2.3 Petrol runs smooth but lacking power

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Lowlander

Lowlander

Member
Posts
16
Location
Netherlands
Hi All,

My name is Simon and I live in the Netherlands.
A year ago I started the resto of my series IIA, Petrol, 2.3 SWB. Good progress (see pics) but the car lacks power. Max speed is only 40 mph (needs almost a mile to get there.
I did a complete overhaul of the engine and gearbox. Cylinder head was done by Turner.

Compression is on the low side for all 4 cylinders, see measurements below.
Wet compression test gives +/- 10 psi pressure increase.
Engine starts very easy, and runs very smooth. 1st and 2nd gear are fine, but feels like that the car in 3rd and 4th gear is lacking power.
Based on other related threads in this forum I tried to add all relevant data below (after the pictures)
Any help/guidance would be very welcome! thanks!

n4g5LA.jpg


IoiXeH.jpg


Compression test:
CYL : DRY - WET
1: 125 - 130
2 : 130 - 135
3 : 120 - 130
4 : 130 - 140

Ignition timing
0 degrees
Mechanical advance checked with strobe light

Valves: Tappet clearance (Cold)
all checked: 0,01 inch / 0,25mm

Airfilter
Filter thoroughly cleaned; no obstructions;
Filter bath: new oil (filled @ max indicator level)

Fuel supply
New mechanical fuelpump
Clean filter pumpfilter
New in line filter

Dizzy
Dwell angle 59 degrees
New condensator
New contact points
Contact points gap set at 0,014" / 0,30mm

Spark plugs
New plugs (Champion)
Electrodes coloured Light brown
Gap checked

Cylinder head
Turner overhaul (new valves, new valve springs, lead free valve seats;
improved gasflowing of both inlet & exhaust ports)
all bolts rechecked on torque (all okay)

Pistons
New pistons + pistonrings (Turner)
Timing chain
New (Turner)
Head gasket
New (Turner)

Carburettor
Weber ICH 34
thoroughly cleaned
idle/mixture set using the Weber procedure
Rechecked settings with CO meter
idle set at 700 rpm (runs very smooth)
 
Welcome! That is the cleanest Land Rover engine I've seen in a long time!:)
The compression readings are a bit on the low side for a new engine (book values are 145 lbf/in for 7:1 and 160 lbf/in for 8:1) but the difference in wet/dry readings suggests the rings are still bedding in.
I think TDC is too retarded for the engine to produce much power. I would try a static setting of 6 deg BTDC and then adjust by ear - advance the timing for the highest idle speed and then retard it if the engine is knocking when you accelerate in 4th gear. The settings in the manual are not really applicable to modern fuels, so the best way to get it right seems to be trial and error ;).
It's also possible there's a fuel delivery problem, but first step is to check the timing.
 
i dont want to appear rude but please excuse me if i sound it but are there any issues with the drive train binding,ie brakes?,
p.s your land rover looks an absolute gem,
ryn
 
Don't trust new condensers, they are nowhere near as good as they were 50 years ago, try another. You haven't mentioned the coil, it might be worth trying a new one, they are not too expensive and it's always a good idea to have a spare. If you Rev it from under the bonnet and hold it on high revs, does the fuel filter keep plenty of fuel in it? Are you still running the engine in after its rebuild?

Col
 
Thank you all for your input!

Changed Timing: started with 6 degrees static, advanced timing for as long as rpm increased w/no-knocking: this indeed improved performance, 3rd gear is better, 4th is still weak. Topspeed is also a little higher but still below 45 mph.

Checked binding: all wheels rotate freely; also brake drums stay cool. Not sure how I can test other parts of the drivetrain, welcome any suggestion.

No work done on the block;I added some pictures of the cylinder walls.
I only did some light honing of the cylinder walls before reassembly

Will try new condenser and coil; the fuel pump bowl stays full at high rev; the inline filter has some air in it but the amount of fuel in the inline filter stays stable.

56VQiz.jpg

6xrogc.jpg

yiBXi2.jpg
 
Your compression readings are better than my 2.25 and my 109 station wagon is good for 55-60 mph on a long flat road, so I don't think it is the engine. If the coil or condenser doesn't improve thing, I'd be looking at the carb

Col
 
Did you check the ring gap after you honed the cylinders? But even if you are losing a bit of compression, that should improve as the new rings bed in.
On the carb side, a few suggestions:
- possible partial blockage. I know you cleaned the carb, but these Webers have multiple fine drillings and sometimes cleaning can loosen dirt that then causes more problems.
- float level may be too low
- main jet is too small (should be 165)
- incorrect carb - I know that sounds like a silly statement, but the 34ICH comes in 3 sizes and only the largest choke 29mm will work properly with the L-R engine.
 
Found the issue this morning: the throttle valve did not completely open (so indeed the carb-side!),I reset the pedal/linkage and car runs perfect now. Did not test max speed but 50 mph was no issue. Thank you all for your help! Very much appreciated!
 
Good! Those bores are worn but you should still get plenty of power. My accelerator pedal had slipped on the shaft and I was down on power, took 2 days to work that out! It happened slowly so each drive it was slightly worse.
 
Hi Simon .. Simon here from Switzerland.
Good to know you got sorted .. I would be interested in knowing about the Dizzy settings, you mention the dwell angle of 56deg .. I'm also running a 2nquarter petrol but with an electronic dizzy from 123, no one so far has been able to tell me what the correct curve should be on the thing and the curve table bears no real relation with reality it seems .. so the question is , what does the dwell angle mean? like should the maximum advance in degrees not exceed it?
Cheers
Simon
 
Simon Perks said:
Hi Simon .. Simon here from Switzerland.
Good to know you got sorted .. I would be interested in knowing about the Dizzy settings, you mention the dwell angle of 56deg .. I'm also running a 2nquarter petrol but with an electronic dizzy from 123, no one so far has been able to tell me what the correct curve should be on the thing and the curve table bears no real relation with reality it seems .. so the question is , what does the dwell angle mean? like should the maximum advance in degrees not exceed it?
Cheers
Simon
Click to expand...
Simon
This guy is on several forums and is highly recomended does rebuilds on old distributors not used him myself as I run diesel at present.
http://www.distributordoctor.com/
 
Blackburn said:
Simon
This guy is on several forums and is highly recomended does rebuilds on old distributors not used him myself as I run diesel at present.
http://www.distributordoctor.com/
Click to expand...

Thanks Mate, now i've ordered the dizzy and the coil from them .. if my one wife livid ever finds out i'm blaming you :D so that plus valve seals and a new timing chain when the snow clears up here .. it's no fun working in 4 feet of snow and minus 10
 
Simon Perks said:
Hi Simon .. Simon here from Switzerland.
Good to know you got sorted .. I would be interested in knowing about the Dizzy settings, you mention the dwell angle of 56deg .. I'm also running a 2nquarter petrol but with an electronic dizzy from 123, no one so far has been able to tell me what the correct curve should be on the thing and the curve table bears no real relation with reality it seems .. so the question is , what does the dwell angle mean? like should the maximum advance in degrees not exceed it?
Cheers
Simon
Click to expand...

Hi Simon, the dwell angle is the angle that the dizzy cam moves with the points closed. So in a 4 cylinder engine the dizzy cam has 4 lobs, the angle between the centre of the lobs is 90 degrees. The period with the points closed (in my case) is 56 degrees: so 56 degrees closed and 34 degrees open. If you increase the points gap the dwell angle will decrease (v.v.).

Ignition timing is to determine when the points will open; dwell angle (or points gap) determines for how long the points stay open. You first need to set the gap/dwell angle before setting ignition timing. Good luck
 
Agreed, you can set the points closed time by gap of dwell, ideally both should give the same result. The dwell is the time when the coil is charging up. At low revs or on singles its not an issue as there is loads of dwell but once you get to 6 cyl or 8 on points it gets critical. Then you start getting twin points or twin dizzys and coils. Trouble is the points opening varies with dwell and gap and that varies with wear so you end up always having to set the points to keep the timing right.
Points matter:
https://assets.publishing.service.g...-Supermarine_Spitfire_PR_XI__G-PRXI_05-03.pdf
 
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