Metric Mechanic 2900 Sport

[digger]

i would think the bearings would go out well before the cam got ate away if the pump failed. the cam might have been wiped already if the oil was wrong or the hard weld cam was not done properly

[jneumss]

Well, I finally got to spend some quality time with the iX - pulled the engine and transmission yesterday. I haven't gotten into the bottom end or the head much, but I think that I may have found a potential cause for the loss in oil pressure and wandering temperature gauge.

When I bought the car, it had a blown head gasket and the cause was 3 head bolts had backed out and were totally loose. So after fixing that, I drove the car for about 7 months. Now, upon tear down of the coolant system I've found that the previous owner must have used some of that stop leak junk and several of the coolant hoses were almost completely blocked.

I'm wondering if the some of the stop leak got into the oil system and is blocking or partially blocking some oil supply to the head.

Additionally, I'm wondering if the blockages in the coolant system was what was causing my temperature to fluctuate.

More investigation to follow.

[zaq123]

I'd be checking this head for cracks as well. How sure are you that it was some kind of stop leak? Maybe oil sludge from leaking head gasket/cracked head? Do you know any history on this car? Did PO do MM kit himself? What exactly was he trying to fix with the stop leak crap?M20 oil pump looks like pretty basic design, hard to imagine it's just failed for no reason. Post some pics once you dig into it.

[jneumss]

I'd be checking this head for cracks as well. How sure are you that it was some kind of stop leak? Maybe oil sludge from leaking head gasket/cracked head? Do you know any history on this car? Did PO do MM kit himself? What exactly was he trying to fix with the stop leak crap?M20 oil pump looks like pretty basic design, hard to imagine it's just failed for no reason. Post some pics once you dig into it.

I am planning on having the head and the block cleaned and checked out, as well as the oil pump. The reason I think it was stop leak was the consistency of it, it was almost like silicone sealant that had cured and it was filled with metal flakes that looked just like stop leak does. However, I have never used it or seen what it looks like first-hand after it has been added to the coolant. Would oil sludge have a soft, rubber like consistency like that?

As for what he was trying to fix with it, I am not sure. There is some evidence on the oil pan and block that there may have been a few older coolant leaks around the thermostat housing, water pump, and at the port at the back of the engine, but nothing that I noticed actively leaking since I have owned it.

I have paperwork for this engine being sent to MM and built to their 2900 Sport specification in 2007. The owner of the shop who did the install was the original owner of this car, but the restored after he had sold it to the owner that I bought the car from. After owning the car for almost 2 years, it is very evident that it was not maintained very well since it was redone in 2007. I will definitely post some pictures and description as I get into it further.

[zaq123]

what color was that junk? Could be anything...coolant sludge, oil, overuse of the gasket maker etc

[Bearmw]

Did they perform their famous "surface turbulence" black magic on that head?

[digger]

Did they perform their famous "surface turbulence" black magic on that head?

Lol, of course mate.

Can the op tell us if those piston generate any squish ? Is the circumference of the piston dome somewhat similar to oem or is the chamfer at a different angle ?

[jneumss]

what color was that junk? Could be anything...coolant sludge, oil, overuse of the gasket maker etc

It was a dark gray color.

[jneumss]

Lol, of course mate.

Can the op tell us if those piston generate any squish ? Is the circumference of the piston dome somewhat similar to oem or is the chamfer at a different angle ?

The pistons don't have any "Surface Turbulence" steps in them and the chamfer is pretty close to stock, but it is consistent all the way around with a flat step down instead of an inverted dome.

Did they perform their famous "surface turbulence" black magic on that head?

"Surface Turbulence" grooves in head and valves.

I understand wanting to create turbulent flow in the combustion chamber, so as to limit knock at this CR, but I cannot quantify how effective this stuff all is. My guess is that the different boundary layers interacting would have quite nonlinear turbulent behavior especially at high rpms. Since the stock combustion chamber has many boundary layers interacting and that is largely turbulent already, adding grooves and machine marks would possibly create more turbulent flow.

[MrBurgundy]

What's with the hate towards MS? That would be more than enough for his setup.

[Kershaw]

You have to learn who to listen to and who to take with a grain of salt.

Megasquirt is more than enough for any m20.

[digger]

The pistons don't have any "Surface Turbulence" steps in them and the chamfer is pretty close to stock, but it is consistent all the way around with a flat step down instead of an inverted dome.

"Surface Turbulence" grooves in head and valves.

I understand wanting to create turbulent flow in the combustion chamber, so as to limit knock at this CR, but I cannot quantify how effective this stuff all is. My guess is that the different boundary layers interacting would have quite nonlinear turbulent behavior especially at high rpms. Since the stock combustion chamber has many boundary layers interacting and that is largely turbulent already, adding grooves and machine marks would possibly create more turbulent flow.

What I mean is the piston dome has a chamfered part about 5mm wide around the circumference, is it at the same “angle” as OE pistons ? Im wondering if you get the head and piston dome close enough like 1mm you can get some squish happening the surfaces need to be approx parallel to get a proper squeeze

[MrBurgundy]

You have to learn who to listen to and who to take with a grain of salt.

Megasquirt is more than enough for any m20.

off topic, your sig is great. LOL

tis indeed a silly place

[jneumss]

What I mean is the piston dome has a chamfered part about 5mm wide around the circumference, is it at the same “angle” as OE pistons ? Im wondering if you get the head and piston dome close enough like 1mm you can get some squish happening the surfaces need to be approx parallel to get a proper squeeze

I'll get some modeling clay and check out what the clearance is at the chamfer.

[zaq123]

typically, if the squish area is not too great, engine runs dirty since the fuel doesn't burn too efficiently.
I'm not an expert but I'm not sure I understand MM piston profiles correctly. I get their design to avoid P to V contact. What about the actual squish area? M20 head has that front stepped wide area to achieve proper squish that corresponds with piston's squish band hence oem piston's design has that wide area on the band (pic). Had to tell from the pic of MM head above.....Does MM machines the head to set proper squish and reshapes the combustion chamber to match those pistons?