Buyer Beware
 

I received the new gas struts for my rear decklid and front hood today.

The new struts for the front hood worked fine.

The new strut for the rear decklid wouldn't hold up the decklid. I re-installed the Rennline mechanical strut I had purchased last week, adjusted the hood stop buffers and then the rear decklid worked fine also.

Next I pulled out the old rear decklid gas strut and compared it to the one I hard just received and the part numbers were different. I had forgotten that there are 2 versions of the gas strut - a 300N standard version / 911-512-331-01 and a 600N heavy duty version / 911-512-331-02.

My car has 1 strut on the rear decklid, so it needs the 600N version. Other 911's that have 2 struts on the rear decklid can use the 300N version.

For me, ever since Pelican Parts updated their online ordering website a few years ago I have found it more difficult to find the correct parts for my 75 Carrera. The old version of the website would list both versions of the strut and a description of which version was used in which application. The current version of the website lists just the -01 version of the strut until I clicked on the view catalog button and then both the -01 and -02 versions were displayed. Frustrating.

Had similar issues recently with parts for my 911 and Cayman. The new system makes it challenging to know if you are ordering the right parts or not.

I did some part number searching in the Porsche part catalog that I had downloaded (see above quote) to get a better understanding of when Porsche used the -01 300N rear decklid strut versus the -02 600N rear decklid strut.

Since the 74-77 911 / 911S, 76 912E, and 74 Carrera have a lighter rear decklid, those models use a single 911-512-331-01 (300N) "gas pressure spring" (strut).

The 75-76 Carrera has the heavier (whale tail) rear decklid and uses a single 911-512-331-02 (600N) strut, while the Carrera with factory air conditioning installed (the A/C condenser is mounted to the underside of the decklid) uses two 911-512-331-02 (600N) struts to handle the extra weight.

So my frustration in ordering the wrong part number from Pelican Parts is self inflicted.

Always check the factory parts catalog for the relevant parts numbers!

http://forums.pelicanparts.com/uploa...1730350572.jpg

http://forums.pelicanparts.com/uploa...1730350572.jpg

As others have already said - great thread and thank you for sharing the knowledge and experience gained.

One question - have you considered a 2nd wideband sensor for the other bank? I have a twin plug 3.5 engine that the PO did with only one sensor; adding one for the other bank helped with low speed part throttle drivability as it accounts for minute variations between banks. Just a thought…

Hi phelix,

Yes, the thought has occurred and I have an O2 sensor bung on the 4,5,6 bank collector. I just last week went out for a low load (TPS around 2.5%) auto tune session to tweak in the VE table values at 1500 rpm and above and the car runs more smoothly now in the low speed part throttle region.

Thank you for sharing your experience on adding a second O2 sensor to the ECU, I'll keep that in mind.

Smoothie Rear Bumper
 

I saw a forum thread earlier this week about the look of the 74-89 911 rear bumpers with the mandated 5 mph crash bumpers with the large US style bumperettes versus the look of the Euro bumperettes versus the shaved bumper and it got me thinking about the look of my 1975 911.

75 911s (Duane) had posted a photo of his 75 911S with a smooth rear bumper and I thought "I want that too". So I searched the forum for his thread, which I have copied the link to below, and found on page 10, post 194 thru post 198, he goes thru the process of modifying his rear bumper, so I decided to try doing the same with my rear bumper.

http://forums.pelicanparts.com/porsche-911-technical-forum/878569-born-75-me-my-new-911s-10.html#post9479788

My 75 rear bumper as is:

http://forums.pelicanparts.com/uploa...1732244235.jpg

I don't have access to affordable TIG welding so I used JB Weld to fill-in all of the unneeded holes in the bumper. I started by covering the backside of the hole with Gorilla tape, then applying JB Weld to the front side filling the hole not quite to the surface.

I fabricated the same type of slotted bumper mounting brackets but I made the slots open to the sides so I can remove / replace the M8 x 20 carriage bolts.

http://forums.pelicanparts.com/uploa...1732244720.jpg

http://forums.pelicanparts.com/uploa...1732244720.jpg

http://forums.pelicanparts.com/uploa...1732244720.jpg

http://forums.pelicanparts.com/uploa...1732244720.jpg

http://forums.pelicanparts.com/uploa...1732244720.jpg

http://forums.pelicanparts.com/uploa...1732244720.jpg

http://forums.pelicanparts.com/uploa...1732244720.jpg

http://forums.pelicanparts.com/uploa...1732244720.jpg

http://forums.pelicanparts.com/uploa...1732244720.jpg

Since the height of my mounting brackets is the same as the thickness of the rubber spacer that goes at the front of the bumper strut, I deleted the rubber spacer and did not have to shorten the length of the bumper struts in order to position the bumper properly on the car.

On Monday, I take my bumper to the local fab shop to get the slotted mounting brackets TIG welded to the inside of the bumper. Then I can remount the bumper and check for proper fit.

Then I will remove the bumper, sand the JB Weld areas, apply a thin coat of Bondo, sand the bumper smooth, then take the bumper to the body shop to get it painted GP White (code 908).

Smoothie Rear Bumper
 

I got the bumper mounting brackets TIG welded to the inside of the bumper yesterday. The JB Weld and Bondo I had applied handled the heat of welding, the original paint near the weld locations was cooked, so I set about sanding off most of the original paint, then applying another skim coat of Bondo to the JB Weld filled holes and block sanding. When I was satisfied with the finish, I thoroughly degreased and dried the inside of the bumper then sprayed gray primer. After a 1 hour dry, I flipped the bumper over and used jack stands (with folded microfiber clothes taped on to protect the fresh paint on the inside of the bumper) to hold the bumper off the floor, thoroughly degreased and dried the outside of the bumper then sprayed 3 coats of gray primer (first - light dust coat, then 2 medium coats).

Next, off to the body shop to get the outside of the bumper painted in GP white.

TIG welded mounting brackets

http://forums.pelicanparts.com/uploa...1732683071.jpg

http://forums.pelicanparts.com/uploa...1732683071.jpg

Bumper prior to block sanding Bondo:

http://forums.pelicanparts.com/uploa...1732683155.jpg

http://forums.pelicanparts.com/uploa...1732683155.jpg

Smoothie Rear Bumper
 

I got the bumper back from the body shop today and installed it. The smoothie rear bumper looks good and by removing the bumperettes (7.5 lbs each), rubber molding strips (0.5 lb each) and converting from the US shock absorber bumper struts (4.5 lbs each) to the Euro hollow tube bumper struts (1 lb 9.5 oz each) I trimmed 21.8 lbs off the tail end of the car.

Bumper mount as installed:

http://forums.pelicanparts.com/uploa...1733268881.jpg

Original rear bumper:

http://forums.pelicanparts.com/uploa...1733268920.jpg

Smoothie rear bumper:

http://forums.pelicanparts.com/uploa...1733268972.jpg

Thank you Pelican Parts forum for the inspiration!

That came out real nice!

That's one smooth rear end

Looks great and reduces the weight where it counts!

Updated Table of Contents
 

This forum thread is long. Below is an updated table of contents to help you navigate thru it.



CIS to ITB EFI conversion: pg1 post 1-20, pg2 post 21-27

Brake conversion / weight reduction: pg2 post 28-30

Wiring improvements: pg3 post 41-42

Crankcase tear down: pg4 post 62-66

Heads tear down: pg4 post 68

Head stud removal: pg4 post 69

Engine wiring harness: pg4 post 72, 76

Parts cleaning / refinishing: pg5 post 81, 90, 96-99, pg6 post 100-105

Distributor modifications: pg6 post 106-107

Engine compartment seals: pg6 post 109-110

Engine lid seal: pg6 post 115

Rod and chain holder tools: pg7 post 126

Convert to moisture resistant connectors: pg7 post 129-132

Ground connections: pg7 post 136

Updated wiring diagrams: pg7 post 139-140

Piston weight: pg8 post 141

Engine air baffle modification: pg8 post 142

Updated sprocket supports: pg8 post 146-147

Piston / cylinder assembly: pg8 post 148-150

Fan, fan housing, alternator assembly: pg8 post 151-152

Deck height and compression ratio: pg8 post 153

Ignition timing set up - more info: pg8 post 154-155

Rod weight and piston/cylinder assignment: pg8 post 160

Crankcase clean and assembly: pg9 post 161-178

Valve train mock up: pg9 post 179

Piston to valve clearance: pg10 post 181

Engine assembly: pg10 post 182-194

Engine / transaxle installation: pg11 post 202-207

Camshaft break-in: pg11 post 209

O2 sensor controller calibration: pg14 post 263-266

Camshaft replacement: pg14 post 267-275

Final headers / exhaust fabrication: pg14 post 276, pg15 post 287, 292

Dyno tune / test results: pg15 post 295-296

Accel Enrichment Table: pg16 post 304

VE Table discussion: pg16 post 306-313

Rear decklid / front hood struts and rubber buffers discussion: pg16 post 316, 318-320 & pg17 post 322-323

Smoothie rear bumper fabrication: pg17 post 326-328



Hope you find this thread to be helpful.

Good luck with your DIY project!

The backside looks fantastic. HUGE improvement. Kind of like my old car - except I moved the top of the plate to be flush with the top of the bumper. ;)http://forums.pelicanparts.com/uploa...1733350120.jpg

Dan,

The bumper turned out awesome! Of course I'm biased! :-)

Front Bumper Tuck
 

My next project for the P75 is converting from the heavy US shock absorber front bumper struts to the hollow tube Euro bumper struts.

I deconstructed the front bumper and valance, removed the fog lamps and removed the windshield washer system (reservoir, pump and tubing back to the dash) - I don't use either of these and I had been carrying around 2 gal of washer fluid for the last 18 years.

The rubber front molding strip on the front of the front bumper is secured by a series of plastic rivets and a plastic retaining strip across the face of the bumper and secured at each end by a Phillips head sheet metal screw. To remove, I took out the screws at each end and then carefully peeled the rubber molding strip off its plastic retaining strip. This reveals the bumper mounting nuts hidden underneath the rubber molding strip.

It took me a bit to figure out the side mounting bolts for the valance are beneath the bumper and that the front valance is not attached to the front bumper like the rear valance is attached to the rear bumper. Therefore, I came to understand that I had to remove the front bumper first (which included detaching the front turn signal lamp housings from the bumper before I could pull the front bumper away from the car), then the valance side mounting bolts were exposed and I could remove the front valance. I also removed the fog lamps from the front valance before I could pull the front valance away from the car.

http://forums.pelicanparts.com/uploa...1733882620.jpg

http://forums.pelicanparts.com/uploa...1733882620.jpg

http://forums.pelicanparts.com/uploa...1733882620.jpg

Next, I replaced the old US style bumper struts with the Euro struts. The Euro struts have an M12 stud at the base of the strut (versus M8 on the US strut) so I used a Dremel tool with a metal cutting bit to open up the slot at the strut attachment point on the body.

I also wanted to pull in (i.e. tuck) the front bumper into the body, so I deleted the rubber bumpers at both ends of the strut which meant I needed to add 3 M12-40mm washers to take up the extra M12 stud length protruding thru the slot in the attachment point on the body. Since the body tub is getting wider from the front end back to the windshield, I had to trim one of the M12-40mm washers to get it to fit.

http://forums.pelicanparts.com/uploa...1733883377.jpg

http://forums.pelicanparts.com/uploa...1733883377.jpg

http://forums.pelicanparts.com/uploa...1733883377.jpg

http://forums.pelicanparts.com/uploa...1733883377.jpg

Next, I mounted the bumper to check fit. I was high on the left side, low on the right side, so I removed the bumper, loosened the bumper strut mounting nuts, remounted the bumper and used a floor jack to persuade the bumper into correct alignment then tightened the strut mounting nuts, then removed the bumper.

http://forums.pelicanparts.com/uploa...1733884547.jpg

Now I could mount the front valance. Once it was tightened into place, I mounted the front bumper, reinstalled the front turn signal lamp housings and tightened down for the final time the bumper mounting nuts. I had installed and tightened down the rubber side accordion pieces to the bumper before the final bumper mounting, so now I connected the accordion pieces to the front fender extensions and tightened the fender extensions to the front fenders and the front valance.

I used a split fork tool to carefully remove the plastic rivets and the plastic retaining strip from the face of the bumper. Then I carefully worked the rubber molding strip back onto the plastic retaining strip. Now I could "pop" the rubber molding strip back onto the face of the bumper by pushing the plastic rivets into their plastic cups in the bumper and secure the ends of the rubber molding strip by inserting the Phillips screw at each end of the rubber molding strip.

Before the front bumper tuck:

http://forums.pelicanparts.com/uploa...1733887202.jpg

After the front bumper tuck (and fog lamps removal):

http://forums.pelicanparts.com/uploa...1733887280.jpg

Love the bumper tuck. I did this last winter and, to me, it's a much better look.

US to Euro spec headlight conversion
 

One last item I have wanted to address with my car is the headlights. Specifically, I have the US spec sealed beam style lamps with the "oversize" trim ring and I have always preferred the cars with the Euro spec H4 lamps, so I decided to make a change.

http://forums.pelicanparts.com/uploa...1735848629.jpg

While I was at it, I decided to try an LED conversion as well so I bought and installed the Rennline EL13 conversion kit. Unfortunately, the car just doesn't look right to me with these lights.

http://forums.pelicanparts.com/uploa...1735848719.jpg

So I decided to buy the Porsche H4 headlight assemblies (p/n 911-631-113-00), the Porsche headlight trim ring (p/n 911-631-141-00), H4 halogen bulbs, small light bulbs, etc. When I got the parts from our forum sponsor I wasn't sure how everything was supposed to go together so a short thread asking for guidance (see link below) yielded a bounty of valuable information including a suggestion to use the thin fender to headlight seal (Porsche p/n PCG-631-115-00 formerly 644-631-115-00). The H4 headlight assemblies fit much better with the thin seals than they did with the thick headlight seal.

http://forums.pelicanparts.com/porsche-911-technical-forum/1171986-headlights-us-euro-h4-question-need-your-help.html#post12381210

Thick seal:

http://forums.pelicanparts.com/uploa...1735849579.jpg

Thin seal - headlight assembly fits better:

http://forums.pelicanparts.com/uploa...1735849634.jpg

I made up some wiring pigtails to bring parking light power to the small light bulbs in the H4 headlight assemblies.

http://forums.pelicanparts.com/uploa...1735849798.jpg

http://forums.pelicanparts.com/uploa...1735849798.jpg

H4 headlights installed with the parking lights on.

http://forums.pelicanparts.com/uploa...1735849798.jpg

US spec to Euro spec headlight conversion completed.

http://forums.pelicanparts.com/uploa...1735849798.jpg

Nice change, Dan.

Updated (2) Table of Contents
 

This forum thread is long. Below is an updated table of contents to help you navigate thru it.



CIS to ITB EFI conversion: pg1 post 1-20, pg2 post 21-27

Brake conversion / weight reduction: pg2 post 28-30

Wiring improvements: pg3 post 41-42

Crankcase tear down: pg4 post 62-66

Heads tear down: pg4 post 68

Head stud removal: pg4 post 69

Engine wiring harness: pg4 post 72, 76

Parts cleaning / refinishing: pg5 post 81, 90, 96-99, pg6 post 100-105

Distributor modifications: pg6 post 106-107

Engine compartment seals: pg6 post 109-110

Engine lid seal: pg6 post 115

Rod and chain holder tools: pg7 post 126

Convert to moisture resistant connectors: pg7 post 129-132

Ground connections: pg7 post 136

Updated wiring diagrams: pg7 post 139-140

Piston weight: pg8 post 141

Engine air baffle modification: pg8 post 142

Updated sprocket supports: pg8 post 146-147

Piston / cylinder assembly: pg8 post 148-150

Fan, fan housing, alternator assembly: pg8 post 151-152

Deck height and compression ratio: pg8 post 153

Ignition timing set up - more info: pg8 post 154-155

Rod weight and piston/cylinder assignment: pg8 post 160

Crankcase clean and assembly: pg9 post 161-178

Valve train mock up: pg9 post 179

Piston to valve clearance: pg10 post 181

Engine assembly: pg10 post 182-194

Engine / transaxle installation: pg11 post 202-207

Camshaft break-in: pg11 post 209

O2 sensor controller calibration: pg14 post 263-266

Camshaft replacement: pg14 post 267-275

Final headers / exhaust fabrication: pg14 post 276, pg15 post 287, 292

Dyno tune / test results: pg15 post 295-296

Accel Enrichment Table: pg16 post 304

VE Table discussion: pg16 post 306-313

Rear decklid / front hood struts and rubber buffers discussion: pg16 post 316, 318-320 & pg17 post 322-323

Smoothie rear bumper fabrication: pg17 post 326-328

Front bumper tuck: pg17 post 335

US to Euro spec headlights: pg17 post 337


Hope you find this thread to be helpful.

Good luck with your DIY project!

Great thread !!

License Plate Lights for the Smoothie Rear Bumper
 

Today I addressed the vehicle code issue of lights for the license plate on my smoothie rear bumper. Since I wasn't up to fabricating my own solution, I did an internet search for a lighted automobile license plate frame and found Radiantz LED Lighting. Their license plate frame is USA made (Brookings, OR) cast aluminum with a black powder coated finish with 18 white LED's.

I removed the muffler to give me full access to the backside of the rear bumper.

Testing the LED license frame.

http://forums.pelicanparts.com/uploa...1737256417.jpg

This unit uses a simple 2 wire connection: white for +12V and black for ground. I used crimp-on 1/4 inch blade connectors to connect the LED license frame wires to one of the original license plate light wiring pairs (I used the driver's side wiring pair). The original wiring pair is gray for +12V and brown for ground, so my connections are easy to remember: light to light and dark to dark. Of course if I get it wrong, the LED's don't light up as they are polarity specific.

I drilled a 1/2 inch hole in the bumper to pass thru the LED license frame wires.

http://forums.pelicanparts.com/uploa...1737257132.jpg

I bought one of the wiring grommets for the rear bumper (p/n 911-505-347-00) and installed it in the hole I had made to protect the LED license frame wires.

http://forums.pelicanparts.com/uploa...1737257357.jpg

I used black electrical tape and wrapped the LED license frame wires and passed the wires thru the grommet in the bumper. Then I assembled the LED license frame and the license plate to the license plate mounting bracket with M5-0.8 x 10 mm stainless steel counter sunk machine screws that use a 3 mm hex head to make it more challenging to steal.

http://forums.pelicanparts.com/uploa...1737257504.jpg

Next, I made the wiring connections to the car wiring and secured the wiring with adhesive backed mounting squares and cable ties.

http://forums.pelicanparts.com/uploa...1737257652.jpg

I replaced the muffler, then tested the LED license frame.

http://forums.pelicanparts.com/uploa...1737258751.jpg

Now I think I'm done with my DIY projects for a while....

Just One More Change - Honest!
 

Okay, at the end of an earlier post I said "Now I think I'm done with my DIY projects for a while....", well I guess a short while.

I decided to complete my 75 Carrera front end modifications by replacing the US spec front side marker lights with the Euro front side rubber molding pieces (p/n 911-505-307-00 left and 911-505-308-00 right) as I like their look better.

So I removed the front bumper again and removed the side marker light housings. I also dismounted the front marker light housings so I could pull the front bumper away from the car.

http://forums.pelicanparts.com/uploa...1739069664.jpg

Then I removed the rubber accordion pieces that fit between the bumper and the front fender extensions. I loosely mounted the front side rubber molding pieces. Then I needed to trim off the rubber flap on the bumper end of the rubber accordion pieces with a utility knife and I remounted the rubber accordion pieces to the front bumper. Then I tightened the side rubber molding pieces and the rubber accordion pieces to the bumper.

Then I sat the bumper on the front bumper mounting struts and remounted the front marker light housings to the bumper and finally I remounted the front bumper to the car.

Here is the front of the car in stock US spec trim from April 2023:

http://forums.pelicanparts.com/uploa...1739070581.jpg

Here is the front of the car today with the various modifications done (H4 headlights, bumper tucked 1/2 inch, fog lights removed, and side marker lights replaced with rubber molding pieces plus I reinstalled the right side rear view mirror which I had added in 2007 then later removed).

http://forums.pelicanparts.com/uploa...1739070807.jpg

Good luck with your DIY projects and enjoy!

MoBetta!

One Last Detail
 

When I did the front bumper tuck, I removed the fog lights and filled the mounting and electrical wiring holes with rubber grommets. I knew that was only a temporary fix so this week I got busy with a permanent solution.

I removed the front bumper and the front valance, then removed the chin spoiler from the valance then hammer and dollied the valance to flatten out the area around the center mounting hole. After sanding back to bare metal front and back around the fog light mounting holes, I hand formed two 3 1/2 x 4 inch pieces of .020 inch sheet metal to lay flat against the backside of the valance - one for the each fog light. Then I applied an even coat of JB Weld to each patch piece and placed them on the backside of the valance and held them in place with wood blocks and metal spring clamps.

After a 24 hour cure, I removed the wood blocks and spring clamps and sanded off excess JB Weld from both sides of the valance. Then I masked off the outside lip and applied two light coats of under coating to the backside of the valance and removed the masking tape.

Turning back to the front of the valance, I applied a thin coat of Bondo to each fog light area and waited for the Bondo to harden, then I sanded off the excess Bondo. After cleaning the front side of the valance with degreaser, I applied two coats of primer, then let the valance cure overnight.

The next morning I took the valance to the local body shop to get a sealer coat, base coat in GP White (code 908) and clear coat on both sides.

Two days later, I picked up the painted valance, reassembled the chin spoiler and then installed the valance and the front bumper. The front bumper project is now completed.

Hammer and dolly work

http://forums.pelicanparts.com/uploa...1740629210.jpg

Epoxied patch pieces

http://forums.pelicanparts.com/uploa...1740629305.jpg

Under coated backside

http://forums.pelicanparts.com/uploa...1740629359.jpg

Bondo applied to frontside

http://forums.pelicanparts.com/uploa...1740629424.jpg

Before photo

http://forums.pelicanparts.com/uploa...1740629473.jpg

After photo

http://forums.pelicanparts.com/uploa...1740629526.jpg

Smoooooth, Dan! I like it!

Oil Breather Tank
 

When I converted the CIS to ITB EFI, then later rebuilt the engine, I decided to leave the evaporative charcoal canister in place and to add a filter to the end of the oil breather hose that originally ran from the filler neck of the oil tank to the post air filter side of the air inlet box on the CIS.

http://forums.pelicanparts.com/uploa...1744761802.jpg

Initially the air filter on the end of the breather hose worked fine with no oil leaks, but after 3k+ miles I started to see oil that had accumulated in the filter dripping onto the engine tin along the peak of the 4,5,6 cam tower and then on down to the lower front corner of the exhaust valve cover and I decided I needed to replace the filter with a breather tank.

After a short internet search, I chose a Moroso unit (#85475) that has an AN-16 breather inlet to match the 1 inch ID of my breather hose. I used a grinder to grind down the AN-16 threads to make the tank inlet a smooth slip fit so I could use the existing hose clamp to secure the breather hose to the tank. i also substituted a 3/8 inch pipe thread plug in place of the Moroso supplied drain valve as the install location does not have room to accommodate the drain valve.

The first step in the breather tank install was to remove the evap canister as I had decided to mount the breather can in the space occupied by the evap canister. I cut the vapor vent hose from the fuel tank and routed it to face down towards the ground in the gap between the rear shocks cross bar and the back of the cabin. I also cut out the canister purge hose that ran from the pipe fitting in the engine fan shroud to the evap canister, and I used a piece of Gorilla tape and a short length of the purge hose to plug the pipe fitting.

Breather tank mounting area:

http://forums.pelicanparts.com/uploa...1744763890.jpg

Removed evap canister:

http://forums.pelicanparts.com/uploa...1744763952.jpg

Plugged fan shroud hose fitting:

http://forums.pelicanparts.com/uploa...1744764036.jpg

Next, I fabricated a mounting bracket between the inner fender well and the left mounting hole of the supplied breather tank mounting clamp; the right mounting hole of the supplied breather tank mounting clamp would be bolted to the existing evap canister mounting bracket. The fabricated mounting bracket was made from 1 1/2 inch wide, 1/8 inch thick aluminum flat bar stock cut to 3 1/2 inches in length. I made about a 20 degree break at the midpoint along the length of the mounting bracket to accommodate the angle of the inner fender. I used 1/4 inch sheet metal screws to attach the bracket to the inner fender and M6 x 20 mm bolts, washers and Nylock nuts to attach the breather tank mounting clamp to the left and right mounting brackets.

http://forums.pelicanparts.com/uploa...1744765307.jpg

http://forums.pelicanparts.com/uploa...1744765307.jpg

I didn't want to leave the pointed ends of the sheet metal screws in the right rear fender well, so I used a grinder to trim back and smooth the ends of the screws and hopefully prevent a catastrophic right rear tire failure.

http://forums.pelicanparts.com/uploa...1744765951.jpg

http://forums.pelicanparts.com/uploa...1744765951.jpg

http://forums.pelicanparts.com/uploa...1744765951.jpg

Cam Tower Oil Disribution Tube Orientation
 

I have been chasing down and fixing small oil leaks on the 4,5,6 side and have it mostly fixed, but I got to thinking about the orientation of the oil distribution tube in the camshaft housings and decided to pull the intake valve covers and take a look.

Glad I did as I found I had the oil distribution tube on the 4,5,6 cam tower 180 degrees out of alignment - when I was assembling cam towers I got one of them wrong. When you have the oil feed fitting and the oil plug out of the cam tower as I had during engine rebuild, the oil distribution tube can rotate freely by hand.

An oil drip would form at the bottom of the exhaust valve cover at the #6 end:

http://forums.pelicanparts.com/uploa...1747698939.jpg

Incorrect oil tube orientation on the 4,5,6 cam tower - the 2 visible holes should be pointing at the camshaft lobes not at the valve cover:

http://forums.pelicanparts.com/uploa...1747699191.jpg

Correct oil tube orientation on the 1,2,3 cam tower, notice the hole pointing at the rocker arm oil lube hole:

http://forums.pelicanparts.com/uploa...1747699277.jpg

This photo, if you look closely at the scratchy mirror image, shows the oil feed / alignment thru hole visible at both the oil feed and oil plug holes in the cam tower. The oil plug has a pointed end that fits into the thru hole at the end of the oil distribution tube and locks the orientation of the oil feed tube so oil goes where it is supposed to:

http://forums.pelicanparts.com/uploa...1747699847.jpg

I rotated the oil distribution lube to the correct orientation in the 4,5,6 cam tower and re-installed the oil plug at the back end (# 6) of the cam tower to lock the oil distribution tube orientation, then I re-installed the oil feed fitting at the front end (# 4) of the cam tower and re-attached the oil feed line. Then I re-installed the intake valve covers and spark plug wires.

http://forums.pelicanparts.com/uploa...1747700164.jpg

I'll see if not having oil sprayed at the inside of the 4,5,6 valve cover has any effect on my last small oil leak. And clearly having the oil sprayed at the correct locations on the 4,5,6 camshaft lobes and rocker arms will promote longer life.

Living and learning.

My TPS Got Noisy And Had To Be Replaced
 

After watching a situation develop since I installed ITB EFI and with only 4500 miles on the system, I concluded that the TPS (throttle position sensor) had gone bad and needed to be replaced. By gone bad, I mean the TPS had become increasingly noisy especially at the low % TPS end of the wiper.

With TunerStudio connected to the MegaSquirt2 ECU and the engine running, warmed up (no WUE - warm up enrichment), and at idle (950 rpm), the % TPS would swing from -0.5% to +1.7% and when I SLOWLY opened the throttle just off idle the TPS Acceleration Enrichment would start firing and the idle speed would become erratic and the injector pulse width would start jumping. When I let the throttle return to the idle setting, the system settled back down.

On the freeway, this behavior translated to bogging / hesitation whenever I was at very light throttle cruising along on level road (for example: at 65 - 70 mph (approx 3000 rpm)). Again, with TunerStudio connected, running and a datalog recording, I could see the TPS Accel Enrichment was triggering and the AFR was very rich at 11:1 with a target of 14.0:1.

The Green Spikes in the bottom graph are from the TPS Accel Enrichment firing:

http://forums.pelicanparts.com/uploa...1749177414.jpg

Since the CIS to ITB EFI conversion kit I installed has ITB's from Race Hardware Developments, I went to the RHD website in search of information regarding the TPS used with my ITB's. I found the TPS part number plus a good discussion on why RHD recommends using Alpha-N (TPS) versus Speed Density (MAP sensor) load sensing with ITB's.

http://forums.pelicanparts.com/uploa...1749185328.jpg

The RHD FAQ page also states that the MAP signal can only be used in conjunction with the Alpha-N. In TunerStudio, that option is on the General Settings page and is called "Multiply MAP (Caution!)". I tried running my engine with this setting set to "multipy" but my vacuum signal is weak and erratic due to the large degree of intake and exhaust valve overlap with the camshaft I am running, and I could not control the engine speed below about 3000 rpm so I run my tune with this setting set to "don't multiply".

http://forums.pelicanparts.com/uploa...1749185837.jpg

So, I replaced the TPS with the BMW unit (13-63-1-721-456) listed on RHD’s website.

When I removed and checked the old TPS with a DMM it looked okay at DC, but I knew it was noisy and triggering from the Accel Enrichment spikes on the datalog I recorded.

Anyway, I ordered a new BMW TPS from Pelican which I received today. After checking all my ground and power wire terminations and wire connectors as okay, I installed the new TPS, performed the TunerStudio TPS calibration, checked for fuel pressure/leaks and started the engine.

TPS Calibration dialog box in TunerStudio:

http://forums.pelicanparts.com/uploa...1749185622.jpg

Now % TPS at idle varies much less - +0.5% to +0.7%, I was able to reduce the TPS dot threshold from 25%/s back to 15%/s, and after running auto tune the car cruises down the freeway with the AFR right around 14.2:1.

I also found that with the new TPS and a stable % TPS signal that I had to add 0.4 ms to the TPSdot Accel Enrichment pulse width adder in order to achieve smooth tip-in response without bogging or intake back firing.

http://forums.pelicanparts.com/uploa...1749185837.jpg

Old TPS (bottom, part number and other markings obscured) versus new TPS (top with BMW logo and part number):

http://forums.pelicanparts.com/uploa...1749178330.jpg

I had the same issue way back when with my kit- the TPS sensor was trash and causing all sorts of problems. In fact, I ended up replacing every component of my kit other than the ITB's with better, non Amazon-generic crap parts. Makes a big difference, whoda thunk it!

That's a really conservative AE. I'm surprised that you're adding so little fuel!

My TPS Got Noisy And Had To Be Replaced
 

Now that I have verified that a new TPS has solved my ITB EFI drive-ability problems, I have several take-aways I want to share.

1. If I were starting the CIS to ITB EFI conversion project today, I would have set up my MegaSquirt2 tune file using Alpha-N (TPS) load sensing instead of Speed Density (MAP sensor) load sensing. Even with the relatively benign camshaft in my stock 2.7L CIS motor, I could not get as smooth a tip-in, or throttle transition response, using Speed Density load sensing as I have now with Alpha-N load sensing.

2. I have ordered another BMW TPS (13-63-1-721-456-BOE on Pelican) to keep in stock as a spare (I choose to pay the extra $$ for the BMW branded part instead of the less expense alternatives). I decided it would be a good idea to have a collection of critical spare parts on hand for my now rather bespoke 2.8L hot rod engine. Along with a spare TPS, I have spares for the Pertronix ignitor, the 14Point7 O2 sensor interface, and the wide band O2 sensor.

Tps
 

Dan,
as usual, you go about debugging issues in a data driven, fact based manner. I appreciate the feedback, especially when provided with good data to back up your findings.

I've used quite a few TPS sensors, typically aftermarket,... with good success over the years, but occasionally not.

I also found the OEM BMW sensor recommended by Rama at RHD to work very well, but at a much higher cost then the aftermarket units.

My focus has always been to provide a cost effective EFI kit for the DIY crowd and good price/performance is still my focus....however, if a component provides inadequate performance, the lesser initial cost is misleading.

Thanks for the heads up ....in this case, providing the OEM part makes the performance worth the added price.

regards,
al

Is the stock BMW sensor a standard potentiometer? Is so, can you use a hall effect sensor? Non-contact sensors should last for a very long time.

For my TPS, I sourced the Variohm sensor from Digikey—it features a standard D connector and fit my BMW throttle motor. It's also dual sensing which is needed for DBW.

https://www.variohm.com/products/motorsports-sensors/rotary-position-sensors-for-motorsport/euro-xpd-d-shaft

https://www.digikey.com/en/products/detail/variohm/EURO-XPD-2832-812-214-911-00/22286984

Yes, the RHD recommended TPS is a potentiometer. Yes, you can replace the potentiometer TPS with a Hall effect TPS. You may need to fabricate a mounting plate to mount it to the RHD ITB. The RHD ITB's in my set up are not DBW, so dual sensing is not required.

I don't think the mount would be a problem. Mine is fitted to a BMW throttle motor. In fact, I removed the BMW sensor from the throttle motor. I imagine I tossed it. Too bad, I would have given it to you. I've learned a lot from your thread.

I also had problems with the non-oem TPS (two broken aftermarket units, two ruined track days). The BMW unit was much more stable. I think the potentiometer is more ‘curve’ than linear though, and it still gave me problems with tuning (persistent backfires at low-rpm tip-in) so I ditched it for a hall effect sensor which allowed me to use Alpha-N with a lot of success.

Dan,

Can I trouble you to post a picture of your TPS VE table?

I’m going to switch to TPS myself soon.

Thanks,
Rutager

Hi Rutager,

Here are screenshots of my current Alpha-N tune with the new TPS - I still need to do some more Auto Tuning in the cruise region of the VE table.

http://forums.pelicanparts.com/uploa...1749319540.jpg

http://forums.pelicanparts.com/uploa...1749319540.jpg

http://forums.pelicanparts.com/uploa...1749319540.jpg

http://forums.pelicanparts.com/uploa...1749319540.jpg

http://forums.pelicanparts.com/uploa...1749319540.jpg

Hi Rutager,

Here is a close up of the VE table, the other screenshot was too small.

http://forums.pelicanparts.com/uploa...1749320192.jpg

Thanks so much Dan!

I haven’t done a ton of comparisons on my MAP versus TPS to get a basic tune, but I wonder if making a few of the sections in normal cruising range closer together just like you have done near idle would make a smoother running car?

So, yes, making the vertical scale (% TPS Load) smaller steps near 0% TPS gives you finer control for tip-in as the engine moves off idle and I did that with both the VE and the Ignition Advance tables - that was a recommendation from Al and it really works.

You can probably stretch out the horizontal scale a bit as you are probably rev'ing to 6500 rpm max?

Before you make the switch be sure you know what the kPa is for idle and for cruising on the highway, level and steady, at say 65 mph. Let's say it's 50 kPa at idle and 70 kPa at cruise. Those two load levels in Alpha-N will correspond to say 0-1% TPS for idle and 10% TPS for highway cruise.

Now you can take the cell values from the 50 kPA row of the Speed Density VE table and put them in the 0% TPS row of the Alpha-N VE table.

Next take the cell values from the 70 kPa row of the Speed Density VE table and put them in the 10% TPS row of the Alpha-N VE table.

Since 100 kPa is wide open throttle on a naturally aspirated engine, then take the cell values from the 100 kPa row of the Speed Density VE table and put them in the 100 % TPS row of the Alpha-N VE table.

Then take the rest of the cell values from the Speed Density VE table and fill in the rest of the Alpha-N VE table. You won't be using any of the cell values for rows with less than 50 kPa (or your actual idle kPa value) on the Speed Density VE table in the Alpha-N VE table as these rows represent % TPS values less than 0 % TPS.

Use the same procedure above for the AFR table and the Ignition table.

Then I used "Tune Analyze Live!" (auto tune) while driving the car over a range of conditions to tweak in the VE table.

Then if you choose, you can take the car to a dyno shop and have a calibration technician optimize the VE and Ignition table values for max torque and hp.

This is the procedure I followed when I converted my tune from Speed Density (kPa load) to Alpha-N (% TPS load).