MSD Ignition or Weber Carb Issue?
- Thread starter CESLAW
- Start date
flatchat(Chris)
Supporter
A wild overlap cam can give low readings at cranking speed.
Now do us a favour, do a complete tear down of the motor , thoroughly clean, measure and test everything --post your findings then the engine doctor Jac will be able to diagnose a remedy treatment.:shifty:
Now do us a favour, do a complete tear down of the motor , thoroughly clean, measure and test everything --post your findings then the engine doctor Jac will be able to diagnose a remedy treatment.:shifty:
Your motor has not been running for a few days, in that time some of the lifters will/could have bled down/collapsed from sitting with the valve open, this alone could be the reason for the low comp readings as those particular valves will not be opening fully & have as much open time in order to get a full cyl of air. Also did you do the comp test with throttle wide open??
RichardH
AKA The Mad Hat Man
Compression test carried out without the carb refitted.
I refitted the distributor to try and keep timing about right, but havent refitted the carb as , with the engine in the car, the distributor is pretty tight between the carb and the bulkhead. Leaving the carb off, gives more room to play around and, if the engine does need to be stripped, then there seemed no point in refitting it yet.
I will try today to repeat but with a squirt of oil in each cylinder. That might give an indication of duff rings?
I have no electrical power in the garage I use to store the car, so am very limited in my capabilities there. I cannot get a compressor in there to do a proper leak-down test (not that I have the equipment).
I am getting more despondent with every move. I am almost getting to the point of trailering the car to somewhere that can do more detailed checks quickly and has the capabilities to strip and refurb, if necessary. Unfortunately I know of no-one local in the UK that I know has a good reputation in this sort of work, and am reluctant to just turn up at a local garage with my "baby".
I refitted the distributor to try and keep timing about right, but havent refitted the carb as , with the engine in the car, the distributor is pretty tight between the carb and the bulkhead. Leaving the carb off, gives more room to play around and, if the engine does need to be stripped, then there seemed no point in refitting it yet.
I will try today to repeat but with a squirt of oil in each cylinder. That might give an indication of duff rings?
I have no electrical power in the garage I use to store the car, so am very limited in my capabilities there. I cannot get a compressor in there to do a proper leak-down test (not that I have the equipment).
I am getting more despondent with every move. I am almost getting to the point of trailering the car to somewhere that can do more detailed checks quickly and has the capabilities to strip and refurb, if necessary. Unfortunately I know of no-one local in the UK that I know has a good reputation in this sort of work, and am reluctant to just turn up at a local garage with my "baby".
RichardH
AKA The Mad Hat Man
I must have mis-understood you Jac. Surely if the lifters drain down and the valves dont open properly, that wont affect CR? I could understand if they didnt close properly.
Ah! You are saying that if the inlet valve is open for a very short time - then the induction stroke cannot draw in a full charge and therefore isnt compressing the full swept volume? Yup - i can understand that. Not sure what i can do about it though? I was cranking for about an hour or so, and was counting at least 8 compression strokes on every crank, before i checked the pressure.
Ah! You are saying that if the inlet valve is open for a very short time - then the induction stroke cannot draw in a full charge and therefore isnt compressing the full swept volume? Yup - i can understand that. Not sure what i can do about it though? I was cranking for about an hour or so, and was counting at least 8 compression strokes on every crank, before i checked the pressure.
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Good, you got that. Richard you have to find out if the low reading in #2&3 is definite. While I understand that the car is your 'baby', the motor is a fairly basic 302 & any local mechanic worth his salt should be able to help, even if you simply chuck it on a trailer & take it to them for a leak down test & post the results from that. A few silly things can happen to SBF's with extended layups like sitting in paint/panel shops awaiting repairs etc- stuck valves in guides is one- rotted out 'hot box' in inlet manifold is another( That nearly drove me insane tracking that down -was burnt thru under tin cover & pumping hot exhaust gas into valley/crankcase, only noticeable under load ). Stuck dizzy mech advance weights could be another culprit. Get a leakdown test done--Do you know any piston aircraft mechanics, they are doing leakdowns all the time on 50hr checks.
Thats why Im concerned, Your spark plugs have 14mm 0.750" reach threads with washers, I cannot think of any Iron Ford heads that use these, they are mainly 14mm x 0.460" taper seat or in the older stuff 18mm x 0.460" taper seat. Can you take a pic down a spark plug hole??
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I see what Jac Mac is worried about.....and agree. How about posting a better shot of the spark plugs, taken from the side with a full view of the length of the tip of the electrode, please.....from what I can see in the second shot of 4 spark plugs, it looks like the electrodes have been bent up to come into contact with the tip.....that would not be good.
Hoping it's just an illusion from the angle at which the photo was taken.
A photo down through the spark plug hole as requested by Jac would be more definitive as to whether or not the pistons are making contact with the plugs.....might be difficult to get an auto-focus camera to focus on the piston top if it's deep in the hole, though, can you safely rotate the pistons to TDC before you take the photos?
Doug
Hoping it's just an illusion from the angle at which the photo was taken.
A photo down through the spark plug hole as requested by Jac would be more definitive as to whether or not the pistons are making contact with the plugs.....might be difficult to get an auto-focus camera to focus on the piston top if it's deep in the hole, though, can you safely rotate the pistons to TDC before you take the photos?
Doug
I was looking at the first pics you have with disy out. Down in the hole it looks like there was alot of bronze deposited. Jac was talking about the "C" dimension needing to be less than "A". It just looks like it may have not been so causing alot of load on the bronze gear. To me it also looks like the gear is quite worn.
Now if this had a load like that on it is it possible that it has jumped cam timing? This could cause low compression readings also. Like they say a leakdown is best. Your compression readings can also be affected by battery strength and cranking speed.
It just sounds like cam timing to me. Maybe caused by excess drag from improper install of the distrubutor. But I am by no means and expert on a Ford. Hope it helps and good luck.
Jim N
Now if this had a load like that on it is it possible that it has jumped cam timing? This could cause low compression readings also. Like they say a leakdown is best. Your compression readings can also be affected by battery strength and cranking speed.
It just sounds like cam timing to me. Maybe caused by excess drag from improper install of the distrubutor. But I am by no means and expert on a Ford. Hope it helps and good luck.
Jim N
flatchat(Chris)
Supporter
I'll put my money on the electronic dizzy bitz --is it IR (infra red) breaker or magnetic ? Modules can give grief as well -- is the coil OK ?
Swap these items out and lets know :blank:
Swap these items out and lets know :blank:
Chris could well be correct, heck we might all be.
1. The cam is a basic Comp Cams flat tappet hyd, oil pump is Hi-Vo---doesnt/didnt need a bronze gear.
2. Richards symtoms on post #123 are a bit of everything,--wont start---runs on 4 or 5 cyls--runs ok--stalls @ intersections---- starts after 20 min's, sounds like seizure/ compression lock when cranking..... There is a host of possibilities there, hard to guess whats been cause/results.
A pic of plug seat area ( Taper or Washer face ) plus an approx thread count of hole in head or measure of depth will eliminate that concern.
1. The cam is a basic Comp Cams flat tappet hyd, oil pump is Hi-Vo---doesnt/didnt need a bronze gear.
2. Richards symtoms on post #123 are a bit of everything,--wont start---runs on 4 or 5 cyls--runs ok--stalls @ intersections---- starts after 20 min's, sounds like seizure/ compression lock when cranking..... There is a host of possibilities there, hard to guess whats been cause/results.
A pic of plug seat area ( Taper or Washer face ) plus an approx thread count of hole in head or measure of depth will eliminate that concern.
RichardH
AKA The Mad Hat Man
Rite Folks
I think, to use a technical expression, I have been talking B011ixs! - at least a bit mis-leading....
The head is not steel - it is Aluminium!
The Electronic Ignition Unit is an MSD 6AL.
The distributor is an Accel 43001A which is, i believe, a magnetic impulse type.
There are 14/15 threads in each plughole.
The Plugs are NGK BP6ES type. The data, for which is....
14mm Thread, 19mm (3/4") Reach, 13/16" (20.6mm) Hex Size, Gasket Seat, Non-Resistor, Removable Terminal, JIS Height, Projected Tip, .032" (0.8mm) Gap, Heat Range 6. Interestingly no Ford is mentioned on the NGK site as a recommended user.
There is very little distributor gear debris (I could only see one small shard) in the distributor access hole.
The HV Oil pump is pn SPR22441128.
The coil is an MSD Blaster2 Red coil.
I think, to use a technical expression, I have been talking B011ixs! - at least a bit mis-leading....
The head is not steel - it is Aluminium!
The Electronic Ignition Unit is an MSD 6AL.
The distributor is an Accel 43001A which is, i believe, a magnetic impulse type.
There are 14/15 threads in each plughole.
The Plugs are NGK BP6ES type. The data, for which is....
14mm Thread, 19mm (3/4") Reach, 13/16" (20.6mm) Hex Size, Gasket Seat, Non-Resistor, Removable Terminal, JIS Height, Projected Tip, .032" (0.8mm) Gap, Heat Range 6. Interestingly no Ford is mentioned on the NGK site as a recommended user.
There is very little distributor gear debris (I could only see one small shard) in the distributor access hole.
The HV Oil pump is pn SPR22441128.
The coil is an MSD Blaster2 Red coil.
GREAT photos!! Good news, no contact with the electodes! SO GLAD it was just an optical illusion on the photos before. No need to rotate to TDC now......
I count 12/13 threads on the plugs, should be no problem with 14/15 threads in the hole.
Starting to suspect the MSD box/Accel unit......such a mystery!
What say you, Jac....looks like a tapered seat to me?
Doug
I count 12/13 threads on the plugs, should be no problem with 14/15 threads in the hole.
Starting to suspect the MSD box/Accel unit......such a mystery!
What say you, Jac....looks like a tapered seat to me?
Doug
MOST of the Alloy heads use gasketed plugs, Richard will have to find out or ID the heads & check for manf reccomendation to find out for sure--main thing is they are correct length.
Back to what to do---leakdown to find what # 2 & 3 are up too, then if thats OK try for a restart. A good known points dist & coil hotwired temporarily might be a good plan to eliminate the the Accel/MSD. Richard, its pretty obvious your struggling with what will seem like a tidal wave of possibilities here & it might be prudent to check with some fellow Ford/GT40 guys in your area to find someone who is up to speed on this stuff. Im sure whatever is really the original cause is fairly simple and just needs someone who can work thru this in a point by point manner BEFORE trying a restart. There a a few other possibilities that need to be eliminated like cam timing, bent pushrods etc.
Back to what to do---leakdown to find what # 2 & 3 are up too, then if thats OK try for a restart. A good known points dist & coil hotwired temporarily might be a good plan to eliminate the the Accel/MSD. Richard, its pretty obvious your struggling with what will seem like a tidal wave of possibilities here & it might be prudent to check with some fellow Ford/GT40 guys in your area to find someone who is up to speed on this stuff. Im sure whatever is really the original cause is fairly simple and just needs someone who can work thru this in a point by point manner BEFORE trying a restart. There a a few other possibilities that need to be eliminated like cam timing, bent pushrods etc.