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Veteran
Posts: 194
 
Location: Dorset, England | 6000 mls and 2 yrs ago I rebuilt my '58 2bbl poly to stock specs albeit with rebore & crank grind.
En route to my next -ahem- hillclimb competition it started knocking. I stopped immediately.
I've pulled the motor and find that the #3/4 rod bearings have spun, and all the others show signs of fatigue. The mains are fine. Rod journals need a grind.
Most people's reaction no doubt, will be that it's is because I rag it mercilessly, however in my defense, I have never over revved it or abused it from cold.
One thing that has always bothered me though, is that if I haven't fired up the car for more than a week, it takes an age, & I'm talking about a nailbiting 20 seconds or so for the oil pressure to start building. After that it's fine and instant. The oil pump clearances are all in spec.
I meticulously cleaned all the oil ways throughout the motor and converted it to full flow and modern filter (Hotheads kit).
The only thing I can think of is that during those cold start ups the damage was done. Are these engines known for this with the long pick-up pipe or should I start looking at the pump in greater detail?
I have never run it low on oil and use a 'classic' mineral 20/50w. Once running, it always maintains at 60psi (or at least on the line on the gauge). I have checked the gauge under hard cornering conditions and it has never faltered.
The other problem, which I needed to investigate anyway, is oil consumption.
I didn't use a breaking in oil. It started bad and has just got worse, to the extent that it went from the hi to lo marks on the dipstick in 40 miles! I had supposed there must be and oil control ring issue, but no, they are fine & there's no evidence of oil by passing the rings.
It is evidently getting in via the intake valve stems. The valves and combustion chambers are badly coked.
The valve stem clearances are within spec. However, the valve stem seals that Felpro provided in the gasket set do not sit over the tops of the guides and just ride up to the top of the stem, and I believe act as a little pump by sucking up a cap full of oil every time the valve opens which then gets sucked in through the guide.
My question is: Do polys have a specific valve guide seal that I need, that covers the top of the guide and stays there and did I just get a rogue set in my last gasket box? Can anyone recommend the correct seal?
The manual doesn't say to install the seal over the guide, just to assemble it on the stem (which I thought was odd when I built it).
Any help or advice would be gratefully received.
Thanks, John.
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Expert
Posts: 3402
 
Location: Chestertown, NY ( near Lake George) | What was the rod bearing clearance when the engine was first redone? I doubt valve seals would ever cause that much oil use, look at ring gaps, piston to wall clearance and oil ring tension/condition. My friends 59 326 never been rebuilt , just rod bearings and intake gaskets, gets 600 miles per qt. using 15/40. |
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Expert
Posts: 3035
Location: N.W. Fla. | What oil pump? The break in oil thing is about wear on the cam, best to use break in oil & pre-SM oil in the engine, though this damage isn't in the area where zddp is of importance. Oil pressure should come up in a couple of seconds. Did you replace the anti-drain back check ball assembly? What oil filter did you use? |
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Elite Veteran
Posts: 888
Location: Peoples Republic of Oregon | "Spun", as in the insert actually rotated within the rod? Or do you just have the damage as shown?
If oil pressure takes "a nailbiting 20 seconds or so for the oil pressure to start building" then you have a drain-back issue.
What filter is used? Is the filter right-side up? Down? Sideways?
IMHO, twenty seconds is a long time to wait for the gauge to start moving...BTW, where is the pressure tap? electric or manual gauge?
The seal usually found in a gasket set will be an umbrella type and it should sit at the top of the stem. This is the OEM design.
If you want a clamp-on style they are available but the guide must be machined to accept them. |
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Veteran
Posts: 194
Location: Dorset, England | The oil pump is the stock unit.
This pic shows the filter and housing. Fram PH8A. Oil pressure gauge is the stock manual gauge fed from the stock tapping next to the distributor.
As a modern filter it should not drain, and it was one of the reasons for upgrading to a modern cartridge set up. I don't believe it was a rogue filter as the 500 ml filter was no different.
I must have a drain back issue - out of the inlet side of the pump?
The bearings on the 3/4 journal had spun as can be seen in this poor photo. They had actually flattened out enough to foul and stick to each other.
As you suggest the valve guide seals are OEM type, can you explain the excessive consumption> Have you experienced similar issues with them? |
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Expert 5K+
Posts: 7417
Location: northern germany | flattie45 - 2015-09-02 4:31 PM
The oil pump is the stock unit.
This pic shows the filter and housing. Fram PH8A.
FRAM! i'm not saying this was the culprit but google frame oil filter problems. lots of people experienced disintegrating fram filters causing plugged oil passages and engine damage. i'd open it. |
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Expert
Posts: 3035
Location: N.W. Fla. | 1960fury - 2015-09-02 4:02 PM
flattie45 - 2015-09-02 4:31 PM
The oil pump is the stock unit.
This pic shows the filter and housing. Fram PH8A.
FRAM! i'm not saying this was the culprit but google frame oil filter problems. lots of people experienced disintegrating fram filters causing plugged oil passages and engine damage. i'd open it. |
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Elite Veteran
Posts: 888
Location: Peoples Republic of Oregon | From this perspective I'll venture that two things are happening relative to drain-back:
•The filter is draining (bad valve) and,
• the oem anti-drain back assembly is perhaps blocked open by something.
I don't know if you can get a Wix 51515 but it is a superior filter. As an option, you might also check with a heavy equipment dealer for a filter.
My JCB backhoe uses the same ¾-16 nipple and the oem oil filters have similar internal specifications as some of the Wix. http://www.wixfilters.com/
When you disassemble the engine pay particular attention to the valve assembly and tell us what you find. It is not uncommon, at least in this shop,
to find that the valve is incomplete, having been removed previously and some parts were 'lost' and the remaining parts installed without regard to
whether or not they would function. |
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Veteran
Posts: 194
Location: Dorset, England | wayfarer - 2015-09-03 5:46 PM
When you disassemble the engine pay particular attention to the valve assembly and tell us what you find. It is not uncommon, at least in this shop,
to find that the valve is incomplete, having been removed previously and some parts were 'lost' and the remaining parts installed without regard to
whether or not they would function.
I've cut open the filter, nothing appears to be wrong there, except for the alarming amount of white metal. I shall see if your preferred WIX filter is available here.
Now the only valve that I'm aware of in the oil system of motor is the ball in cylindrical cage which sits in the block just above the rear main cap. I understood this to be a pressure relief affair to ensure oiling if the filter was blocked.
I replaced it with the block off replacement that Hot Heads sell with their modern filter mounts to ensure full flow. I am not aware of any other devices that might be termed anti-drain back assembly. Please teach me.
The pump has been sitting on the bench now for 4 or 5 days and the oil within it has still to bleed out through the pick up pipe. If I turn the drive oil immediately rises out of the outlet.
I'm now considering if I should opt for the later 340 pump conversion that Hot Heads do.
As for the oil consumption through the intake guides I am at a loss as what course to take, if the seals I fitted are, as you said correct OEM type that sit at the top of the stem. There has to be a better way of controlling the amount of oil being sucked in.
Here's another odd characteristic though. After rebuild the crankcase breathed heavily. There is no PCV. The manual says it is meant to breath in through the filler cap & out of the breather on the other rocker cover, but it just breathed heavily out of the filler.
Could there be a connection? I re-iterate that there is no sign of any blow past the rings. The piston ring lands and skirt are clean as a whistle, as you'd expect from an engine with 6000 miles on it.
Please advise if any more photos would be useful for diagnosis.
Thanks for your help so far, John H. |
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Elite Veteran
Posts: 888
Location: Peoples Republic of Oregon | Since you have replaced the oem check valve assembly then it may not be an issue. The stock parts are on this page http://www.qualityengineeredcomponents.com/?page_id=909
By your description the oil pump seems to be ok....turn the shaft and oil moves...
If you change the oil pump do yourself a huge favour and buy the Melling M50. http://omnitek.co/mellingcatalog/#ag/part/M-50
The adapter gizmo only adds work and does not improve anything.
If the stem clearance is correct then even without a umbrella you should not be consuming that much oil....I am not sure what would cause 1qt/40 miles consumption.......maybe if you drizzle it down the carb throat.......
"...it just breathed heavily out of the filler."
IMHO, On a fresh engine, there should be very little air movement within the crankcase. Assuming that the rings are properly installed and have seated then only a minute amount of anything will get past. This of course leads to the question, did you do a cylinder compression and leakdown test at any time?
Here are some thoughts on the 'clamp-on' style stem seals: http://www.qualityengineeredcomponents.com/?page_id=1357
Edited by wayfarer 2015-09-04 12:19 PM
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Veteran
Posts: 194
Location: Dorset, England | "did you do a cylinder compression and leakdown test at any time? "
Compression test yes - all cylinders showed between 150 & 158 psi, most around 155.
I didn't have the means to do a leak down regrettably.
Your valve stem seal article expresses just what I was thought is occurring. I shall remove an exhaust valve tomorrow and see if it shows similar evidence of oil breathing as the intake. Interesting that you say that it will cause pre ign as I have been suffering from that.
Have you got a 'clamp on' type that you have found that fits, and that you use?
I agree that the level of oil consumption is extreme and that there ought to be very little air movement out of the crankcase.
"By your description the oil pump seems to be ok....turn the shaft and oil moves... " When I rebuilt the motor I did check the internal pump tolerances and they were all in spec according to the manual.
The only improvement I can think of making for anti drainback is to get a downward facing filter mount. I may have exhaust pipe clearance issues though, which is why I had gone for the angled one.
Thanks for staying with me on this, your comments are very helpfull.
I will get to the bottom of my various issues, but it's unlikely I'll do it alone!
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Expert 5K+
Posts: 8445
Location: Perth Australia | Instead of a downward facing filter, what about a remote mount one?
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Expert
Posts: 3402
Location: Chestertown, NY ( near Lake George) | A leak down test is really the definite test for ring seal. |
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Elite Veteran
Posts: 888
Location: Peoples Republic of Oregon | There are several clamp-on seals available, all determined by stem dia with several options for the guide diameter that you will have to machine your guides to.
http://www.ebay.com/itm/16-COMP-Cams-3-8-VITON-Valve-Stem-Seals-for...
The upside filter is not a problem as long as the filter has the proper anti-drain back assembly inside. This info will be noted in the Wix catalogue. |
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Expert 5K+
Posts: 8445
Location: Perth Australia | Really, there is something weird going on here
I cant see how you could loose 1 litre of oil in such a short time, did it always use that much?
To use that much oil, it surely smoked really badly and would have spat oil out of the exhaust
The rocker covers shouldnt hold much oil at all, it should just drain back down to the sump, so it not like there is much oil sitting there to get sucked into a loose valve stem
I would expect to see a very clean looking valve if it was passing oil like that, as it would wash away any deposits
There is no combustion in the intake run (normally) to burn deposited oil (although, the valve itself does get quite warm, but no where near as hot as an exhaust valve)
I do wonder what evidence your looking for for oil getting pass the rings?
Without a pcv valve system, the crankcase ventilation uses a draft tube, which requires vehicle movement to work, so some slight smoke out of the filter at idle, when warm, just sitting there, would not be a problem
This sort of looks like a bad build (sorry), but it looks like poor ring or piston fit is causing it to use oil and breath heavily and spinning the big ends on one journal would normally indicate the bearings were either the wrong size or fitted wrong, blocking the oil port
Just how I see it (apart from seeing it as terribly unfortunate for you)
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Expert
Posts: 2312
Location: Arizona | How accurate is your assessment of 20 seconds to build up oil pressure? I've never had a car where I've changed oil and installed a dry filter to take more than 10 seconds, if even that, to fill the filter and start to show oil pressure. Does the car ever ping or knock, supposedly that can be very hard on the rod bearings. Getting a good pressure reading on the gauge doesn't necessarily mean you are getting good oil flow anywhere downstream of there. I"m not familiar with the oil circuit in that engine but in a lot of engines the pressure tap is right past the pump so obstructions downstream prevent oil flow but the pressure still looks great. I have a vague recollection that sometimes even the wrong lifters will mess up the oil flow by blocking the circuit but still allow enough oil for the lifters to work. One quart in 40 miles should product a lot of smoke if it's not just leaking out somewhere. |
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Veteran
Posts: 194
Location: Dorset, England | Okay, with all your help I believe I'm beginning to get a handle on what has happened here.
The cause of my troubles has been excessive oil ingress via the intake valve stems.
The effect was to cause pre ign (pinging, knocking, pinking, call it what you will) - which was severe enough last year to make me back off the timing and add octane booster- which has caused the premature failure of the rod bearings. I had noticed some very light pinging under load conditions a couple of miles prior to hearing the big end knock.
The long time it took for oil pressure to build must have played a part.
I had often noticed black patches under the tailpipes, but as they were always left when the car had been idling, typically from cold, I had supposed it was incomplete combustion.
I had got people following the car to make a note of the amount of smoke for me, and they said that it was not excessive except under load, when it would be greater than expected.
Before I rebuilt the very tired and clogged up motor I had connected a rubber hose to the breather 'draft' tube and run it to the back of the car to get rid of the crankcase fume that was getting in the car.
I had left this in situ after my rebuild. When I removed the motor last week & disconnected this hose some brown water (oily condensation) ran out. I think that this was causing the motor to breath heavily through the oil filler cap as it it was effectively blocked by a 'U bend' in my rubber hose.
So far I have only removed one pair of valves and checked the guide tolerances. I shall now do all the others and see if any are excessive. These heads do not have guide inserts.
I shall get of the Viton stem seals and fit those as the OEM umbrellas are evidently not doing anything.
At least the exhaust valves do not seem to be oiling up.
The following photos are all of the same cylinder. After just 6000 miles!
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Expert
Posts: 3035
Location: N.W. Fla. | The draft tube system isn't very good. It depends on air flowing by the end of the tube to suck out all the nasty fumes, condensation, ect. Adding a long hose probably defeated the system. Should add a PCV valve where the draft tube is currently located.
"Now the only valve that I'm aware of in the oil system of motor is the ball in cylindrical cage which sits in the block just above the rear main cap. I understood this to be a pressure relief affair to ensure oiling if the filter was blocked. " A lot of people think it's a by pass, but the ball effectively blocks any real amount of oil getting through there. It's an anti-drain back valve, the ball blocks the oil from draining from the cartridge filter & is shoved up into the hole by the oil pressure coming out of the pump. |
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Dodge 325 poly experts - advice please
