my M110 performance build thread

[odl21]

Hi,
I thought I'd share the progress of my build of a high performance M110 engine. Hopefully I may also gain some pointers on bits I need.

I have high mileage '78 core engine that i'm building to this spec:

1) dblias cams, timed in with offset woodruf keys
2) titanium flat valves
3) 260# valve springs with titanium retainers
4) CP custom forged pistons based on euro spec dome
5) carrillo custom rods (longer)
6) 0.75mm copper head gasket
7) triple weber 40 carbs on a hand made intake manifold
8) head ported, in particular smoothing of the intake port and matched to intake
9) custom ARP head studs
10) 1mm bore increase
11) crank offset ground 3mm to increase stroke - final capacity = 3025cc
12) lightened flywheel and all balanced with knife edged crank weights

my current calculations make the US spec engine actually about 7.44:1 compression ratio and mine will be 10.29:1. should make power to about 8500rpm with good torque. not sure on the power but guessing about 260-270hp.

this is going in my w123 coupe which has a close ratio 5 speed transmission and custom made low ratio limited slip diff. the car weighs about 1050kg.

still thinking about the distributor but currently planning stock with a crane CD ignition unit. i'm not too happy about the complicated mechanical drive for the distributor and oil pump and would ideally replace it with a crank trigger and dry sump oil setup. also hoping to make some kind of windage tray if space permits.

anyway, parts i need if anyone can help are:
a) flywheel
b) distributor and drive housing
c) water pump housing
d) vibration damper
e) crank and water pump pulleys
f) a good cam box with healthy bearings (one bearing was burnt out in my core engine).

i'm currently at the stage of having the engine stripped down and having measured everything for the compression calcs to allow the ordering of custom parts and am ready to have the crank and block hot tanked and machined.

i've stripped the head, cleaned and blasted it and am ready to start work on the head grinding. sonic checked the cylinder bores for thickness and figured out what valves and valve springs to use.

i've sourced all new 12.9 hardware or ARP bolts for every fastener including ARP flywheel bolts (for a ford pinto 2 litre!). also have one the fancy AMG valve covers.

designed and specified a new oil filter arrangement to take a standard large 13/16" spin on filter and use -12 braided hose for the oil return line from the head.

not managed to find a bearing to use for the smaller rod journals yet but i'm sure a call to clevite will solve that.

i'm pretty surprised how big the stock inlet valves are. no reason to go bigger, even with larger capacity and higher revs i think. also the general design and 'beefyness' of the engine is pretty impressive.

[fha772]

That sound's pretty impressive, I shall be watching this thread with great interest.

What gearbox are you using?
I'm toying with the idea of fitting a Getrag box out of a 190E 2.5-16V, at the moment.

[odl21]

Update on rod bearings. The merc journals are an odd size - very wide for their small diameter. In the entire 872 page clevite catalogue, the only thing suitable for about 3-3.5mm reduction in journal size was from a 1920's 2.0 petrol tractor! Anyway - 6 of them are on order and should be with me in a little over a week.

[oldsinner111]

Old21 why did you increase stroke?Most people destroke for more power.

[odl21]

Because the stroke is very short by default and I can't increase the bore by more than 1mm. It's hard to get the compression I need without the extra capacity. It's not going to rev that high and the new internals are significantly lighter. I'm also using a longer rod to reduce side forces so the extra stroke shouldn't cause an issue.

[E36T]

I did something similar (without the extra bottom end work - just new rings) some years ago, and used a Megasquirt EFi and motorcycle throttle bodies (GSX-R11, iirc).

Quite a bit of head work, cams, custom exhaust, crank trigger... Estimated ~245hp once done. Certainly much more than standard, and still nice to drive.

I toyed with the idea of carbs as I had 4 pairs of Weber 40DCOEs available (only needed 3, obviously!) but went with the EFi as it was new to me and offered a chance to do something a bit different. The carbs were a fall-back position that I didn't need to use.

The M110 (especially in a coupe) is a great engine, and definitely worthy of this sort of work.

Good luck!

[Woody Worker]

Originally Posted by odl21

Hi,
I thought I'd share the progress of my build of a high performance M110 engine. Hopefully I may also gain some pointers on bits I need.

I have high mileage '78 core engine that i'm building to this spec:

1) dblias cams, timed in with offset woodruf keys
2) titanium flat valves
3) 260# valve springs with titanium retainers
4) CP custom forged pistons based on euro spec dome
5) carrillo custom rods (longer)
6) 0.75mm copper head gasket
7) triple weber 40 carbs on a hand made intake manifold
8) head ported, in particular smoothing of the intake port and matched to intake
9) custom ARP head studs
10) 1mm bore increase
11) crank offset ground 3mm to increase stroke - final capacity = 3025cc
12) lightened flywheel and all balanced with knife edged crank weights

my current calculations make the US spec engine actually about 7.44:1 compression ratio and mine will be 10.29:1. should make power to about 8500rpm with good torque. not sure on the power but guessing about 260-270hp.

this is going in my w123 coupe which has a close ratio 5 speed transmission and custom made low ratio limited slip diff. the car weighs about 1050kg.

still thinking about the distributor but currently planning stock with a crane CD ignition unit. i'm not too happy about the complicated mechanical drive for the distributor and oil pump and would ideally replace it with a crank trigger and dry sump oil setup. also hoping to make some kind of windage tray if space permits.

anyway, parts i need if anyone can help are:
a) flywheel
b) distributor and drive housing
c) water pump housing
d) vibration damper
e) crank and water pump pulleys
f) a good cam box with healthy bearings (one bearing was burnt out in my core engine).

i'm currently at the stage of having the engine stripped down and having measured everything for the compression calcs to allow the ordering of custom parts and am ready to have the crank and block hot tanked and machined.

i've stripped the head, cleaned and blasted it and am ready to start work on the head grinding. sonic checked the cylinder bores for thickness and figured out what valves and valve springs to use.

i've sourced all new 12.9 hardware or ARP bolts for every fastener including ARP flywheel bolts (for a ford pinto 2 litre!). also have one the fancy AMG valve covers.

designed and specified a new oil filter arrangement to take a standard large 13/16" spin on filter and use -12 braided hose for the oil return line from the head.

not managed to find a bearing to use for the smaller rod journals yet but i'm sure a call to clevite will solve that.

i'm pretty surprised how big the stock inlet valves are. no reason to go bigger, even with larger capacity and higher revs i think. also the general design and 'beefyness' of the engine is pretty impressive.

I've got many of the parts you're still looking for I think, except the flywheel I sold that with the 5 speed GETRAG 717.402 that the car was equiped with, I'll have to dig through my storage to be sure. I kept most everything except the block from a 1984 Euro FI 185 HP 280SE, I've got the complete cylinder head and the set if high compression pistons and rods. I'm pretty sure the engine designation was M110.989. You can PM me if you think of any other parts you're looking for, and I'll PM you once I find out exactly what I still have.

[odl21]

Hi woody, I've actually found all the parts I need now. Just waiting for some custom parts before short block assembly starts.

[Woody Worker]

Originally Posted by odl21

Hi woody, I've actually found all the parts I need now. Just waiting for some custom parts before short block assembly starts.

Cool, good luck it will be interesting to see where you can get to with your project, and how fast you'll get once it's complete!

[odl21]

longer h beam forged con rod from carrillo. 480g vs 780g for the Mercedes rod.

[odl21]

Arp main studs from a ford pinto are the correct fit. Obviously need 2 sets (or 3 to do 2 engines). Arp head studs were also available without needing to be custom made.

[E36T]

Originally Posted by odl21

Arp main studs from a ford pinto are the correct fit. Obviously need 2 sets (or 3 to do 2 engines). Arp head studs were also available without needing to be custom made.

Thanks for the update. Very useful info.

[JUNAID786]

I was also under the impression that a shorter stroke will allow an engine to rev up more freely. I do understand that the lighter rod could compensate for that. What about the rev limiter? What's your max rev going to be and how you going to do it?Is there any distinct advantage of the weber carbs over the mfi? Will you be using the stock fuel pump? If so how are you going to get the fuel pressure down for the carbs?

[Frank Reiner]

odl21:

Would you mind sharing the dimensions of the con rods; big end bore, small end bore, and center-to-center length?
And what will be the finished rod journal size and the stroke?

[odl21]

NASCAR casidiam dlc coated wrist pin. 77g vs 136g for the Mercedes pin.


Nice new genuine weber DCOE 40.