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Discussion Starter · #1 ·
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With a fresh overhaul on my 907 '77 S1 motor. When the engine temps reach normal, I need to keep revs 4K+ to hold oil pressure up away well into the operating range on the un-numbered gage. While I'm cautioned to hold revs to 3,500 for 500 miles. I'm setting to run with a calibrated gage now to cal the old transducer and panel instrument. But I'm running 20W50 and thinking that a straight 50 would provide a measure of relief. Yes? A synthetic is preferable? Whose: Red Line, Lucas, Brad Penn, Valvoline? Thanks folks Murray
 

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Cal H
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Who did the rebuild? Was it someone real familiar with the 9xx engine? Hope the sump pick up is not sucking up air, if the pick was seated correctly then that would not be the problem.

I would think if synthetic oil is the preference then amsoil with zddp would be high on the list. The one for classic cars/high performance oil has elevated zddp levels
 

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Get an accurate mechanical gauge on it and see what the pressure really is. As a general "Rule of Thumb" you should see a minimum of 10 psi at idle and an additional 10 psi for every 1,000 RPM. Not only should you limit your RPM's during break-in, you should try not to hold the RPM's steady for any length of time. At least the first 500 miles. You should use a high ZDDP oil for break-in and I personally also use a can of Marvel Mystery Oil. You do not want to use a synthetic, too slippery. The break-in period is when wear is the highest as parts are smoothed out against each other. Once break-in is over wear is supposed to plateau at a low level til you get to "old age" and wear starts increasing again as the surfaces of the parts fatigue and start wearing again. At 500 miles you change the oil and filter and revert to a regular maintenance schedule.
David Teitelbaum
 

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Discussion Starter · #4 ·
I shouda waited until I had run with the calibrated Snap On gage before crying here. Yeah today 75 F outside air it goes to 65 psi max engine cold. Tun up to operating temp at idle set now at 1200 the cal gage reads low 20's never less than 22 psi. With 22 on the cal gage the panel instrument is bottom at the end of the gage marking arc. I have no issue with thse figures. Good to go. I did the rebuild myself. The motor as I received it had a crushed oil screen assy. The screen was a wire reinforced paper material with little flow area left. So I tried another 907 sump and found interference again. So I cut off the crushed screen assy and TI welded up a new SS square screen into which I put multiple layers of screen material about .25" above the sump floor. I was and still am curious why the dimensions of my two pickup tubes and sumps interfered. After all this I have an extra 907 motor w/ JH heritage, 103's, Solex on CL for $500. It has good cam hsgs. Thank you for the replies. Murray
 

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Hi Murray. We have almost identical cars!, mine is yellow too. But I switched to Speedlines and a PO redid the interior in dark green and cream leather. Mine is 165H. Re the oil: for the last four years I've been using Mobil 1 V-Twin 20/50 full synthetic. I was advised to do do so for the high ZDDP content. I used to run VR1 20/50 and I always thought the engine sounded a bit clicky and I would get a small amount of blow by under hard acceleration. The top end was so much quieter and no more blow by after switching to the Mobil 1. On start up from cold my pressure builds within 5 seconds and goes all the way to max. Then once warm, at idle my gauge reads 1/2 and at speed I get just under max. From what I have learned this is normal for an S1.

There is something quite beautiful about how the 907 sits in an S1. It's a visual engineering masterpiece and completely compliments the uncluttered body design. This is what makes the S1 special.
 

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Discussion Starter · #7 ·
S1 eng cover and oil

Yes indeed the 907 is pretty motor! Here's a pic of the engine cover I devised. My car came without any engine cover, a used cover was procured but did not have the second oil, coolant access cover. So made a male mold/pattern for a cover with a plexiglass window. I want to paint the plexi mounting screws black. I have no idea what model the used main cover came from but it did not clear the intake cam cover nor the Delortos, needed considerable rework to get adequate clearance and then the secondary cover. No question this is not authentic anything. And fiber glass work isn't all that much fun. The previous owner of my S1 had a black vinyl interior installed....not my choice but we live with it. Yes thanks Britman, I will go to the Mobil 1 motorcyle oil. I have nice, but not all that healthy tappet sounds and man that 107 cam has to produce some wicked impacts. The 103 cams are really benevolent. Do you have photo of your interior and of your engine cover? thanks Murray
 

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