doug73cs

I've had this http://sdsefi.com in my '73CS and very happy with it.  Nice not to need a computer to do the set up.  Lot's of local '02 cars and racers using it.  Very good tech support as excellent install manual.  Excellent web site with lots of info that will help you regardless of what system you eventually but.

HTH

Thanks to all - question answered. The springs in the CS are the same configuration as the '02 - as in linear.

Doug

I have been in discussion with two providers on 8" coil over spring kits to replace my ST front springs for my 73CS.  Both are in agreement with the replacement spring rates - 300 to 325ft/lb to replace the ST springs 265ft/lb.  I don't want a significant change to the stiffness as much as the ability to adjust the ride height.

I'm curious as to why higher rated springs for coil overs?  

Any informed advice on this appreciated.

Doug 

I said I would post my conclusions when this was sorted so here it is - spark plug wire set.  

At the end of the day the single biggest factor was a set of 3 year old plug wires that I replaced with OEM type Bosch.  All of the hesitation and sputtering accelerating from idle to cruise is gone, WOT is smooth and consistent from 3000 to redline (in the mid 12's A/F ratio) and cruise at light constant throttle is slightly lean (mid 15's A/F) until engine load increases and the A/F responds appropriately.  Still running one grade hotter plug which I may leave for now.

When this all started I was jetting 50 150 185 and now 45 140 185.  This was probably a contributing factor to improving the "performance" of the engine.

The one thing that needs attention is the richness at idle (A/F in the mid to high 11's) that I'll try to lean out a touch but if it has to stay rich to run right - so be it.

Thanks to all for the comments and suggestions.

Doug

Running out of options here.  

Tomorrows work includes:

Confirm correct valve adjustment

Compression test all cylinders ( curious about the numbers anyway)

Swap in old dizzy cap to compare

Confirm all plugs have good spark (done once - do again)

Test #1and #2 wires by switching them (remember to switch back)

Liberal but selective use of ether start spray to test for any vacuum leaks

The runners are full open unless the gas suddenly developed high cholesterol - no rags, tampons ,dead rodents  etc to be found.

I'm hoping the problem is with the plug wires but no one locally sells them so if I have to replace them I have to make them up our wait for Mr Blunt to ship if I order them.  If it's the dizzy I can get a rebuilt from IE but again that means delay in shipping to Canada.

Will report.

Edit:

Valve lash fine

Dizzy cap - no change with old so swap back to the new one

Good spark all

#1 and #2 wires swapped - no change

No vacuum leaks found

Still trying things - went to 45 140 (drop from 150) 185 and the lower rpm/cruise operation improved but still rough and lacks power at WOT

Plug wires?  They produce spark when pulled and grounded to the block and the likelihood that they would cause such discrepancies in pairs?

Valves were freshly set (by me so....) but I will check.

But thanks

Airflow.  Thanks Toby - this helps - I was unsure whether there were three variables at work at idle/low/mid throttle or just idle and mains.

I have a wideband meter in the car and that does help see what is going on.  I'll focus on the idle and mains for start, low throttle and cruise and then main and air jets at WOT.  Was 50/145/185 now currently 45/150/185.

Some questions and confirmations on what I think are basics for setting up a 38/38 weber. I have a stock motor and cam, Petronix, hotter coil and correct timing with less than 30,000miles since an unknown rebuild. The car drives between 2000' and 6000'. Personally, I think the carb is more than the engine needs given spec and altitude which makes getting it running well without be over rich at some point is difficult.

What does a "hotter" range with respect to spark plugs have on ignition?

The idle circuit controls mixture to 2000 rpm, the mains through the whole range and the air corrector can fine tune mixture above 4500rpm - correct?

Does the air corrector jet have any effect at the lower rpm range? Say 2500 to 4000?

Any comments on the questions appreciated.

Thanks to all for confirming that the line marked 2 is the correct reference to align with the oil bar - the casting under it doesn't have a notch so the bar will do.

As far as setting the #1 piston to TDC, I marked the pulley and the tab cast into the lower timing cover when I had the head off so that should suffice.  I can't see the OT mark on the fly wheel but that could be for any number of reasons (rust, dirt, human error).

Thanks again - I may be back.

After a year of ignoring this I am ready to reassemble the engine and getting my 76 Sahara back on the road – hopefully solving old problems without creating any new ones.

In order to get the head and block playing nice I need to set the cam sprocket to the crank and I want to get it right the first (second actually) time.  It’s a 1974 E12 head and unknown block ( #5461577) with flat top pistons rebuilt approximately 10,000 mi ago.  A decent stock motor that doesn’t burn oil.

As it sits, the piston in cylinder 1 is at TDC (as is #4), the cam lobes on cyl 1 both point down with the exhaust coming on next and cam lobe #4 is fully open on intake.

There is only one set of notches on the crank pulley and it is after TDC relative to the tab cast into the lower timing case at the bottom of the photo (my white mark on the pulley opposite the tab is at TDC). 

The cam sprocket mounting flange is set with mounting holes are “square or parallel” to the plane of the cylinder head and the dowel is at 7 o’clock. 

The mounting flange has a line followed by the number 2 cast into the edge preceding my white mark that indicates where the cam sits (with the flange square and parallel to the head) centered on the oil bar.

With the #1 piston at TDC, is the line on the mounting flange with the #2 what I set the cam sprocket to using the oil bar as the centerline? 

Mlytle,

I did variations of "rear coilover" and never thought to include "towers" so thanks for that.  It's always asking the right question that gets the right response.  I'll continue the search but the green one from moespeed looks very familiar and did add 1.5" to the height as suggested by Creede.

Thanks Creed, hadn't thought about the height of the towers and length of travel - good point.  

I recall seeing another installation using heavier gauge wall thickness pipe and replacing the OEM towers.  Also thought of doubling up the sheet metal of the wheel arch with a 2" skirt around the tower using plug welds.  

Trying to avoid a roll bar connection.

Doug

I'm looking for examples/how to do's of rear coilover conversions - particularly the reinforcement of the to end shock mount "towers".  I'm slowly going through the Project blog pages - all 34 times 20 of them so any assistance would be appreciated.

Doug

Just assuming - two very rich and two lean but I get what you are saying - should all be the same.

Feed by same single weber carb so probably not carb/fuel related.  Checked multiple times by three different people that the leads are correct to and from distributor to plugs for firing sequence 1-3-4-2.  Valves all set at .007 cold.  Good spark (grounded to block while cranking to test) with new plugs.  Swapped in another distributor to test and no change.  Assume since the cam wasn't TDC when the crank pulley and flywheel were that it must have to do with the engine timing not ignition timing.

Still have to resolve the timing chain issue before I can do anything else.

No, the valve train is fine so maaaybe 3 teeth but definitely out by 10 - 12 degrees. When the engine was running cylinders 1 and 4 were back and sooty and 2 and 3 were tan to white/grey. I assume that means the plugs on 1 and 4 were firing after TDC and 2 and 3 before. The plug to 3 was defective so replaced with new set and then did the TDC reset which gets me back to the problem at hand. But it ran with out the sound of metal to metal contact.

I'll pull the tension plug and let the chain sag, reach down into the bottom with some coat hanger (special BMW tool...) and try to see if I can lift/fish the chain off the crank sprocket and pull up the slack - assuming there is some slack.

Doug

Where to start?  

Turns out the crank cam sprocket was rotated 4 teeth from TDC relative to the crank pulley TDC and the flywheel timing mark TDC.   In an effort to get this thing to run better I removed the cam sprocket, lifted the chain and rotated the cam to get the TDC mark to line up with the oil spray bar.  This was done with the chain wired in place to prevent it from slipping off the crankshaft double sprocket - or so I thought.  Now all TDC marks are in agreement.

Put everything back together, put the plugs in and leads on then turned the key.  There was/is a clack, clack, clack sound from the front of the engine that I'm pretty sure is from something hitting the lower timing chain cover.  The other symptom is the engine has a point about 10-15 degrees either side of TDC where turning the engine with a socket on the pulley nut where rotation becomes blocked until you really reef on the ratchet bar and then it turns freely.  Happens in either direction.  Happens every time you go back across TDC even after you rotate through 360 - something binds at the same point but not enough to lock it up.

In looking at the Haynes digram of the timing sprockets, chain and guides  I'm guessing that in putting this back together I have allowed the chain on the guide side to drop off the double sprocket one or two links.  Then when the tension goes back on the chain when the tension plug pushes the chain to the centreline the chain engages the sprocket with a small loop hanging down.  Because the upper and lower sprocket are two fixed rotating points the chain tensioner cannot take up the slack and the loop flops around hitting the case.

So a couple of questions other than "has anyone else done this"?  

Can the loop be somehow flipped over a tooth or two - you're doing this blind from above reaching down into the lower timing case - and how best to do this?

or

Can this only be resolved by removing the lower timing cover and everything associated with that (rad, alt, water pump, crank pulley etc)?

Forecast is 3" of rain mixed with snow over the next three days so this is as good a time as any to do this. I just pray this is really the problem.

Any advice appreciated,

Doug

? 

Just ordered mine.  Looking forward to seeing myself.

My car is a 76 which according to the Haines manual only has the one notch for TDC.  Thanks for the advice.

Round two of sorting a rough motor.

The crank pulley is keyed into the crankshaft so there is only one correct orientation

When the crank pulley TDC notch lines up with the casting stub on the lower timing case the TDC notch on the cam sprocket should also line up with the oil spray tube over the valve assembly - correct?

My cam notch is past TDC when the crank pulley notch is at TDC.  This also means the rotor is well past plug lead #1 so firing as exhaust is opening?

If this is the problem - and I think it is - then remove chain tension plug and lift chain off the cam sprocket and turn it back to TDC.  Is this possible without taking off the upper timing cover?

Sometimes I amaze myself - the things I do.

Doug

Still have to figure out why the 1+4 are rich and 2+3 are lean.  With only one carb into a common manifold it isn't the carb/fuel system.  My worst nightmare would be the timing chain skipped a tooth left or right which might explain this issue.  Can't remember how many teeth are on the cam sprocket but one tooth could be 10 - 15 degrees which is huge.

But thanks again.

Through switching plug leads and plugs around I confirmed that plug  #3 is pooched, bought a new set of NKG (since they didn't have Bosch WR7DC) and did the pull the lead on each cylinder with the engine running to test.  The engine runs much better (still a little rough) and I can continue setting up the carb when my main fuel jets arrive via post.

Thanks all and Peterschop in particular. 

Will check the plug as well.  Thanks.

How do you check if the Petronix pickup is not the problem? If the Petronix works on cylinders 1, 2 and 4 can it fail on cylinder 3?

Peterschop - I had a spare cap and tried it with no luck.  I'll try your suggestion and get back to you.