I'm sure cars know...
Discussion
Took a potential buyer out for a spin in the S3 earlier. All was going well until I thought I'd demonstrate the brakes.
Honking down a sliproad, I put the 'box in neutral and gauged my braking point.
At the appointed moment I threw the anchors out and the car pulled up... which is just as well really otherwise we'd be decorating a traffic island right now :D
Since then it doesn't seem to want to run properly. The idle is OK, but it won't pull (sounds like it's on 3 cylinders). You can trickle through town just off-idle and it seems fine, but plant your foot and it's like someone turned the sparks off.
My best guess is fuel starvation; I once had the offside tank outlet block up, so I thought maybe with the hard braking something had been dislodged causing a recurrence. To test the theory I put a gallon in the nearside tank but it made no difference.
Oil pressure and temperature are normal, nothing seems to have dropped off, guess I'll have to get the spanners out.... :smash:
Two other possibiities are: first, I'd just put fuel in the tank. Contaminated fuel?
Second, I'd just washed the car: water in the tanks?
However I've washed it the same way plenty of times before without any problem, so I guess that's out...
Honking down a sliproad, I put the 'box in neutral and gauged my braking point.
At the appointed moment I threw the anchors out and the car pulled up... which is just as well really otherwise we'd be decorating a traffic island right now :D
Since then it doesn't seem to want to run properly. The idle is OK, but it won't pull (sounds like it's on 3 cylinders). You can trickle through town just off-idle and it seems fine, but plant your foot and it's like someone turned the sparks off.
My best guess is fuel starvation; I once had the offside tank outlet block up, so I thought maybe with the hard braking something had been dislodged causing a recurrence. To test the theory I put a gallon in the nearside tank but it made no difference.
Oil pressure and temperature are normal, nothing seems to have dropped off, guess I'll have to get the spanners out.... :smash:
Two other possibiities are: first, I'd just put fuel in the tank. Contaminated fuel?
Second, I'd just washed the car: water in the tanks?
However I've washed it the same way plenty of times before without any problem, so I guess that's out...
Well, if I could I'd change the 
to a 
...
I decided to investigate the running problem. It seemed like fuel starvation so I pulled the fuel pipe off the rear carb and hung it in a jar. With the ignition on I got 275ml of fuel in 15 seconds, or 1.1L a minute. Now I figure that even at full bore the car wouldn't use that much so that's not the issue.
Rather than strip the carbs I thought I'd check the cylinder compressions 'just in case'.
I whipped the plugs out and the rear two were oiled up while the front two were normal. I'd bead-blasted them just a couple of weeks back so I know this is a new phenomenon as they weren't like that before.
I also noted that there was a lot of oil dripping off the bottom of the engine and covering the starter motor, which it hadn't before. Bear in mind that the last job I did on the car was to replace the oil breather pipe from the crankcase to the air cleaner box, so I just assumed that it was dripping oil vapour...
Anyway, the compression tester is a bit of a pig to get a good seal down in the depths of the head cavities, so when I got 50-60 psi on the front two cylinders I wasn't too perturbed, I just thought the tester wasn't screwed in tight enough.
When number 3 came up at 165 psi I got worried, and when number 4 read 170 I knew I'd found the fault.
Opening the air cleaner revealed that the trumpets of the rear carb, and that area of the filter box, were liberally plastered with oil.
The oil on the dipstick is still clean.
So, my diagnosis is that the head gasket is blowing between numbers 1 & 2, losing combustion gases into the crankcase, blowing the oil up into the air cleaner, through the rear carb and fouling the rear two plugs.
Now why the hell it chose to blow just as I braked for a junction, I don't know.
Is this a common failure mode for head gaskets on Esprits?
Needless to say I'll have to fix it: with a blown HG I guess it knocks hundreds off the value of the car and I wasn't expecting to sell it for much anyway!
I'm too much of a gentleman to merely bodge a new gasket in and sell it quick, so it'll be an engine-out full-rebuild job, probably more than the car is worth...
to a ... I decided to investigate the running problem. It seemed like fuel starvation so I pulled the fuel pipe off the rear carb and hung it in a jar. With the ignition on I got 275ml of fuel in 15 seconds, or 1.1L a minute. Now I figure that even at full bore the car wouldn't use that much
so that's not the issue. Rather than strip the carbs I thought I'd check the cylinder compressions 'just in case'.
I whipped the plugs out and the rear two were oiled up while the front two were normal. I'd bead-blasted them just a couple of weeks back so I know this is a new phenomenon as they weren't like that before.
I also noted that there was a lot of oil dripping off the bottom of the engine and covering the starter motor, which it hadn't before. Bear in mind that the last job I did on the car was to replace the oil breather pipe from the crankcase to the air cleaner box, so I just assumed that it was dripping oil vapour...
Anyway, the compression tester is a bit of a pig to get a good seal down in the depths of the head cavities, so when I got 50-60 psi on the front two cylinders I wasn't too perturbed, I just thought the tester wasn't screwed in tight enough.
When number 3 came up at 165 psi I got worried, and when number 4 read 170 I knew I'd found the fault.
Opening the air cleaner revealed that the trumpets of the rear carb, and that area of the filter box, were liberally plastered with oil.
The oil on the dipstick is still clean.
So, my diagnosis is that the head gasket is blowing between numbers 1 & 2, losing combustion gases into the crankcase, blowing the oil up into the air cleaner, through the rear carb and fouling the rear two plugs.
Now why the hell it chose to blow just as I braked for a junction, I don't know.
Is this a common failure mode for head gaskets on Esprits?
Needless to say I'll have to fix it: with a blown HG I guess it knocks hundreds off the value of the car and I wasn't expecting to sell it for much anyway!
I'm too much of a gentleman to merely bodge a new gasket in and sell it quick, so it'll be an engine-out full-rebuild job, probably more than the car is worth...
Yeah, I think they do know. When I was selling my Europa years ago, one guy came over and the thing started pukeing oil out the head gasket by the exhaust manifold.
Next time, after the new head gasket, I went to start it before the buyer came over. Would not start for anything. After much head scratching, I determined the dizzy was a tooth off and after correcting that, it started right up.
Dr.Hess
Next time, after the new head gasket, I went to start it before the buyer came over. Would not start for anything. After much head scratching, I determined the dizzy was a tooth off and after correcting that, it started right up.
Dr.Hess
Autocross7 said:
So for my future reference...
Does the motor have to come out to put a new head gasket? I know with theFerrari 308, the heads would unbolt and pull off, then drop in the new gasket...
surely Lotus would not be more complicated that the Ferrari...
Drive topless!!!
Cameron
It doesn't HAVE to come out, but while I'm at it I could fix that oil leak... and this blowing gasket... and a new timing belt... and... and...
Hi,
Sorry to hear of your troubles. I am suspicious of it being a headgasket leak, especially if it's just oil which is leaking. A blown headgasket will also usually leak coolant past the seal. Is your coolant level low? Is there a tan/milky goo on the dipstick and/or oil filler cap? Have you changed the oil? Any emulsion present here? What kind of oil pressure are you seeing at the gauge?
The oil rebreather could also be a problem. The momemtum of the car would cause any excess oil to migrate to the rear of the plenum. What does your air filter look like?
You really need to do a leakdown test on all cylinders before deciding what repair is needed. What concerns me most about your Headgasket diagnosis is the lack of leaking coolant in your description.
Not to alarm you, but I think there's a possibility that you may have realized one of the banes of the earlier cars, namely; Blow-by from crowned #1, #2 pistons. Probably not, but until you do a leakdown, it cannot be eliminated from the list of possibilities.
It is also possible that under extreme braking the weight of the head pulled or lifted itself and stripped any number of studs from the block, compromising the headgasket seal. Remote indeed, but possible.
I once had the mounting studs of the carburettor strip and lift completely out of the intake manifold on a 1968 Lincoln Continental for the very same reason - Hard Braking. This was the largest Holley 4-BBL made at that time, so it had some heft to it.
This was 300 miles from home, but I was able to limp the car home by tying down the carburettor sufficiently for it to seal using some baling wire in a sort of tourniquet arrangement on both sides. Had to Heli-coil the Intake Manifold and install new studs once home. Best of Luck!
Happy Motoring!... Jim '00 Boxster
>> Edited by lotusguy on Saturday 25th June 18:54
>> Edited by lotusguy on Saturday 25th June 18:54
Sorry to hear of your troubles. I am suspicious of it being a headgasket leak, especially if it's just oil which is leaking. A blown headgasket will also usually leak coolant past the seal. Is your coolant level low? Is there a tan/milky goo on the dipstick and/or oil filler cap? Have you changed the oil? Any emulsion present here? What kind of oil pressure are you seeing at the gauge?
The oil rebreather could also be a problem. The momemtum of the car would cause any excess oil to migrate to the rear of the plenum. What does your air filter look like?
You really need to do a leakdown test on all cylinders before deciding what repair is needed. What concerns me most about your Headgasket diagnosis is the lack of leaking coolant in your description.
Not to alarm you, but I think there's a possibility that you may have realized one of the banes of the earlier cars, namely; Blow-by from crowned #1, #2 pistons. Probably not, but until you do a leakdown, it cannot be eliminated from the list of possibilities.
It is also possible that under extreme braking the weight of the head pulled or lifted itself and stripped any number of studs from the block, compromising the headgasket seal. Remote indeed, but possible.
I once had the mounting studs of the carburettor strip and lift completely out of the intake manifold on a 1968 Lincoln Continental for the very same reason - Hard Braking. This was the largest Holley 4-BBL made at that time, so it had some heft to it.
This was 300 miles from home, but I was able to limp the car home by tying down the carburettor sufficiently for it to seal using some baling wire in a sort of tourniquet arrangement on both sides. Had to Heli-coil the Intake Manifold and install new studs once home. Best of Luck!
Happy Motoring!... Jim '00 Boxster
>> Edited by lotusguy on Saturday 25th June 18:54
>> Edited by lotusguy on Saturday 25th June 18:54
lotusguy said:
Hi,
Sorry to hear of your troubles. I am suspicious of it being a headgasket leak, especially if it's just oil which is leaking. A blown headgasket will also usually leak coolant past the seal. Is your coolant level low? Is there a tan/milky goo on the dipstick and/or oil filler cap? Have you changed the oil? Any emulsion present here? What kind of oil pressure are you seeing at the gauge?
The oil rebreather could also be a problem. The momemtum of the car would cause any excess oil to migrate to the rear of the plenum. What does your air filter look like?
You really need to do a leakdown test on all cylinders before deciding what repair is needed. What concerns me most about your Headgasket diagnosis is the lack of leaking coolant in your description.
Not to alarm you, but I think there's a possibility that you may have realized one of the banes of the earlier cars, namely; Blow-by from crowned #1, #2 pistons. Probably not, but until you do a leakdown, it cannot be eliminated from the list of possibilities.
It is also possible that under extreme braking the weight of the head pulled or lifted itself and stripped any number of studs from the block, compromising the headgasket seal. Remote indeed, but possible.
I once had the mounting studs of the carburettor strip and lift completely out of the intake manifold on a 1968 Lincoln Continental for the very same reason - Hard Braking. This was the largest Holley 4-BBL made at that time, so it had some heft to it.
This was 300 miles from home, but I was able to limp the car home by tying down the carburettor sufficiently for it to seal using some baling wire in a sort of tourniquet arrangement on both sides. Had to Heli-coil the Intake Manifold and install new studs once home. Best of Luck!
Happy Motoring!... Jim '00 Boxster
>> Edited by lotusguy on Saturday 25th June 18:54
>> Edited by lotusguy on Saturday 25th June 18:54
Cheers Jim:
Well, I didn't think it was THAT heavy braking! I've certainly braked harder when out by myself; it was just for a demo that it stops as well as it goes, and in a straight line.
I think I'll drop a fibrescope down the plug holes to see what the pistons look like.
As for the coolant leak, I did check that and the oil. The coolant level is where it usually is and there's no mayonnaise on the dipstick.
I had a Triumph Spitfire when I was a lad that blew three (pattern) head gaskets across between two cylinders before I finally fitted a genuine item and never had any more problems. That car also had no coolant problems as far as I can recall.
I did think the oil gauge was reading a bit oddly last time I drove the Esprit, that I assumed was due to the gases. If you open the airbox with the engine running there's a steady smoky plume of what smells like exhaust gas emitting from the breather at the rear of the box. The filter in that area is soaked in oil.
It has since got extremely difficult to start, probably as the rear plugs have fouled again.
I hear what you say about the head lifting; it is one I've never come across before. My next thought after head gasket was that the head itself might have cracked, but I genuinely wasn't thrashing the car (it had warmed up by then and I don't think we had more than about 5500-6000 rpm up before the braking incident).
I won't know for certain until I strip the motor, but I have had thoughts about selling it 'as is' and letting someone else have the hassle...
Ian
sanj said:
It is also possible that under extreme braking the weight of the head pulled or lifted itself and stripped any number of studs from the block, compromising the headgasket seal. Remote indeed, but possible.
Please tell me you're not serious. Please!!!
Well, it might be an issue if you were retarding at a couple of hundred G. But then I think the cylinder head would be the least of you worries.
The brakes on my S3 were good, but not that good.
OK, quick update: I couldn't lay my hands on the Videoprobe at work, my fibrescope has flat batteries so I had to use the work's standby 'scope which has no articulation!
I was therefore only able to survey the piston crowns: they all look OK, varying degrees of carbon from none at all to about 50% coverage, most of the pistons seem to have some oil sat on them.
I'll nip in tomorrow and borrow the Videoprobe, that has full articulation so I should be able to see the blow-by from the gasket if there is any...
I was therefore only able to survey the piston crowns: they all look OK, varying degrees of carbon from none at all to about 50% coverage, most of the pistons seem to have some oil sat on them.
I'll nip in tomorrow and borrow the Videoprobe, that has full articulation so I should be able to see the blow-by from the gasket if there is any...
Hmmm. Twenty thousand pounds-worth of this:
failed to prove conclusively that the head gasket has blown - at least not in the way I expected it to have. Reconsidering my diagnosis, I'm wondering just how the crankcase could be pressurised and not the coolant, as mentioned by various people. It would have to be blowing between a cylinder and the oilway to the cylinder head. Fair enough, but why the low compression on TWO cylinders? The Videoprobe didn't reveal any damage to the edge of the gasket that's visible inside the cylinder.
So there I was, leaning over the engine, when I noticed:
Holy crap, maybe that's the problem, the timing belt has jumped! Not tht that would explain the symptoms entirely, but hey, I need straws to grasp here...
Well, if you've ever tried to check the belt timing you'll know what came next.
Car up in the air, grovel underneath, turn crank with spanner. Climb in engine bay and examine cam timing marks. Swear. Grovel underneath, turn crank.... etc etc.
Eventually I decided it would be quicker if I took the airbox and alternator off. So I did. It seemed as though the timing WAS out, so off came the belt. Well, I tried following what it says in the manual but I couldn't for the life of me move the semi-auto tensioner either in or out, once I'd slackened the locknut. It looks to me like it's already as far out as it's supposed to go, but it won't wind either way.
Hmmm again.
Anyway, I retracted and locked the tensioner, took the belt off, retimed all the pulleys, put belt back on and retensioned.
Then I did a compression test.
Exactly the
same...
Now I'm concerned that I may have one or more bent valves, although I can't hear anything ticking as I turn the engine over. Suppose I'll have to build a leakdown tester next, then it'll be time to check the valve clearances.... it, I may as well just pull the engine like I was planning to...
failed to prove conclusively that the head gasket has blown - at least not in the way I expected it to have. Reconsidering my diagnosis, I'm wondering just how the crankcase could be pressurised and not the coolant, as mentioned by various people. It would have to be blowing between a cylinder and the oilway to the cylinder head. Fair enough, but why the low compression on TWO cylinders? The Videoprobe didn't reveal any damage to the edge of the gasket that's visible inside the cylinder.
So there I was, leaning over the engine, when I noticed:
Holy crap, maybe that's the problem, the timing belt has jumped! Not tht that would explain the symptoms entirely, but hey, I need straws to grasp here... Well, if you've ever tried to check the belt timing you'll know what came next.
Car up in the air, grovel underneath, turn crank with spanner. Climb in engine bay and examine cam timing marks. Swear. Grovel underneath, turn crank.... etc etc.
Eventually I decided it would be quicker if I took the airbox and alternator off. So I did. It seemed as though the timing WAS out, so off came the belt. Well, I tried following what it says in the manual but I couldn't for the life of me move the semi-auto tensioner either in or out, once I'd slackened the locknut. It looks to me like it's already as far out as it's supposed to go, but it won't wind either way.
Hmmm again.
Anyway, I retracted and locked the tensioner, took the belt off, retimed all the pulleys, put belt back on and retensioned.
Then I did a compression test.
Exactly the
same... Now I'm concerned that I may have one or more bent valves, although I can't hear anything ticking as I turn the engine over. Suppose I'll have to build a leakdown tester next, then it'll be time to check the valve clearances....
it, I may as well just pull the engine like I was planning to... Dr.Hess said:
Could you look at the valves with your scope thingie?
How far out was that cam? One tooth/several teeth? Although a head gasket could fail between any thing, given your other findings, I'm betting on a bent valve. I'd say pull the motor.
Dr.Hess
The scope can only 'look back' on itself so far; I could get enough curve to see the gasket and the heads of whichever valves were open, but too close to be able to see whether the stems were bent.
I may be able to go in through the inlet manifold and spot a bent stem, but I guess a clearance check would show that up anyway.
I just can't figure out how even a bent valve would explain all the oil being blown out of the crankcase breather...
I fancy building a leakdown tester now, just for the hell of it!
An old sparkplug will make a good starting point...Poor compression and pressurised crankcase ?
Could be broken compression rings on those cylinders.
If the engine momentarily seized, that could also explain the cambelt jumping.
Just a theory of course.
Paul.
PS I removed the cylinder head from an S2 Esprit once with the engine in situ. Never again, we had to remove a chassis tube (we didn't butcher it, the tube was designed to be removed). That had a different chassis to the S3 of course, but I would still remove the engine/gearbox as an assembly simply for the ease of access once it's out.
I pulled mine (S3)to change the exhaust manifold, put it all together, then had to do it all again a month later to change the clutch. Ho Hum..........
>> Edited by B16 RFF on Tuesday 28th June 02:12
Could be broken compression rings on those cylinders.
If the engine momentarily seized, that could also explain the cambelt jumping.
Just a theory of course.
Paul.
PS I removed the cylinder head from an S2 Esprit once with the engine in situ. Never again, we had to remove a chassis tube (we didn't butcher it, the tube was designed to be removed). That had a different chassis to the S3 of course, but I would still remove the engine/gearbox as an assembly simply for the ease of access once it's out.
I pulled mine (S3)to change the exhaust manifold, put it all together, then had to do it all again a month later to change the clutch. Ho Hum..........
>> Edited by B16 RFF on Tuesday 28th June 02:12
Hi,
The Plot Thickens... Although I find Paul's theory quite intriguing, I cannot reasonably fathom the engine 'momentarily seizing'.
But, based on your new information, primarily the timing belt jumping and the semi-automatic tensioner being fully tightened, here's my theory.
You had a tensioner failure. Possibly the bearing seized, but more likely either the bushes, the pivot pin, or the split pin which 'holds' the pivot pin in place failed. This possibly occured as the tensioner was being adjusted the last time the timing belt was replaced - a ticking time-bomb. I say this because the tensioner was all drawn up - that cannot passively occur.
The belt was never really drawn up sufficiently. It was new, and so very tight. The installer may just have mistakenly gotten the proper tension reading as the tensioner was all drawn up.
As the belt wore, it stretched, becoming looser. Finally, it became loose enough that the torque of the starter caused the crank pulley to jump a few teeth under the belt, throwing off the timing and resulting in some internal damage to the reciprocals.
Jump one tooth - Scary!, two teeth - "Do You Feel Lucky Today Punk?", three teeth - Sayonara Valve San!
Sound far fetched? Well, people often underestimate the torque a starter motor has - more than enough to turn the crank pulley under an improperly tensioned belt.
Plus, ask me how I know all this - the very thing occured to my old '85 Esprit. The car was running great, just 1,000 miles or so off a total rebuild. I stopped the car - at a Lotus Dealership no less - taking Jim Knowles to buy his S4s.
After, I re-started the car, it ran terribly, but ran. Turned out I only lost enough tension to jump the belt a single tooth, so luckily, no damage occured.
In my case, the split pin on the pivot pin hadn't seated all the way initially and worked it's way loose over time - 1,500 mi. Once it did, the pivot pin caused the bearing to shift loosening the belt tension along with it.
Sorry to have to be the one to tell you, and I hope I'm wrong. But, I bet if I'm not spot-on, I'm not far off. I suspect you'll find the tensioner to be the instigator of all this. I just hope the damage isn't too bad, but some part of 8 valves ain't great + the headgasket.
I really think the semi-automatic tensioner is a better deal than the later eccentric one because it can make up for the belt loosening over time. But, it is more complex and prone to more types of failure.
Best of Luck, and keep us all posted.
Happy Motoring!... Jim '00 Boxster
>> Edited by lotusguy on Tuesday 28th June 06:22
The Plot Thickens... Although I find Paul's theory quite intriguing, I cannot reasonably fathom the engine 'momentarily seizing'.
But, based on your new information, primarily the timing belt jumping and the semi-automatic tensioner being fully tightened, here's my theory.
You had a tensioner failure. Possibly the bearing seized, but more likely either the bushes, the pivot pin, or the split pin which 'holds' the pivot pin in place failed. This possibly occured as the tensioner was being adjusted the last time the timing belt was replaced - a ticking time-bomb. I say this because the tensioner was all drawn up - that cannot passively occur.
The belt was never really drawn up sufficiently. It was new, and so very tight. The installer may just have mistakenly gotten the proper tension reading as the tensioner was all drawn up.
As the belt wore, it stretched, becoming looser. Finally, it became loose enough that the torque of the starter caused the crank pulley to jump a few teeth under the belt, throwing off the timing and resulting in some internal damage to the reciprocals.
Jump one tooth - Scary!, two teeth - "Do You Feel Lucky Today Punk?", three teeth - Sayonara Valve San!
Sound far fetched? Well, people often underestimate the torque a starter motor has - more than enough to turn the crank pulley under an improperly tensioned belt.
Plus, ask me how I know all this - the very thing occured to my old '85 Esprit. The car was running great, just 1,000 miles or so off a total rebuild. I stopped the car - at a Lotus Dealership no less - taking Jim Knowles to buy his S4s.
After, I re-started the car, it ran terribly, but ran. Turned out I only lost enough tension to jump the belt a single tooth, so luckily, no damage occured.
In my case, the split pin on the pivot pin hadn't seated all the way initially and worked it's way loose over time - 1,500 mi. Once it did, the pivot pin caused the bearing to shift loosening the belt tension along with it.
Sorry to have to be the one to tell you, and I hope I'm wrong. But, I bet if I'm not spot-on, I'm not far off. I suspect you'll find the tensioner to be the instigator of all this. I just hope the damage isn't too bad, but some part of 8 valves ain't great + the headgasket.
I really think the semi-automatic tensioner is a better deal than the later eccentric one because it can make up for the belt loosening over time. But, it is more complex and prone to more types of failure.
Best of Luck, and keep us all posted.
Happy Motoring!... Jim '00 Boxster
>> Edited by lotusguy on Tuesday 28th June 06:22
Interesting theory, Jim.
Still does not explain the crankcase pressurising though.
Re my momentary seizing idea. If it is broken piston rings, then whatever caused that to happen (lubrication failure?) could also have caused the momentary seizing as the rings self destructed. Or maybe that coupled with the slack belt resulting from the faulty tensioner.
I think Ian said he had just taken it to 5/6k revs; again that could cause the belt to jump if it was slack and/or the engine was not fully warmed up and expanded.
Come on Ian, pull the engine and strip it. You must have almost 24 hour daylight oop north, and you don't really need to sleep. We want to know.
Paul.
>> Edited by B16 RFF on Tuesday 28th June 13:24
Still does not explain the crankcase pressurising though.
Re my momentary seizing idea. If it is broken piston rings, then whatever caused that to happen (lubrication failure?) could also have caused the momentary seizing as the rings self destructed. Or maybe that coupled with the slack belt resulting from the faulty tensioner.
I think Ian said he had just taken it to 5/6k revs; again that could cause the belt to jump if it was slack and/or the engine was not fully warmed up and expanded.
Come on Ian, pull the engine and strip it. You must have almost 24 hour daylight oop north, and you don't really need to sleep. We want to know.
Paul.
>> Edited by B16 RFF on Tuesday 28th June 13:24
Oh dear. This is NOT looking good.
Knocked up a leakdown tester to day to find that NONE of the cylinders appear to hold pressure.
Numbers 1 & 2 though are the worst; as fast as I can pump compressed air in, it comes out of the crankcase breather. In the case of no. 1, it's accompanied by a 'clonk' that can be felt through the crank pulley, as though the pressure is causing the big-end to knock on the crank.
Now the only thing that could cause this is, as far as I can see, the 'crowning' problem that lotusguy mentions... but the pistons looked OK on the scope and appear to move correctly with the crank, so unless the rings have all vapourised, what the hell is going on?
I've recovered my engine crane from the guy who's had it for the last two years, but not sure when I'm going to get time to pull the engine out now...
Knocked up a leakdown tester to day to find that NONE of the cylinders appear to hold pressure.
Numbers 1 & 2 though are the worst; as fast as I can pump compressed air in, it comes out of the crankcase breather. In the case of no. 1, it's accompanied by a 'clonk' that can be felt through the crank pulley, as though the pressure is causing the big-end to knock on the crank.
Now the only thing that could cause this is, as far as I can see, the 'crowning' problem that lotusguy mentions... but the pistons looked OK on the scope and appear to move correctly with the crank, so unless the rings have all vapourised, what the hell is going on?
I've recovered my engine crane from the guy who's had it for the last two years, but not sure when I'm going to get time to pull the engine out now...
Could the clonk be the piston tipping in the bore when you apply the air? I take it there was no big end noise, as there surely would be if there was that much clearance on the bearing.
What is this 'crowning' of which you speak? Melting piston crowns perhaps. I could understand that on a turbo, but I think your car is NA.
As an aside, was the NA car ever sold in the States?
Paul.
>> Edited by B16 RFF on Friday 1st July 10:49
What is this 'crowning' of which you speak? Melting piston crowns perhaps. I could understand that on a turbo, but I think your car is NA.
As an aside, was the NA car ever sold in the States?
Paul.
>> Edited by B16 RFF on Friday 1st July 10:49
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