John Veninger

So I have to ask. What is wrong with your current engine?

Nicholbry

TBF! (that would be T for thrust rather than timing). The PO apparently did not service the pinch collar. After thousands of dollars servicing this engine to bring it up to specs (timing, rebuilt tensioner, motor mount, oil pan gasket, starter, new flexplate, battery, positive bat. cable, power steering lines & reservoir, etc., etc.) I discover the cause for my low idle and difficult starts after warm. The car still runs, but it is only a matter of time. I've only put 1500 mi. on her before finding the problem. She only has 69K mi. on her now and is so beautiful that I can't imagine parting her; nor can I sell it and expect to recoup anything in this condition so I have to move forward w/ the project.

My budget is shot; was shot long ago, so I am taking care of some other (more affordable) things now while I hunt for a viable swap. I don't trust my abilities to do it either so I'm having to pay a shop $2K for the service; provided that there are no snags. This is why I am trying to sort potential "snags" w/ my selection of engine before doing so.

If I understand, Vilhuer, I should be able to swap my '90 engine for an '89 engine w/o any modification to the wiring harnesses as the differences you mentioned shouldn't affect the electrical connections; correct? I should also add that my car is Canadian spec. I'm not expecting that to be an issue, but just in case I thought I should say.

Thanks again and if you guys know of anyone w/ a reasonably priced engine out there that would swap well do let me know.

UKKid35

Sorry to hear of your misfortune. Ideally you need a donor Timing Belt Failure engine and then swap the heads from yours. Not sure whether the cost savings would make this worthwhile unless you were doing the work yourself.

Nicholbry

Didn't think about that as an option, thanks. Unfortunately I don't have the skills to complete that project nor a fellow 928 buddy to assist w/ any obstacles.

Nicholbry

What obstacles, if any, might I encounter when mating an 1989 into my 1990 S4 (i.e. computer brain, deleted/added system monitoring, wiring harness, etc.)?

drnick

it sounds as if the only issues are electrical, and all easily solved if the car does not have cats. im not an expert on the cats and the ignition protection/exhaust temp system but it seems that if you dont have cats then you dont need the electrical ignition protection/exhaust temp things either.

jon928se

I'ld go with the 87 Engine. Use it's short block and bolt your later better heads on the top. Sell the 87 heads to someone with Timing Belt Failure.

Consider swapping the pistons and rods from your car to the 87 short block if they look in better nick. The only real risk when you purchase is the condition of the 87 block.

Oops edit - AFAIK know the block is essentially the same so you should have no problems bolting 90 externals to an 87 block - including the exhaust gas temp sensors should you wish to perpetuate a system that is known to cause central drive shaft failures.

John Veninger

Nicholas is looking for a drop in solution, so swapping engine parts doesn't seem to be an option.

Nicholbry

I have the factory set up.

I hadn't heard of the exhaust gas temp sensor affecting the drive shaft; how are they related to this drive shaft problem?

Trying to keep my shop bill to a minimum and I'm concerned about cracking open an engine and asking for sealing troubles.

Dead on! My pockets are emptying from this project and any major work required to convert will only add to my $2000 labor to swap.

Thanks guys, keep it coming. I still need a clear answer about what specific problems I would need to overcome in getting the engine to mate to the car w/o problems with the brains or any system for that matter. Details are appreciated. You guys are the greatest!

Jim bailey - 928 International

good point..."there are some very un trustworthy sellers on the internet and ebay..... you could spend quite a bit of money and get another engine just like the one you have." Just as Nicholas could advertise a RUNNING 1990 S-4 engine with about 60,000 miles so can anyone else, especially if sold "as is " no warranty !

Nicholbry

I haven't been able to locate anyone living in my area who has experience with such a task. I wouldn't be of much help anyway and just a tool caddy of such a project. My first mechanic job ever was just this past month w/ the motor mount and oil pan gasket exchange, to put things into perspective. I've taken a look at the manual details concerned with the project and it is a bit daunting by my standards. It even took me a week to do the aforementioned work that I did as I fought trying to get the cross member to line up. I can just imagine trying to get all of the other variables to line up for mounting, like at the flywheel. I simply don't have anyone to lean on down here that I am aware of.

Someone else had proposed this as an option and it will be worth considering if I find such an engine. So far this thread has not yielded anyone with a Timing Belt Failure engine. And, indeed I would cherish the opportunity to visit with guys who share my passion for this vehicle and who could point some things out to me that I haven't learned about already.

Indeed I plan to; however, I don't know that I would feel anymore confident with low measurement numbers. My own measurement yielded only .34mm of movement which is at the low end of the acceptable range. This measurement was confirmed 3 times. It wasn't until after I dropped the oil pan gasket that the problem was realized.

Good advice indeed which is why I'm treading with caution. Any engine that I pick will have its end play tested and oil pan dropped before any money exchanges hands; even if I have to drive all the way across the country to pick it up myself or request someone local willing to check it out for me from this Rennlist resource. The only exception would be if I bought from one of the 928 companies, GermanAutoDismantlers, DCAutomotive or the like and would allow for some recourse.

Thanks for the advice and helpful tips. I'll put them to use where I can.

So, if anyone out there knows of someone w/ an engine, either with timing belt failure or not, feel free to chime in or PM me with details. Thanks again to all who are trying to help!

Nicholbry

Just posting the question again.

Nicholbry

OK, I located and purchased a 1987 S4 engine with 39K miles registered from new to only one owner in the Beverly Hills, CA area this past week. The mileage was confirmed via CarFax and pics from the odometer. The engine is still in the car at a salvage yard awaiting my arrival to pick-it up. I've only seen pics of it since it is on the other side of the country (Cali). The story is that the wiring harness caught fire and burned along with the intake tubes, and fuel rail covers; basically anything on either side of the motor that was plastic/rubber. All plastic/rubber at the fire wall and in the front of the engine are without harm; a testament to just how minor the fire was. Even the paint didn't darken on the intake system. I really only need the block for my use anyway due to Thrust Bearing Failure I discovered on my '90 S4.

So here's my question. My mechanic will be performing the work of pulling the engine and mating the lower block to my '90 S4 heads. What I would like to know is, what details or points of concerns might I convey to the mechanic regarding this block swap from some of you guys that know these cars inside/out? FYI, the mechanic works primarily on Porsche, BMW, Merc.; but has only worked on a few 928s (motor mount exchanges, torque tube replacements, timing belt replacements...that sort of thing). Despite his limited work on the 928, he is methodical and the only mechanic I trust around here to her. Nonetheless, I realize from owning this unique car there are those finer details that often get overlooked which are vital to the performance and longevity of this car. Those are the things that I am concerned about. Due to some sludge (from the worn bearing material) I discovered in the oil pan, I will have him flush the engine/system a couple times before operation. He will be reinstalling all engine accessory equipment (alternator, pwr. steering pump, AC, etc.) since most of it was replaced just recently. He will also be reinstalling the water pump, timing belt, tensioner, all accessory belts, etc. that was done only 1500 miles ago. For good measure I will have him put another water pump gasket on just in case.

I am listening to what you guys have to say regarding anything from torque values to replacing stress related items like special nuts, bolts, critical inspections, etc. I need peace of mind after all is back together. After 2.5 years of ownership and $12,000 =/- in parts and labor, I've only logged 1500 worrisome miles on her due to problems the previous owner did not disclose or I was too green to recognize. Any suggestions would be greatly appreciated.

69gaugeman

If you did a MM pan gasket install, removing heads and replacing them really is within your abilities. This forum will help with any issues you run into. The key is laying out / organizing all the parts and fasteners as you go. With a $30 engine stand and rent an engine hoist, and the WSM and rennlist, you can do the head replacement. Then if you really want your mechanic can install the engine for you.

Vilhuer

First things first. Check for trust bearing failure. Its known problem that 928s tend to mysteriously burn right after TBF has been diagnosed.