2.5-16V Head Damage / Rebuildable - PeachParts Mercedes-Benz Forum

dbenz · #1 02-25-2004, 06:01 AM

Looking for some advice!

Time to take all the parts I have and either build a HOT non-turbo 16V engine or sell the parts and stuff a 400hp US engine in my second 190E 2.3-16V with a 6-Speed. Right now I'm leaning towards the 16V route just because I think remaining with the original type engine would provide a much better handling car.

First item up for discussion is the Head. This goes to show that not all failure is due to chain/tensioner problems.

Intake camshaft lubrication failure caused it to camshaft to break. Good thing is that it did not produce and valve damage when it broke. Just did not run to good on two cylinders.

See attached photo of the damaged head. Can’t seem to make it work. I’ll try it later again.

Here are my questions.

1. I want to install hotter camshafts in the engine. I have a set of 2.3-16V camshafts. Is it possible to regrind them in order to produce what I want, or best just to purchase hotter camshafts?
2. Is this head repairable – build up and line bore for the new cams?
3. Would like to increase the lift of the intake valves, as it was done on the EVO II from 10mm to 11mm. Possible? Worth the effort?
4. Have a set of EVO I pistons that I would like to run with an 11:1 compression ratio. (97.3mm diameter)
5. Head ported, if repairable, to accommodate larger pistons and increased displacement.
6. Have a brand new 2.5-16V Crank. Wife thought I was crazy when I picked it up in Germany back when the EUR was weak. Anyway, it has 4 counterweights, unlike the 2.3-16V. Want to run lightweight rods (<500g each) and reduce the rotating mass by knife-edging the crank. Crank has a stroke of 87.20 mm giving the engine a displacement of 97.3 x 87.2 = 2594 ccm.
7. Do the 91-93 190E 2.3’s use a double timing chain? I would like to stay with the double chain of the 2.5-16V for reliability but only have the head from that engine. Have tons of 2.3-16V engine parts but they are all single chain. Could convert to single chain like the EVO II engine. I hear the 2.5-16V cranks fit in the later 2.3 (non 16V) blocks at least according to Bekkers.

I have other stuff that needs to be discussed. But this should get the ball rolling on the engine build questions that I have.

Thanks for all the help -- dbenz

mbdoc · #2 02-25-2004, 08:09 AM

When MB raced the 16V engine they could manage about 250HP & that was from the "EVO" engines. YOU will spend a bunch of $$$ trying to get that type of HP & the engine will become VERY un-realiable. THE biggest problem is OIL delivery. THE oil pump in the front cover just won't keep up with demand.

Jim Villers · #3 02-25-2004, 11:59 AM

dbenz ....... If you want to stay with the current engine, I would go with a turbo or supercharger verses the stroker/custom cams/high compression setup. Almost everything for this engine is custom and expensive. Whichever direction you head, think about converting early to a modern digital engine management system with electronic fuel injection.

For about the same money, you could probably drop a 5.0L Ford into the car and it would have significant more potential.

Glen · #4 02-25-2004, 12:31 PM

Jim,
Have you had a chance to dyno tune your car with the new injectors?

re: digital EFI...I really wish California would change it's position on modifying stock engines in relation to emission control systems. Currently, we are not allowed to change from stock even if said change would improve emmisions!

I wish I could run an aftermarket EFI system and verify emission output at an independent or state run testing facility...

Glen · #5 02-25-2004, 12:59 PM

David,
re: stroking the 2.5 crank...it's already ~7mm longer than the 2.3, and with 97.3mm pistons you'd be at 2.6 liters...how much displacement do you want?

Also, correct me if I'm wrong, but the engine is already over-square...by a good margin. Lengthening the stroke by 5 or 10 mm will make is LESS over square but still over-square (barely at 10mm). It's my understanding that, IN GENERAL, over-square engines like to rev and make power at higher RPMs, while under-square engines make more torque at lower RPMs. Obviously, there are exceptions...

Personally, I think it makes more sense to build a forced induction engine based on mostly stock components. My reasoning is that WHEN something breaks, it's easily replacable without having to go through a bunch of re-machining...my $.02.

dbenz · #6 02-26-2004, 01:25 AM

Hi M.B. Doc, Glen and Jim,

Thanks for your replies.

- Jim, right now I have a lot of extra parts that I have collected over the last 5 years that I would like to turn into an engine. The plan is to definitely go to a digital engine management system with knock control, that’s why I feel like I should be able to bump up the compression a little.
- Glen your right about the over-square. I deleted that portion from the original post, thanks for keeping me in line.
- MB Doc, after your comment I looked up to see what Mercedes did different on the EVO II engine and they used an oil pump that I think from a diesel, and then driven by a separate chain off the crank. The pump housing number is 602 181 00 01, that’s what makes me think it’s from a diesel engine. Would have to look at the bottom of the block to see how difficult it would be to recreate.

I realize that right now the trend seems to be to put forced air on almost everything and I have not ruled that option out. If I go with that option I still think it’s worth spending some money on machine work to ensure a good breathing engine with minimal rotating mass, even though with a turbo it’s less critical.

Question: Do the later model 2.3-liter engines use a dual chain?

Goal is a 225hp+ car with weight of less than 2600 lbs. Looking for manual window crank mechanisms and a roof clip or complete non-sunroof 190E parts car. May be a hard thing to find here in the US but you never know what is sitting around.

Still in the planning process, but that’s how all projects start –

David

Jim Villers · #7 02-26-2004, 08:59 AM

Glen .... After installing my larger injectors, I have only had one dyno session to work on adjustments. I first set the map for non-boost and then worked on the boost parameters. The settings resulted in 11:1 fuel air (VERY rich) in the upper RPM's and I didn't have time to go back and readjust the fuel map. The engine was producing 170 HP at the rear wheels at 5500 with a falling torque curve. Torque began falling as the F/A went below 12:1 at 4500. I decided to just go with those settings as safe and VERY conservative. I had burned pistons on previous outings and I did not want to do that again.

The 170 rear wheel horsepower is equivalent to about 212 horsepower at the flywheel. I have recorded as high as 179 HP and feel that 180 HP should be a reasonable tuning goal (225 flywheel HP).

I'll keep you posted.

Itgb · #8 02-28-2004, 01:12 AM

Quote:

The 170 rear wheel horsepower is equivalent to about 212 horsepower at the flywheel. I have recorded as high as 179 HP and feel that 180 HP should be a reasonable tuning goal (225 flywheel HP).

Jim,

Why use such a high driveline loss pecentage? From your numbers it's about 19%. I've heard more around 17% as the norm for manual transmission RWD. I am going to dyno my car next weekend(trying to break the 150 rwhp & tq barrier) and the site that is putting on the event uses 16%. Just curious.

Giancarlo

Jim Villers · #9 03-02-2004, 10:21 AM

Giancarlo ..... You can use any ratio that you feel comfortable with. 20% is just the rule of thumb that I had picked up. It is just a way to approximate the improvement above "advertised" numbers. My 16 valve had 128 rear wheel horsepower before any of the modifications.

pentoman · #10 06-01-2006, 12:09 PM

Quote:

Originally Posted by M.B.DOC

When MB raced the 16V engine they could manage about 250HP & that was from the "EVO" engines.

Not sure where you got that.. but Cosworth originally designed the engine to produce 320bhp. In race trim the very last models produced up to 400-420bhp, with a poor idle and very high revs though!