It's been quite a while since the last update. I've been working it the M5 as I have time and I am getting close to firing it up for the first time. Looks like we left off with the rebuilt head and new timing chain guides ready to go on. I decided not to run the 3.6 liter cams for now but I did opt for an S14 Evo exhaust cam gear to retard the exhaust cam by a few degrees for a bump in the mid-range.
After cleaning the mating surfaces and the head bolt holes it was time to install the rebuilt head. OE gaskets, head bolts, chains, guides and hardware were used:
I used Curil T sealing compound between the head and cam tray. Some sources say these pieces were mated without any sealant between them originally and some say they were sealed. Mine did not appear to have any sealant between these pieces. Since nobody seems to know what they were sealed with if they indeed were sealed, I took a guess. With any luck it won't leak any more than it used to.
The front cover went on and then the hardened Fahey crank hub. Then the tappets, cams, sprockets, upper chain and S50 tensioner:
I used the stock exhaust sprocket for the initial setup to make sure everything was right on the marks:
Then went back and swapped in the Evo pulley on the exhaust cam:
With a little thread locker on the oil pump nut I was comfortable bolting the oil pan on. Then it was time for the headers. This is a job I'm really glad I did outside of the car. To be honest I'm not even sure how you'd be able to reach some of the nuts with the engine in the car. With all of the primary pipes in place I finally got to slip the collectors on and admire their fitment.
Normally I like to attach the engine and transmission and hoist them up into the engine bay from underneath. This time I decided to drop the engine in by itself since the subframe and steering gear had just been installed and I didn't really want to remove it all again. It went surprisingly well, and most importantly, the install was accomplished without damaging the firewall insulation which is no longer available.
Torquing the front hub nut to 325lb/ft:
Re-sealed transmission ready to go on. Torquing the output flange before wresting this thing up and into the car while lying on my back. Not actually as bad as I imagined it would be.
While the body was up in the air I put the refurbished fuel tank back in. The rear suspension, diff, axles and subframe will all be redone as I work my way through the rest of the car.
The self leveling suspension system was removed. I still have all of the pieces in a bucket because I'm afraid to throw it away. It was quite the mess and apparently the reason that the previous owner stopped driving the car.
These cars always seem to be a mess in the drivers rear corner of the engine bay because of the hydroboost system and this one was no exception. All of the plumbing has been replaced to give it the best chance of staying clean for a while. The brake accumulator and pressure switches are new and I replaced the big o-ring at the front of the booster that always leaks. I also rebuilt the power steering pump.
The original alternator bearings weren't sounding great so I installed a rebuilt unit. I decided to use the smaller bodied B35 / S38B36 style starter as well which will make replacement much easier if necessary.
New OE water pump and thermostat and some of the cooling system plumbing started:
Since both original fuel pumps seem to be locked up from sitting around with old fuel in them I opted to modify the original in tank unit to accept a submerged high pressure pump. I will remove the external fuel pump entirely and use a reducer to go from the 12mm fuel hose the normally fits the inlet of that pump to the 8mm line that runs up to the engine bay.
The next logical step in my mind was to bolt the throttle bodies on, but with them on I noticed that they didn't move as freely as the set on my 3.6 liter.
The linkage was crusty and the little bearings for the main linkage shaft as well as those for the smaller throttle shafts had seen better days. The small bearings for the throttle shafts were particularly in need of attention since they are sealed bearings and the seals on most of them were visibly worn or even missing entirely. As I learned on the 951, those little throttle shaft seals can cause vacuum leaks when they go bad. So I opened that can of worms by completely dismantling the throttle bodies. All of the steel parts of the linkage aside from the shafts themselves are being re-plated while I wait for replacement bearings. The throttle plate screws turned out to be the biggest challenge since they are a unique oval head machine screw with a metric thread with a non standard head angle. After searching for days I reached out to a machinist to modify some machine screws that are perfect in every way other than the head angle. I suppose the throttle shafts themselves could be modified to accept a more common 90° head screw but considering how rare S38 parts are I really would rather not do that if it can be avoided. I'll post up some photos of the throttle bodies as I get them back together.
So far the body has received very little attention but I did work on the tail a bit. The original lights were looking pretty sad so I thought I'd see if I could bring them back without repainting. Here's a before and after:
Then onto the body itself:
Those ugly rubber strips that fill in the gaps between the body and the US bumpers look a little wavy. They almost all look that way. It'll be much better with the Euro bumpers on it but for now it'll be alright.
That's it for this update but there's plenty more coming soon.
After cleaning the mating surfaces and the head bolt holes it was time to install the rebuilt head. OE gaskets, head bolts, chains, guides and hardware were used:
I used Curil T sealing compound between the head and cam tray. Some sources say these pieces were mated without any sealant between them originally and some say they were sealed. Mine did not appear to have any sealant between these pieces. Since nobody seems to know what they were sealed with if they indeed were sealed, I took a guess. With any luck it won't leak any more than it used to.
The front cover went on and then the hardened Fahey crank hub. Then the tappets, cams, sprockets, upper chain and S50 tensioner:
I used the stock exhaust sprocket for the initial setup to make sure everything was right on the marks:
Then went back and swapped in the Evo pulley on the exhaust cam:
With a little thread locker on the oil pump nut I was comfortable bolting the oil pan on. Then it was time for the headers. This is a job I'm really glad I did outside of the car. To be honest I'm not even sure how you'd be able to reach some of the nuts with the engine in the car. With all of the primary pipes in place I finally got to slip the collectors on and admire their fitment.
Normally I like to attach the engine and transmission and hoist them up into the engine bay from underneath. This time I decided to drop the engine in by itself since the subframe and steering gear had just been installed and I didn't really want to remove it all again. It went surprisingly well, and most importantly, the install was accomplished without damaging the firewall insulation which is no longer available.
Torquing the front hub nut to 325lb/ft:
Re-sealed transmission ready to go on. Torquing the output flange before wresting this thing up and into the car while lying on my back. Not actually as bad as I imagined it would be.
While the body was up in the air I put the refurbished fuel tank back in. The rear suspension, diff, axles and subframe will all be redone as I work my way through the rest of the car.
The self leveling suspension system was removed. I still have all of the pieces in a bucket because I'm afraid to throw it away. It was quite the mess and apparently the reason that the previous owner stopped driving the car.
These cars always seem to be a mess in the drivers rear corner of the engine bay because of the hydroboost system and this one was no exception. All of the plumbing has been replaced to give it the best chance of staying clean for a while. The brake accumulator and pressure switches are new and I replaced the big o-ring at the front of the booster that always leaks. I also rebuilt the power steering pump.
The original alternator bearings weren't sounding great so I installed a rebuilt unit. I decided to use the smaller bodied B35 / S38B36 style starter as well which will make replacement much easier if necessary.
New OE water pump and thermostat and some of the cooling system plumbing started:
Since both original fuel pumps seem to be locked up from sitting around with old fuel in them I opted to modify the original in tank unit to accept a submerged high pressure pump. I will remove the external fuel pump entirely and use a reducer to go from the 12mm fuel hose the normally fits the inlet of that pump to the 8mm line that runs up to the engine bay.
The next logical step in my mind was to bolt the throttle bodies on, but with them on I noticed that they didn't move as freely as the set on my 3.6 liter.
The linkage was crusty and the little bearings for the main linkage shaft as well as those for the smaller throttle shafts had seen better days. The small bearings for the throttle shafts were particularly in need of attention since they are sealed bearings and the seals on most of them were visibly worn or even missing entirely. As I learned on the 951, those little throttle shaft seals can cause vacuum leaks when they go bad. So I opened that can of worms by completely dismantling the throttle bodies. All of the steel parts of the linkage aside from the shafts themselves are being re-plated while I wait for replacement bearings. The throttle plate screws turned out to be the biggest challenge since they are a unique oval head machine screw with a metric thread with a non standard head angle. After searching for days I reached out to a machinist to modify some machine screws that are perfect in every way other than the head angle. I suppose the throttle shafts themselves could be modified to accept a more common 90° head screw but considering how rare S38 parts are I really would rather not do that if it can be avoided. I'll post up some photos of the throttle bodies as I get them back together.
So far the body has received very little attention but I did work on the tail a bit. The original lights were looking pretty sad so I thought I'd see if I could bring them back without repainting. Here's a before and after:
Then onto the body itself:
Those ugly rubber strips that fill in the gaps between the body and the US bumpers look a little wavy. They almost all look that way. It'll be much better with the Euro bumpers on it but for now it'll be alright.
That's it for this update but there's plenty more coming soon.
I've always loved an E28.