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Steve's 3.1 SC-L rebuild


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So, after a few years of procrastination, research, begging, stealing and gambling i'm about ready to start the grand reassembly.

Barrels are refurbished, heads are back from the shop, spare parts are purchased.....mostly, measuring is done, cleaning complete.....mostly, i even built a proper workstation in the garage to be more organised and clean!

I'm just waiting now for all the hardware to come back from the plater and i'm going to start. I thought i'd start a thread, garnish some advice from you more experienced and try and throw some light on the 3.1 at the same time. I've hunted high and low and found pretty much zero info apart from a few documents here and there and one helpful specialist ( most of them didn't believe and some were really quite rude ). Plenty of rumours.....some i'm not sure are true!

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So i just laid the pump in as i haven't given it much attention since the strip down.

I had a quick look and it seems that it is 930 pump. I know that the case has been open before and i guess that is when it was fitted. As far as i know the turbo pump was not fitted as part of the original 3.1 conversion in the factory so it must have been added later. I remember it had a nut missing from one of the studs when i disassembled it and the intermediate gear looks dogeared.......now replaced.

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The pick up mesh seems a little strange also, it is part of the sump cover assembly, you can see in the next picture.

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I fount the two pins in the case had migrated out of position by about 5mm, i drifted them back into position with an aluminium punch quite easily , is this a common problem does anyone know?

Further inspection show almost zero backlash and no end float so i'll refit it as is.

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One question, maybe someone can help? The junction between the pick-up and the case of the pump looks like it had some kind of seal that is breaking up. Photo below, it looks like glue.....any ideas?

20220114_144415.thumb.jpg.ed3956b99ea68891d8e22232e14799fb.jpg

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Really interesting stuff, please keep the progress updates coming.  I don’t know much about the internals, but you could try emailing Mike Bainbridge he is a font of knowledge and is a helpful guy.  
 

 

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Those ones are used between the engine case and the oil pump and between the oil cooler and engine case.

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3 hours ago, Northy said:

Really interesting stuff, please keep the progress updates coming.  I don’t know much about the internals, but you could try emailing Mike Bainbridge he is a font of knowledge and is a helpful guy.  
 

 

Haha, he was the only helpful specialist ! Sadly covid ruined my plans to go up there......its a long way from the south of France!!

Maybe i'll give him a bell....

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If you're interested watch this guy, he's by far the best i've found, He's seriously switched on and explains how.....and more importantly why.  Porsche trained and happy to spread the knowledge. He answers all questions on his youtube channel and is super informative. 

Klassik automotive https://www.youtube.com/channel/UCbo48hJkHDikGut5DoL6-sQ

It's not easy to pick up the intricacies of these engines as not too many experienced guys have the time or the inclination to hand out the info. Understandable when it's their livelihood.  But......it's not rocket science! I spoke with Mike Bainbridge for quite a while, very nice guy.

I also watched Kav911, homebuilt by Jeff, Nick Fulljames, read Wayne Dempsey, Bently and the Porsche official manual ( thanks Nice, great download ) They all have things to offer and they all make mistakes. I'm an engineer by trade so i have a reasonable competent filter!!

Since i came by this car i've definitely learned a few things......nothing and i mean nothing is cheap!!  there are almost no "work arounds" you must do it properly in order to do it once!!! I've made a few stupid mistakes that have cost me dear but thats part of the process! You guys are lucky in the UK as you have access to almost everything, spares, specialist services etc etc.....down here it's a bit thin on the ground and mega expensive....and with Brexit completely screwing up cross boarder trade.....i shouldn't start!!!  This summer i will drive to the uk for holidays and bring the bits and pieces to refurb, wheels, fuel metering, fan housing etc etc!!

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Yesterday evenings' little mission, renewing the epoxy on the rear of the chain housing.

Process, draw a nice little circle around the area ( don't want it looking like a Jackson Pollock) , dress back the surface with scotchbrite or Dremel ( very lightly), degrease thoroughly then apply J-B Weld (very expensive) properly ensuring you work it into the material to get proper adhesion.....lastly try to make it look nice!

20220114_144745.thumb.jpg.8e77b7ad67d85b400c28e4b06b9d18d4.jpg  20220115_173600.thumb.jpg.acb989bfaeca12754b5a311348895a9d.jpg  20220115_173616.thumb.jpg.92cc9b2698e53b4309d448e00a61fa4b.jpg

 

 

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Oil pump disassembled, easily done.

Careful to keep the correct engagement of the rotors.

20220117_165128.thumb.jpg.8eebf9eca60f084838d70958490867e1.jpg        20220117_165517.thumb.jpg.e014aa1c4d6dfea1948197649cee8c7c.jpg  20220117_170850.thumb.jpg.22e4a4b0cb21a4ec357f2d2e261f6c9e.jpg    20220117_171408.thumb.jpg.c66e49c56dadf7dc626b3f950e5f060e.jpg   

Scavenge rotors slide off the shafts, woodruff key off and then slide the pressure assy back through the centre plate.

Pressure rotors secured together with zip-ties to keep the mesh positions.

Some scoring on the scavenge side but nothing too serious. I'm going to skim a few thou off and reassemble.

 

20220117_171648.thumb.jpg.eaec68e0878e430202103c359a11b643.jpg   20220117_171723.thumb.jpg.1f0a74ef4f6099f68f6d4a73fe575206.jpg

I'm informed to refit the pickup ( after cleaning and re-plating ) with JB-weld and re-torque to case bolts to 6 ft/lb with loctite 270.

 

 

Next is oil squirters!!

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20220119_135503.thumb.jpg.ccff3aefa0e0b8edddba5669a6ba6a0c.jpg

Clean and degrease with MEK ( the king of solvents ), mask off around the hole

Then apply JB to both pick up and pump case and lay into the block with the strainer in to make sure the position is perfect.  Now hurry up and wait...

20220119_140337.thumb.jpg.16af53e12805b5fbb1dcd2bb8735707a.jpg

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Ok thats that sorted!

Just cleaned up the excess with a dremel and made the filet seal around the tube all nice, next get the centre plate skimmed and put it back together!

20220120_133151.thumb.jpg.1b88093c08ff18e1589f16dac921fcaf.jpg  20220120_152517.thumb.jpg.c2c922a921782bccce2e4163d25778e4.jpg

 

20220120_135124.thumb.jpg.e8f13cbf2fe915d6fb91c84e74b44b75.jpg

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Here's a question, with the 930 pump, bearing in ming that the piston squirters need to be replaced anyway, should i fit the 930 piston squirters?

The 930 pump has  larger scavenge and pressure rotors as apposed to the 964 pump which just has a larger scavenge (when compared to the SC model) so maybe its best to use the larger squirters ?

🤔

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So, todays mission, remove piston squirters.......without damaging the bore!!

Step 1 Tools

Dremel with small round grinding bit, slide hammer, 5mm sturdy self tapping screw, screwdriver, pick, brake cleaner and a blowtorch.

20220124_161759.thumb.jpg.4933eb2fadb33b13f6d34849a3c367cc.jpg 

2 Grind away staking....very carefully

PS1.thumb.jpg.1215a548e331f114191cadf23a23c2d8.jpg 

Then continue through the orifice plate, it will spin but it cannot resist the dremel!!

You can grind away the plate completely with zero risk to damage the case bore, if you drill now like others describe you risk not going straight and doing some damage. Play it safe. Once you get it out, remove the spring with a pick and turn the case upside down to remove ball-bearing.

 PS2.thumb.jpg.00f178d28f1267f0474cb403c4bff1aa.jpg

3 Apply fire !!!! hahahahahah

4 Insert you 5mm self tapping screw, use a decent steel one about 8-10 cms long.

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5 Use your slide hammer to tap them out

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FYI,  Piston squirters for the 3.0l are 6.24mm and i measured up the case holes at 6.285mm......ish ( i've read plenty of........questionable info on the size of these things )

None of them were loose, they were all being help by their loctite and were not being retained by the staking.

20220124_150946.thumb.jpg.d28a77f570e5064570aae1ae0e3ba82c.jpg   20220124_151202.thumb.jpg.883397c7beebf45889867cad1aaad44c.jpg

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  • 3 weeks later...

It was a long way to come, but i saved the shipping costs 🙂

Seriously good turnaround time,  for metering head - strip, clean, rebuild, test, strip and rebuild again, test again and paint WUR -gut and refurbish and test, Airslide -strip, repair rebuild and test, cold start injector test and clean........3 days!!!

Top service, many thanks to Colin at K-Jet Specialist in Tanah Merah!!

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  • 1 month later...

20220310_101123.thumb.jpg.1afaa61aa5826bca0086ab933d3da103.jpg       20220310_102051.thumb.jpg.026e74c7ae65e41fd2e6545eb990cfa3.jpg    

 

 

Little mission, Oil Pump back together

 

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Hardware off to the platers...........that was a lot of cleaning from a very gracious friend!!

Lets see how it turns out......never realised quite how many studs there are in this engine!!

 

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Edited by Gezzer
photo adjust
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But....crankshaft nightmare!

I've measured my crank and rods today, rods are good but crank is under spec on the rod journals )-: .........a rainy day measuring in the garage

Small end bushes replaced already, just a little hone on number 5

20220313_141023.thumb.jpg.d7a08af0de38c09187d2c2eb39fb02a2.jpg  measurments.jpg.7a45de4e99c2542b895fc5840a0d5813.jpg

Anyone know a reliable crank grinder in France ?!!! 

Need to go to 1st undersize -0.25mm

I used three pint bore mics on the rod and i'll double check with two point to check ovality, but they look good. I'm reliably informed that these 930 rods are super strong!

20220313_134502.thumb.jpg.c4c4e519757aa406a4ce9d0adc614762.jpg

 

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Oooooooff....first quote from UK workshop.....and that doesn't include the undersize bearings!

Not mentioned but it includes plug removal and cleaning

Crack test crankshaft................................£39.10
Re grind big end journals x 6....................£241.50
Polish all journals post tuftride..................£141.96
Re harden crankshaft...................................£125.00 / £150.00 depending on weight
Balance crank, flywheel assem, if req..........£159.79
Balance con rods if req x 6...........................£96.60
 
Still checking if we can supply bearings
All prices subject to vat @ 20%
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19 hours ago, Gezzer said:

Oooooooff....first quote from UK workshop.....and that doesn't include the undersize bearings!

Not mentioned but it includes plug removal and cleaning

Crack test crankshaft................................£39.10
Re grind big end journals x 6....................£241.50
Polish all journals post tuftride..................£141.96
Re harden crankshaft...................................£125.00 / £150.00 depending on weight
Balance crank, flywheel assem, if req..........£159.79
Balance con rods if req x 6...........................£96.60
 
Still checking if we can supply bearings
All prices subject to vat @ 20%

That looks about right for the pricing. I had a crank reground last year with the same grind, the price of bearings will be the largest cost and from memory around £800! Good luck with the rebuild.

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