Hey guys

I've got a 1275 LS engine (Running 10psi boost from an SC12 blower) that is filling the rocker cover with oil quicker than it can drain.
It's fine as long as I keep it under 5,000 rpm but builds up with high revs and also fills my oil catch can (surprisingly it doesn't blow smoke - valve seals must still be good). Cam bearing is in the right way, I built the engine approx 10yrs ago and haven't noticed this issue until now.
There is no blow by, good compression (140psi - low compression pistons) but I suspect the rocker assembly has a bit of wear and is letting too much oil past. I can see it pouring out around the rocker arms/shaft. Does the shaft usually wear before the rocker bushes? If so I will just chuck in a new shaft and see how it goes otherwise might be a good excuse to but some rollers in. Any other suggestions? I have heard of the feeler gauge with a small restrictor hole in it, to reduce flow, but not too keen to go this way.

cheers
Rick

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1310 SC 1969 Morris Deluxe - 15psi boost
1293 1968 Morris Deluxe Miglia - 45 Weber
HSV Maloo Z Series - Comp Cam - 300rwkw

Check top end clearances . I have heard of fitting a restrictor as being common practice

Thanks Ian

Do you mean rocker to shaft clearances? There doesn't seem to be any slop in them when unloaded. Might have to pull the rocker gear off and have a closer look at shaft wear.
Just not too keen to put a new head gasket in after undoing the rear head bolts. (bit of a mission to remove the supercharger etc)
When you say it is common the fit a restrictor, are you referring to the feeler gauge with hole option?

cheers
Rick

_________________
1310 SC 1969 Morris Deluxe - 15psi boost
1293 1968 Morris Deluxe Miglia - 45 Weber
HSV Maloo Z Series - Comp Cam - 300rwkw

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

I had my rocker cover filling with oil and making a mess of my engine bay when at high revs also. I fixed this by putting an extra breather on my bell housing so for the bottom end..... fixed the problem:) I even changed new rings and pistons trying to solve the problem but it was just a $50 issue haha

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1964 smooth roof panel van
1967 Mk 1 X-Police cooper s
1970 mini k
1975 leyland

Thanks for the comments guys but Mick as mentioned above I am certain the cam bearing is the correct way as I confirmed this when I built the engine (as I had come across the cam bearing issue before). Carter, I actually have a bell housing breather, a timing chain cover breather and a rocker cover breather all going into a catch can vented to atmosphere but based on your comment I might just double check that there are no blockages in them, thanks mate.

cheers
Rick

_________________
1310 SC 1969 Morris Deluxe - 15psi boost
1293 1968 Morris Deluxe Miglia - 45 Weber
HSV Maloo Z Series - Comp Cam - 300rwkw

Hi, this has happened to a few people over the years, and the causes and cures have varied

Usually i think these are a combination of issues, and one cure may not be the answer


with 10psi boost, and light load piston rings and usually most reconditioners seem to bore engines with too much piston to bore clearance, its quite possible to have ring blow by at high revs, and you can't duplicate that by revving it.as its only under load. What brand of pistons and rings ?

Another potential issue is as you say, too much oil up top. Wear, thin oil when hot, sump pressure not letting it return, relatively poor oil drain to sump flow on 1100S blocks, combination of potentials

The simplest way to restrict the quantity of oil up top is loosen the rocker posts a little and put a very thin feeler gauge shim under the post that supplies oil. Drill a hole in the shim of say .030" or .040" and make sure that lines up with the holes to allow oil flow. Check the oil flow out the rockers now with oil hot and no rocker cover on at idle, and test after the mod.
You really don't need massive flow up there and you could go smaller on the hole

I could also believe detonation( which is easy to get on a supercharged car ...and you may not hear it until a piston fails) could contribute to your problem...... what sort of ignition and timing do you run ?

cheers Lindsay Siebler

_________________
1967 EX works rally mini restoration virtually complete OBL45F
1965 Mk1 Cooper S
1970 Colt 1100F SS
2014 Mitsubishi Imiev fully electric daily driver
1948 Allard M coupe Olds 215 v8 project
1971 Twin cam Escort ex Uk championship winning rally car project

G'day Lindsay

Much appreciated, thanks mate. If it is an accepted practice then I will give the feeler gauge method a shot. I can 1/4 fill the rocker cover by just holding it at 5k rpm for about 10 or so seconds whilst stationary (so with no boost or load and watching from the oil fill hole). This is a 1275LS block but very similar to 1100S re solid back of engine. I would imagine that the old blocks would have more drain area with the lifter covers.
I am running Mahle low comp dish top pistons and standard rings that came with them. Not sure of the brand rings but I know that these pistons have an extra ring v's the Hypertec pistons that I originally ran in this engine. I ended up blowing the ring lands out of the Hypertecs at 15psi boost due to some detonation. I did have chrome rings on the Hypertecs but these are standard black type on the Mahles.
I run a Pulsar dizzy (standard advance springs) with MSD boost retard module that takes timing off the top per pound of boost.
Currently about 18deg static and about 27 all in. Boost is about 7-8 psi around town but gets to 10psi on the highway (at approx 130kph +) and this is when the rocker cover fills.
I can't hear any detonation at the moment but I have heard it before (on dodgy fuel) and have had to dial up the boost retard (control knob in cabin for this) from time to time,but not for a while. I guess there could still be detonation/knock that I can't hear that could be effecting things. I have had this setup running for about 10 years now but with a Mikuni HSR for the last 5 years. Haven't had the issue until the last couple of years, but it is getting driven a bit harder of late, and as you mention wear could also be a factor.

I will give the feeler gauge method a shot. I see Mini kingdom have some 1.5 rockers (cast non roller type) for $310. Might be worth a look also.

cheers
Rick

_________________
1310 SC 1969 Morris Deluxe - 15psi boost
1293 1968 Morris Deluxe Miglia - 45 Weber
HSV Maloo Z Series - Comp Cam - 300rwkw

Hi rick, you must have it all pretty close to correct
The Mahles are actually ACL low comp pistons with ACL rings, nothing magic , but have lasted well ....big oil ring slot would not be ideal for big hp or load
I assume that at 10lb boost you are running about 17 degrees total... that would be close to the mark ...could only play a bit with E85
I personally don't like many roller rockers, high wear, breakages, anodising failing, pins falling out
OEM were subject to much testing, unlike aftermarket ...maybe rebush ??
You may have just damaged the pistons / rings a bit over the years when you have had detonation
Have you had any body follow you when you boot it and back off to see if it blows smoke ?
How do you like the MIKUNI HSR Is having an accelerator pump system a bonus with the supercharger ?

cheers Lindsay Siebler

_________________
1967 EX works rally mini restoration virtually complete OBL45F
1965 Mk1 Cooper S
1970 Colt 1100F SS
2014 Mitsubishi Imiev fully electric daily driver
1948 Allard M coupe Olds 215 v8 project
1971 Twin cam Escort ex Uk championship winning rally car project

G'day Lindsay

I just checked it again today and am actually at about 15deg advance at idle, not at total. I found that I need a lot of initial advance to overcome load stumble with the Mikuni. (I am running a Bosch starter so all good). The Pulsar dizzy has 12deg mech advance which is 24deg at the crank. 15deg + 24deg = 39deg total all in, but then the MSD retard module takes off 1 deg per pound of boost (at the current setting), so at 10psi is it pulling off 10 deg of the advance so at all in I have around 28-29 deg advance (39 deg less 10 deg retard). Sounds like a lot of advance doesn't it but this is what it likes. No audible detonation but if I dial back the MSD retard to 0.5 deg per pound I can hear ping.

The Mikuni is worlds ahead of the HIF6 SU that I was running. It actually has an oversize accelerator pump fitted by Vintage performance in the US. You can't drive it like an SU though, as in you can't come into a roundabout in 4th gear and floor it and expect the acc pump to compensate (big lean out to 18:1 AFR). Just not enough airflow across the venturi. But when you use the correct gear (say 2nd into the roundabout) then all good. There is no restriction at all through the throat at full noise, so a lot better flow (not even a butterfly). I have done a lot of needle profiling to get it to where it is now though. This car has never been on a dyno but it does spin 3rd gear single wheel (no lim slip). I have timed it at around 13-14 sec quarter mile. It does have a rich cruise at 11.5:1 but this was a compromise for drivability and fuel economy is not a concern (is at about 13ltrs/100km at the moment). I am running BPR5ES plugs to avoid foul which are a pretty hot plug by all accounts but worked out to be the best in testing.

I really think that this oil issue is more related to rocker wear though (as opposed to crank pressure)as I can see the oil pouring out around the rockers/shaft in neutral so with no boost . Oil Pressure is fairly consistent through the rev range at 50-60psi.

I have also heard bad things about the minisport alloy roller rocker hence my interest in the cast steel style 1.5 high lift ones at mini kingdom. Not really interested in rebushing the factory rockers due to the need to use reamers etc.

I have had other mini club drivers behind me and it doesn't blow smoke at all. Just dumps it out he oil catch can onto the road.

I have attached a photo of the engine bay. It has been cleaned up a lot since this photo and the catch can is now under the front guard.

cheers
Rick

_________________
1310 SC 1969 Morris Deluxe - 15psi boost
1293 1968 Morris Deluxe Miglia - 45 Weber
HSV Maloo Z Series - Comp Cam - 300rwkw

There is a lot of work and thinking gone into that project, impressive
A couple of thoughts from me I do not recommend resistor plugs ... you lose some of the spark that you already don't have enough of..... It looks like a Bosch T coil , so with that and pulsar dissy you won't have much quality spark, the plug leads are very long, another loss of spark.(it all adds up) You must have quite a large chamber in the cyl head to get away with that total ,
You must be close to detonation all the time. Dr mini had 39 total until he fitted my long duration ignition system , and now its more like 34 I believe. and considerably more performance. I have been running a locked at 32 degrees distributor in my road car for 5000k ,and no issues starting, most of the race dissy we do are locked, and what I am getting at is that the15 at idle could go to 18 -20 and that would improve low speed performance considerably, but then the curve is wrong. There is also a possibility you have less total timing than you think ,as all modules retard timing up to 4 degrees ( checking timing at 7000rpm will test this ) My supercharged moke with 200hp and alloy head has 28 total, but its on E85 that helps timing and cooling considerably. I have just built a 1275 supercharged efi with ECU and big sprintex supercharger and am running 20 deg total being very conservative on tune as it does not lack performance ,,,so you can see why I think 29 is high
It does sound like the rocker gear is a major contributor. Go for that
Thanks for the observations on the Mikuni, I tried to buy one off vintage in usa and they stuffed me around badly
cheers Lindsay

_________________
1967 EX works rally mini restoration virtually complete OBL45F
1965 Mk1 Cooper S
1970 Colt 1100F SS
2014 Mitsubishi Imiev fully electric daily driver
1948 Allard M coupe Olds 215 v8 project
1971 Twin cam Escort ex Uk championship winning rally car project

Just a thought, someone I know has had problems with "rubber" (neoprene, plastic etc) elbows in the inlet tract...they were collapsing an sucking air...just something to bear in mind...his fix was to use exhaust elbows atc

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"Show me the Mini!"

Thanks Lindsay - really appreciate it. Building the intake manifold was the most work.
I had no dramas at all with Vintage Performance, must have been lucky. They have pictures of my engine bay on their website.
Like you say, I may have less timing up top than I think as I am assuming the boost retard is removing the amount of timing that it specifies on the dial/ adjustment knob. There is no real way for me to tell under boost (cant use a timing light at speed!).
I know that I am getting 39-40 from about 3,800 rpm before boost retard.
I did try a bit more static advance with good results but (around 22deg) but it really struggled to start when warm. Strange that you can crank with so much advance.
I might even recheck the tdc mark on the crank pulley as I machined it up out of alloy and from memory I just copied the placement of the mark from the original harmonic balancer (don't think I checked it against the flywheel). At the end of the day, I am tuning the ignition by ear (as in as much advance as I can without hearing detonation).
The head is stock 1275LS and stock cam. Probably a good candidate for the high lift rockers. Have you had any experience with the C-AHT436 forged rockers?
Compression test has only about 130 - 140psi across the cylinders but it may be the tester.
Yeah, that is a transistor coil, I have a GT40R that I am setting up on my new mini build with pulsar dizzy (that I have regraphed), might be worth bolting that up to see if there is any difference. Once I sort this oiling issue I might try some non resistor plugs too. I didn't realise that they made much difference.

What head are you using for the EFI build? I assume that it is a cross flow based on the dramas people have been reporting with the siamese EFI dilema. (Unless you are injecting on the cold side of the blower)?

Pretty happy with the way it is going though, keen to move back to the new mini build (1293 running 45 weber) and all CS gear.

viewtopic.php?f=2&t=98649&hilit=oew+miglia

Hi 9YaTaH. Thanks for that but that elbow is super thick and always stays firm.

cheers
Rick

_________________
1310 SC 1969 Morris Deluxe - 15psi boost
1293 1968 Morris Deluxe Miglia - 45 Weber
HSV Maloo Z Series - Comp Cam - 300rwkw

Hi Rick, you have done an excellent job on your project
there are so many moves forwards , backwards and sideways on things like this that it is hard to focus sometimes.
I have more thoughts as you reveal more.
Maybe you can feed a known amount of pressure into your boost retard to check what it does ? a mityvac ?
Is it possible that you pumped the throttle (with an accelerator pump) when trying to start it with more base timing. A hot fuel mixture in a hot inlet manifold can preignite and make it hard to start ( I tell my customers with locked ignition and 32 degree not to pump a weber when hot for that reason, whereas my road car with 32 degrees has a hif44 and had no issues.
I have no experience with those rockers
You could run 12v alternator power to your gt40r and pulsar dissy .. I don't think it will fail the module, the risk is on you, but you will get more spark ( don't try it with points)
The EFI sprintex supercharged is all A plus , 9.0:1 head, block ,crank , rods , lowered dish . with injectors (2) close to inlet of supercharger, and throttle body/ idle speed motor is Daewoo (GM style).WOLF ECU I run a bypass to lower inlet temps and in the bypass I have built a blow off backfire valve. Dyno tuned, not super high HP, but massive torque from 1800rpm on with tall diff, quiet except for lovely supercharger whine on higher boost. Delight to drive, Quaife diff.. So nice I am thinking of a 998 version, as in my mind the improved harmonics of the 998 versus 1275 may make it more pleasant to drive
The 200 hp sprintex supercharged moke has 10.0:1. E85, alloy5 port head, bypass system 2" SU and a very trick version of our ignition system incl variable soft rev limiter, LSD, a lot of dyno tuning 12.5 sec 1/4 mile
cheers Lindsay
I had a serious go at building a conventional efi 5 port on engine dyno , but the scavenging in let valves made the injection time impossible to balance practically

_________________
1967 EX works rally mini restoration virtually complete OBL45F
1965 Mk1 Cooper S
1970 Colt 1100F SS
2014 Mitsubishi Imiev fully electric daily driver
1948 Allard M coupe Olds 215 v8 project
1971 Twin cam Escort ex Uk championship winning rally car project

Hi Lindsay

All excellent ideas. I must admit that I haven't spent a lot of time trying to increase spark strength.
I do have a mityvac, but it only creates vac not boost as far a I remember.

On the subject of the rocker cover oil, even at idle it appears as though the push rod holes are full of oil up to about 10mm from the top. They are still draining, but when revving it it creates the illusion that the oil is coming up out of the push rod holes. Maybe there is some crank pressure that is stopping the oil from pouring down the holes. I also removed and inspected the rockers and shaft and there is some wear on the bottom of the shaft and rockers but the top of the bearing surface and shaft where the oil holes are dont seem too bad. Anyway, I will try the feeler gauge trick tomorrow which should sort it with a view of upgrading the rockers to those forgies when the cash is available.

cheers
Rick

_________________
1310 SC 1969 Morris Deluxe - 15psi boost
1293 1968 Morris Deluxe Miglia - 45 Weber
HSV Maloo Z Series - Comp Cam - 300rwkw