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Saturday, July 11, 2020

Doug's Domain

Doug Vetter, ATP/CFI

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Saturday, June 24, 2017

Transmission Overhaul Quotes

This week I finally got around to calling a few local transmission shops for quotes and found two that appear to be willing to do the overhaul for a lot less than I was quoted last year.

After some phone tag the shop around the corner from me said they would be willing to tackle the job but the guy with the experience called me back and said he frankly hates working on the 4L30E. I asked why. He said (and this is a direct quote) "they're garbage designed for a Chevette...you know what that 30 means, right?". I shrugged off the slighting of my transmission as well as the car in which I learned to drive a manual transmission and told him what I wanted. He said it would run about $1600 including the kits and a new converter. I also asked whether he could clean the case and other parts for me if I decided to tackle the rebuild myself. He said "sure".

The second shop I spoke with was a dedicated transmission shop (not a franchise). The owner answered and I asked for a labor quote for a rebuild including a master kit and bushing kit. Perhaps sensing I wasn't your typical "my car is broke and so am I" consumer, he recommended I add sprags to the build (something I was planning as well) and installation of a Superior shift kit. I told him that while I was considering Superior's Super Servo and Sonnax's 2nd clutch wave spring I wasn't really aiming to change the shift profiles. He noted that their shift kit isn't designed to change profiles as much as correct some problems inherent in the design and added that he's had good luck with them. His quote was $1200 including the master and bushing kits but less sprags and converter. With those items I'm probably looking at $1400. If I add the Super Servo and wave plate upgrades I'll probably be in the neighborhood of $1500.

Since both quotes are within the realm of reason, a fraction of that originally budgeted, and not far off the investment in special tools and custom engineering (to say nothing of the time) I knew I'd require to complete the job myself I am now leaning toward a professional rebuild so I can focus on the engine build. In this scenario I expect the head and transmission to be back in hand by the time I'm wrapping up the bottom end assembly. I figure this will shave at least a few weeks off the project and allow me to wrap things by the end of August, which is important because I discovered more rust forming around my windshield so the car has to go back to the paint shop yet again this fall.

OEM Parts Order

I mentioned earlier that I like to use Pelican Parts for OEM parts searches because they stock multiple vendors for each part. This came in handy as I ordered a few more items for the engine build:

(Image: Closeup of set of INA OEM lifters for the M52)

The lifters look perfect, though they came drenched in so much oil that it leaked out of the packaging and saturated the shipping box. I'm surprised UPS didn't declare it an environmental disaster, but I'd rather have them fully oiled and protected from rust. I was also concerned that the valve cover gasket and grommets would be made of some inferior (harder) rubber but I found both were made of the same high quality flexible rubber as the BMW branded parts. Hopefully that will translate into no leaks in the long term.

I saved $400 on this order alone, mostly due to the lifters being a bulk of the order and yet half the price of the BMW OE lifters with my discount ($30). The valve cover gaskets were less than half of the cost of the OE parts as well.

Speaking of discounts, I said last time that my dealer's parts rep gave me a flat rate of 25% for the first big order. That turned out to be incorrect. One of the features of the cost tracking spreadsheet I developed allows me to enter both the retail price and the actual price paid for each part, from which it calculates the discount expressed in both USD and a percentage. I initially entered prices that represented my typical 20% off discount so when I entered the actual prices from the invoice I expected some increase in the calculated discounts. What I didn't expect was how many parts were discounted far in excess of 25%. Most were 30% or more and a few of the big ticket items were close to 40%. So my parts rep definitely gave me the deal of a lifetime. I saved $1600 off list. Not bad.

Autohead Performance: Change in Plan

I called Peter at Autohead this week to ask him to ship me one of the boxes he had custom designed to ship heads safely across the country. I also discussed with him exactly what I will be shipping to him.

I originally thought I'd ship the head to him fully assembled including the cams and cam trays so he could give them a clean bill of health but I recently decided to pull those items and send only the basic head to him as well as the new springs and seals. I decided to do this mostly to limit the risk and cost associated with shipping these very expensive parts. As a result of this change I am planning to take my cams and trays to my technician for his assessment. If he says they can go back in service I'll reinstall them without concern.

Peter said that the weight of the head, without cams, trays, and lifters is around 53 pounds. This is well under the maximum UPS shipping weight limit, of course, but it's not trivial either, so the less I ship the better. As we wrapped up the call he requested that I ensure the head is drained of oil (which will require removal of the check valve) and wrapped in a plastic bag to ensure whatever oil remains does not leak out and saturate the box.

One minor impact of this change in plan is that I will need to acquire a set of magnets to retain the lifters in the cam trays as they are removed from the head. 50sKid used simple round ceramic magnets because they were cheap, but I don't like that solution because they don't hold the lifters securely and ceramic magnets are generally brittle and tend to leave little magnetic particles behind. I am considering some coated neo bar magnets.

Oil Pump Upgrade Options

The oil pump is a known weak point in the BMW M52 and derivatives. It is known to fail in two ways. The most likely scenario is that the reverse-threaded nut that fastens the sprocket to the oil pump shaft loosens up or falls off completely and the sprocket wanders off just beyond the splines and then spins without actually driving the pump. The other issue involves cracking of the oil pickup tube, which causes air to be sucked into the pump. Both failures result in no oil pressure and, if the driver is not quick to turn off the engine, serious engine damage as well. These failures, while largely relegated to vehicles exposed to track conditions (continuous high RPMs and rapid RPM changes), are prominent enough that the aftermarket has come up with a few fixes.

The least expensive fix involves securing the sprocket to the pump's splined shaft with a drilled nut and some safety wire. While this is definitely better than the original factory arrangement the problem is that this does not necessarily allow what I would consider a proper torque for the nut. The nut is simply too thin, the threads are too fine and the material (intentionally) soft so it is easy to over-torque the nut and strip the threads. Of course a torque wrench can be used to limit the torque applied, but not all torque wrenches can do reverse threads, so if yours can't you're buying a new ($$$) torque wrench for this stupid little nut.

The alternative fix is the Achilles Motorsport solution, which involves pressing in a new double-D keyed shaft into the pump rotor. The shaft is drilled and internally threaded to accept a bolt that is drilled so it too can be safety wired. While this solution is definitely the better of the two fixes it's also significantly more expensive.

I decided to purchase the Achilles solution to serve as an insurance policy against pump failure. My options were to buy a new BMW pump and ship it to them so they could install the upgraded shaft ($340) or simply have them press the new shaft into a new BMW rotor and disassemble the pump as required to swap my existing shaft/rotor assembly for their modified one ($250). As this video shows replacement of the rotor assembly is trivial so I went with the latter option. The perk of this solution is that I will be able to retain the factory rotor and shaft so if I discover something wrong with the Achilles parts I can swap them for the factory parts and return the kit for a refund.

As far as the pickup tube is concerned, one solution is to install the reinforced tube originally designed for the 2.8L Z3. Another solution is also provided by Achilles, which adds more extensive reinforcements to either the original or Z3 tube and sells the resulting product for $55. I don't see the advantage in that product over the stock Z3 tube, at least for my application, and I know I can get the Z3 tube for less than $55 with my discount so I'm planning to go with that.

ShureShop Table Replacement Hardware Arrives

I called Shure this week and requested a new set of hardware for the table. They agreed to ship it out ground and the package arrived late in the week. Today I used the hardware to wrap up the table assembly.

With the casters in place I moved the table around a bit. Due to the rubber tread on the casters the table moved easily and silently. Although the table will remain stationary for the duration of my project the casters will come in handy later as my brother moves the table around to accommodate the as yet unfinished garage layout.

(Image: View of ShureShop table assembled in work environment)

I also rigged up my task lights. Because the upper clamp on the crappy light stand I bought essentially failed (or was not manufactured properly) it wouldn't hold up the modest weight of the lights so I used a spare BMW hose clamp combined with a piece of heat shrink tubing to lock the top mast at full extension. I left the lights on for about 15 minutes and could not believe how hot the enclosures were. I can't see these lights lasting particularly long as a result, but again, as long as they last the duration of the project I'm happy.

Next Up

I have to purchase all the transmission kits and parts, a few more valve train parts, engine stand, shop crane and load leveler. The buying spree is not over but I can see the light at the end of the tunnel.

Mileage: 266200