A little advice, 616 engine N/G - PeachParts Mercedes-Benz Forum

Stevo · #1 11-04-2007, 11:19 AM

The 616 parts car engine I have installed has low compression as it "almost" started when I added some oil to the cylinders. So I am pretty sure its rings DOH!! I think I'll squirt some Marvel Mystery oil in and let it set a while but I need some advice on an "alterant" plan.

I have rebuilt a couple of these 616 engines but buying new pistons and having the block re sleeved is easy compared too making decisions about used parts. I have a few "parts" engines around including a block with almost no "ridges" and three good piston sets plus one more good piston, a couple good cranks..you see where I'm going. I was thinking of taking pistons and block too the machine shop (good shop where I have had other work done) and have them check my measurements and make sure they can match the "odd" piston and rod to the rest. I'm hopping all they will need too do is re sleeve after checking my assessment of the used parts. My question is "is this "mix and match" something thats not done?
The parts car engine with low compression had a leaking rear main seal (I know the mechanic that took care of the car) so I pulled the crank, replaced the seal, bearings, timing chain ect..so when I think about it, why not replace the block and pistons??

300SDog · #2 11-04-2007, 07:30 PM

Steve, probly you wanna talk to Tom Walgamuth at Indiana. He's built couple of these engines with used pistons successfully. Strikes me low mileage 240D spare engines are now gettin scarce.

kerry · #3 11-04-2007, 08:39 PM

I'd do a compression check and try to pull start it before deciding to rebuild it.

t walgamuth · #4 11-04-2007, 08:55 PM

I have used three from one and one from another engine used. You must measure them to see if they meet specs, if they all do then you will want to weigh them and match the one to the three, I believe. then you install the sleeves and match the sleeve size to the pistons. Be sure to follow the FSM recommended clearances. They are a lot tighter than most engines.

I have a good used set of 240 pistons for sale in parts if anybody needs them.

Also there are two slightly different sizes of pistons. I believe the number is stamped on the top of the piston.

Tom W

Ken300D · #5 11-05-2007, 07:21 AM

Considering the level of effort you are talking about in rebuilding the engine, maybe you should continue to try to get the car to start. After it has run some with good clean oil, the rings may free up, settle in and continue on just fine.

Have you adjusted the valves yet? I would set them a tad loose just to be sure they are seating the best they can. If they have been run tight, they may be either burned or not seating well.

Ken300D

t walgamuth · #6 11-05-2007, 07:42 AM

I agree with Ken.

Tom W

Stevo · #7 11-05-2007, 12:07 PM

Good feed back, yes, I agree starting the car if only too check out the body the engine has been transplanted into is the way too go(I know it will need shocks). Pull starting is an option. This engine is out of a car that had a fire in the cabin, gal got home from work went in the house for the evening and next morning came out too find her car toasted on the inside (electrical fire). Beautiful body (the car

), no dents, no rust, good tires. I knew the mechanic that took care of it for her, thats how I knew it needed a rear main seal. Point is, it was a daily driver and had better compression then. The car did sit around for over a year after I bought it ($300) So maybe there is hope that the rings could free up, I wonder what the chances are

I did adjust the valves, new timing chain, timed, rebuilt vacuum pump new clutch,P/p, lower end bearings. All this stuff can be transferred to the "new" block & pistons. After all how many times does one get to pull an engine that is clean, none of the bolts are going too break off, no surprises

The oil pressure comes right up when I crank it (new batt) , fuel comes out at the injectors fittings, it would light off if it had compression and putting oil in the cylinders resulted in "almost" doing so. Oh the compression test, I'll have too do it again. The gauge wouldn't "hold", it went up over 200#s but the needle would drop, after I buttoned everything back up I found a lose fitting on the gauge, DOH, another senor moment, but I really dont need a gauge to be pretty sure theres no compression. I may re do it today. Anyway thats the story on the engine, sorry too be so windy.

As too my "mix and match" idea, I wasn't sure if such a thing is done or not since I dont have a long time background of wrenching on these things. The block I have is from an engine that was "rebuilt" (I didn't do it

) and apparently the rings never "seated". The engine used a qt of oil every couple hundred miles and the woman just forgot to put oil in. I bought it when a "knock" developed and pulled the engine too find just the slightest "ridge" on # 1, and NO cross hatch marks on any cylinder walls

. Did they forget too run the hone in the cylinders and thats why the rings never seated?? Maybe the cylinders only need to be honed and new rings in std pistons. #1 crank journal and the rod are shot but no damage to the cyl wall. I really dont feel qualified enough to take all the measurements to determan what I need too know so...if the engine in the car doesnt free up its rings I think I should take the "new" block and pistons to the machine shop and see what they say. I know it sounds like allot of work and time involved but "whats time to a pig"

Tom could you tell me about the pistons you have in case mine dont work out? Hope all this makes a little sense.

Stevo · #8 11-05-2007, 07:44 PM

Fixed the leak in the compassion gauge and heres the numbers 245, 300, 240, & 270.

And just as I was getting ready to put the GPs back in an unsuspecting friend (MB person) dropped by and volunteered to "pop the clutch" as I towed it with the truck. She was running by the time we got to the end of the driveway. It started again after two hours, drove it around 9 miles, but the proof will be if she lights off in the morning. I may still do the mix and match rebuild

t walgamuth · #9 11-05-2007, 10:32 PM

That should be enough compression to give pretty good service and decent starting. The minimum cold is about 220.

What would you like to know about the pistons? My favorite machinist measured them and they will meet specs, or I would have tossed them. They are left over from a couple of motors that I got with broken rods.

They are from a 123 240 or 300 na (takes the same pistons). I think I am asking $100 plus shipping.

Tom W

kerry · #10 11-05-2007, 10:38 PM

Quote:

Originally Posted by Stevo

Fixed the leak in the compassion gauge and heres the numbers 245, 300, 240, & 270.

And just as I was getting ready to put the GPs back in an unsuspecting friend (MB person) dropped by and volunteered to "pop the clutch" as I towed it with the truck. She was running by the time we got to the end of the driveway. It started again after two hours, drove it around 9 miles, but the proof will be if she lights off in the morning. I may still do the mix and match rebuild

That's good news. Add your story to the list of those who couldn't get their engines started with the starter after sitting a while but which fired up with a tow.
Lets make a new commandment. If your going to store a 616 or 617 for a substantial period of time, store it at the top of a long hill and you'll be fine.

Stevo · #11 11-07-2007, 10:26 AM

Quote:

Originally Posted by t walgamuth

That should be enough compression to give pretty good service and decent starting. The minimum cold is about 220.

What would you like to know about the pistons? My favorite machinist measured them and they will meet specs, or I would have tossed them. They are left over from a couple of motors that I got with broken rods.

They are from a 123 240 or 300 na (takes the same pistons). I think I am asking $100 plus shipping.

Tom W

Tom I would like too buy your pistons. Can you tell me if they are from the early 123s (91.00mm) or the late (90.90mm) PM me and we can make arrangements.

Stevo · #12 11-07-2007, 10:54 AM

Quote:

Originally Posted by kerry

That's good news. Add your story to the list of those who couldn't get their engines started with the starter after sitting a while but which fired up with a tow.
Lets make a new commandment. If your going to store a 616 or 617 for a substantial period of time, store it at the top of a long hill and you'll be fine.

I spoz its still possible that the rings could be freed up, I'm thinking a good soaking with Myster oil. I used 1/2 auto trans fluid and 1/2 lub oil squirted in the GP holes (2 healthy squirts ea). It showed by almost starting (a couple encouraging stumbles) that the issue was with rings not valves. It did start almost right away when we towed it then the next morning, no start. Now when I try and start it she tries to start, sounds like its "stumbling", like its firing on the one cylinder with 300 lbs compression but cant quite make it. She sort of stumbles along till the battery gets week. I know she'd light off with another tow. The interesting thing is, she didn't do the "continual stumble' before the tow (one or two stumbles), which might show the compressions come up on the three low cylinders. If Tom sells my his pistons I will get a short block together and continue to mess with this engine, its a great "learning experience".

Ken300D · #13 11-07-2007, 11:48 AM

You need to run the engine a lot longer than for a nine-mile trip to get the rings in good working order, if they are gooped up.

Is the car licensed to drive with no problem? If there's no issue driving around, then I'd say you need to take that nine-mile trip again at moderate highway speeds (55 mph) and then get on the Interstate highway system for a few hours at 65-70 mph.

Are you getting much smoke running along?

The additional thing to consider is the condition of your starter. They get old and don't turn the rpms necessary to start the car.

Ken300D

Stevo · #14 11-07-2007, 12:15 PM

Quote:

Originally Posted by Ken300D

You need to run the engine a lot longer than for a nine-mile trip to get the rings in good working order, if they are gooped up.

Is the car licensed to drive with no problem? If there's no issue driving around, then I'd say you need to take that nine-mile trip again at moderate highway speeds (55 mph) and then get on the Interstate highway system for a few hours at 65-70 mph.

Are you getting much smoke running along?

The additional thing to consider is the condition of your starter. They get old and don't turn the rpms necessary to start the car.

Ken300D

The car doesn't have current tabs and I would want to put insurance on it too drive around much and I already have too many cars on the policy

I know this is just the price of doing biz, but you're right, thats what I need to do, tow start it again and drive it hard. , the batt is new and the starter is good. Of course it smoked like crazy when she first lit off due too all the oil I squirted in there but after the little drive it wasn't smoking much, you could see some back there if you really looked close, not much.

300SDog · #15 11-07-2007, 01:07 PM

Same color as one of yer others? If so then registration/ insurance is entirely transferable. Nobody actually checks serial numbers. Gotta run it hard to blow out chambers and loosen the rings before puttin it away for Winter you understand. Never let legal technicality get in way of saving spare 240D engine says me.