Don Terrill’s Speed-Talk

Hi everyone,
Can someone clear this up for me ? Does a street driven Dart block SBC with mild solid roller, Morel Ultra Pro lifters, Yella Terra shaft rockers, 7 litre pan, melling 10554 pump 10/40 oil and max rpm 7000 - need oil restrictors ?
At final assy with manifold off, using modified distributor to prime pump and rotating crank I have noticed at full lift there is quite a big leakage
as the roller pivot pin hole intersects the oil gallery.
While this is no surprise, is it a good idea to try and reduce this ?
Cheers Mike

Maybe I should ask the question this way - Under what circumstances do SHP blocks need oil restrictors ? Dart spec sheet says there are no provision
for restrictors, but Moroso and others make them to suit these blocks, any info appreciated

RT Machine wrote: ↑Tue Feb 13, 2018 3:54 am Hi everyone,
Can someone clear this up for me ? Does a street driven Dart block SBC with mild solid roller, Morel Ultra Pro lifters, Yella Terra shaft rockers, 7 litre pan, melling 10554 pump 10/40 oil and max rpm 7000 - need oil restrictors ?
At final assy with manifold off, using modified distributor to prime pump and rotating crank I have noticed at full lift there is quite a big leakage
as the roller pivot pin hole intersects the oil gallery.
While this is no surprise, is it a good idea to try and reduce this ?
Cheers Mike

Isnt the tappet smaller in that area?

No the diameter .903" is parallel

redliner wrote: ↑Tue Feb 13, 2018 2:08 pm

RT Machine wrote: ↑Tue Feb 13, 2018 3:54 am Hi everyone,
Can someone clear this up for me ? Does a street driven Dart block SBC with mild solid roller, Morel Ultra Pro lifters, Yella Terra shaft rockers, 7 litre pan, melling 10554 pump 10/40 oil and max rpm 7000 - need oil restrictors ?
At final assy with manifold off, using modified distributor to prime pump and rotating crank I have noticed at full lift there is quite a big leakage
as the roller pivot pin hole intersects the oil gallery.
While this is no surprise, is it a good idea to try and reduce this ?
Cheers Mike

Isnt the tappet smaller in that area?

Running 10w40 oil I wouldn't think about restrictors on a street ride.

Something doesn't sound right if your lifters are bleeding oil straight out of lifter gallery
With things set up correct restrictors are rarely needed with a dart block

I have a Dart Big M Sportsman for BBC and I do not run oil restrictors...High Volume oil pump runs at about 60-65PSI oil pressure with no restrictors and normal oil pan and filter setup. There are 2 or 3 oil ports in the Intake Valley I forgot to plug during my build and during the first startup, the oil pressure was 25PSI and started leaking oil from the front intake gasket. Only took a couple minutes to figure that one out Didn't have issue either time as you described though.

BTW, I did the same questioning about if I needed Oil Restrictors or not during my build and in the end, the conclusion for me was that there are rare circumstances that require the use of oil restrictors, but you'd probably know if you needed them due to other part or system requirements calling for them. Some even debated drilling small holes in the oil plugs behind the upper timing gear to provide a little better lubrication coverage, while others strongly disagreed. I simply used all the plugs provided with the block and was good to go.

MELWAY wrote: ↑Tue Feb 13, 2018 6:00 pm Something doesn't sound right if your lifters are bleeding oil straight out of lifter gallery
With things set up correct restrictors are rarely needed with a dart block

Melway, thanks for reply, agree big time, restrictors not needed, as was suggested by some, after careful examination, there must be a problem with the position of the lifter galleries or the their diameter is too large, being the owner of a cnc tooling shop, i am surprised they could be enough out of position to not allow most combinations of cam and lifters without any intersection of the oil gallery holes at full lift, the fact that it has BB cam bore means the cam base circle is much larger than std SHP block this raises lifter further up the lifter bore. lifters are .812" further raising the lifter,
Today i ran oil pump at 500 rpm and using an accurate gauge it shows 60 psi, with stock Melling 10554, just a benchmark thing totally different to a running engine, perhaps the leak is not as bad as i think it is. Dart probably wont admit a fault, i have yet to receive an email reply, so the cheapest fix is order a new cam with smaller base circle to re - position the lifters lower. Anyone else had the same problem ?

Contacted Chris Straub who sold the cam and lifters to me and he assures me the leak is not an issue, many engine builders he deals with see this
with the same setup, - happy days!

If you do have a positive leak path through lifter body to oil gallery I would definitely be running restrictors to control flow and feed crankshaft. Or at high rpm the leakage could starve crank

MELWAY wrote: ↑Thu Feb 15, 2018 5:34 am If you do have a positive leak path through lifter body to oil gallery I would definitely be running restrictors to control flow and feed crankshaft. Or at high rpm the leakage could starve crank

I hear you mate - that was the point of my first post, given its priority oiling to crank first, then maybe that's why Chris says it will be fine.