32 replies to this topic

[Air2air]

I am having a hell of a time with this problem, and some big gurus here in the states can't figure it out.  On throttle lift I get this rattle that is a lot like pinging.  It is not exhaust related, been all through that.  

 

To get the sound you have to be between 2000 and 3000 and either in neutral or decelerating.  It is not in the drivetrain; it will do it at rest now.  I am really worried something is gonna happen.

 

Early on we looked at the LCB hitting the Hardie Spicer...and it was.  But I fixed that and still a noise.  Been driving me so crazy I made this vid.  When the noise is on you see the red text:

 

Edited by Air2air, 07 November 2014 - 04:56 AM.

[dklawson]

Todd, sorry, though I saw your thread on MM I haven't read it.  Therefore, some of my suggestions below may be repeats of information from the MM thread.

 

Your post above says that the sound now can be produced "standing still" with the engine revved between 2k and 3k RPM.  I cannot turn up my speakers at work but I heard several sounds in the video that may be what you are focusing on.  Since it is easily heard in the passenger compartment and the car does not have to be moving, turn your focus to things that may be bolted on either side of the firewall and bulkhead.  Look for things as diverse as cracks in the floor at the subframe mounts and welds on the dash rails.  Look for items in the engine bay that may be just slightly loose that are tapping.  Having a passenger along for the ride like you did on the video may prove very helpful in isolating a region where the sound seems to originate from.

[Air2air]

Todd, sorry, though I saw your thread on MM I haven't read it.  Therefore, some of my suggestions below may be repeats of information from the MM thread.

 

Your post above says that the sound now can be produced "standing still" with the engine revved between 2k and 3k RPM.  I cannot turn up my speakers at work but I heard several sounds in the video that may be what you are focusing on.  Since it is easily heard in the passenger compartment and the car does not have to be moving, turn your focus to things that may be bolted on either side of the firewall and bulkhead.  Look for things as diverse as cracks in the floor at the subframe mounts and welds on the dash rails.  Look for items in the engine bay that may be just slightly loose that are tapping.  Having a passenger along for the ride like you did on the video may prove very helpful in isolating a region where the sound seems to originate from.

 

Thanks Doug, in fact last night I was thinking about making your cool valve spring tool to check the rockers and springs.  I have the Dodds 1.5 rockers, about a year old, and there is a decent amount of wiggle play that may be a rocker bushing.  Jeremy at Jet said to look for a broken spring.

 

Good to hear that it could still possibly be something external, I remounted and rebent the header a couple times now.  Yeah I'll check around the engince bay right now...thanks for all your great advice, and I don't just mean here.

[Stevie W]

Hi Todd,

 

Listening to your video, the noise and at what engine speed and throttle openings it happens at does sound like worn big end bearings. These tend to rattle at "lift-off" of the throttle and dissappear on full throttle.

I had the same noise as you on my Mini and thought it was one of the hardy spicers hitting my LCB but a week later my oil pressure started to drop alarmingly and the noise got worse. What's your oil pressure like over the rev range from idle to, say, 4000rpm. 

 

Please don't take my idea as gospel it's just my thoughts, and I don't know how new your engine is or what mileage it has done, so maybe talking utter rubbish (trash!)

 

Hope you get it diagnosed and sorted soon.

 

Best regards, Steve.

[Air2air]

Listening to your video, the noise and at what engine speed and throttle openings it happens at does sound like worn big end bearings. These tend to rattle at "lift-off" of the throttle and dissappear on full throttle.

I had the same noise as you on my Mini and thought it was one of the hardy spicers hitting my LCB but a week later my oil pressure started to drop alarmingly and the noise got worse. What's your oil pressure like over the rev range from idle to, say, 4000rpm. 

 

Thanks Stevie, not the best news.  The engine's a year old, new from MiniMania.  However it has been my daily driver and has many a fun mile.  Now that you mention it my oil pressure doesn't go over 50 anymore and likes to stay down at 20-30.   Others have noticed this too.

 

Well this gives me additional incentive to poke about the valvetrain and hope I can find something there....

[Stevie W]

 

Listening to your video, the noise and at what engine speed and throttle openings it happens at does sound like worn big end bearings. These tend to rattle at "lift-off" of the throttle and dissappear on full throttle.

I had the same noise as you on my Mini and thought it was one of the hardy spicers hitting my LCB but a week later my oil pressure started to drop alarmingly and the noise got worse. What's your oil pressure like over the rev range from idle to, say, 4000rpm. 

 

Thanks Stevie, not the best news.  The engine's a year old, new from MiniMania.  However it has been my daily driver and has many a fun mile.  Now that you mention it my oil pressure doesn't go over 50 anymore and likes to stay down at 20-30.   Others have noticed this too.

 

Well this gives me additional incentive to poke about the valvetrain and hope I can find something there....

 

Ah ok, the low oil pressure might be an indcation of big end trouble. Hope you get it sorted....very nice car by the way!!!

[jaydee]

What oil are you using?

[dklawson]

Todd, I know it may seem odd for me to read a thread on one board and respond to it on another but I have my reasons.

 

I don't necessarily agree with Jemal's advice on going from 0.016" to 0.012" on the valve clearance for those 1.5:1 arms.  Stock arms are about 1.2:1 so if you take the ratio of 1.5/1.2 you get 1.25.  0.012" x 1.25 = 0.015"  That's the nominal tappet clearance just based on the rocker arm length and does not include any recommendations associated with your particular cam.  When you close the valve clearances up you risk the valve not closing properly when things are hot.  The old expression was:  "It's better to hear a valve than to burn one".

 

Regardless, I do agree with Malcolm's suggestion that if the noise is better/different when you adjusted the tappet clearance, maybe you should try a set of standard rockers.  If you don't have the standard ones anymore, just find a good used set off of eBay.  For good economical rockers, the stamped steel ones from a 1275 Austin America are good choices (according to Vizard).  For just a test, almost any stamped set of arms from an A-series engine (small bore Sprite, Midget, etc) will be good.

 

You said Larry mentioned de-coking the engine.  WIth as few miles as you say the engine has, I doubt there is much buildup.  However, you can clean the top end if you want.  One of the easiest over the counter products to use for this is Sea Foam which you can get at any parts store and/or Walmart.  Follow the directions on the can.  A quicker home method (and no... I am not making this up) is to get the engine up to temperature, remove the air filter, and bring the engine speed up to about 2k RPM using the idle speed screw.  With the engine running fast, take a clean pump bottle and spray a mist of water into the carb intake.  You want a mist, NOT a stream.  Pump it in as quickly as you can until the engine starts to struggle a bit and sounds like it is loosing speed.  Go through a cup or so of water.  The water will vaporize in the chamber and effectively steam clean things.  It's a very old and effective technique.  To see the results you can place a sheet of white poster board behind the exhaust pipe and watch as the black spray collects and runs down the board.

[Air2air]

 

 

Ah ok, the low oil pressure might be an indcation of big end trouble. Hope you get it sorted....very nice car by the way!!!

 

Thanks awfully Stevie - yours too.

 

What oil are you using?

 

Hi Jaydee, Castrol GTX 20/50.

 

Todd, I know it may seem odd for me to read a thread on one board and respond to it on another but I have my reasons.

 

I don't necessarily agree with Jemal's advice on going from 0.016" to 0.012" on the valve clearance for those 1.5:1 arms.  Stock arms are about 1.2:1 so if you take the ratio of 1.5/1.2 you get 1.25.  0.012" x 1.25 = 0.015"  That's the nominal tappet clearance just based on the rocker arm length and does not include any recommendations associated with your particular cam.  When you close the valve clearances up you risk the valve not closing properly when things are hot.  The old expression was:  "It's better to hear a valve than to burn one".

 

Regardless, I do agree with Malcolm's suggestion that if the noise is better/different when you adjusted the tappet clearance, maybe you should try a set of standard rockers.  If you don't have the standard ones anymore, just find a good used set off of eBay.  For good economical rockers, the stamped steel ones from a 1275 Austin America are good choices (according to Vizard).  For just a test, almost any stamped set of arms from an A-series engine (small bore Sprite, Midget, etc) will be good.

 

You said Larry mentioned de-coking the engine.  WIth as few miles as you say the engine has, I doubt there is much buildup.  However, you can clean the top end if you want.  One of the easiest over the counter products to use for this is Sea Foam which you can get at any parts store and/or Walmart.  Follow the directions on the can.  A quicker home method (and no... I am not making this up) is to get the engine up to temperature, remove the air filter, and bring the engine speed up to about 2k RPM using the idle speed screw.  With the engine running fast, take a clean pump bottle and spray a mist of water into the carb intake.  You want a mist, NOT a stream.  Pump it in as quickly as you can until the engine starts to struggle a bit and sounds like it is loosing speed.  Go through a cup or so of water.  The water will vaporize in the chamber and effectively steam clean things.  It's a very old and effective technique.  To see the results you can place a sheet of white poster board behind the exhaust pipe and watch as the black spray collects and runs down the board.

 

Thank you Doug, I will add that to my bookmarked list of your docs at https://sites.google...son/home/files.

 

As you can see from the vid I just took above, I might be in for an expensive week.  Even worse it's my daily driver.  Just wish somebody knew what this is.

 

Thanks for the quote about hearing the valves rather than burning them.  Taking them down to 0.012 from .016 did change this noise from the simulated plinking it was doing in the driving video, to now sounding officially like a bag of rocks.  Yeah I wish I had my stock rockers to use Mal's suggestion and swap out the Dodds.

[dklawson]

Now that I am at home and can turn up the sound I must say that the noise is not pleasant and it is very concerning.  Take Thorton's advice from MM and use a "pipe" to probe for the noise.  This is also an old-school and very effective technique but more commonly done with a LONG screwdriver.  You place the handle against your ear and the tip against various locations on and around the engine.  When the tip is near/over the source of the noise it will be obviously louder.  It is certainly worth taking the time to try.  

 

I hope it is nothing major.  If it is, do not discount buying a running, smaller engine to use until you can spend the money and time on the 1275.  Engine rebuilds are not cheap and are more economical when you do the assembly work yourself.  A DIY rebuild of a 1275 can be anywhere from a few hundred to $2k depending on what you do.  Professional rebuilds are a lot more.  Let's hope it doesn't come to that.

[Air2air]

Doug thanks...er..I think.  This engine was a new $7K 1330 from Mania just over a year ago, and boy the wife did not like that.  Nothing is in the oil or on the drain plug except the usual xmas tree.  

 

This is gonna require another credit card...

Edited by Air2air, 08 November 2014 - 02:52 AM.

[Air2air]

Mal I should've done that before, will get one of those, thanks.

A friend told me to take off the rockers and look for big divits in the faces and stems.  There weren't any here, but we may have a smoking gun here at #8 pushrod. 

• Note the groove in the adjuster screw ball on #8, but can't tell if it was worn in, or a manufacturing defect.  
• The closeup pic looking down on the head, note the hole for #8 has a small wear groove on the side farthest from you.
• #8 pushrod's cone end is so bent it wouldn't stand up.  Note the polish marks on the side.  Couldn't see any damage around the cone.
• Note the pitted stem face on #5 valve.  You guys tell me what that means.  The rocker face is clean - they all were.

 

 

 

[dklawson]

Yuck.  I wish this were not your daily driver.

 

The galling on the ball end could have been caused by several things but my gut feeling is that the particular arm became bound up perhaps from a valve spring that was fully collapsed at max lift.  The bent pushrod suggests this also.  That may have contributed to the damage on the end of the valve stem.  I doubt any of this was related to a manufacturing defect.  I believe you said this was a MM engine with 1.5 arms.  If you put the rocker gear back on (excluding the obviously terrible one and its pushrod) and turn the engine over by hand, how close are the valve springs coming to full compression?  

 

I would still be hoping for a solution that involved less than a full rebuild.   As such, I would consider taking the head off and having a machine shop go through it completely.  Have them check all the valves and replace those that are suspect.  Perhaps the valve guides are also tight.  Prior to re-fitting the head, source a set of standard ratio arms.  You can buy standard length forged arms but they will be expensive.  If you can find a set of stamped arms they will serve you well until you decide you want to do something different.  Obviously get a new set of pushrods.  Any binding that may have caused the one pushrod to bend may have affected the others.  Hopefully that same damage has not been transferred to the cam lobes and lifters.  With the head off you may be able use a retrieval magnet to pull the lifters out to inspect them and the cam lobes.  (Paint mark the lifters so you put them back in exactly the same spot... don't mix up their order/location).

Edited by dklawson, 08 November 2014 - 12:04 PM.

[tmsmini]

Todd:

I am sure I have a set of rocker gear from one of my engines that you can borrow/have if needed.

Just let me know.

Terry

PS: I may not have a spare shaft to go with the rockers.

Edited by tmsmini, 08 November 2014 - 04:45 PM.

[Air2air]

Hi Terry - thanks for the offer, it may be my only chance to make the Santa Cruz run tomorrow.

 

Doug, Lance pointed out an interesting theory last night, this is from my post at MM:

 

There are two things going on here:  First, the pushrod was running up against the side of the pushrod hole and second was whatever made it do that.

 

Lance noticed the offset in the Pierce head between #8 stem and the pushrod hole.  As you can see in the looking-down pic it's over .25".   His theory is that the shimming on the rocker was done to favor it to center on the valve, not on the pushrod.  This positioned the pushrod right up against the hole - towards the passenger side.  But if you shimmed the rocker to center the pushrod in the hole, then the valve stem would be off-center on the rocker.  Notice the two shims on the inside, positioning the rocker out towards the passenger side to do this.

 

So the outside shim wore slightly over time and the pushrod was already right up against the hole, and you can see the polish marks on it.  The pushrod's bend is only around the cup area.  I think it's because at max lift the cup/ball contact area was so offset it was squishing it even harder against the side of the hole. 

 

Notice the Dodds rocker (1 year old) bushing oil groove full of sand or glass bead that was left in there during assembly, and what a great job it did scoring the bushing.

 

 

Edited by Air2air, 08 November 2014 - 06:00 PM.