Restoring my first 914

For all you Porsche 914 fanatics!

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Darren C
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Re: Restoring my first 914

Post by Darren C »

Cheers guy's, I need a little convincing as I know they could be better :roll:

Today is my 914 anniversary.....

It's exactly 12 months since I picked the car up from Southampton Docks :shock: :)

I can't believe it's been a whole year and such a big journey to get the car restored. All that's left to do really now is fit the wheels and drive it down for an MOT :wink:

Not the best time of year to be doing this weather-wise but for me it's going to be my ideal Christmas weekend.....tinkering in the garage on the very final touches to complete the little car. :)
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Re: Restoring my first 914

Post by jackstowers »

Shame it won't be registered in time for New Year's Day at Brooklands
David

1973 914 zambezi green
1972 911T (lhd 71E engine)sadly sold
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Re: Restoring my first 914

Post by Darren C »

You can’t rush a good wine David. :wink:
I hope to be at Brooklands on New Years Day anyway. I can’t believe it’s come around so quick, it seems only yesterday I was meeting you and the other guy’s, looking at your 914’s and asking numerous questions. It’ll be good to catch up with everyone again, I presume you're going?
Anyway, I couldn’t wait until the weekend to wash and clean the wheels to get the tyre fitters paw prints and soap off. I gave them a good clean this morning (in the dark) and finished them off this evening (again in the dark). After a chamois I brought them into the house to dry. :)
Off into one of my sheds and unpacked the nice new centre caps that I got in the summer with my large order to 914rubber. I’d taken one over to the anodisers to use their special meter to check firstly if they’d been anodised at all and to what thickness. :?
The chap said they’d had a chemical brightening process before between 6 & 8 microns of clear anodise applied.
I considered having them re-anodised to a thicker coat but the chap said that he couldn’t do that without dulling them down a little because he couldn’t replicate the chemical brightening on site. After a little thought I decided to leave them as supplied. They’re a relatively cheap item so if in 5 years they corrode I can just buy some more.
Tonight I went over the 5 wheels and selected the one to be the spare then fitted the centre caps to the remaining 4. These were bloomin tight to get in, even with a little PH neutral soft soap, in the end I had to use a block of softwood and mallet to get them in. :roll: Hopefully they won’t fall out easily!
I couldn’t resist placing the bolts in the holes loosely to see how they looked. :wink:

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I have to work tomorrow (this time of the year is the busiest at work than any other :( ) and won’t get home until late when it’s dark, so fingers crossed after dropping my son off on Christmas afternoon I’ll have an hour of daylight in the garage to get them back on the car. :)
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jackstowers
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Re: Restoring my first 914

Post by jackstowers »

We will be there indeed, be good to catch up
David

1973 914 zambezi green
1972 911T (lhd 71E engine)sadly sold
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Re: Restoring my first 914

Post by Darren C »

As I was off work today I decided to take advantage and get the wheels fitted to the car. I got up at dawn (before the rain swept in) and started by coating the mounting faces with a light smear of copper grease. This should stop them sticking to the brake discs over time and help prevent corrosion. :wink:
I carried each wheel in turn out of the house down the road and into the garage block in a wheel relay race to beat the rain clouds. All inside the garage (a bit cosy I can tell you as there’s hardly room to squeeze down each side of the car let alone do it with 4 wheels in the way) I set about copper greasing the newly plated wheel bolts and sitting them neatly on 4 sheets of kitchen roll by each hub.
Having checked the owners handbook for the torque setting (for 39mm bolts) I set my wrench and fitted all 4 wheels before finally removing the axle stands to drop the car onto the floor and torque the bolts up. :)

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Within minutes of opening the garage door this morning the car (freezing cold from overnight) began to condense moisture over every surface from the warm humid air entering the garage. By the time the wheels were fitted the car, to my dismay, was dripping wet with condensation! I chamois it off but it fogged up straight after so there was nothing I could do until it physically warmed up to the outside temperature. :(
I retired to my shed and unpacked the front undertray that I’d had previously blasted and powder coated. With the axle stands now removed and back into the shed I could fit the tray over the steering rack. I’d got some rubber trim from Woolies, they list it as “mudflap” trim, some call it feather or lip edge, but it’s the same stuff as original. The lip on the Woolies trim is about 4mm wider than the old trim, but apart from that its identical. I’d put the trim on the undertray in the same orientation as the old one that came off, but had to admit the old one didn’t look great when it was on the car.

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I fitted the tray after cleaning up and waxoiling the bolts, but wasn’t happy with the fit of the seal to the car underside. Lying under the car looking at it I pondered for a while (while watching the suspension arms slowly fog up with condensation!) and decided to take the tray back off, remove the seals, flip them over and refit the tray.
Perfect!
With the seals reversed the curl in the lip met the underside of the car and followed the contours perfectly to close all gaps. :)

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With the axle stands gone I went around and did a little touching up just as the wind and rain moved up a gear so I called it a day as the wind kept lifting and rattling the half open “up and over” door allowing the rain to blow all over the rear of the car. :roll:
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Bewildebeest
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Re: Restoring my first 914

Post by Bewildebeest »

Well done Darren. I've been looking forward to this more than my Christmas dinner. (Yes really)

With the next bit of sunshine can we have some full on side shots ???
Darren C
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Re: Restoring my first 914

Post by Darren C »

:lol: Very funny, let’s hope "her indoors" doesn’t read your review of her cooking! :roll:

Today I was up and out before dawn to attend a classic car show in Wickham Square, North of Fareham. There’s always a varied turnout of cars and today was no exception. My favourite car of the day had to be a lovely burgundy 912, with a 3 letter 3 digit 912 plate. Seemed like a nice guy until I mentioned DDK and it hit a nerve with some passed forum squabble or something? Hey ho life’s too short for all that.
Anyway I had a nice day out and the weather stayed dry which helped.
I got home mid afternoon and straight on to the 914.
I took the carbs apart and fitted my new 32mm venturi’s in place of the 28’s, reduced the air correctors to 175’s and the mains to 125’s.
The engine ran up easy then as it was warming through it started to splutter and died? :shock:
Since I’d fitted a fuel return, when the engine stopped I couldn’t hear the pump? :(
Hmmm, lifted relay cover and took out the Brand new genuine Porsche relay and swapped it with an old one that came with the car, pump ran up again….bloomin annoying. :evil:
I did notice that the large voltage regulator fastened to the relay board had got a very hot bracket where it screws onto the relay board (not the dome cover, just the brackets)??? :? I’m wondering now if its on the blink or I’m getting excess voltage (which might have killed the new pump relay?) or that's actually normal?
The gauge on the dash shows a shade over 14V when running so on initial inspection seems ok. I need to get my meter on it tomorrow in the daylight.
Does anyone else have a hot voltage regulator when running?
With the relay swapped over I ran up the car and all was good again, apart from a hot reg bracket, but I need to fine tune it now as I have suspicions on the timing as I’ve not checked that since buying the car.
Jobs for tomorrow. :wink:
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Darren C
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Re: Restoring my first 914

Post by Darren C »

This morning, making use of the dry weather, I sorted a few jobs out on my Audi before mid morning then moved onto the 914.

All went well first thing. I turned the engine over by hand (spanner on the alternator nut) and revealed the timing marks on the fan. I gave them a degrease with a small paint brush soaked in cellulose thinners, before using a very fine modellers brush to paint the thin line white. I carefully continued this across the fan blade to cover the width of the fan in a bright thin white line.
With the relay replaced yesterday I started the engine and warmed it through. The alternator output was checked and by meter was 13.44 volts so no issue there, which was a relief.
Next I set and checked the timing to the 27 degrees mark at 3500rpm with the vac pipe off. It was a tiny bit out but nothing to shout about. With it reset spot on I did up the clamp and put my strobe light away just as a friend turned up with his dwell meter.
A quick check of the dwell and it was all good at 45 degrees.
I was just about to fine tune the idle speed and the engine died, just like yesterday?
Today in daylight I could see better than yesterday evening and after initially suspecting the relay (I took it out and tested it….but it was ok) I noticed the fuse on the relay board looked burnt.
On closer inspection it had blown but in a heated slow way which meant that the two halves touched when cold and parted when hot. This was causing the issue yesterday. When the engine was cold it ran up, when it warmed through it parted and cut the engine out.
This was a 25A fuse, so something was amiss?
I spent the afternoon chasing myself around in circles and discovered a partial earth on the 87 pin of the fuel pump relay connection in the relay board when the 14 pin plug (nearest the bulkhead) was disconnected?
At first I thought it must be a fault in the relay board so removed it from the car for testing but all seemed good. After a bit of head scratching and staring at the Haynes wiring diagram I noticed in very fine print, a take off from the fuel pump relay pin 87 (built into the relay board) that feeds pin 12 on the 12 pin connector at the rear of the relay board (nearest the boot). This has a white wire that feeds the FI Supplementary Air Valve that I’d removed when fitting the Carbs. Inadvertently when I reconnected up the main wiring loom I’d got one spare male spade in a single housing and one female spade from Temperature sender II that were both located by the coil. With everything reconnected and the FI loom off the car I’d foolishly connected these two wires together on the basis that they were the only two connectors left and were the correct position on the engine as the loom lay to joint together. WRONG!
So in reality I’d put a resistance to earth on pin 87 of the Fuel pump relay via the Supplementary Air Valve cable…Doh! It was a slow heat of the fuse on the relay board that eventually blew it.
Having realised my mistake I disconnected the wire just as my friend who was googling “blown fuse on 914 relay board” came up with a short on the Supplementary Air Valve wire!
Suffice to say I swapped the fuse over for a 16 Amp (instead of a 25A) as I have no rear heated window and to give a better earlier indication of any future faults.
It wasn’t a relay after all, just a self made error. :oops:
The voltage regulator still runs warm to the touch, but as there’s a vent opening under it in the relay board and I’m measuring 13.44V, I suspect that its normal to run warm?
On the bright side though....I have the carbs running sweetly. No nasty spitting back or popping that you usually get as a compromise with Carb conversions. :)

Just need to sort out the advance curve now on the dizzy.
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911hillclimber
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Re: Restoring my first 914

Post by 911hillclimber »

That reads to be a busy day at the office compared to me timing my little Honda twin!

Good going, going to wheel it out soon and take a picture or two?
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Darren C
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Re: Restoring my first 914

Post by Darren C »

Wheel it? :wink:

I hope to drive it out soon :)
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Darren C
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Re: Restoring my first 914

Post by Darren C »

After the weekends tinkering and setting up of the Carbs and timing etc I wanted to get the vacuum advance working on the original Distributor as changing to a fully centrifugal (which most people do) has its issues with flat spots and poor mpg.
That said if I can’t get the original vacuum advance to work with these carbs then I may still need to go down the centrifugal route, but not before trying :wink:
Currently with all the tinkering at the weekend the car runs well with the vacuum plugged. Connect it up with my new pipe and the car runs worse?
This got me thinking and reading up on line articles and also some old 1970’s Weber books I have.
I think the issue is that the new carbs have a single vacuum port with a short stub pipe on each carb and the original FI took the vacuum from the combined manifold at the chamber.
The pipes on the IDF are “ported” vacuum take off, which isn’t quite the same as manifold or “direct” vacuum.
The ported vacuum take off is shown highlighted in red below and is a 15mm long 5mm diameter pipe sticking out from the carb.

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There’s plenty of conflicting information on the internet and reading numerous articles just confuses you more. Many people advise to drill and tap a point in the intake manifolds to get a “direct” vacuum but there is already provision for this on the IDF that most people forget (arrowed as "vacuum ports"). There are two plugs next to the two mixture screws for manifold vacuum take off.
Problem is buying something that fits these (most vendors don’t understand what you want) so tonight after work I set about making some on the lathe.
After removing a blank plug and id-ing the thread as M4, I cut down four 20mm pieces of stainless 5mm diameter bar left over from making the throttle linkages.
The next stage was to face off chamfer and machine a 5mm length on the end, down to 4mm diameter and under cut the shoulder to 3.3mm and cut an M4 thread on it.
Next I faced off the other end and drilled a 3.2mm hole 13mm deep. This was then tapped out to M4 to a depth of 6mm.
The idea is that the plugs that came directly out of the carb to blank the holes will fit exactly the ends of these tubes to blank them. This is to ensure that I have some flexibility in using all or none of these tubes in the end. I plan on experimenting at the weekend with my bank of 4 vacuum test gauges to see and measure exactly what’s happening at the new “direct” manifold and at the carb “ported” tubes. (I’ll post some pictures at the weekend) :)
Finally to finish off the new manifold vacuum pipes I drilled the last 7mm in length at 2mm diameter through the middle of the M4 male thread to ensure it still has a decent wall thickness and strength.

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It was difficult getting a good focus on the camera as these are so small! :wink:
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Darren C
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Re: Restoring my first 914

Post by Darren C »

Today I thought I’d investigate the vacuum/timing characteristics of my car in an attempt to understand the optimum method for ignition timing and use of vacuum advance with a standard dizzy using Weber 40idf carbs. :)

As I’ve said before, it would be nice to keep the original dizzy (if I can get it to work well) with the carb conversion. It’s a bit like one of those Top Gear challenge specials. I have a fully centrifugal 009 with 050 advance curve lurking in a box in my shed. If I can’t get the original dizzy to work well, then the box is opened.

The first thing I did today was take out the Weber manifold vacuum plugs and fit my new tubes on cylinders 1 & 2.

Next I connected vacuum test hoses to these points (leaving the “ported” vac pipe still plugged and my blue “bespoke” vac pipe disconnected)

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The hoses were run to my Carb Synchroniser panel gauges 1 & 2.
I then connect gauge 4 to the carb on banks 3 & 4; to its single ported vac pipe and ran up the engine with no connection to the vac diaphragm on the dizzy (as you do to time the car).
After warming through and sitting a tad below 900 rpm I could measure the vacuum in the intake manifolds of cylinders 1 & 2 and the ported vacuum of the carb on bank 3 & 4.

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To my surprise I had a reading on 1 & 2 and nothing from the ported vac pipe on the carb over 3 & 4 ?? :?

Hmmm. The balance on 1 & 2 was fine, but zero on the carb ported pipe.

I gently rev’d the engine to around 1200rpm and from about 1000 upwards I started to get a reading on gauge 4 from the ported carb vac.

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Not a great vacuum but watching and comparing “ported” with “direct” (manifold) vacuum, the results are that my 2.0L engine has manifold vac from idle to around 1500 RPM which peaks around 1000 and drops off to zero as the carb reaches about 15% open. The ported vac however, starts at zero when at idle, then slowly increases up to 1100RPM where it balances out with the direct vac (as that decreases) so overall the maximum ported vac is much less that the manifold vac at idle. It’s not a very good vacuum and only present for a short period of time. :roll:
Interestingly with the timing set at 27 degrees BTDC at 3500 with vac pipes disconnected as per instructions; the timing at idle is barely 2 degrees BTDC (with vac pipe disconnected). With the vac pipe connected using manifold vacuum to the pipe on the dizzy diaphragm closest to the body it pulls the diaphragm at idle to just past TDC, retarded by a degree or so (hard to tell without markings)
Since this is the “factory standard” diaphragm pipe to use for the 2.0L with the other pipe (furthest from the dizzy body) left unused, I’m quite surprised by the findings?
Is this timing at idle correct?
I’d have expected it to be a few degrees BTDC? :?

Can anyone shed any light on the timing at idle with the vac pipes connected as above on a standard 914 2.0L, for comparison please?
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Re: Restoring my first 914

Post by Bruce M »

The vacuum connection nearest the dizzy body is normally the retard port?

I've got this data from the factory manual but I think this is for the 1.7/1.8 not the 2.0.

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Darren C
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Re: Restoring my first 914

Post by Darren C »

Thanks Bruce,

Yes I believe that table is for 1.7 & 1.8. and that the 2.0L is different.
However it does show an advance timing at idle. (The vac measurements are pretty much what I'm reading in mm)
From a little digging I've been told the timing of a 2.0L at idle is "around" TDC. It's not really where you measure it as the "books" state 27 BTDC at 3500rpm, and give no indication of where it should be at idle.
Having timed my car this way and used manifold vacuum to the diaphragm pipe on the dizzy nearest the body (the one you call the retard pipe) which is where it should be on a 2.0L; my gut feeling based on how the cars running now, is that I would benefit from a few more degrees of advancement at idle.
I'm sure I've got it running and timed by the book (including the correct dwell which can give 3 or so degrees of timing adjustment).
It's my OCD that's maybe making me look for something thats not there; combined with my experience of tuning multiple engines in the past that gives me this gut feeling that with these Webers fitted I need a few more degrees of advance at idle to optimise what I've built.
If it ever stops raining today :roll: I plan on trying the vac pipe connected to the other (unused on a 2.0L) pipe on the diaphragm. This is the one that folk normally use and refer to as the "vacuum advance". In reality I believe this is the "ported" vac pipe connection, and the one your calling the retard, is the one used for "direct" or manifold vacuum.
The early carb cars used both. Working on that basis it gave you a pull on the inner diaphragm chamber at idle, a pull on both around 1200RPM and nothing after 15% throttle on either. Looking at this logically all it did in effect was offer vacuum at idle and no vacuum early on in the throttle opening as one balanced out the other. This nips the vacuum in the bud at low throttle but seems its loaded in favour of retarding timing at idle. If I play about and put my "direct" vacuum on the outer diaphragm pipe only I'll think I'll initially get what I'm looking for but may get a little too much advancement between 1100-1200rpm.
It's going to be interesting to measure and document all this as I can't currently find any record anywhere of this data.
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Darren C
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Re: Restoring my first 914

Post by Darren C »

Just been tinkering/experimenting in the garage this afternoon. It finally stopped raining! :)
So here’s what I’ve found today.
If the manifold “direct” vacuum is applied to the outer pipe on the distributor diaphragm (against the standard Factory installation) I get my “in my mind”, ideal advancement at idle, running about 4 degrees BTDC at 900 rpm.
Trouble is that as the engine revs the 27 degrees BTDC mark is reached way too early (2000 rpm) and overshoots to give excessive advancement above 2000 rpm.
So I cant place the manifold vac pipe on the outer pipe of the distributor diaphragm. :(

On a whim I rigged up a second vac pipe from some spare hose with a Tee and connected it up to the Weber ported vac tubes (the brass one) that's in the initial photo had the blue hose attached. I paired up each Weber ported vac tube and connected that to the outer diaphragm pipe and left the manifold vac hose connected to the inner diaphragm pipe. (As per an early 1.7L carb car)
Sceptical if this would work with a 2.0L distributor, I ran up the engine.
Bingo!
I kept a nice 5 degrees or so (hard to quantify without a scale) advancement BTDC at idle and as I gently rev’d the engine up to 3500 rpm it made the 27 degree mark right on target!
I may have answered my own question. As seen yesterday by gauge, the ported vac rise eventually matches the direct vacuum so cancelling each other out early and preventing advancement past the 27 deg BTDC. :)
It certainly looks like the best ignition timing installation for Weber twin carbs on a stock cam 2.0L using the stock distributor is to run both a ported and direct vacuum pipe (like Porsche did on the earlier cars) after all. :roll:

Problem now is I need to make a second one of those nice bespoke vacuum pipes to run between my carbs ported vac take offs and the outer distributor diaphragm pipe. :wink:
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