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93SE CAM question - 104 intake cam with which gear 104 or 107? - Page 2 - Engine/Ancilliaries - The Lotus Forums Jump to content
MikieP

93SE CAM question - 104 intake cam with which gear 104 or 107?

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Boost being reduced to ~.65bar is a sign that the ECU thinks that conditions are not right for full boost. It can be temperature related, too high or low, or it could be fuel related. If the ECU is detecting a lean condition, it can reduce boost for several minutes.

All without seeing a check engine code.

Your shop should be looking at fuel pressure, air fuel ratio, and coolant temperatures. They should use freescan/tech1 to look at the BLM to see if the numbers are greater than 128.

It could also be that the wastegate is not adjusted correctly, or that the turbo is building boost faster than the ECU can control it, so it is seeing boost spikes above a threshold.


Travis

Vulcan Grey 89SE

My Lotus Photo and Projects Album

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Travis,

 

Thank you for some insights! I will forward these bits of info to them. I was given a new Waste Gate by the first mechanic (Jaime Goffaux) without explanation which this shop did NOT install so thinking it may be part of, or the problem...

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Travis,

 

Drove her home from shop for another try out today. A small chip now in the center of windshield on the passenger side, oil pressure seems low (hardly ever gets to center of gauge even at 3000rpm and hits just inside the red on idle when stopped, idle seems to almost stall unless the A/C switch is turned on even though there is no A/C, a fairly annoying rattle in the engine compartment at around 2500-3000 rpm mostly noticeable during decel and finally, seems to never get over .67 bar boost. I suppose that is not bad, but only got 55 miles on her so far. The one issue I do not understand is that they tell me I am getting "heat soak" and need a larger charge cooler and / of charge cooler radiator to get consistent over .67 bar boost. Dunno. Still have yet to see anything even close although I have been told that the S4s got that just fine with the same CC setup. Ideas? Getting there I suppose.

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Unfortunately it sounds as if again you among several others are dealing with garages with lack of a fcuking clue about what they are doing. How is it possible that so many exists now days. One of the most crooked trades in the world.....!!!


Chunky Lover

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The heat soak suggestion is b.s.  Chargecooler effectiveness/high MAT temperature won't restrict boost.  If you had excessive knock due to pre-ignition, then that would restrict power.  Sounds like the shop knows just enough to be expensive or dangerous...

 

Your boost is being restricted by the ECU most likely to protect the engine either because your ECU thinks your engine coolant temp is too low/too high, or because you have a lean condition, or a sensor reporting data that makes the ECU think it is lean.  Could be a bad sensor like the O2 or it could be that your secondary injectors aren't puttin gout enough fuel, or that your fuel pump isn't putting out enough fuel.

 

You need to use freescan to log some data and send it to someone.

 

Your stall at idle could be due to the IAC (idle air control valve) stepper motor, it could be that the minimum air rate bleed screw is incorrectly adjusted, or a few other things.

 

Your low oil pressure could be worn bearings, worn oil pump, wrong oil, or a loose oil pickup olive seal.  Or a bad gauge/sender.

 

You need to have these things verified (simple tests)

 

1)oil pressure (verify the gauge is correct with another gauge), and whether your pressure is low or normal.

2)coolant temperature to the ECU (not the dash temperature, they use different senders).

3)fuel pressure, including rising fuel pressure with boost.

4)IAC counts when engine is warm at idle, after IAC stabilizes, don't touch throttle.

5)BLMvsBLM cell in freescan to see if the ECU thinks you are lean.

6)O2 sensor volts in freescan.

 

Then worry about fixing the various issues.  Some are simple like cleaning the IAC, or adjusting minimum air rate bleed.  Some are more difficult like replacing the injectors or fuel pump.  Or replacing the oil pump or engine bearings.


Travis

Vulcan Grey 89SE

My Lotus Photo and Projects Album

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Thanks guys. I thought I was smelling fish there. Engine was completely rebuilt from main bearings on up. The problem here is that there are essentially no real Lotus specialists anywhere near Washington, D.C. at all and you take what you can find that will take you in. Also, we only have 87, 89 and 93 octane gas here, all with 10% ethanol. Could this be the issue for the boost? I did notice a .72 briefly on the drive home as I want to break the engine in before denting the floor boards.  Weird. I am dreaming of a Sparky visit every night!

 

Oil gauge is 12:00 at 3000+ rpm once warmed up, higher when cold though, otherwise never gets any higher 12:00, and sometimes touches the high red end on idle? Will try to get the laptop to work on it this weekend and see what it tells me. Going to be fun.

 

Engine temp gauge stays above 83F unless stalled in traffic. Will try and talk to shop again on Monday but hard to tell them they are full of it since there is no where else to go, even to get oil changed. lol. I did buy three Lotus filters from JAE last week though.

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They are using their break in oil I hope, and I do not know what that is. I plan on using Royal Purple 20W-50 Full Synthetic on the first change after that is dumped. And, you are correct that it does make a difference, I just do not know the effect of break in oils.

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Break in oils tend to be monograde and be lighter viscosity than the higher number of the multiigrade oil. You don't typically run the break in oil for long.

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Older 910's (pre-1992?) used chilled cast iron tappets. If you go with a high lift cam like either the 104 or Kemps high-lift 107, then replace the tappets with the later steel parts. They also have a slightly longer skirt that Lotus recommends for use with high-lift cams. Or... what I think they said was that cast iron tappets should not be used with high-lift cams.

 

This is the wrong way around. The steel cam followers have shorter skirts and I think there is a warning in the workshop manual or a TSB about using the steel followers with high lift cams.

 

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This is the wrong way around. The steel cam followers have shorter skirts and I think there is a warning in the workshop manual or a TSB about using the steel followers with high lift cams.

 

 

 

 

I can measure mine when I get home.  I have the steel followers in my cam towers now, they are off the engine presently.  And I have my old cracked cast iron followers in a box.  I did have to go to all new shims when I changed to the steel followers, since the thickness to the pad for the shims is different between the iron and steel followers.


Travis

Vulcan Grey 89SE

My Lotus Photo and Projects Album

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The skirt lengths of the cast iron cam follower is 22 mm and the steel cam follower is 21 mm with crown/pad thicknesses of 5.54 mm and 5.69 mm respectively.

 

Garry Kemp does some steel followers with a longer skirt of 25 mm that have a crown/pad thickness of 6.25 mm with a weight of 48.5 +/- 0.5 grams.

Edited by sailorbob

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