Houston We Have A Problem

andyjanet

Full Member
Latest update on the compression:

cylinder 1 - 125
cylinder 2 - 90
cylinder 3 - 120
cylinder 4 - 75

Looks like the head's going to have to come off sometime in the future.

Rae
Just the wrong time of year, suns a shining you should be out in the van not stuck with your head under the bonnet ?
 

scoobydiver

Full Member
Think I've found out why the van has not been running too well. I did a compression test and these are the results......can you spot the difference?

Cylinder 1​
View attachment 44999

Cylinder 2​
View attachment 45000

Cylinder 3​
View attachment 45001

Cylinder 4​
View attachment 45002

It could be a tight tappet or a burnt valve: as no water has been used, the oil has no signs of mayonnaise at the cap and I've run it on LPG I would think I've burnt a valve.

Rae
ohhhhhhh dear
 

StreetSleeper

Full Member
Decided it was time for some more investigative work to be done........so off comes the cam cover and this is what I found after wiping away the oil......oh dear. Spun the engine over.


46512

And this is the bottom.

46514

This is cylinder no. 2, a little better.

46513

I would doubt this is due to wear or lack of oil, more than likely a foreign body or the engine may have just snapped a cam belt, bent a valve and a quick, cheap rebuild has been done just to sell it. Any opinions are more than welcome but, as no loose pieces of metal were found in the nearby area, I'm more inclined to have a cynical view on this matter.

Rae
 

StreetSleeper

Full Member
Cylinder no.3 you can see one or two marks.

46531


But the scoring seems to go right the way round the bottom on this cylinder.

46533

More signs of wear.

46532

Maybe totally wrong here, and please don't hold back if you have a better explanation, 2 & 4 cylinders were always the low compression and yet, on investigation, 1 & 3 seem to have been the damaged ones. My conclusion is 1 & 3 cylinders have had the valves replaced and whatever work was needed to get it on the road again and 2 & 4 were just left alone hence the low compression now on those cylinders.

Rae
 
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saxonborg

Full Member
Cylinder no.3 you can see one or two marks.


View attachment 46515

But the scoring seems to go right the way round the bottom on this cylinder.

View attachment 46516

The adjacent cam looks in fine condition.

View attachment 46517

Maybe totally wrong here, and please don't hold back if you have a better explanation, 2 & 4 cylinders were always the low compression and yet, on investigation, 1 & 3 seem to have been the damaged ones. My conclusion is 1 & 3 cylinders have had the valves replaced and whatever work was needed to get it on the road again and 2 & 4 were just left alone hence the low compression now on those cylinders.

Rae
Assume we are looking at heavy cam wear/scoring. Your prognosis seems to fit the bill. Whatever caused the scoring might have at some point entered the cylinder so I presume head off next.
 

Molly 3

Full Member
I wouldn't rule out an oil problem could be part blocked oil gallery's or wrong grade of oil . good luck with your further investigation Bazz
 

StreetSleeper

Full Member
Assume we are looking at heavy cam wear/scoring. Your prognosis seems to fit the bill. Whatever caused the scoring might have at some point entered the cylinder so I presume head off next.
Hello Eric,
Looks more like new cam, new valves and, while we're in there, hardened seats.

Rae
 

StreetSleeper

Full Member
You’ll get there Rae. Sounds like a logical explanation. Good luck
Hello Alan,
Well at least we're getting there, I can see a light at the end of the tunnel.........I just hope it's not a train coming towards me.

Rae
 

StreetSleeper

Full Member
I wouldn't rule out an oil problem could be part blocked oil gallery's or wrong grade of oil . good luck with your further investigation Bazz
Hello Bazz,
Very good point, the old Pintos were infamous for that.

Rae
 

andyjanet

Full Member
Looks like a cheap replacement cam shaft to me, it’s got paint marks on original parts didnt have paint on and some of the cheap replacements the round part of the cam was never finished off properly, can you get hold of a recon head by the time you’ve paid someone to strip and rebuild it would be cost effective to rip one off and fit the new one all set up
 

StreetSleeper

Full Member
Hello Andy,
Can't get another head for love nor money so that's not an option. Can only find patented cams, sorry cam. There's been a few ideas thrown around and one option that seems to be more appealing: the camshaft may have been a cheap, patented one for whatever reason and the oil feed holes have been blocked at some point and so we have excess wear. There are no marks or signs of wear on the buckets so what I'm wondering can I just slip a new camshaft in? I would imagine the camshafts have to be machined to a high tolerance so my thinking is if one camshaft comes out the replacement, in theory, should be exactly the same. If this is the case, happy days, no need to re-shim.

Rae
 

andyjanet

Full Member
Aye but you’d nee to get one with the same profiles, reshiming isn’t a problem if you are replacing the valves or grinding it will need reshimming anyway
 

nabsim

Full Member
Its years since I did anything with cams Rae and memory is a bit cloudy, don’t the lobes on the shaft open the valves not close them? If that’s the case then you have to do more than the cam to cure the problem.

They put those pinto engines in loads of things so may be worth checking some specialised sites (modifier/trikes etc.).
 

St3v3

Full Member
I guess it would be nice to try a compression test with the cam removed, if that's possible...
 

helen262

Full Member
It looks like oil starvation, or shimmed up incorrectly which could give low compression if the valves are not shutting fully or soon enough
 

eurajohn

Free Member
Have you actually checked the valve clearances with feeler gauges?

If you can find someone with a "leak down tester" it will be possible to determine where, if anywhere compression is being lost.
.
 

Markd

Full Member
I reckon you've got enough evidence to justify pulling the head and consider rebuilding it.
Just changing the cam (and probably the buckets) is unlikely to cure the low compression which are probably valves not sealing.
With replacement heads not available this is the only option short of an exchange engine
 

SquirrellCook

Full Member
What a pain in the *** Base circle wear on a cam should never take place. The clearance is to allow oil to be drawn on to the loaded surface. This is the down side of allowing the tappet clearances to close up. Tight is bad as well as loose. If the valve seats erode it will reduce the clearance. That's not the end of the world as long as the cam to follower clearance is maintained. I expect all you will need is a new set of valves. The valve seats cut and a new camshaft. Hardest part will be finding a good engine remanufacturer to do it.

Mark
 
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