Mower oil in flat tappet ingine?

[porkchop01]

Originally Posted By: Merkava_4
Originally Posted By: porkchop01
Its a 1970 F100 and the engine came from a 1970 LTD. Also, I have a straigt 30W oil in it now and at full temp it has about 60psi at 2100 rpm and about 30psi at idle,hot.


I talked to my friend who is a machinist. He said that 390 engines are sensitive to exhaust valve springs. I told him you put an RV cam in and used the stock springs. He said that if the springs don't match the heads and the RV cam, the pushrods will press on the lifters too much and collapse them; making the same sound as a lifter that's not getting enough oil. He also said that he recommends using an oil pump intended for a Checker cab with the 390; they have a higher pressure.
That part was checked at assembly and the oil pressure is plenty good. The lifter tick is only at cold start and is gone as soon as oil pressure shows on the needle.The sae30 that is in it now shotened the amount of time it takes for pressure to come up in the mornings compared to the 20w50 and the 15w40, now that we are starting to get cooler temps in the A.M. I was wanting to switch to a 10w30 with the higher ZDDP for longer cam life. The engine runs strong and is solid as a rock.
Last night I was at a Walmart about 35 miles from me and foud they stock Rotella T5 10w30 and its only $16 for a gallon, wich is cheaper than the VR1 that I ordered from Oreilys. Will be getting some of that after the VR1 is done.

 

[TFB1]

Originally Posted By: Merkava_4
I talked to my friend who is a machinist. He said that 390 engines are sensitive to exhaust valve springs. I told him you put an RV cam in and used the stock springs. He said that if the springs don't match the heads and the RV cam, the pushrods will press on the lifters too much and collapse them; making the same sound as a lifter that's not getting enough oil. He also said that he recommends using an oil pump intended for a Checker cab with the 390; they have a higher pressure.


Sounds like a old wives tail to me, the valve train geometry on the FE is exactly the same on intake and exhaust... As long as the cam has similar specs on intake and exhaust there will be no difference... Yes valve springs should be matched to the cam used...

The 390 Checker cab statement is laughable, they never ever used a Ford engine(maybe you need another machinist) ... The first units from the late 50s used a Continental 6cyl in either flathead or OHV design, in the mid 60s engine choices were Chevrolet 6cyl or V8... A Perkins diesel was a very limited option in the late 60s... Melling, TRW, etc have std, high volume and high pressure pumps for FE or about any other engine built by the big three since WWII...

 

[mechtech2]

If higher valve spring pressures cause the lifter to collapse, the lifters have too high a leak down rate, or otherwise are substandard.

greenfordtruck has posted a great option with the Rislone ZDDP additive [for older V8s and such with possible valvetrain wear problems].