frothy oil

[HMBAtrail]

I just finished rebuilding the 350 race motor and it's about the best I've ever done. The motor leaped to life almost immediately on the paddock starter. Through the gear gazer the oil appears frothy. I am running external oil lines straight to the cam cap. High output oil pump. Piper 277 cam. 20/50 oil. There is plenty of oil exiting the cam center (yes, there is a roll pin in the cam to restrict oil).

I wonder if the motor is slightly overfilled. Thoughts?

[themoudie]

Aye HMBAtrail,

That begs the question, how much oil did you put into the engine?

In my 450 MKIII road engine I use 4.25 Imperial pints, or 5.1 US pints, or 2.4 litres.

However, I have seen and filled both 250 and 350 narrowcase racing engines, using a 20W/50 mineral oil, with 3.5 Imperial pints, or 4.2 US pints, or 2.0 litres for short track/sprint races (Brands Hatch "Indy Circuit", 1.2 miles or 1.94 Km in length) of 8 laps, if I remember correctly? The idea behind reducing the volume of oil was to enable quick engine warm up and reduce potential clutch drag, this being the era of no sighting laps and dead engine push starts. The engine oil was drained after each meeting and fresh oil used to replenish.

Here are two links to similar requests for information that have been posted on this forum:

Oil_quantity_for_Mototrans_250_deluxe_model

Engine_oil_quantity?

I hope that this helps you to come to a positive conclusion and able to enjoy riding/racing the beastie.

Good health, BillR

[etsjw]

Greetings,
On my narrow case 250 (external oil feed, roll pin in the G&W cam) I have found that the oil used can make a difference in the
amount of foaming as seen on the top bevels thru a gear gazer.
For example RedLine synthetic 20W-50 had a tendency to foam until the oil was hot.
Currently using AmsOil V Twin 20W-50 synthetic. No foaming at all, engine runs a little quieter, and clutch action is great.
Hope this helps.
John