No Compression

[anonymous-user]

Ok engine is a 2.2 S4 Esprit block and crank, seriously tweeked, no turbo Sport 300 Head.
Up until 2007 I had a problem with con rod stretch and the pistons hitting the head at high revs, (JE+ 30 piston). Did a lot of work decking the pistons etc, and it looks like this is sorted.
But at end 2007 I lost compression in No4 cyl, and of course assumed again that I had broke a piston, head off but nothing wrong, head back on cam gaps set right and no problem, (although the car did only run 100km in 2008 due to my ill health, it was started every 2 weeks and brought up to operating temp)
Ran the car over the weekend, free practice 10 laps no problem (50KM), went out for qualifying engine stopped after 1 lap (5Km), towed the car to the pits, no compression in No 2. (engine had cooled in this time).
Towed the car home, and next day still no compression in No 2. Head off last night, very slight mark on the piston in the vicinity of the rear most exhaust valve, (in the 3 ocklock position looking from the front of the car) no mark on the valve, but a small mark on the head corresponding to the piston mark. Valves are all sealing fine.
I do not see how it can be a valve touching the piston as no marks, and nothing like enough damage for the piston to have touched the head, I cannot see how it is a sticking valve as there was no compression when the engine was cold the next day.
My best bet is that I was real stupid and got a stone into the piston when I changed plugs, I try to watch this and blow the plugs with an air line, but maybe not careful enough.
Appreciate any comments or experience.

[Boosted LS1]

If the head is off the engine you could pour some parrafin into the ports and see if the valves are sealed/seated? Or remove them and inspect them. Any sign of detonation, broken top ring? Hopefully not.

[anonymous-user]

Valves are sealed and seated, checked, top ring looks perfect, no undue movement in the piston, and the plug was undamaged.
I've broke a few pistons as rod stretch is common on the engine, and always seen damage to the spark plug.
Pulling the two ex vlves to check they moe in the guildes

[Pumaracing]

What do you mean by "no compression"? Do you really mean absolutely nothing registering on the gauge or just a much lower reading than other cylinders?

If the rings and head gasket are ok then absolutely no compression would indicate a valve sticking open.

[anonymous-user]

Yes absolutly no compression, nothing on the gauge, and when engine is cold, so not heat 'sticking'.

[Pumaracing]

Sticking can be due to carbon build up, slightly bent valves and other things than heat. Just because it was still doing it with the engine cold means nothing. The problem can only be in the valve train. Gaskets and rings don't start and stop working at random. I presume it's a solid lifter engine so it can't be hydraulic lifters pumping up? You need to have the top end examined in detail. Valve, guide and seat condition and clearances, tappet and bore condition and clearances. Either there's a discernible mechanical fault or some dirt or swarf clogging something up.

[anonymous-user]

Thanks for your interest.
Don't think it can be carbon build up, engine only done 100Km from last build and its never done more than 500Km between strip downs, but its very stressed, I am based in Kuala Lumpur and as you may know Lotus are Malaysian owned, 900 engine is very rare here, so Lotus like it and they run a simulation for me at Hethal and said it was 260 Bhp without a Turbo, I'm not convinced its that powerfull but it is powerfull, it is only run for 12 - 35 Km races a year, plus practice and qualifying, (so under 600 km a year)and its striped at least once half way throught the season, you could eat off this engine.
As you may know good mechanics are cheap here, so I tend not to do the 'spannering' but I suppervise and specify everything, I went to see the engine today and got my mechanic checking for a sticking valve, he has checked the valves are straight, I'm going back tommorrow, But I think a forign body (a stone) may have got in it is very hard to keep things out of the plug gallery, and although I very carfull and aware of the problem I wouldn't put my lifeon astone not having got in at aplug check.
If you see my earlier post I had asimiler problem before on Nummber 4, that was put right by just stripping and reassembly.

[Mr2Mike]

If really can only be the valves, rings and gaskets don't randomly decide to seal one day and not the next.

Has the head had uprated valve guides fitted? My brothers mini had some competition guides fitted (long while ago, can't remember what type) that turned out to be incompatible with the valve stems and they used to stick badly. There were marks visible on the valve stems where it had apparently been partially welding to the guide.

[Pumaracing]

Berw said:

As you may know good mechanics are cheap here, so I tend not to do the 'spannering' but I suppervise and specify everything.

Hmmm, In my experience 'good' mechanics are rare as rocking horse s**t no matter where you live and really top class ones capable of spotting and rectifying any problem no matter how obscure are more or less non existant. I've had my fair share of customer's race engines buggered comprehensively by their so called "race mechanics" who in truth hardly knew a spark plug from a crankshaft.

I had one customer who swore he never over revved the engine I built him but if you went and watched him race you could hear it valve bouncing as he screamed his way round corners in one gear lower than everyone was using, completely oblivious to the tortured sounds coming from the engine bay. Every time he bent a set of valves the head would get whipped off and sent back to me with a "I dunno why this keeps happening to me." He did used to use a really good mechanic who I knew personally but then to save costs he went to this new lad who was just starting up and his first task was to take the head off yet again for me to refurbish. I actually drove the head back to them that time because I was on the way past to watch a race so I got a chance to look at the engine.

I had a horrible sinking feeling when they lifted the bonnet and the top of the block was sealed tight with tank tape. "That's to stop anything falling into it while I waited for the head back" said the mechanic. "Well I hope you got all the water out that of the bores first that would have got in when you lifted the head off" I said.

Of course he hadn't. Every time you drain the cooling system and lift a head there will be a few drops of water left around the gasket and in the head which get into the bores and they need to be blown and wiped out meticulously and then liberal quantities of WD40 or similar applied until it's fit for storage until the rebuild. Not only had he left the water in the bores, the tank tape was making things worse by stopping it evaporating back out. After two weeks in mid summer sat steaming gently inside like that he'd rusted the piston rings to the bores and more or less buggered the whole bottom end. The customer was furious, the mechanic was red faced, I got a rebuild out of it and after finding the same mechanic had messed a load of stuff up for other customers in the series he rapidly lost his trade.

As an aside when I lift a head off a still working engine I drain the cooling system, start the engine, run it for just 30 seconds or so to get enough heat into it to evaporate any last traces of water and then leave it for an hour or so for that to happen. Then when you whip the head off it's nice and dry inside to start with.

Oh, I've just remembered. Different customer, different mechanic, same race series. I got asked to build a complete engine plus a spare head and cam assembled ready to fit in case of emergency. I already had the bottom end parts so the guy's mechanic got the two top ends ready to post down to me. Thinking he was being helpful he took both old heads outside, pressure washed everything and then wrapped it all up tightly in polythene before boxing it. By the time the courier had got it down to me every single ferrous component in the heads was rusted to buggery. Both cams, all the tappets, valve springs, studs, rockers. If he'd just packed it all oily as they came off the engines it would have been fine. So first job was to throw most of it away and buy several hundred quids worth of new parts. Hey ho.

Then there was the mechanic who fabricated an air box for the carbs for the race engine I'd just built for his driver. Unfortunately he designed it with some of the nuts that held it together on the inside not the outside. Didn't take long for the first of those to vibrate loose and get sucked in. An engine with flat top pistons and 1mm squish clearance doesn't take kindly to a 6mm nut flying down an inlet port. Five grand's worth of engine buggered on its first outing.

Oh and the mechanic who didn't realise you had to prime the oil pump before you start a new engine for the first time if it's been sat for a while. He fitted the brand new race engine I'd recently built for the driver, connected the battery up and just cranked it until the battery was flat to try and get oil pressure up. The he fitted another fully charged battery and did the same again. By the time he thought to phone me for advice it was rattling and he'd scored all the crank bearings. I think that's the first engine I've built that got buggered before it had even started up. I actually think that may have been the same mechanic who rusted the bores up in the first story but it's too long ago to remember.

Even when you tell them what to do it doesn't always help. I went to watch a race at Donnington Park one weekend which I had a few customers racing in. First corner after the start and someone spun and everyone else piled into the back of him. About 20 cars got caught up in it and the race was stopped for half an hour while the carnage was cleared up. The drivers were all stood around chewing the fat and I wandered about looking at the damage. One of my guys who I'd just built the first engine for had comprehensively stuffed the front end of the car in although no obvious engine damage. I asked him how he'd got back to the pits so fast when the tow truck was so busy. "Oh I just drove it back he said. It started up again ok."

"Yeah but the radiator was destroyed so there was no water in the engine" I pointed out.

"Oh it was only one lap and I drove slowly" he replied.

I told him it would NOT be alright and given the engine was already stinking hot when he crashed it would have been fried by the time he drove another two miles with no coolant. "The bottom end will be ok but the head will already be warped" I said and told him to take it off and send it to me asap before the next race in two weeks time. He patted me condescendingly on the shoulder, said don't worry it'll be fine and walked off. Ok f**k you mate I thought and said no more. His mechanics were flat out just trying to get the bodyshell repaired in the time available. No one even thought to look at the engine until the night before the race. New radiator in, fill it up with water, start it up and watch all the water piss back out of the cylinder head joint. The head was warped 20 thou and no time to do anything about it. He missed the race and lost his entry fees. You can lead a horse to water...

Dave Baker
Puma Race Engines

[Simon Says]

Pumaracing said:

Berw said:

As you may know good mechanics are cheap here, so I tend not to do the 'spannering' but I suppervise and specify everything.

Hmmm, In my experience 'good' mechanics are rare as rocking horse s**t no matter where you live and really top class ones capable of spotting and rectifying any problem no matter how obscure are more or less non existant. I've had my fair share of customer's race engines buggered comprehensively by their so called "race mechanics" who in truth hardly knew a spark plug from a crankshaft.

I had one customer who swore he never over revved the engine I built him but if you went and watched him race you could hear it valve bouncing as he screamed his way round corners in one gear lower than everyone was using, completely oblivious to the tortured sounds coming from the engine bay. Every time he bent a set of valves the head would get whipped off and sent back to me with a "I dunno why this keeps happening to me." He did used to use a really good mechanic who I knew personally but then to save costs he went to this new lad who was just starting up and his first task was to take the head off yet again for me to refurbish. I actually drove the head back to them that time because I was on the way past to watch a race so I got a chance to look at the engine.

I had a horrible sinking feeling when they lifted the bonnet and the top of the block was sealed tight with tank tape. "That's to stop anything falling into it while I waited for the head back" said the mechanic. "Well I hope you got all the water out that of the bores first that would have got in when you lifted the head off" I said.

Of course he hadn't. Every time you drain the cooling system and lift a head there will be a few drops of water left around the gasket and in the head which get into the bores and they need to be blown and wiped out meticulously and then liberal quantities of WD40 or similar applied until it's fit for storage until the rebuild. Not only had he left the water in the bores, the tank tape was making things worse by stopping it evaporating back out. After two weeks in mid summer sat steaming gently inside like that he'd rusted the piston rings to the bores and more or less buggered the whole bottom end. The customer was furious, the mechanic was red faced, I got a rebuild out of it and after finding the same mechanic had messed a load of stuff up for other customers in the series he rapidly lost his trade.

As an aside when I lift a head off a still working engine I drain the cooling system, start the engine, run it for just 30 seconds or so to get enough heat into it to evaporate any last traces of water and then leave it for an hour or so for that to happen. Then when you whip the head off it's nice and dry inside to start with.

Oh, I've just remembered. Different customer, different mechanic, same race series. I got asked to build a complete engine plus a spare head and cam assembled ready to fit in case of emergency. I already had the bottom end parts so the guy's mechanic got the two top ends ready to post down to me. Thinking he was being helpful he took both old heads outside, pressure washed everything and then wrapped it all up tightly in polythene before boxing it. By the time the courier had got it down to me every single ferrous component in the heads was rusted to buggery. Both cams, all the tappets, valve springs, studs, rockers. If he'd just packed it all oily as they came off the engines it would have been fine. So first job was to throw most of it away and buy several hundred quids worth of new parts. Hey ho.

Then there was the mechanic who fabricated an air box for the carbs for the race engine I'd just built for his driver. Unfortunately he designed it with some of the nuts that held it together on the inside not the outside. Didn't take long for the first of those to vibrate loose and get sucked in. An engine with flat top pistons and 1mm squish clearance doesn't take kindly to a 6mm nut flying down an inlet port. Five grand's worth of engine buggered on its first outing.

Oh and the mechanic who didn't realise you had to prime the oil pump before you start a new engine for the first time if it's been sat for a while. He fitted the brand new race engine I'd recently built for the driver, connected the battery up and just cranked it until the battery was flat to try and get oil pressure up. The he fitted another fully charged battery and did the same again. By the time he thought to phone me for advice it was rattling and he'd scored all the crank bearings. I think that's the first engine I've built that got buggered before it had even started up. I actually think that may have been the same mechanic who rusted the bores up in the first story but it's too long ago to remember.

Even when you tell them what to do it doesn't always help. I went to watch a race at Donnington Park one weekend which I had a few customers racing in. First corner after the start and someone spun and everyone else piled into the back of him. About 20 cars got caught up in it and the race was stopped for half an hour while the carnage was cleared up. The drivers were all stood around chewing the fat and I wandered about looking at the damage. One of my guys who I'd just built the first engine for had comprehensively stuffed the front end of the car in although no obvious engine damage. I asked him how he'd got back to the pits so fast when the tow truck was so busy. "Oh I just drove it back he said. It started up again ok."

"Yeah but the radiator was destroyed so there was no water in the engine" I pointed out.

"Oh it was only one lap and I drove slowly" he replied.

I told him it would NOT be alright and given the engine was already stinking hot when he crashed it would have been fried by the time he drove another two miles with no coolant. "The bottom end will be ok but the head will already be warped" I said and told him to take it off and send it to me asap before the next race in two weeks time. He patted me condescendingly on the shoulder, said don't worry it'll be fine and walked off. Ok f**k you mate I thought and said no more. His mechanics were flat out just trying to get the bodyshell repaired in the time available. No one even thought to look at the engine until the night before the race. New radiator in, fill it up with water, start it up and watch all the water piss back out of the cylinder head joint. The head was warped 20 thou and no time to do anything about it. He missed the race and lost his entry fees. You can lead a horse to water...

Dave Baker
Puma Race Engines

some funny stories here but you are not referring to mechanics but bloody monkeys you can teach theory all you like but to teach common sense is not so easy i built many tuned motors for friends when i was youger(years ago)and got fed up with them doing similar things to those mentioned above,even one that that let a freshly built motor on fast tick-over with no coolant then wonder why it stalled(so he thought)20 minutes later,he was to busy chatting to someone about his new engine and out of ear reach dhead,i soon nipped that in the bud and concentated on my own career and cars.

Edited by Simon Says on Thursday 23 April 15:24