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philharmonic
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!8837 will start fine then run great 50-65 lb. oil pressure. Then when I get off the freeway oil pressure dives to like 10 lb. at idle. Lots of valve clatter until I get the RPMS up to like 1200, New oil and filter same problem.

John Finch
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20w/50? Oil cooler free flowing oil internally and air through the fins? Just some quick easy fix thoughts. Best of luck.

philharmonic
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Thanx,
I use 20-50w GTX Is there anything better?

Greg Fletcher
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That's typical of a worn 907 engine. High wear areas that can cause that are the inner and outer rotors in the oil pump and the main bearings. I think Castrol GTX 20w50 is the best oil for this engine.

philharmonic
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Thanks Greg,
I hope I do not have to tear down my engine to do the mains. Some kind of pro shop must have built the top end. It has no low end then at about 3500 RPMS it just lights up and takes off like a rocket-no oil pressure problems then. Or for long 35-70 mile drives the car feels power full and sounds fine and average 50-60 lb. oil pressure..

Jensen Healey
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The stock JH is a torqueless wonder. The short stroke motor is more suited for high rpm use as Lotus intended.

It costs a bit of money to get these cars to pull at lower revs but the 907 becomes magical when built to later Esprit specs. Of course you'll never see 27 mpg again after the cams, HC pistons, Dellortos, 2.2L crank and flow work are done. Oh well!

Make sure you are getting enough ZDDP for your classic car. Castrol Syntec 20-50 for Classic Cars has it. Valvoline VR1 has it. Diesel and motorcycle oils have it. Red line has it. If you use regular oil then you should consider a ZDDP additive.

No, your engine won't blow up tomorrow without it but it's cheap insurance.

Kurt

 

philharmonic
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Thanks Kurt,
I may try another oil. The shop I go to out here is the local Ferrari shop (the only guys who will get near it) and they say stick to the GTX 20w-50 so I do not know. I like the sound of a modern rebuild (2.2 crank, HC pistons, lightened flywheel, accusump, porting and polishing, flow bench work)but all that stuff is expensive!!! Remember I got the car for a grand so building a $5k engine is a hard sell to the wife'anator plus i am not trying to win some vintage race.. Look I got this car to have fun with and have something interesting to work on. ZDDP what is it its it important?

SpeedyMitch
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Jensen Healey wrote: Castrol Syntec 20-50 for Classic Cars has it. Valvoline VR1 has it. Diesel and motorcycle oils have it. Red line has it.

I have been using Valvoline VR1 20w-50. Would any of these other oils (i.e. Redline) help with low oil pressure issues on a worn 907?

My experience is that synthetic oils are 'thinner' - any idea how that would effect the oil pumps ability to prime and maintain pressure?

Jensen Healey
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Hi Phil, ZDDP is zinc and phosphorus that prevents metal to metal contact. It smears on the surfaces just as the oil shears. Oil has been formulated with it for years but now they are reducing the amounts to prevent degrading the catalytic converter. That's why you'll find more ZDDP in oil made for vehicles without converters. Our cams and piston skirts like it!

I'm not suggesting any modifications, just noting your off-idle performance is normal and that changing it is costly. Rev that baby!

Hi Mitch, Volume is more important than pressure. If you have 10 lbs per 1000 rpm you're good to go.  Ferrari guys reduce the viscosity to get to this standard. Thick oil doesn't flow as well as thin. If your oil pressure hits the maximum at 3500 rpm then you have the same flow at 3500 and at 7000 rpm where you might need more.

Those of us who just drive on the street don't need to know any of this stuff, but its fun!

When I rebuilt my spare motor I swapped the oil pump from the original. It made 40 lbs at idle on the old motor and 20 lbs on the new one. Go figure, probably a clogged passage.

Kurt

 

philharmonic
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Hi Kurt,
Thanks for the info. What is a good quality additive you would recommend for the 907?

Brett Gibson JH5 20497
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At the East Coast Nationals this year we had a tech session on oil's and ZDDP came up as thee most important item to have in older engines, the lack of it especialy in a new rebuilt engine can mean life or death to one. It was also discussed that the early rope seal engines suffer the most from lack of ZDDP.

You might say well I never used it before so why now, actually you probably were using it but now it's something being taken out, so on your next oil change just make sure you have it even if your not sure about it, it wont hurt.

Brett

Jensen Healey
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Hi Phil, After further reading, I can't recommend trying to formulate your own brew. Oil engineers spend their careers doing this.

Since too much ZDDP can chemically attack metals, (more than .20%), and we don't know how much is in modern SM oils, (probably under .05%), there's no way to know how much to add. Moss Motors sells ZDDPlus FWIW.

Unless you are installing new or re-ground cams this is not a critical issue. Just use the GTX for Classic Cars or Valvoline VR1 at your next oil change. No worries.

Kurt

Last edited on 11-04-2010 08:55 pm by Jensen Healey

philharmonic
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OOPS! I just am trying an off the shelf cam lubricant. The engine sounds a tiny bit better but loss of oil pressure at low RPMS is still a problem. I am thinking about a minor rebuild(no such thing). Just mains and valves and guides minor cam work. I guess rings and wrist pins and oh yea just about everything... I might just drive her till she blows! OH NO! Or my next step Oil Pump rebuild?

Jensen Healey
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Your oil pressure is normal for a worn 907. If it doesn't go below 10 lbs you should be fine.
Loss of oil pressure could be related to wear in the main and/ or rod bearings, or wear at the oil pump rotors.

The oil pick-up in the sump may be clogged.

There's a plastic gasket where the oil pump mates to the accessory housing that used to be available in different thicknesses.  There are critical measurements that are described in the manual that determine which thickness to use. This could also affect the pressure.

Or your guage is shot and the oil pressure is OK.
 

Last edited on 11-05-2010 01:20 am by Jensen Healey

philharmonic
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Thanks,
For now I am just going to drive and enjoy! As long as it pulls this strong I know i can do better but just now, on this hot day, driving to get ice cream with my daughter with the hard top off following the coast home it runs pretty darn good.
Phil

John Finch
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That sounds like a great ride! Hope its just the gauge.

philharmonic
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OK I added "Competition Cam lubricant and break in oil" It has zinc and it has made a huge difference! My cams and valve train seem a lot quieter, my oil pressure has stabilized, the car seems even faster and more powerful. Big Thanks to you all here at the Message board. I would have never guessed that this zinc lube would make such a difference. WOW!

Gary Martin JH 15371
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I recently tried to buy Valvoline VR1 at my local auto parts store for an engine I had just rebuilt (not a 907 but a Dodge 360). I wanted it since it has the ZDDP. They had it in stock, but they asked me what I was putting it in and I said a street car. They then told me they could not sell it to me as it is only for racing use.  Guess I should have told them it was for a race car. Do certain states not allow VR1 for street use, or did I just get a wacky sales person ? Anyone run in to this before ?

Gary

Last edited on 11-06-2010 05:25 pm by Gary Martin JH 15371

Jensen Healey
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No problems buying it here. The VR1 states on the back of the container "for high performance passenger cars and race cars."

If they don't want to make a sale, buy it elswhere.

philharmonic
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The problem of low oil pressure at idle began with an oil change. That should have clued me in that I removed something the engine needed.

dwalls1
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Pray tell, what was it?

philharmonic
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It is just called "Comp. Cam break in oil" I got it at my local Speed shop "Winchester Auto" Unreal my oil pressure is better and although i still have some valve noise it is not the Ping, Ping, Ping that i was experiencing.



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