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Hgpilot

XF 4.1 popping!

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Could be a bent pushrod, wiped cam lobe or a lifter that bleeds down/might be sticky (Could be the reason why it's rattling when cold and not as bad when it's warm the hydraulic part of the lifters can get stuck particularly if they sit with a valve open for long periods of time), I'd bet it's an exhaust valve, you can do an easy check then you start it cold grab a spray bottle with water and spray the exhaust manifold on each cylinder if one isn't hot it will show up, that's your cylinder that has a problem

 

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I had this on my wagon years back, the exhaust was filling with raw mixture and popping like this. It just decided to do it right in front of some cops, they pulled me over thinking I was being a smart-arse and doing key-bangers. It was caused by silver paint on my dizzy cap tracking and earthing the spark from the terminals.

All suggestions I agree with but also suggest looking at the rotor and cap. You could have some cross- or misfiring between dizzy terminals as I described.

Sent from my CPH1903 using Tapatalk

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35 minutes ago, Thom said:

Could be a bent pushrod, wiped cam lobe or a lifter that bleeds down/might be sticky (Could be the reason why it's rattling when cold and not as bad when it's warm the hydraulic part of the lifters can get stuck particularly if they sit with a valve open for long periods of time), I'd bet it's an exhaust valve, you can do an easy check then you start it cold grab a spray bottle with water and spray the exhaust manifold on each cylinder if one isn't hot it will show up, that's your cylinder that has a problem

 

Yeah maybe. I hope not though! I originally thought it was exhaust valve but I have good compression on all cylinders. The pop doesn't come through the exhaust at all, only the carb. But If your right, I might look at a new engine. Thanks! 

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19 minutes ago, gerg said:

I had this on my wagon years back, the exhaust was filling with raw mixture and popping like this. It just decided to do it right in front of some cops, they pulled me over thinking I was being a smart-arse and doing key-bangers. It was caused by silver paint on my dizzy cap tracking and earthing the spark from the terminals.

All suggestions I agree with but also suggest looking at the rotor and cap. You could have some cross- or misfiring between dizzy terminals as I described.

Sent from my CPH1903 using Tapatalk
 

Was it popping from your carby like mine? I have wondered about the dizzy cap as there is some corrosion on it. 

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3 hours ago, Hgpilot said:

Here is a video of it running when cold

 

 

And when its warm

 

 

Let me know if links dont work. Thanks!

 

i'd wonder if that's a sticking valve.
i'd consider starting it up with the rocker cover off(it's going to splash some oil everywhere) you may actually see something obvious.

another thing i'd consider.. is blocking off the EGR plate. see if it's something like that? 

 

this XF was a bent push rod.. below

 

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try taking one of the leads off one at a time.. (running on 5cyls at a time..) don't try this when the motor is running.. pull one off.. start it.. test.. refit, try another and so on

if it stops popping, will at least give you the cyl that's an issue(i actually wondered if it was 2 leads round the wrong way, but seems weird it gets better warm)

 

is the carby bolted too tight, or loose(too tight can cause an air leak also)

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Yeah maybe. I hope not though! I originally thought it was exhaust valve but I have good compression on all cylinders. The pop doesn't come through the exhaust at all, only the carb. But If your right, I might look at a new engine. Thanks! 
If the exhaust valve isn't opening you will still pass a compression test, it's even possible that cylinder will measure higher than the others, a closed exhaust valve Will causing popping out the carb on every second time that cylinder fires as the fuel is getting to the cylinder and being ignited but then it has to escape out the carb instead of the intake and then the cycle repeats

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14 minutes ago, Thom said:
2 hours ago, Hgpilot said:
Yeah maybe. I hope not though! I originally thought it was exhaust valve but I have good compression on all cylinders. The pop doesn't come through the exhaust at all, only the carb. But If your right, I might look at a new engine. Thanks! 

If the exhaust valve isn't opening you will still pass a compression test, it's even possible that cylinder will measure higher than the others, a closed exhaust valve Will causing popping out the carb on every second time that cylinder fires as the fuel is getting to the cylinder and being ignited but then it has to escape out the carb instead of the intake and then the cycle repeats

i aggree, i'd be looking for a bent pushrod
My mate's rambler had a loose rocker arm causing similar, and BGDAVs 408 was similar when one of the roller rockers fucked itself 

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11 hours ago, deankdx said:

try taking one of the leads off one at a time.. (running on 5cyls at a time..) don't try this when the motor is running.. pull one off.. start it.. test.. refit, try another and so on

if it stops popping, will at least give you the cyl that's an issue(i actually wondered if it was 2 leads round the wrong way, but seems weird it gets better warm)

 

is the carby bolted too tight, or loose(too tight can cause an air leak also)

 

That's a good idea. I will try that. I am thinking you guys are onto something because(I probably should have mentioned this) it used to run really rough but I never noticed a pop. The fisrt time I head the popping was after I pulled all my old plugs out, gave them a clean, and put them back in. Perhaps I had that cylinder not firing at all until I cleaned the plug. Thanks!

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10 hours ago, Thom said:
12 hours ago, Hgpilot said:
Yeah maybe. I hope not though! I originally thought it was exhaust valve but I have good compression on all cylinders. The pop doesn't come through the exhaust at all, only the carb. But If your right, I might look at a new engine. Thanks! 

If the exhaust valve isn't opening you will still pass a compression test, it's even possible that cylinder will measure higher than the others, a closed exhaust valve Will causing popping out the carb on every second time that cylinder fires as the fuel is getting to the cylinder and being ignited but then it has to escape out the carb instead of the intake and then the cycle repeats

 

Ah I see. This is why I'm here! You guys know your stuff! 

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Ok, So, you guys must be right. Pulled all leads off one at a time and sure enough... stops popping when cylinder 4 lead is off. In fact, it runs smooth as with cylinder 4 unplugged. I can't touch the exhaust on all cylinders except 4 I can grab hold of. I have never worked on a push rod engine before, and I am no mechanic but I will see what I can do. Any suggestions on what I do from here? Thanks! 

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Was it popping from your carby like mine? I have wondered about the dizzy cap as there is some corrosion on it. 
It was out the exhaust, but the popping could also come out the carby if the mixture and or timing is out by the right amount.

Sent from my CPH1903 using Tapatalk

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1 hour ago, Hgpilot said:

I have never worked on a push rod engine before, and I am no mechanic but I will see what I can do. Any suggestions on what I do from here? Thanks! 

unclip the accelerator cable(don't loose the clip, clip it back onto the carby separately , it slides off over the cable end. then the cable sits over the ball)
undo the cable holding nut half a turn, then unscrew the plastic part so you can manoeuvre the cable off.

then undo the rocker cover loose bolts(they are nearly always loose causing leaks)

remove rocker cover, look at number 4 rockers, take a photo..
something will be up the shit.. could be just a rocker loose, but pushrods on crossflows are made of cheese.. so expect a bent one. 

someone on here might have a spare one laying around to send you if you are lucky(i used to have about 20 odd spares, but got rid of all my stuff when i moved) 

i can't recall if there's anything special doing up the rocker again, pretty sure it will just be reasonably tight... if it's wiped a cam lobe on that cyl it might be still shit due to a dead lifter.. . (ideally if you can make a hook to get the lifter out on that push rod you'd consider having a look... but just getting it going again is a good start)
by a dead lifter, i mean one that is worn out due to cam lobe being worn out.. i had an engine like this once, and just stuck another second hand lifter in place and ran it a while longer.. but it will need a new cam, lifters, (and when you pull it out, you'll see it needs a timing chain.. and then you start thinking.. how worn is the rest.... just get it running first.. might be fine)


so in short, 
pull the rocker cover off.. see if the rocker is loose or split or damaged.. (or worse, a valve issue)
or see the bent pushrod laying next to the other .. 

they are one of the simplest engines in many ways.. (simpler than a lawn mower even)

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37 minutes ago, deankdx said:

unclip the accelerator cable(don't loose the clip, clip it back onto the carby separately , it slides off over the cable end. then the cable sits over the ball)
undo the cable holding nut half a turn, then unscrew the plastic part so you can manoeuvre the cable off.

then undo the rocker cover loose bolts(they are nearly always loose causing leaks)

remove rocker cover, look at number 4 rockers, take a photo..
something will be up the shit.. could be just a rocker loose, but pushrods on crossflows are made of cheese.. so expect a bent one. 

someone on here might have a spare one laying around to send you if you are lucky(i used to have about 20 odd spares, but got rid of all my stuff when i moved) 

i can't recall if there's anything special doing up the rocker again, pretty sure it will just be reasonably tight... if it's wiped a cam lobe on that cyl it might be still shit due to a dead lifter.. . (ideally if you can make a hook to get the lifter out on that push rod you'd consider having a look... but just getting it going again is a good start)
by a dead lifter, i mean one that is worn out due to cam lobe being worn out.. i had an engine like this once, and just stuck another second hand lifter in place and ran it a while longer.. but it will need a new cam, lifters, (and when you pull it out, you'll see it needs a timing chain.. and then you start thinking.. how worn is the rest.... just get it running first.. might be fine)


so in short, 
pull the rocker cover off.. see if the rocker is loose or split or damaged.. (or worse, a valve issue)
or see the bent pushrod laying next to the other .. 

they are one of the simplest engines in many ways.. (simpler than a lawn mower even)

 

Thanks, I pulled the rocker cover off (didn't unclip the throttle cable though :/) and sure enough I have a loose intake push rod and the exhaust rod is not even connected! 

 

Check this out! (ignore my noisy kids)

 

 

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1 minute ago, Hgpilot said:

Thanks, I pulled the rocker cover off (didn't unclip the throttle cable though :/) and sure enough I have a loose intake push rod and the exhaust rod is not even connected! 

 

Check this out! (ignore my noisy kids)

i don't know how loose they are meant to be anymore but i've had them loose and still fine. (valve lash) there's meant to be some pressure on them from memory, but the lifters might need bleeding up with a bit of run time and that slack might be gone. 

 

i've seen instances where people have gently straightened a bent push rod(if it's not kinked) slapped it back in and it's good to go for a while.. you could try this without issue to test the rest of the engine.. but i'd plan on getting at least one replacement push rod.

 



 

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Yeah no others have any play at all. The exhaust rod was disconnected at the top. I pulled the whole rod out and it looked straight. The intake rod I think may be off at the bottom. My father is coming over tomorrow and he used to be a mechanic so I'm going to get him to check it out. I am happy with temporary fixes as this is only a temporary engine in this car until I can afford a 351! (So probably in there forever)

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if you wound the engine over to a different position, the others would be loose also.. 

 

if the push rod that fell out is still straight it could just be refitted and  probably good enough for now.

 

v8 clevo's can be painful things.. make sure you have someone on board when you go to fit one of them. if your Dad was a mechanic you'll be set, he'll know whats going on for sure.. just hopefully is a bit of a bush mechanic and lets the worn stuff stay in for now.. (these crossflows run forever while even worn out, you'd get sick of adding oil to it while waiting for it to die completely if it was patched up. )

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1 hour ago, deankdx said:

if you wound the engine over to a different position, the others would be loose also.. 

 

if the push rod that fell out is still straight it could just be refitted and  probably good enough for now.

 

v8 clevo's can be painful things.. make sure you have someone on board when you go to fit one of them. if your Dad was a mechanic you'll be set, he'll know whats going on for sure.. just hopefully is a bit of a bush mechanic and lets the worn stuff stay in for now.. (these crossflows run forever while even worn out, you'd get sick of adding oil to it while waiting for it to die completely if it was patched up. )

 

Yeah that's what I thought, but no they are all touching. Some are just pushing the spring down more than others. Yeah dad is a Bush mechanic alright, he will probably look for a straight enough stick to put in there! 

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Looking at just the video of the rockers I'm going to guess wiped cam lobe, if the pushrods are straight.

Don't know where the pictures are anymore but I had a crossflow wipe a cam lobe, was EFI so no carb issues but it was very tappy sounding and lost a fair amount of performance.

If the motor is nothing special probably be just as easy to replace it vs repair it - I repaired mine but it was only 10,000km old from a full rebuild at the time.

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These days it's so easy to wipe a lobe. People don't realise (like I didn't) that these old flat tappet motors need to run oil with decent zinc in it. I was caught and paid the price (3rd cam in 80k), from now since the last cam, I'm only using race oil with full zinc or standard oil with zinc additive put in. So far so good.

However both times I wiped a lobe, (one inlet, the other exhaust) none of this popping occured, it just got all clacky and dropped a cylinder. I do hope that's what is causing your problem if it is a wiped lobe, as multiple problems can be a head fuck.

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2 hours ago, Mr Polson said:

Looking at just the video of the rockers I'm going to guess wiped cam lobe, if the pushrods are straight.

Don't know where the pictures are anymore but I had a crossflow wipe a cam lobe, was EFI so no carb issues but it was very tappy sounding and lost a fair amount of performance.

If the motor is nothing special probably be just as easy to replace it vs repair it - I repaired mine but it was only 10,000km old from a full rebuild at the time.

 

14 minutes ago, gerg said:

These days it's so easy to wipe a lobe. People don't realise (like I didn't) that these old flat tappet motors need to run oil with decent zinc in it. I was caught and paid the price (3rd cam in 80k), from now since the last cam, I'm only using race oil with full zinc or standard oil with zinc additive put in. So far so good.

However both times I wiped a lobe, (one inlet, the other exhaust) none of this popping occured, it just got all clacky and dropped a cylinder. I do hope that's what is causing your problem if it is a wiped lobe, as multiple problems can be a head fuck.

Sent from my CPH1903 using Tapatalk
 

 

☹️ I hope you guys are wrong. I have already thrown $250 in leads, plugs, thermostat housing, water pump, and starter motor.

 I'm holding onto hope because I found the rod out of the lifter completely just floating around. I should know by tomorrow. Thanks! 

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it will probably run again with that pushrod just put back in..

but get your dad to pull out the lifter if he can.. like i said, i stuck in a second hand less worn out lifter and had the engine go another 10,000kms before it was getting tappy again.. 

 

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Alright, update! Dad came over and we pulled the 2 lifters and rods out. Both rods were straight so we put them back in and fired it up. It runs! No pop! Revs up and idles no problem!.

The exhaust lifter is working like a new one. The intake lifter on cyl 4 on the other hand is still a bit loose and tapy. Dad thought that with an engine flush and some new oil the rod might pump back up. Put new oil in and had engine flush along with some liquimoli lifter juice stuff but still lifter taps. I think I should have just put a second hand lifter in like you said deankdx. 

Anyway thanks for your help guys! It's going pretty well now because of the advice I have got here. I will no doubt be back with more questions soon. Thanks! 

 

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