.5, 300SEL 3.5, or 350SE 1971-1975.

When he mentions a M117 engine for the purposes of this thread, he refers to a K-jet 1978 euro-spec engine, as fitted to a 450SE, 450SEL or 450SL/C 1978-1979.

 

[Mercules]

See if you can get a "lend" of a W116 head...

Then dig out one of your spare M117 heads you bought off evil-Bay.

turn both upside down and using a measuring cup and an eye dropper, fill one combustion space with fluid... say cooking oil... until its just about to overflow.

Start with a measuring up of say 250ml... if it takes (say) 125ml to fill a M117 chamber, and only (say) 100ml to fill a M116 chamber, then you are on your way to increasing you compression ratio. You measure the capacity of the combustion space by subtracting the remainder left of the original 250ml....

I believe this is called CC-ing, and engine modifiers use it when modifying heads for performance...

Mercules am I on the right track or not?

Ian.

Pretty much bang on the money Ian... there is a trick to it (and some special tools that make it much easier) but but as long as you are consistant in your testing it can be done at home.

I reckon if you could find a mechanic somewhere with experience building these engines he would be able to tell you the combustion chamber volume for both head types!

Anyone?

 

[John S]

Get a piece of clear plastic about 5mm thick, and drill a small hole near the centre. Place that over each head space you are measuring and meter the water into the head space through the drilled hole. This will keep any variations in measuring technique down to a minimum. You will probably need to swipe a little petroleum jelly on the joining faces face to seal the Aluminium / plastic contact point.

 

[SELfor50]

Thanks for that everyone!! I don't have a set of M116 heads at the moment to conduct the tests, but i'm guessing that the MB bibles that hold all the information regarding tech specs for these engines should detail it down to a t right?

You know those little blue bibles that MB Mechanics have?

Would I be looking for 'combustion chamber' volume if I had one of those books?

 

[John S]

Combustion chamber volume includes the volume left by the piston (when it is at the top of its stroke) and the top of the block. I have seen volumes of cylinder heads listed for Fords and Chevs, but not Mercedes; however if the cylinder head is off you can measure from the piston to the block and calculate that volume to take that from the combustion chamber volume - the difference is the head volume.

 

[Styria]

Well, well, well -- nostalgic thread and posts to the 'nth degree. JohnS, SEL for50, WGB, Oscar (Ossie as he is known to me), B13 in Melbourne, Mercules and, NOT TO FORGET OUR IMMORTAL PRINCE OF ARABIA - still with us of course. Regards Styria