E28 M5 S38 Engine Refresh

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HealeyBN7
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E28 M5 S38 Engine Refresh

Post by HealeyBN7 » Fri Apr 13, 2012 7:13 am

Now that we are solidly in 2012 my (built in 1987) 1988 BMW M5 officially qualifies as a 25 year "vintage" car. Hard to believe. I still consider it a modern new car.

With a little over 265K, and the fact that they just didn't build that many S38 motors, I started thinking about the next 25 years and decided to secure a rescued engine and transmission from a low mileage S38 wreck, while they are still somewhat available.

The S38 is a detuned version of the 24 valve 6 cylinder used in the M1. With six individual throttle bodies and an oversized cam box it fills the engine compartment of the M5 with a lot of visual interest.

Having driven a friends "stroked" M5, which increases the displacement from 3.5 to 3.9 liters, my intention is to strip this engine and perform the same transformation. But, I'll see where this goes as I get farther along.

The first step is to assess what it is that I bought. It came from a BMW club member, but he could not provide leak down data. He stated that the timing chain components were recently replaced (S38 weak point) and it ran perfectly before the accident. Came with a complete harness, ECU, air box and transmission.

It has been sitting on a pallet for the better part of six months, so a lower priority project, then finishing up the Peerless and getting the Healey back on the road. Last weekend I took off the shrink wrap and started to take off the accessories.

I'll chip away at it slowly.

Austin posted a short video. Enjoy.



Dean

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Re: E28 M5 S38 Engine Refresh

Post by malcolmr18zoy » Fri Apr 13, 2012 7:44 am

Hi Dean,
It seems that WMG have blocked the video. I can't seem to be able to play it.
Malcolm

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Re: E28 M5 S38 Engine Refresh

Post by HealeyBN7 » Fri Apr 13, 2012 7:56 am

malcolmr18zoy wrote:Hi Dean,
It seems that WMG have blocked the video. I can't seem to be able to play it.
Malcolm
Oh that is not very nice of them. I'll dig into it and see if we can get it re-posted.

Thanks - Dean

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Re: E28 M5 S38 Engine Refresh

Post by HealeyBN7 » Mon Apr 30, 2012 9:02 pm

So we uploaded the video to vimeo... maybe that works?

http://vimeo.com/40334222

With Steve's leakdown tester and a custom 12mm long reach adapter, I was able to perform a cold engine leak down test. Results are not what I expected. Cams look like new. The S38 engine is known for it's long life bottom end. No air leakage noise from the intake or exhaust manifolds, but what can be made from these numbers...

1 - 24%
2 - 44%
3 - 55%
4 - 60%
5 - 38%
6 - 50%

Engine has not been run for years. Didn't try adding oil. Gave up for the night. Yikes.

Dean

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Re: E28 M5 S38 Engine Refresh

Post by Steve » Mon Apr 30, 2012 9:06 pm

That seems like a lot of leakage. Did you do a compression test as well? Assuming you've spun the engine under power of course.

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Re: E28 M5 S38 Engine Refresh

Post by HealeyBN7 » Mon Apr 30, 2012 9:29 pm

I didn't do a compression test. I would have to pick up a new starter and hook it up, but that is possible. I'll do that next. Spinning the motor means plugging the oil lines or putting them back on temporarily to prevent turning the garage into a super fund site.

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Re: E28 M5 S38 Engine Refresh

Post by malcolmr18zoy » Tue May 01, 2012 11:35 am

Hi Dean,
A leakdown test isn't going to be very accurate on an engine that has sat dormant for an extended period of time. Nevertheless, I would recommend dis-assembling the engine, and checking everything out before re-assembly with new gaskets, and seals. When an engine sits around, piston rings can stick etc, and all sorts of other nasty things can happen. Condensation can cause acid which can ruin bearings etc etc,
Malcolm

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Re: E28 M5 S38 Engine Refresh

Post by HealeyBN7 » Sun Jun 03, 2012 8:56 pm

malcolmr18zoy wrote:Hi Dean,
... I would recommend dis-assembling the engine, and checking everything out before re-assembly with new gaskets, and seals. ...
Malcolm
With Malcolm's excellent advise, I decided to tear it apart. No fewer than 100 fasteners hold the cam tray and head to the block, so a little planning was in order. Two tackle boxes and a kitchen full of zip lock bags got me started. If you make it to the last photo, you'll spot a couple cup cake trays. Don't worry there is still peace in the household, I bought them specifically to use for this project to hold the 24 cam buckets and shims.

S38 engine weaknesses; timing chain (plastic guide wears out or gets brittle), oil pump shaft shears off; front hub loosens (supposedly due to too soft of a hub material). There are upgrades to address these areas, so I'll do a little investigation before I put the engine back together.

The cams sit in a cam tray that is bolted to the head.
IMGP4186.JPG
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Cams are indexed with this cutout and identical (intake/exhaust). Lobes look pretty good.
IMGP4182.JPG
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With the cams, cam buckets and cam tray removed you can finally get to the head.
IMGP4190.JPG
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Looking inside the intake ports, the valves look clean.
IMGP4195.JPG
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Timing chain tensioner shows wear.
IMGP4208.JPG
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Flipping the head over, combustion chambers 1-3.
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This is what the bores look like.
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And the top of the piston. The little cut outs are factory.
IMGP4206.JPG
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Oil pump is driven off a chain in the front.
IMGP4239.JPG
IMGP4239.JPG (54.88 KiB) Viewed 12472 times
And here it is all laid out on the bench...
IMGP4251.JPG
IMGP4251.JPG (56.32 KiB) Viewed 12472 times

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Re: E28 M5 S38 Engine Refresh

Post by Steve » Sun Jun 03, 2012 9:35 pm

That doesn't look bad at all!

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Re: E28 M5 S38 Engine Refresh

Post by HealeyBN7 » Sun Jun 03, 2012 9:59 pm

Steve Simmons wrote:That doesn't look bad at all!
Given how bad the outside looked, I was surprised how clean it was inside. The piss-poor leak down has me still a little concerned about the bottom end.

Tomorrow, I am dropping the block off at Cost Mesa R&D after work (well, if you count after lunch, after work). My plan is to install light weight 10.5:1 pistons to bring back some of the HP that was lost when BMW de-tuned the cars for the US. I do worry about passing smog, so I posted a question on the BMW forum to see if the higher compression introduces a smog related problem. I hope not. Now you know why I like pre-smog cars!

I am taking the head down there as well. They were recommended by a BMW performance shop back east, so depending on how the conversation goes, if it needs work, they may do it, or I may have to ship it back east.

Funny that now it is apart, I am anxious to get it back. I realize now that I am older, it isn't because I am anxious to drive it and experience the thrill, I just don't want to forget how it goes together.

Dean

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Re: E28 M5 S38 Engine Refresh

Post by HealeyBN7 » Wed Jan 01, 2014 11:43 pm

Tanny told me that I wasn't posting enough.

So, I'll bet you thought I just gave up on this project...

I finally got the block and head back. I decided to put together the engine with a stroked crank and 94 mm pistons. This raises the displacement to 3.8L and should put the hp around 310.

It took a year to source all the parts, but I have just about everything now at hand. Still waiting on a crank hub gear and a few fasteners. BMW must really value their rod bearings. I couldn't believe how expensive they were and then I was told that they sold them by the half shell, so I needed to spend twice as much as too much already. Who buys bearings by the half shell? When they arrived (all 12 of them) they were each individually boxed like jewelry.

Enough complaining. I decided to put the bottom end back together. I am diggin' the custom forged pistons to deal with the longer crank. The black anodized aluminum cylinder is funnel shaped to guide the pistons into the bores. Good for only one size, but it did make is easy.
IMGP0042.JPG
Hope to bolt the front together and the head on later this week.

Dean

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Re: E28 M5 S38 Engine Refresh

Post by HealeyBN7 » Fri Jan 10, 2014 8:48 pm

It is nice to have all new timing components...
IMGP0063.JPG
but everything just looks better with headers.
IMGP0067.JPG

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Re: E28 M5 S38 Engine Refresh

Post by Larry Kluss » Sat Jan 11, 2014 10:38 am

The header looks great. Did you fabricate it?

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Re: E28 M5 S38 Engine Refresh

Post by HealeyBN7 » Sat Jan 11, 2014 9:41 pm

Thank you Larry for the thought that I might be capable of crafting these, but in fact they are right out of the BMW catalog for a Euro S38 M5. When I bought them several years ago, they were the last set in inventory. Had to go through hoops to get a dealership to place the order.

Since then, I had them ceramic coated by a place in Oxnard/Camarillo to help keep the under hood temperatures down.

Donna went with me to chase down some S38 valve shims today and we ended up walking through La Brea Tar Pits.

Wish I was there to see this VW pulling a Mammoth in '67.
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Dean

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Re: E28 M5 S38 Engine Refresh

Post by HealeyBN7 » Wed Jan 22, 2014 10:41 am

Finally got the cams timed and set. Decided to advance the exhaust cam a few degrees to bring in a little more low RPM torque. New timing marks will allow additional adjustments once I get it installed.

Hard to believe how long it took to get repeatable values.

Just waiting on a few new shims to set the final lash and dress it out with all the mounts and hoses.
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oil pan small.jpg
Too bad I can't spin it around in the car...
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Re: E28 M5 S38 Engine Refresh

Post by HealeyBN7 » Thu Jan 23, 2014 9:38 am

This wasn't too hard to make with the laser printer, scrap aluminum and acid solution... Now I'll be able to adjust the cams in the car. Unlikely, given all the other distractions in life, but the possibility exists.

Image

Now all the other cars need these labels.

Dean

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Re: E28 M5 S38 Engine Refresh

Post by Martin Keller » Thu Jan 23, 2014 10:04 am

Hi Dean,
That is very impressive.
Can you enplane how to make the label for all of us uneducated car nuts.
Sure would be nice to know how to reproduce old and damaged labels.

:drive
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Re: E28 M5 S38 Engine Refresh

Post by DaveC » Thu Jan 23, 2014 9:18 pm

Martin Keller wrote:Hi Dean,
That is very impressive.
Can you enplane how to make the label for all of us uneducated car nuts.
Sure would be nice to know how to reproduce old and damaged labels.

:drive
Hear, hear!

Just like those who've seen the beautiful body shop tags Dean made for Peerless folk, I'd love to know just how it's done

Dave

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Re: E28 M5 S38 Engine Refresh

Post by Steve » Thu Jan 23, 2014 9:42 pm

I think Dean is afraid the EPA might see this thread and learn about the acid bath in his back yard.

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Re: E28 M5 S38 Engine Refresh

Post by HealeyBN7 » Fri Jan 24, 2014 9:00 am

Martin Keller wrote: Can you enplane how to make the label for all of us uneducated car nuts.
:drive
Sure. Probably best if I start a new thread. Need to think of a good label project first...

As a teaser, here was something small for the Lotus valve cover.

Dean
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Re: E28 M5 S38 Engine Refresh

Post by Martin Keller » Fri Feb 28, 2014 11:16 am

Hi Dean,

Any idea on the how to replicate a data tag/plate.
:drive
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Re: E28 M5 S38 Engine Refresh

Post by HealeyBN7 » Fri Feb 28, 2014 4:19 pm

Martin Keller wrote:Hi Dean,

Any idea on the how to replicate a data tag/plate.
:drive
Just for you Martin.

viewtopic.php?f=1&t=2466&p=18093#p18093

Dean

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Re: E28 M5 S38 Engine Refresh

Post by Martin Keller » Fri Feb 28, 2014 4:27 pm

Thanks Dean. :thumbs:
:drive
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Re: E28 M5 S38 Engine Refresh

Post by HealeyBN7 » Sun Aug 10, 2014 8:24 pm

With the engine almost done a I am just waiting for a few fasteners and harness clips, I thought it would be interesting to baseline the existing motor.

Engine was cold when we took the readings as I was getting ready to adjust the valves. I had a slight hesitation at 3500-4000RPMs. I have been swapping fuel and ignition components from the replacement motor to ensure I don't have a lingering hesitation when the new motor is installed. I think I eliminated the flat spot by swapping the new motor's ECU, so it is once again smooth and powerful.

The numbers are worse then would be expected with a warmed motor, but you can see the variation. Keep in mind it runs smooth and feels plenty powerful.

With Jerry's help and Steve's SnapOn leakdown tester here is what we came up with. (BTW, the HF leakdown tester does not work...not even a little bit).

Image

Dean

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Re: E28 M5 S38 Engine Refresh

Post by malcolmr18zoy » Sun Aug 10, 2014 10:09 pm

Those numbers look pretty bad. You would probably get a big improvement in power and smoothness even if you re-built the engine totally stock. How are you altering the fueling system to compensate for the larger displacement?
Malcolm

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