HELP!!! 300 sel 4.5 - PeachParts Mercedes-Benz Forum

tosbt · #1 08-08-2003, 04:40 PM

I ordered the staintless steel exhaust system from TIMEVALVE, had it installed on a perfectly running 4.5, put it on the ground and damn it started running hot and felt like timeing was retarted. Well, called TIMEVALVE, talked with Scott, well he said, same system I used for 450SEL AND 450SL's, use just a little restriction in the muffler to quiten down some, and has agreed to replace muffler. My question does anyone know the pipe size running the length of the system? I think I may be in for some suppries.

300SDog · #2 08-08-2003, 06:19 PM

Yipes - stainless steel pipes will make the car run hot.... visualize burnt sodium-filled exhaust valves as worst case scenario.

Adjusting valve clearance and going back to regular steel exhaust system for rust-free Texas climate can solve your problem.

Am thinkin Stainless Steel Exhaust might work on diesels in northern climate, otherwise an extremely contoversial item.... especially on high mileage older cars, where cylinder head, valves and valve guides can become toast from hotrod product like stainless exhaust system.

You probably should have come here first, before making decision for stainless pipes..... am certain you'll get lotsa feedback on this item.

#3 08-08-2003, 06:43 PM

were there any heat sheilds within the engine?

psfred · #4 08-08-2003, 07:41 PM

Some points to note:

Stainless steel vs regular exhaust steel will have no effect whatever on engine temp, they are only pipes.

The exhaust for a 450 won't fit, except perhaps the muffler (the front pipes anyway are different). I don't know about restriction in the muffler, but the 450 has a different cam starting in 73.

I would question the installation before the muffler, though -- did someone kink a pipe? Mine has one squashed that I need to replace before doing any highway driving -- has a craked manifold on that side, connection maybe?

Peter

tosbt · #5 08-08-2003, 09:27 PM

I did do a research on this site for TIMEVALVE before I order the complete system and ALL were positive with some reporting 250,000 miles, I've never heard of an heating problem from the tubes being stainless. Remember the manifolds are still cast iron and the tubes dont pick up untill they are below the engine. I DID LEARN today that the first muffler on the timevalve is 13 inches long rather than the 16" on my old system. I told Dave at TIMEVALVE about this and he said that should have no effect on backpressure but I do not agree with that and would like to hear others comments about this.

tosbt · #6 08-08-2003, 10:59 PM

So what I have learned thus far by reading the old threads is that my cam is different from a later 4.5, 73 and later, is could be that this builds more pressure than a 450 sel as Scott said that the system is mostly designed (both forward and rear mufflers) after the 450, a previous post suggest that the air gas mixture should be changed by any change in the exhaust flow??????? that post recomends a lambda tester for fuel mixture. What say you all? I think that 13 inch forward muffler is a real problem.

JoeyTheB · #7 08-08-2003, 11:09 PM

Man, sorry to hear you're having troubles -

Sure sounds like your points are eaten -
Mine has the TimeValve, and started running like that
a couple of years AFTER I installed.

Took me a while to find the culprit -
first I cleaned/repaired the radiator,
then it sat for a year,
then started experiencing same problem this winter
on my 20 mile commute.
Each day it would run a little hotter...

My Rx was to replace points with Crane ignition-
worked for me - no more running hot.

My temp is rock solid now - no more overheating !!!

Joe

tosbt · #8 08-09-2003, 12:10 AM

Thanks, but I started with the Crain. I'm really off here, just not sure.

300SDog · #9 08-09-2003, 02:05 AM

>>>>>Stainless steel vs regular exhaust steel will have no effect whatever on engine temp, they are only pipes.

OK, so we've got exhaust fumes entering hyper-heated environment through stainless steel passages that can get hotter inside than even the thick cast-iron heat dissipating exhaust manifold itself........ and you are saying it will have no effect on the engine?

Looked at SS pipes for my twincam 280/8 long time ago, but chucked the idea when motorheads advized me it would overheat the engine, especially at the cylinder head.

You gotta separate heat from air flow - think of it as sound waves that can toast the engine. And yes, stainless steel will not dissipate heat, instead it gets hotter 'n hotter.

- Just my opinion, but i'm stickin to it....... anybody who recommends stainless steel exhaust in 95*+ Texas envivonment is out of their mind.

TOSBT, am thinkin you got screwed by bad advice from whoever sold you those expensive pipes.

#10 08-09-2003, 06:45 AM

I am confused by all this. Am I understanding correctly that because stainless steel pipe gets hotter than mild steel used for regular exhausts this causes the engine to run hotter? Or, is it because of decreased backpressure that the engine now runs leaner and hence hotter? I don't believe the first one to start with. Stainless steel may be thinner but don't you have additional plating in the engine bay which protects the surrounding areas from exhaust heat? The second point can surely be corrected by enriching the mixture.

Adam

tosbt · #11 08-09-2003, 10:23 AM

Well this is an intresting topic!!! That being said airflow is the problem in all exhaust , if getting hotter because it is stainless steel, better move it fast - and thats what is not happing in my car as we speak. If I can remove the blockage (?) increase airflow then the tempeture gage will tell me the rest of the story. These timevalve systems have been used by many on this board including the monitor, as I have used the search engine on this topic and have found many have used this system without any problems. I think my 4.5 is not the same 4.5 TIMEVALVE (cam difference) has focused on, they keep refering to the 450SEL and the 450SL. I am beginning to beleive that I need more airflow than those cars in the forward muffler. It could be I need to adjust air fule mixture some, but I do not think that is the major problem.

psfred · #12 08-09-2003, 03:03 PM

tobst:

The only differences between the 4.5L M117 in the W108/9 chassis and the one in the W116 is the cam, post 73. It is changed to reduce combustion temp (charge density, probably) likely by reduced overlap. This reduces the amount of NOx produced and permits running without EGR or cats.

I don't see how changing the exhaust is going to make it run hot -- increased back pressure results in lower charge density, so you get less power and less heat.

The composition of the pipes has nothing to do with heat dissipation or restriction. More heat will be lost out the pipe with stainless steel since it is usually thinner -- no need for extra metal to provide a longer usable life. You will get more heat transfered to the surrounding body, but the exhaust on a W108 is a long way from the engine -- the manifolds (not changed in this case) are fairly long.

I would look for other problems that cause overheating -- thermostat, low coolant, dragging brake, etc. You might want to look anything that might get distrubed by raising the car on a hoist, such as the parking brake. I'd guess the overheating is co-incedental rather than caused by the exhaust change.

Peter

tosbt · #13 08-09-2003, 07:24 PM

I have measured all the pipes and they are the same size as the originals, again the forward muffler is 3" inches shorther than the stock and I can only believe that the air flow is restricted by a greater degree than the orginal OEM (which was what came off the car). I am sure that not only will it make it run poorer with poorer air flow but am convinced that the car will run hotter also. Have checked it all. I am going to do two things. (1) take the rear muffler off and run the car without it and see what happens, (2) replace with the different rear muffler TIMEVALVE is sending me and see what happens. Thank you all for your valued opinions and you time. Jim.

psfred · #14 08-09-2003, 07:53 PM

Jim:

Is there an H pipe in the new system? If so, it needs to go, separate pipes necessary. I know what some of the 450 installations (particularly the SL) have very different exhaust setups, and I don't suppose that is just for fun....

A 13" muffler rather than a 16" muffler won't make a bit of difference unless there is something funny with the resonance or one of the internal pipes isn't perforated, or something else is wrong. Could be a resonance problem.

Hope you get all this straightened out, as I am planning on buying a TimeValve exhaust this fall when money permits -- I'm tired of the roar from the cracked manifold and rotten front pipes!

Peter

tosbt · #15 08-10-2003, 09:17 AM

No H pipe in the new system BUT was in old system, joined about two feet from the manifold for about 8 inches, must have been some type of cross fow there, and remember this was the factory system, all marked MB. For your information you can see a picture on DB DEPOT www.bddepot.de/englisch/108/index_1024.html . I just sit here and scrach my head, but I'm cant get away from something acting like a block to air flow. Pushing heat back in to the engine and changing the combustion mixture, or that is not letting exhaust leave the engine at an appropriate rate. If my cam is different from a 450SEL then my requirements for exhaust would have to be different. I think.