Is engine an issue?
Discussion
I have been searching for a Stevens-body Esprit for some time now. I have noticed a lot of the ads mention "engine recently rebuilt", or something along that line, and the cars have less than 40,000 miles on them.
I have also been reading the warnings in the Esprit Fact File about owning a Lotus. I am mechanically inclined, but I would rather spend the majority of my time on the road, than in the garage. Is the engine in the Esprit a problem (if it is maintained properly)? Why do so many Esprit seem to have engine rebuilds?
Alan
I have also been reading the warnings in the Esprit Fact File about owning a Lotus. I am mechanically inclined, but I would rather spend the majority of my time on the road, than in the garage. Is the engine in the Esprit a problem (if it is maintained properly)? Why do so many Esprit seem to have engine rebuilds?
Alan
I'm wondering if I might need a rebuild at 38K. Honestly, it can be very difficult to know how a car was/is maintained unless you do the work your self or have an excellent mechanic available.
For instance, I've been getting most of my work done at the dealer for lack of a better option, and while this looks good on paper (for resale time), I don't care for the local dealer and don't think they do particularly good work.
Point is, it’s a roll of the dice and records only tell so much.
Does that make sense or am I babbling?
Luke.
For instance, I've been getting most of my work done at the dealer for lack of a better option, and while this looks good on paper (for resale time), I don't care for the local dealer and don't think they do particularly good work.
Point is, it’s a roll of the dice and records only tell so much.
Does that make sense or am I babbling?
Luke.
karmavore said:
I'm wondering if I might need a rebuild at 38K. Honestly, it can be very difficult to know how a car was/is maintained unless you do the work your self or have an excellent mechanic available.
For instance, I've been getting most of my work done at the dealer for lack of a better option, and while this looks good on paper (for resale time), I don't care for the local dealer and don't think they do particularly good work.
Point is, it’s a roll of the dice and records only tell so much.
Does that make sense or am I babbling?
Luke.
Luke,
The HCI engines are much more robust in terms of longevity, so I believe at 38K mi. you should be OK. Of course, this assumes that the car hasn't been abused either in maintenance or operation. To add to your confidence level, perform the tests you described below.
The things I would most be concerned about at your mileage would be the Valve clearances, the turbo/wastegate, the valvetrain and the injectors (assuming the ecu checks out on Freescan).
With the longer-life timing belts of the later cars, I suspect overall that valve clearances are not checked and/or adjusted with the same diligence as those of the earlier cars. Allowing the valves to go out of spec ain't a good thing. Also, I have had people from Lotus, Dave Bean and Spencer Motorsports tell me that the valve springs are really only reliable to some 40K mi. (remember that while the camshaft opens the valves, it is the springs which close them smartly and tightly and at around 40k, spring fatigue can become a factor). Also, valve guides (which also act as the valve stem seals on the 9XX engine) can start to leak around this benchmark.
Turbo and wastegate also can be problematic starting in this mileage range (again depending upon the car's use/abuse). Also, consider new ignition leads at this point (at least check the existing ones for resistance on a multimeter).
Finally, given the limited driving of most Esprits, it can take many years (with extended storage in-between) to reach 38K mi. Consequently, there is ample opportunity for fuel injectors to become gunked up with varnish and other contaminates It's probably a good idea to consider flow cleaning them somewhere in this neighborhood.
These are only suggestions on what to watch out for, not necessarily a death knell. If you did 1 or 2 of these things a year 'til you're done, the $ impact won't be too harsh, but the benefits can be amazing.
Happy Motoring! ...Jim'85TE
>> Edited by lotusguy on Wednesday 6th April 06:53
>> Edited by lotusguy on Wednesday 6th April 06:55
Very, very, valuble info Jim. Thanks so much!
I just replaced my coil packs, leads, and plugs and will be doing a fuel system overhaul very soon -- injectors, rail, hoses, filter.
my concern a "rebuild" may be in order is my low (but consistant) compression test numbers (137, 135, 135, 135) and the fact that I seem to get a lot of blow-by and hence oil coming out of the crankcase breather.
I relaize the compression could be the valves (right?) but the blow by is only gong to be caused by worrn rings, right?
Lucas.
I just replaced my coil packs, leads, and plugs and will be doing a fuel system overhaul very soon -- injectors, rail, hoses, filter.
my concern a "rebuild" may be in order is my low (but consistant) compression test numbers (137, 135, 135, 135) and the fact that I seem to get a lot of blow-by and hence oil coming out of the crankcase breather.
I relaize the compression could be the valves (right?) but the blow by is only gong to be caused by worrn rings, right?
Lucas.
Hi,
I agree with Mikey, the key is consistency and you have it. If you want to gauge the rings, do a wet compression test and see if the readings differ considerably, if so, it's the rings, if not, valves and guides.
Also how did you do your compression test? All plugs out, throttle at WOT? Crank engine 'til gauges won't climb any more? Engine warm? cold? Any of these things can mess with your test results.
I think you're obsessing a little on the oil though. Remeber, it's a british car and they all leak. I suspect it's a need to mark their territory as it were.
Happy Motoring! ...Jim'85TE
I agree with Mikey, the key is consistency and you have it. If you want to gauge the rings, do a wet compression test and see if the readings differ considerably, if so, it's the rings, if not, valves and guides.
Also how did you do your compression test? All plugs out, throttle at WOT? Crank engine 'til gauges won't climb any more? Engine warm? cold? Any of these things can mess with your test results.
I think you're obsessing a little on the oil though. Remeber, it's a british car and they all leak. I suspect it's a need to mark their territory as it were.
Happy Motoring! ...Jim'85TE
Do I dare ask what happens when valves go out of spec?
-Chandra
[quote=lotusguy]
The things I would most be concerned about at your mileage would be the Valve clearances, the turbo/wastegate, the valvetrain and the injectors (assuming the ecu checks out on Freescan).
With the longer-life timing belts of the later cars, I suspect overall that valve clearances are not checked and/or adjusted with the same diligence as those of the earlier cars. Allowing the valves to go out of spec ain't a good thing. Also, I have had people from Lotus, Dave Bean and Spencer Motorsports tell me that the valve springs are really only reliable to some 40K mi. (remember that while the camshaft opens the valves, it is the springs which close them smartly and tightly and at around 40k, spring fatigue can become a factor). Also, valve guides (which also act as the valve stem seals on the 9XX engine) can start to leak around this benchmark.
-Chandra
[quote=lotusguy]
The things I would most be concerned about at your mileage would be the Valve clearances, the turbo/wastegate, the valvetrain and the injectors (assuming the ecu checks out on Freescan).
With the longer-life timing belts of the later cars, I suspect overall that valve clearances are not checked and/or adjusted with the same diligence as those of the earlier cars. Allowing the valves to go out of spec ain't a good thing. Also, I have had people from Lotus, Dave Bean and Spencer Motorsports tell me that the valve springs are really only reliable to some 40K mi. (remember that while the camshaft opens the valves, it is the springs which close them smartly and tightly and at around 40k, spring fatigue can become a factor). Also, valve guides (which also act as the valve stem seals on the 9XX engine) can start to leak around this benchmark.
Chandra,
The valve tappets on the 4-Cyl. Esprits are not hydraulic. They are solid and use shims for adjustment. Valves tend to wear in the valve seats what makes the valve-tappet vs. cam play smaller. If this play is too small the valves may not close 100% and get burned o death ...
Cheers
Marcus
The valve tappets on the 4-Cyl. Esprits are not hydraulic. They are solid and use shims for adjustment. Valves tend to wear in the valve seats what makes the valve-tappet vs. cam play smaller. If this play is too small the valves may not close 100% and get burned o death ...
Cheers
Marcus
chandrab said:
Do I dare ask what happens when valves go out of spec?
-Chandra
It mainly affects the valve/cam timing or in other words how long and how far the intake/exhaust valves open. I don't believe anything drastic would happen unless they were way out of spec and then you might burn some valves as Marcus mentioned, but I think you would have to drive very hard for many thousands of miles past the recommended maintenance schedule for that to happen. Generally speaking if the valve timing is slightly out of spec the engine is not running at optimum performance. At least that's how I understand it. If I'm wrong I'm sure one of our list gurus will correct me.
The bottom line is if you stick to the regular maintenance schedules and don't abuse the car the 910 engines are extremely durable. When my machine shop guy (who works on a lot of high performance and race engines) saw the crankshaft and con rods from my engine he was extremely impressed and jokingly remarked that the rods looked like something out of a diesel truck....
FWIW, I checked mine at about 45k miles and they were still well within spec and did not need to adjust the shims.
Cheers,
Jim
95 S4s
>> Edited by jk1 on Thursday 7th April 18:37
I don't think you need to worry too much on a well maintained engine. My Excel has the 912 engine which is a high compression (10.9-1) version of the 910 with the same nicosil liners and similar Mahle pistons. It now has 130k miles on it, the head has never been off and it still revs freely to 7000rpm.
I've done virtually all the maintenance on it myself from 50k miles to 130k miles and have only adjusted the valve clearances once - at the 96k service. It is a PITA job involving removing the cam towers, getting the right shims, getting the permabond A136 etc ...
I guess the valve springs may be a little soft and it may not be giving the same power as when it left the factory, but it feels like it's got at least another 30/50k in it before a rebuild!
Oh, and compressions are all in the 210-220 psi range but would be higher than the turbo due to the much higher static CR
>> Edited by scoule on Thursday 7th April 21:08
I've done virtually all the maintenance on it myself from 50k miles to 130k miles and have only adjusted the valve clearances once - at the 96k service. It is a PITA job involving removing the cam towers, getting the right shims, getting the permabond A136 etc ...
I guess the valve springs may be a little soft and it may not be giving the same power as when it left the factory, but it feels like it's got at least another 30/50k in it before a rebuild!
Oh, and compressions are all in the 210-220 psi range but would be higher than the turbo due to the much higher static CR
>> Edited by scoule on Thursday 7th April 21:08
[quote=chandrab]Do I dare ask what happens when valves go out of spec?
-Chandra
Hi,
Marcus covered it pretty well, but to expand upon his reply slightly, the only way the valves have to shed their heat is to transfer this heat to the head through the valve seats. Oil and Coolant then take the heat away from the head.
Consequently, the valve must contact the valve seat in the head long enough for this heat transfer to take place. If the valve stem/collet digs into the seat to the point where it can no longer come into contact with the head for the total off-cam duration, they will burn.
Also, eventually, you won't have the valves completely closing, and this will result in loss of compression and all sorts of other nasties. You should check valve clearances every 10k mi., 20k mi. on the outside.
I agree the procedure is a PITA, but remember, the entire valve train is hidden from view. I have seen 9XX heads with cracked bucket tappets (Cam Followers in Lotus Parlance) discovered when opening the cover to check clearances. Imagine what may have happened if it shattered at say 6500RPM at speed? Aside from any accident potential, consider the $$$ involved. I cannot take a cavalier attitude toward this procedure, it simply merits a visual check every 10k mi. or so (That's several years worth of driving for most Esprits).
Not to belittle an earlier lister, but you do not have to remove the cam carrier to simply check the clearances, just remove the cover so you can get a feeler gauge in to measure the gaps. You should replace the cover gasket and not reuse them, so every couple of years you have a $10 expense for gaskets and a little Hylomar, a reasonable expense I believe.
Happy Motoring! ...Jim'85TE
>> Edited by Lotusguy on Friday 8th April 05:35
-Chandra
Hi,
Marcus covered it pretty well, but to expand upon his reply slightly, the only way the valves have to shed their heat is to transfer this heat to the head through the valve seats. Oil and Coolant then take the heat away from the head.
Consequently, the valve must contact the valve seat in the head long enough for this heat transfer to take place. If the valve stem/collet digs into the seat to the point where it can no longer come into contact with the head for the total off-cam duration, they will burn.
Also, eventually, you won't have the valves completely closing, and this will result in loss of compression and all sorts of other nasties. You should check valve clearances every 10k mi., 20k mi. on the outside.
I agree the procedure is a PITA, but remember, the entire valve train is hidden from view. I have seen 9XX heads with cracked bucket tappets (Cam Followers in Lotus Parlance) discovered when opening the cover to check clearances. Imagine what may have happened if it shattered at say 6500RPM at speed? Aside from any accident potential, consider the $$$ involved. I cannot take a cavalier attitude toward this procedure, it simply merits a visual check every 10k mi. or so (That's several years worth of driving for most Esprits).
Not to belittle an earlier lister, but you do not have to remove the cam carrier to simply check the clearances, just remove the cover so you can get a feeler gauge in to measure the gaps. You should replace the cover gasket and not reuse them, so every couple of years you have a $10 expense for gaskets and a little Hylomar, a reasonable expense I believe.
Happy Motoring! ...Jim'85TE
>> Edited by Lotusguy on Friday 8th April 05:35
DOH! I wasn't clear in what I wrote. I meant to say that I only needed to adjust them at 96k miles, they were checked every 12,000 miles but they stayed within tolerance for much much longer than I expected.
At 96k miles I opened them up to the mid/high point because a couple had crept under the minimum clearance - but then only by around half a thou.
I certainly didn't mean to imply they shouldn't be checked regularly - this is essential (and easy), just that the probably won't need adjusting often.
Steve
At 96k miles I opened them up to the mid/high point because a couple had crept under the minimum clearance - but then only by around half a thou.
I certainly didn't mean to imply they shouldn't be checked regularly - this is essential (and easy), just that the probably won't need adjusting often.
Steve
The other thing I do is to keep a log of the clearances at each 12k service ... that way you investigate fully if one clearance is closing up quicker than any of the others - a hint at something wearing too fast. Interestingly, a good proportion of the "closing up" is caused by the valve stem hammering itself into the shim rather than the valve receeding in it's seat.
Steve
BTW... Shims from the TR7 / Hillman Imp engines are the same diameter as the Lotus 9xx engines, I knew those days messing with Imp engines would be beneficial! The imp engine was ahead of it's time in 1963, all alloy, OHC, bucket followers etc etc
Steve
BTW... Shims from the TR7 / Hillman Imp engines are the same diameter as the Lotus 9xx engines, I knew those days messing with Imp engines would be beneficial! The imp engine was ahead of it's time in 1963, all alloy, OHC, bucket followers etc etc
scoule said:
The other thing I do is to keep a log of the clearances at each 12k service ... that way you investigate fully if one clearance is closing up quicker than any of the others - a hint at something wearing too fast. Interestingly, a good proportion of the "closing up" is caused by the valve stem hammering itself into the shim rather than the valve receeding in it's seat.
Steve
BTW... Shims from the TR7 / Hillman Imp engines are the same diameter as the Lotus 9xx engines, I knew those days messing with Imp engines would be beneficial! The imp engine was ahead of it's time in 1963, all alloy, OHC, bucket followers etc etc
Hi,
Actually, it is the cam lobe contacting the bucket tappet which is driving the shim into the valve stem, not vice-versa. It is the valve springs which close the valve pulling it into the valve seat.
One caveat on selecting shims. Many 'Indys' cut their own shims down from hardened stock. This may have an O.D. which is slightly off.
I assisted shimming a head on an '88. We checked clearances, mic'd everything, determined the proper shims to use. Dry fit everything and one valve was waaay off. We figured we made a mistake with the math so we rechecked the clearances, disassembled everything, and surprisingly, we did have the proper size shim. So, we reassembled it only to find this valve off again. Disassembly, check, everything ok, reassemble, same thing. On our last attempt, we discovered that the O.D. on this particular shim was slightly off- large of spec. This prevented the shim from fully seating into the tapered collet on top of the valve stem resulting in our errant readings. We ground the outside of the shim so it would fully seat in the collet and evrything matched up prefectly. So know that this can occur. The shims from the 'Indys' are perfectly fine most of the time, but if you run across something similar to what we found, check the O.D. of the suspect shim and determine that it is fully seating in it's valve collet.
Happy Motoring! ...Jim'85TE
>>Actually, it is the cam lobe contacting the bucket tappet which is driving the shim into the valve stem, not vice-versa. It is the valve springs which close the valve pulling it into the valve seat.
This wasn't really the point I was making - the key point was that the wear is in the shim itself causing clearances to close up, caused by the contact with the valve stem, not the valve receeding into it's seat. By hammering I meant the repetitive force applied between the two components.
This wasn't really the point I was making - the key point was that the wear is in the shim itself causing clearances to close up, caused by the contact with the valve stem, not the valve receeding into it's seat. By hammering I meant the repetitive force applied between the two components.
scoule said:
>>Actually, it is the cam lobe contacting the bucket tappet which is driving the shim into the valve stem, not vice-versa. It is the valve springs which close the valve pulling it into the valve seat.
This wasn't really the point I was making - the key point was that the wear is in the shim itself causing clearances to close up, caused by the contact with the valve stem, not the valve receeding into it's seat. By hammering I meant the repetitive force applied between the two components.
Maybe it's just me but something doesn't sound right here. If it was the shim being worn by the valve stem pounding on the shim the measured clearances would open up not get smaller. That would in essence be the same as putting in a thinner shim which opens the clearance. And since the measured clearance tends to get smaller over time not larger, then it would have to be attributed to the valve going deeper into its' seat.
The shims can get a depression worn into them from the valve stem but still not as much as the valve receding into the seat....
Cheers,
Jim
>> Edited by jk1 on Monday 11th April 04:33
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