Thread: 1981 Poo brown two door restore.

New fuel pump installed.
fuelflow 015,Nz made,used to be Ecco brand.nice little plastic housed pumps ,this one’s a piston version so fits the 3.5 mounting and fits right onto hoses standard to a two door classic.
1-4 psi ,probably nothing wrong with old one but looked like it had been on since Noah.

No change to power output by the pump change alone,but definitely less fuel smell after shutdown,still there but less.

There seems to be multiple schools of thought re the oil grade to use in the dampers on stromberg cd175 carbs.
Some say lightest possible/20 sae/lots of difference reading online.
Ive been using that good old 3in1 sewing machine oil,in that classic little bottle that has been around for ever

Stumbled across this snippet courtesy of moss motors in regard to air damper operation.
apologies on the size of the capture..

77526392-3315-4A88-8EFD-417B4CEC5F5C.jpg

With that, I tried 20/50 engine oil in the dampers ,with the aim to slow down the rise of the damper.
Well it’s transformed the power curve ,I now have acceleration,not startling,but no longer have the pedal on the carpet..happy days.

Fuel mixture:
Theoretically , the engine should run best with a slight rise or no shift of the rpm when raising the carb damper with a screwdriver,combine this with a clean colortune blue orange fleck burn and it should be close to ideal,you’d think.
So far I’m getting the best running by increasing the mixture richness slightly away from the above,now giving better cold starting ,reduced shunting off the accelerator and smoother idle.
(datum from needle valve level to bridge,approx 5 or 6 x 90 degree clockwise,turns to sweet spot,so that’s about 1.5 turns richer)
No doubt as the new engine loosens up a tad,might need a tweak,but I’m at that point where I’m looking for any excuse to take her out,do we need milk

My cold starts are awful,despite having renewed shafts plus butterfly on one,and setting the floats on both with a decent cleanup.
Cleaned and reset the choke mech.

Strong fuel smell after light off with the choke needing to be nearly closed off almost immediately to reduce rough running.
Mixture is set spot on,or close for best warm running.
I’m sure the car is starting on the right carb only,and can watch and hear as a few seconds later the drivers side carb stumbles and kicks in,sounds like a badly tuned diesel.

A minute later all is well,the old set of carbs that came with the original engine,with worn shafts and leaking, still kicked off instantly,smoothly without all this drama..

Hot starts often need a couple of goes as well.

Got me thinking I haven’t checked the fuel pressure on the new pump.

CDD89396-C8DC-44F4-98F4-87AFDF3CE9E0.jpg

These are cd175 strombergs,and after some reading,my understanding is that fuel pressure is too high,likely overwhelming the float valve and causing carb to flood slightly.

Evidence is the poor cold starts & strong smell of fuel after shutdown,possibly escaping via the overflow pipe with residual pressure,noticeably on drivers side carb that has the smaller diameter fuel return line.
Experimental solution;install a fuel pressure regulator today.

A4EDABB7-C4FD-4561-B947-0FEFBB52EABF.jpg
As per the pic I set it to 2 psi,will test what the carb is actually getting later,but on a decent run around town today,wow,much much better

Instant throttle response,power delivery very smooth wth more torque ,exhaust note has changed and sounds way better.
No issues with hot starts at all,wow,who would have thought dropping the fuel delivery a couple of psi could make such a large change to drivability.

Originally Posted by westy1

Experimental solution;install a fuel pressure regulator today.

A4EDABB7-C4FD-4561-B947-0FEFBB52EABF.jpg
As per the pic I set it to 2 psi,will test what the carb is actually getting later,but on a decent run around town today,wow,much much better

Instant throttle response,power delivery very smooth wth more torque ,exhaust note has changed and sounds way better.
No issues with hot starts at all,wow,who would have thought dropping the fuel delivery a couple of psi could make such a large change to drivability.

Hello Westy 1,

I checked your location as New Zealand - did you buy the Aeroline fuel regulator locally? I looked on eBay and all the sources are from the United Kingdom.

I used a Holley pressure regulator for a Holden 202 Land Rover Series III 109 conversion and it had to be set via a separate inline pressure gauge to set its pressure. I replaced the failing mechanical pump the previous owner - who had the conversion done - had been using. The replacement was a Facet electric pump. The new fuel system needed a pressure regulator because the Stromberg BX carburettor requires a set pressure otherwise it plays up. The Aeroline fuel pressure regulator looks like a more convenient option by just dialling it in to the required pressure.

Kind regards
Lionel

Howdy Lionel yes you’re quite right,sourced locally via these guys, first of the two.
This is one of two stores catering to classic BMC parts here.
Lots of goodies that cross over to our needs there,but looks like stock resupply is their nemesis currently.

Classic Car Accessories | Classic Car Parts | New Zealand

British & European Ignition Parts

Originally Posted by westy1

My cold starts are awful,despite having renewed shafts plus butterfly on one,and setting the floats on both with a decent cleanup.
Cleaned and reset the choke mech.

Strong fuel smell after light off with the choke needing to be nearly closed off almost immediately to reduce rough running.
Mixture is set spot on,or close for best warm running.
I’m sure the car is starting on the right carb only,and can watch and hear as a few seconds later the drivers side carb stumbles and kicks in,sounds like a badly tuned diesel.

A minute later all is well,the old set of carbs that came with the original engine,with worn shafts and leaking, still kicked off instantly,smoothly without all this drama..

Hot starts often need a couple of goes as well.

Got me thinking I haven’t checked the fuel pressure on the new pump.

CDD89396-C8DC-44F4-98F4-87AFDF3CE9E0.jpg

These are cd175 strombergs,and after some reading,my understanding is that fuel pressure is too high,likely overwhelming the float valve and causing carb to flood slightly.

Evidence is the poor cold starts & strong smell of fuel after shutdown,possibly escaping via the overflow pipe with residual pressure,noticeably on drivers side carb that has the smaller diameter fuel return line.
Experimental solution;install a fuel pressure regulator today.

A4EDABB7-C4FD-4561-B947-0FEFBB52EABF.jpg
As per the pic I set it to 2 psi,will test what the carb is actually getting later,but on a decent run around town today,wow,much much better

Instant throttle response,power delivery very smooth wth more torque ,exhaust note has changed and sounds way better.
No issues with hot starts at all,wow,who would have thought dropping the fuel delivery a couple of psi could make such a large change to drivability.

Return line blocked with rust / crud at / in the spigot on the front of the fuel tank.

Try compressed air down the line. Mine needed wire to clear it.

DL

Changed the rocker arm on drivers side to troubleshoot noisy cold start and warm idle tap on that side.
Made no difference with a newer rocker arm on there.
Could narrow it down to cylinders 4 or 6.
It was masked by my crap Chinese alternator whine.
When this was exchanged for a 40 year old original it was noticeable and doesn’t really go away.
After a hot run it fades but never fully disappears,the other side is dead quiet.



Pulled the intake manifold to investigate,and the lobe on 4 doesn’t look the best with those score marks?
This was the exact area i was getting a sharp tap from!
pushrods rotated on that cylinder,and valves looked to be opening at normal height by eye.
Turning crank over,similar but lesser score marking is also evident on the leading face of cam lobe on a few others.
A close in look at that lobe, does look it’s got a scrape on edge of lobe crest.What would cause this?

A9727937-D423-4330-A5B1-6690104CD222.jpg

Lifters from intake and exhaust on this cylinder in this pic.
EDF1E8D7-EF14-4832-AE9F-165392B1A01F.jpg

Is my camshaft toast?
Is it possible I’ve wiped out that lobe during set up ,with multiple timing adjustments,dry cranking with dubious oil pressure,in order to get the engine to run correctly for cam break in.

Thoughts? Is that wear pattern possibly foreign object damage,a faulty lifter perhaps,or low oil pressure friction wear,anyone had or seen similar?

This engine was heralded as having been built by a reputable engine builder,blueprinted ready to go..
I inherited it with an early two door frame,since sold on,but serves me right for not pulling this thing apart to check for myself instead of having blind faith,so a lesson there..

To get this running sweet,I was off the scale on the timing marks on the harmonic balancer,aka about 15-18 btdc had her singing,but bugged me it wasn’t correct.

Pullled the timing cover off today and found this beauty,,



Recall,there was no water pump gasket,the rocker shafts were second hand,and badly scored underneath.
Chasing that top end tap has led me down the rabbit hole but all for the better,I’d say
Guessing it’s skipped a tooth or two,so timing marks didn’t line up,all for the sake of a $50 timing set..she’ll be right!
No wonder it took a while to find a point where it would start up and run.

With camshaft out,it doesn’t look too bad,definitely some minor gouging on front cam bearing,and a small gouge from what looks like grit,on another,no skills or tools to renew these so they remain in place.

Interestingly the removed camshaft was made at a local shop.
It has a higher lobe height by .7mm compared to the new stock pre pollution carb 3.5 I had made up.
No idea what the installed cam was from or for,but time will tell if it runs differently.

Rebuilt top end with new rocker shafts to replace worn ,new rockers to go with it,and a JP timing set set at +2 degrees.
Replaced the camshaft with an original profile from local camshaft builder.

Only had 30 thou shims,so put these on to reduce some high 80-100 preload,no idea if heads were skimmed,guessing so,as using stock gear here.
So sitting about 60 plus ish now.
This begs the question,why am I getting tappet noise? Valve maybe?

4DFF1E37-EBA0-4409-AEE3-80A2C4A134A5.jpg CF8BF1F4-F9AC-47B2-8383-B94004775E43.jpg

Bed the cam in last night,always slightly scary!
Timing marks now make sense,and kicked off straight away.

9E2AA69F-3FD9-4D75-84E9-7C9F1A337E56.jpg 2B66985C-BF6D-4060-BFCA-64C0DE67C177.jpg BBEA42B1-2673-4FAC-9CF6-4A7155749585.jpg

Test drive results ;Much smoother idle and exhaust note,no slight miss or cam induced rumble at idle,methinks that previous cam may have been trending towards higher and steeper profile evident in the change in power delivery.

Low down torque is better and doesn’t seem to bog down at lower rpm going up my hill.
Would say not quite delivering that higher end power the previous one did, but liking that’s it’s back to standard for the old girl,and making the driving experience more balanced as per original design.

ps;Drivers side tap,still,there! But not concerned for now as way more muted,and won’t do anything more until I change out that top exhaust pipe.

Did attempt to change oil pump gears,but the idle cog wouldn’t fit over post?
Way too tight and didn’t want to force it on as seemed to be an interference fit ,so no way it was going to freely rotate,feared wouldn’t be able to get it of without damaging pump faces.
Measured the post and the ID of cog,both same diameter! mind you came in a blue box so will try a different manufacturer.

The new pressure relief plunger from V8 tuner, wouldn’t easily move into far recess of chamber so installed all the old gear back on,attack that one another day:)
Oil pressure on cold start on that new top end start went to 40 plus,but now has dropped back to 30 and won’t go over that at higher rpm.
Hot idle 5-10 hot but gauge is slightly erratic.