Project: Iron block 5.6 - Page 6 - PeachParts Mercedes-Benz Forum

rwd4evr · #76 08-15-2016, 02:09 PM

Hey tony! I couldn't remember your handle here and BW is so messed up lately.Glad I found you.
So the 5.6 heads have slightly different head bolt placement? I'm working on a 4.5 manual slc for a track day/lemons car possibly and have a couple 5.6 plus a bunch of 4.5 engines to pick parts from. Not trying to jack your thread, but check mine out and throw some of your expirience my way if you can!

http://www.peachparts.com/shopforum/performance-paddock/380094-m117-cam-specs-head-differences.html#post3627185

http://www.peachparts.com/shopforum/performance-paddock/379765-1978-450slc-super-beater-lemons-race-car.html

Tony H · #77 08-17-2016, 09:26 PM

yea I'm still here. My engine project is on hold for now since we are building a house in Nevada. The 5.6 heads will fit an iron block with some machine work but they will decrease the CR on a 4.5 since they have larger combustion chambers. If you have any specific questions I will try to answer them.

rwd4evr · #78 08-18-2016, 04:13 AM

Well I don't want to lose compression at this point. If a turbo comes along eventually I'm ok with 5.6 heads for better flow. Really just want to know about cam specs. I have '73 DJet US motors,117.982/984 I believe, one sel one slc plus another torn down sl. 78/79 kjet 117.985 and an alum 116.9xx 3.8 US TURD. Plus two 5.6 U.S. Motors available for parts. My 4.5 117.985 kjet in the car will be aimed at high revving. Manual trans makes it much more livable and it's not a street cruiser at all. I just want the best cam and head combo I can put together. Highest compression and bigest lift/ duration. I'm thinking of retarding the cams for top end power. I will prob do a little port work if I end up changing heads.

Tomguy · #79 08-18-2016, 11:45 AM

Quote:

Originally Posted by Tony H

yea I'm still here. My engine project is on hold for now since we are building a house in Nevada. The 5.6 heads will fit an iron block with some machine work but they will decrease the CR on a 4.5 since they have larger combustion chambers. If you have any specific questions I will try to answer them.

Will they fit on a stock 4.5 block that hasn't been bored over? Or would the valves hit the deck (or the bores)? It may have been answered back in the thread further, but it'd be nice to see clarification for sure

Frank Reiner · #80 08-18-2016, 02:52 PM

Quote:

Originally Posted by Tomguy

Will they fit on a stock 4.5 block that hasn't been bored over? Or would the valves hit the deck (or the bores)? It may have been answered back in the thread further, but it'd be nice to see clarification for sure

The valves in the 5.6 heads, IN 46.2mm, EX 39mm, will clear a 92mm bore.

rwd4evr · #81 08-18-2016, 03:09 PM

no wonder they dont make much power. all except the very worst small block chevy heads had 1.94?1.50(49.2/40.64mm)and the good ones had 2.02/1.60(51.3/40.64). forced induction is the way to go i guess. shame there isnt an affordable agressive cam set available. now i see why the m119 makes so much more power from a nearly identical emgine. the 5.0 versions are almost 80 hp apart!

rwd4evr · #82 08-18-2016, 03:32 PM

honestly i don't think i would be bothering trying to get more power from a m117 iron block if i didn't get this perfect beater/lemons car with a manual trans setup ready to go more or less(well less really!). gotta clean the tank and get a slave cyl to see how it really runs before i get too crazy i guess. How about m119 heads on an iron block!?

Tony H · #83 08-19-2016, 03:58 PM

I spent a lot of time comparing various cams (Pick n Pull specimens) from 3.5/4.5/5.0/5.6 engines trying to determine what the best choice for my project was. Without going into great detail the general theme is low duration, low lift, the later the engine the more retard and higher LSA-basically motorhome cams. All the cams are retarded quite a bit-especially the 5.6 ones. The best stock Hydraulic cams I could find from a possible performance perspective that are not obscenely expensive are the 02/03 cams from a European 500SL. They have the higher lift of the 5.6 cams and the longer duration/tighter LSA of the 3.5/4.5 cams. I bought a set of these with matched rockers from a fellow forum member.
As far as "performance" cams are concerned I don't think the valve train is robust enough for anything more than stock cams. I have read about noisy, maintenance intensive valve trains using performance cams for a few more HP. The most reliable way to more power is displacement so that is my concept with this project. For a dd that will spend 99% of it's time between 2000-4000 RPM I think it will work well :-)

Tomguy · #84 08-19-2016, 06:12 PM

I am excited to see what your hybrid of old-and-new-school iron block 5.6 will produce in terms of power. Please dyno it after break-in! Very interested to see. Also I'd love to know what it sounds and feels like. You may have a good engine build for 330 crank HP, or it may just be a mid to upper 200s. It may be a good revver, or it may not be. Only time will tell!

rwd4evr · #85 08-19-2016, 06:15 PM

Yes! That is what I've been trying to find out. For your application that sounds correct. My car will be mostly track driven and high rpm abused. When you say retarded do you mean just the intake or exhaust lobe or just in general? And are the 3.5 and 4.5 the same grind? If you have a spec sheet you drew up I'd still love to see it. I'll be running mechanical most likely. Maybe I can find a grinder for a reasonable price.

Tony H · #86 08-19-2016, 10:15 PM

Yea I have spent a lot of time day dreaming about getting my project on the road. I will have to put it in storage for about 1.5 years when we move early next year. The emphasis now is getting it on wheels so I can get it on a trailer. (I will start a thread about the air suspension conversion)
You have probably read all about other members experiences with custom cams-I don't think they are worth the trouble and expense for a small HP increase. When you regrind cams you change the base circle and valve train geometry. you can adjust it out but the rocker now pushes on the valve stem at a different angle causing valve guide wear. The valve train is so small on these heads they just won't accommodate any more lift.
All the cams I checked are very similar with only subtle changes-mostly how much they are retarded. Like I said the later the engine the more retard there is. I was pursuing having some adjustable timing gears made so I could play with the cam timing. It will be off anyway since I had the block decked .030 and the 560 head gaskets I have to use are .025" thinner than the 450 ones.
There used to be some cams ground from new blanks but I don't know what happened to them stage II cams for m117 motor - feind motorsports

rwd4evr · #87 08-20-2016, 12:25 AM

Sold out. Retarded would be better for top end power anyway correct? Y

Tony H · #88 05-24-2017, 11:30 PM

It's been a while since I have done anything with my project other than packing it up and putting it in storage since we are moving but I'm doing some armchair engineering. I'm trying to keep my project as straightforward as possible and I started thinking about my cylinder head choice(again). I had previously decided to use the 5.6 heads with their larger valves/ports and they will fit with some machine work but the downside is the large combustion chambers, the cooling/oil passages need to be matched, the long cam bolts don't line up and the accessories don't fit like the 4.5. I have some K-jet 4.5 heads and took a fresh look at what it would take to turn them into 5.6 heads. The valve guide basic bores are the same so no problem there. New valve seats are no problem and I have 5.6 heads to copy the port design. My concern is breaking through during porting. I'm thinking about experimenting with some junk heads before I go to the expense of new valves.

Tomguy · #89 05-25-2017, 01:04 PM

I wouldn't be surprised if the heads actually had the room inside without worrying about breaking through. The only way to know for sure would probably be to have them sonically examined which would likely cost more than a trip to a U-Pull-It to grab a head to experiment on.

Frank Reiner · #90 05-25-2017, 03:49 PM

Quote:

Originally Posted by Tony H

I have some K-jet 4.5 heads and took a fresh look at what it would take to turn them into 5.6 heads. The valve guide basic bores are the same so no problem there. New valve seats are no problem and I have 5.6 heads to copy the port design. My concern is breaking through during porting. I'm thinking about experimenting with some junk heads before I go to the expense of new valves.

Tony, it seems fair to note that the valve sizes and port area of the 4.5 heads will provide sufficient air flow for over 300HP, particularly with the cams that you have chosen (56/57). I may be mistaken, however, information at hand says inlet valve diam. > 44.2mm(1.74"), exhaust > 39mm(1.54"), inlet port @ manifold > 41mm, exh. port > 34mm.
Why did the 5.6 engine receive larger valves, most notably the inlet? As you have pointed out, the valve timing has been retarded (and shortened), again most notably on the inlet, which results in rather fewer degrees of valve open time while the piston is descending on the inlet stroke. To compensate, an increase of flow area has been provided.
The 56/57 cams open the inlet sooner, are longer, and quite importantly, have lobe centers that are 16 degrees closer than the 18/19 cams of the 5.6 (104 vs. 120). The close lobe centers provide a big overlap flow increase, along with higher velocity, without requiring a larger valve.
A bit of careful cleanup work on a flow bench is likely to yield good results.