M115 200 head into a M115 230 bottom - PeachParts Mercedes-Benz Forum

Takernz_30 · #1 02-27-2009, 09:03 PM

I got a used M115 cylinder head off from '68 200, it passed pressure and crack tests, it's thickness is good for 2 rebuilds. Yesterday, I passed by a car repair shop and had the sign hanging and says FOR SALE: Mercedes engine (short-block), I pulled over and talked to a owner of the shop, when I saw it, it was a M115 short block off from W123 sedan. The owner of the shop says the block had new bearings (cranks and con rods), con rods, 2nd repair-sized piston rings, 1st repair-sized crankshaft on all journals and resurfaced flywheel, as he showed to me the receipts of parts and machine shop costs, it's cylinder head was irrepairable. So,the shop owner said that the owner of the engine gave it to him as a payment of bills. The short block priced at Php25,000(US$ 510), it was fairly priced for a newly-rebuilt short block, the shop owner also provided the camshaft, rockers and cam towers, and papers but he advised me to replace all valves.

Now, I ask you guys, Is it possible to put a 200 cylinder head into a 230 short-block?

roldan from Philipppines

250 Coupe · #2 02-27-2009, 09:11 PM

Can't help you with the 4 cylinder engine but I mixed a six cylinder head and block combo in my 1970 250/8 and the cam was a half tooth off no matter what I did. The car ran but I'm not sure replumbing the oil cooler lines and what not was worth it.

Michael

Takernz_30 · #3 02-27-2009, 09:20 PM

Quote:

Originally Posted by 250 Coupe

Can't help you with the 4 cylinder engine but I mixed a six cylinder head and block combo in my 1970 250/8 and the cam was a half tooth off no matter what I did. The car ran but I'm not sure replumbing the oil cooler lines and what not was worth it.

Michael

ok, what combo you did? 250 head/280block or 250 block/230 head? also, what cam from these engines did you use?

ja17 · #4 02-27-2009, 09:55 PM

Hello,

Most likely not a good match. The 230 head is shaped a bit different on the spark plug side and has an extra row of head bolts on that side. Take the head gasket from the 230 to make sure and place it against the 200 head. You will see all the problems.

250 Coupe · #5 02-27-2009, 09:59 PM

It's been almost 15 years now and I don't remember exactly but I think it was the 2.5 head from the 250/8 and a block from an earlier car. It was also a 2.5 but either didn't have the oil cooler my car did or vice versa.

The original engine had thrown a rod so I bought an engine that needed valve work. I found that the original head would bolt right on the block I'd bought and everything hooked up as far as timing chain and carbs and such but the timing marks would not line up.

Another thing that comes to mind is that the combustion chambers might be different between the two models you are looking at and may cause a incorrect compression ratio. That could also be why I never got the power out of the engine that I expected.

Michael

Takernz_30 · #6 02-28-2009, 03:04 AM

Quote:

Originally Posted by ja17

Hello,

Most likely not a good match. The 230 head is shaped a bit different on the spark plug side and has an extra row of head bolts on that side. Take the head gasket from the 230 to make sure and place it against the 200 head. You will see all the problems.

Like I said M115 200, I think you're referring to M121 200. M121s have 10 head bolts while M115s have 14 (10 M12 + 4 M10). The bolts you're saying are the 4 M10 bolts lined up just above the plugs. The shape of combustion chamber holes of these 2 engines are the same, also some parts of M115 are interchangeable with M121, even 621,615 diesels.

ja17 · #7 02-28-2009, 07:51 AM

Hello,

Yes, I was referring to the earlier M121 engines. In the USA we never had Mercedes 200 engines in 1968. The 200 series engine ended in the Mercedes Finback sedans. I know Mercedes built 200s in the W114 sedans in other countries.

So I guess the question goes unanswered at this point. I would tr setting the 230 head gasket on the 200 head to see what does or does not line up. The compression ratio is cast on the cylinder head below the head casting number. Compare both ratios. You can also "cc" the combustion chambers of each head to compare the compression ratios.

My biggest concern would be that all coolant passages align and the combustion chambers are the same shape so that the gasket seals.

Takernz_30 · #8 02-28-2009, 11:03 AM

Quote:

Originally Posted by ja17

Hello,

Yes, I was referring to the earlier M121 engines. In the USA we never had Mercedes 200 engines in 1968. The 200 series engine ended in the Mercedes Finback sedans. I know Mercedes built 200s in the W114 sedans in other countries.

So I guess the question goes unanswered at this point. I would tr setting the 230 head gasket on the 200 head to see what does or does not line up. The compression ratio is cast on the cylinder head below the head casting number. Compare both ratios. You can also "cc" the combustion chambers of each head to compare the compression ratios.

My biggest concern would be that all coolant passages align and the combustion chambers are the same shape so that the gasket seals.

oh yeah I forgot that M115 200 never offered in US but the 230 does, this is because of emissions. M115 200 are plenty in the Philippines, I never had the chance to see the irrepairable head to compare with my 200 head because the 230 head was already in the scrapyard when I got there.

Is cylinder head gaskets would be best to compare bet 200 and 230 engines?

Takernz_30 · #9 03-06-2009, 12:09 AM

I went to the repair shop where the M115 whole bottom for sale, I tried to fit a 200 head into a 230 bottom with head gasket from 200, it did fit all the 14 bolts are in! I was able to obtain a service manual for M115 and it says that 200 and 230 heads have the same compression ratio 9:1 for euro spec cars only. 220 is different as having longer stroke than 200.