Timing Belt - I probably know the answer to this question

[Three Dee]

I did some head work and replaced the timing belt on my '86 eta a few months ago. Unfortunately that work seems to be wasted, as the engine is exhibiting some other (probably terminal) problems. Since I have a wrecked '89 325i that I've been mining for parts, and since that car happens to have an engine and transmission, I'm going to convert my eta to i specs.

The question is, so I REALLY have to get a new timing belt? It probably has less than 5,000 miles on it. Seems a waste to toss it with so few miles on it.

[Boise]

I always figure when in doubt replace it. A new timing belt is $11.83 (plus shipping) for a Goodyear brand from Blunttech...about the same price as three or four gallons of gas.

[dnguyen1963]

Do a risk analysis! For the cost of a new TB, I would pay the money.

[fatsooo]

depends on who you ask.

i remember reading from some very reputable people on this forum (i forgot who) said you dont need to if its barely used.
the issue of tensioning > untensioing > tensioning the belt came up, IIRC they said it wouldnt be an issue.

that put aside, my opinion, its better to be safe than sorry.

[paperplane94]

All I can say is
10-12 buckaroos...

[Varinn]

The issue with the TB retentioning is due to the spring tensioner. The cords in the belt stretch the most in the first few thousand KM of use. The belt tensioner is designed to hold proper tension AFTER stretching, not before. When you re-use the belt it no longer slackens off after break in and you end up permanently running it at a higher load instead of temporarily during break in. This is bad for bearings, sprockets, and obviously the belt itself. I dont want to discredit any of the "experts" here but is your engine really worth risking over the cost of a big mac and coke because some guy on forum says it works for him? Use the idler, but buy the belt.

IF you had the tool and experience to confirm and re-install the belt at the proper running tension without needing the spring I'd say go for it, but writing this thread means thats not likely the case. Good luck on the rest of the swap! Does your 86 have the round c101 already?

[Three Dee]

The issue with the TB retentioning is due to the spring tensioner. The cords in the belt stretch the most in the first few thousand KM of use. The belt tensioner is designed to hold proper tension AFTER stretching, not before. When you re-use the belt it no longer slackens off after break in and you end up permanently running it at a higher load instead of temporarily during break in. This is bad for bearings, sprockets, and obviously the belt itself. I dont want to discredit any of the "experts" here but is your engine really worth risking over the cost of a big mac and coke because some guy on forum says it works for him? Use the idler, but buy the belt.

IF you had the tool and experience to confirm and re-install the belt at the proper running tension without needing the spring I'd say go for it, but writing this thread means thats not likely the case. Good luck on the rest of the swap! Does your 86 have the round c101 already?

I think you lost me.... "Round c101"? Do you mean the diagnostics connector? If that is what you mean, then no. I'll have to swap in the appropriate wiring, of course.

[Three Dee]

By the way: I haven't been finding timing belts in the $11-15 range! About $30 is what I've been finding.

[Boise]

By the way: I haven't been finding timing belts in the $11-15 range! About $30 is what I've been finding.

As I said above, Blunttech for $11.83

http://www.blunttech.com/ShopByVehicle.epc?q=1989-BMW-325i--Sedan&yearid=1989%40%401989&makeid=31%40%40BMW&modelid=977%3ABT%7C5%3AED%7C66%3AMBC%7C168%40%40325i%2520Sedan&catid=240154@@Engine%20Mechanical&subcatid=240274@@Timing%20Belt&mode=PA

[Varinn]

I think you lost me.... "Round c101"? Do you mean the diagnostics connector? If that is what you mean, then no. I'll have to swap in the appropriate wiring, of course.

All e30's have a large harness connector that attaches the engine harness to the body harness for a bunch of shit, I don't remember all the specifics but on some of the early e30's the plug has less wires overall and a square body shape vs the later models which utilize the plug for more wiring connections and have a large round body. Putting (as far as I know) ANY of the m20b25 motors in while using the full motronic 1.1/1.3 engine harness will require either splicing the connections together, making your own "adapter harness" by making a short haness with the corrosponding plugs, or by removing and re-pinning one harness or the other.

I was preparing to do this to my '84 325e actually, planned install was this weekend but a 1990 shell fell into my lap and the whole project has shifted over so I don't have any first hand experience of the swap. Just countless hours of research.

This thread is very helpful

http://www.r3vlimited.com/board/showthread.php?t=100939&highlight=eta+89+head

http://i73.photobucket.com/albums/i237/mcgrath_01/85318iC101.jpg

[Three Dee]

All e30's have a large harness connector that attaches the engine harness to the body harness for a bunch of shit, I don't remember all the specifics but on some of the early e30's the plug has less wires overall and a square body shape vs the later models which utilize the plug for more wiring connections and have a large round body. Putting (as far as I know) ANY of the m20b25 motors in while using the full motronic 1.1/1.3 engine harness will require either splicing the connections together, making your own "adapter harness" by making a short haness with the corrosponding plugs, or by removing and re-pinning one harness or the other.

I was preparing to do this to my '84 325e actually, planned install was this weekend but a 1990 shell fell into my lap and the whole project has shifted over so I don't have any first hand experience of the swap. Just countless hours of research.

This thread is very helpful

http://www.r3vlimited.com/board/showthread.php?t=100939&highlight=eta+89+head

http://i73.photobucket.com/albums/i2...85318iC101.jpg

I just didn't remember hearing it called a "c101" connector. Our '86 has the small "D" shaped connector, the '89 has the big round one.

[Three Dee]

Hey, Boise! Thanks for the BluntTech link! I'll be adding that to my list of parts places. :D

Pelican and Bavarian Autosport have been my two main suppliers, except for the few things I can get locally (and for a decent price) here in the Heart o' the Bluegrass.

[Three Dee]

By the way, Varinn: For the time being (at least) I'll simply be dropping the '89325i engine into our '86 eta car. That engine has in the neighborhood of 300,000 miles on it, and it's having problems maintaining oil pressure at idle. and the lifters are noisy. I'm pretty sure the valve guides are worn, as I occasionally get some oil smoke at start-up, if it has been sitting awhile. When I had the head off recently the cam looked pretty good, but some of the rockers were showing some serious wear, which of course isn't helping the valve train noise any at all.

Sigh.....

[Boise]

Hey, Boise! Thanks for the BluntTech link! I'll be adding that to my list of parts places. :D

Pelican and Bavarian Autosport have been my two main suppliers, except for the few things I can get locally (and for a decent price) here in the Heart o' the Bluegrass.

Another good place to shop for OEM parts for cheap is www.autohausaz.com. I have ordered most of my parts from them and they have been great.

[e30conv2]

Oem belt & idler pulley replace cheap insurance. As you know the belt is compromised once used.