engine and drivetrain Just back from my engine builder.....

[markmac]

Has been a few weeks since I was at his shop, owed him a visit. All my parts and pieces are out and on the bench (cylinder head stuff that is). Tappets are out being polished and coated - and since he hasn't heard anything he told me the assumption is that there aren't any problems with them. Cylinder head is on a jig and will by weeks end have all the machining done to install new valve seats - beryllium exhaust and either steel or Moldstar for the intakes. He was telling me about this Moldstar material and how superior it is to the other (but substantially more expensive). Going to get a quote on it before I decide (link below). Gave him the go ahead to finish the engine so Pistons (CP) and Conrods (Carillo) are next. Scary spending the money but time to sh*t or get off the pot. Going to be some really great posts for my blog over the upcoming weeks/months. Sadly, this image is from several years ago so that gives you an idea on the progress on this (freaking pitiful). When working with folks like this I never ask them (or let them) do anything I can't pay for (novel idea that some don't practice) - things can get out of control really quickly if you aren't careful, you just don't want to get in a position of having someone "repo" your unreplaceable engine bits because you can't afford to pay for services rendered.

www.alpinabmw2002.com

http://www.performancealloys.net/MotorsportApplications.htm

[TobyB]

I think you're going to have a hard time getting #1 to light...

t

[markmac]

That is what happens when the f*cknut (PO) threaded the plug in wrong. Gets filled in all the way, peened then machined out. Alot of work and expense for a careless error. No taking chances with a helicoil on this one.

www.alpinabmw2002.com

[oldguy]

I've used moldstar in heads and it has worked well, I've also utilized Trojan as well. Both were great in titanium valved engines that required extensive cooling of the valve face due to their race nature.

If this was a race engine that was turbocharged and running titanium valves, I would recommend trojan or moldstar. If this is a NA motor with stainless valves than I believe many steel alloy seats would work fine without stepping upto a more expensive seat material.

That said, I don't know what spring pressure you plan on running, how wide your margin is, and what fuel/induction this motor is planning on running.

manganees bronze guides might be preferred in your application to silicon bronze. BeCu can also be utilized for guides with amazing results as well. Just remember the dust is pure carcinogen. Keep your work wet, and check local laws regarding disposal of coolant. May fall under hazmat guidelines.

[markmac]

It sounded to me like the Moldstar seats were going to be n the $400 range which I think is probably a little pricey. It isn't a Turbo motor so it maybe overkill. I don't recall now what the guides were made of but will get that info here at some point. Valves are steel, but have had a special coating (again forgotten) applied that increase the hardness of the stem - image here:

Not me doing any of this work so no concern of breathing in nasties (unless I need to worry about second hand?). Exciting for me to finally be getting some forward progress on this.

www.alpinabmw2002.com

[markmac]

I've used moldstar in heads and it has worked well, I've also utilized Trojan as well. Both were great in titanium valved engines that required extensive cooling of the valve face due to their race nature.

If this was a race engine that was turbocharged and running titanium valves, I would recommend trojan or moldstar. If this is a NA motor with stainless valves than I believe many steel alloy seats would work fine without stepping upto a more expensive seat material.

That said, I don't know what spring pressure you plan on running, how wide your margin is, and what fuel/induction this motor is planning on running.

manganees bronze guides might be preferred in your application to silicon bronze. BeCu can also be utilized for guides with amazing results as well. Just remember the dust is pure carcinogen. Keep your work wet, and check local laws regarding disposal of coolant. May fall under hazmat guidelines.

Schnitzer slide throttle, Kugelfischer Mechanical Injection

[allbim]

Are you are heat-treating the head to bring the welded areas back to normal hardness before installing (shrinking-in) the new valve seats. I hope the welding material used, is heat-treatable.

[oldguy]

Are you are heat-treating the head to bring the welded areas back to normal hardness before installing (shrinking-in) the new valve seats. I hope the welding material used, is heat-treatable.

The casting of the heads, usually A356 material, usually requires no heat treat post "as cast".

In addition, the type of heat treatments utilized in A356 would only serve to lower strength and reduce elongation, in favor of dimensional stability. Since the head was already working, we only increase the chances of over aging it. Not really fixing anything that's broken.

Would I want to run that head on a million dollar race car in the 24 hours of lemans? Nope. Would I run it in a vintage car that's going to see sparse weekend races. Totally.

[markmac]

I don't know (but will ask), those welded areas have been peened (you may or may not be able to tell from the images). He indicated that ALL of the material on the head was in VG conditon (big relief). My engine builder is very (very good), works with the likes of Steve Jennings (cosworth fame), Dave Vegher, extensive experience with Cosworth BD race motors, Hart 420R, BMW M12 and a wide variety of others (midget, super bike etc.,). Looking forward to Friday and seeing the work done on my head, gave him the go ahead before Thanksgiving and here we are in March (my timing was not so good as I ended up behind two HART 420R motors that are headed for Lemans).

www.alpinabmw2002.com

[oldguy]

It sounded to me like the Moldstar seats were going to be n the $400 range which I think is probably a little pricey. It isn't a Turbo motor so it maybe overkill. I don't recall now what the guides were made of but will get that info here at some point. Valves are steel, but have had a special coating (again forgotten) applied that increase the hardness of the stem - image here:

Not me doing any of this work so no concern of breathing in nasties (unless I need to worry about second hand?). Exciting for me to finally be getting some forward progress on this.

www.alpinabmw2002.com

That coating was probably some type of DLC/PVD type coating. Carbon raptor, diamond coatings etc are all names for similar items.

The advantage of a moldstar seat vs a steel alloy seat is heat transfer. The valve contacts the seat at a "margin". That's the 45 degree angle in the middle of a 3 angle valve job. The width of that "margin" can be .010" all the way out to .045" or more. The smaller the margin, the better the flow (in theory). The smaller the margin, the less space for heat to be transferred out of the face of the valve (fact). Heat transfer is based on two items. Contact surface area (margin width), and spring pressure. So with a moldstar seat you can run narrower contact areas because you transfer more heat out of the head of the valve. Since this sounds like a schnitzer 250hp rally motor setup, I think you'd be fine with nice steel alloy seats front and back. Nothing to trick going on there. Now if you were considering a 600HP turbo 10k rpm twin cam build, then I would reconsider.

Beryllium Copper(BeCu) and You.

BeCu dust and vapors are lung carcinogens. If you work with the material under coolant when machining, you're good if you have good common sense. Since you're not casting it either, then your safe. Unless you start grinding on your ports (valve guides or seats) and breathing in the dust, your risk for exposure is nil. Moldstar and Trojan are not BeCu and do not have these issues. BeCu is stronger than either but only marginally. True BeCu is utilized in a number of industries but is difficult to manufacture in the US due to health concerns. Items such as "no spark" tools, or bearing surfaces in mission critical parts are some of the uses for it. Ping used to make an ultra forgiving set of golf irons out of cast BeCu. I still want a set just for grins.

[markmac]

Great information - interesting. I am guessing the Moldstar seats are going to be more coinage than I want to spring for. Some things make sense, others don't (this may be one). When AlpinA ran this motor they were making 275-280 hp, that is my expectation as well. We haven't really changed anything so in theory it should be the same. When it is all done it will go on his super trick engine dyno (which will be a great day, but a nervous day) so the proof will be in the pudding so-to-speak. I am building the engine to last, I don't have the cash to tear it down every 10 hours and "freshen" things up so cam profiles and other haven't been changed or altered to try and raise the HP.

www.alpinabmw2002.com

[TobyB]

Heat transfer is based on two items. Contact surface area (margin width), and spring pressure.

ah- there's a third factor, not that it varies all that much in most applications-

it's valve dwell time, or, how long the valve's closed. It usually only matters

when the valve's not seating all the way or the cam ramp angle's messed

up, but dwell on the seat can make a difference if an engine's already marginal

and you add a much longer- duration camshaft...

pedantically, I'm sure...

t

[allbim]

It sounded to me like the Moldstar seats were going to be n the $400 range which I think is probably a little pricey. It isn't a Turbo motor so it maybe overkill. I don't recall now what the guides were made of but will get that info here at some point. Valves are steel, but have had a special coating (again forgotten) applied that increase the hardness of the stem - image here:

Not me doing any of this work so no concern of breathing in nasties (unless I need to worry about second hand?). Exciting for me to finally be getting some forward progress on this.

www.alpinabmw2002.com

That coating was probably some type of DLC/PVD type coating. Carbon raptor, diamond coatings etc are all names for similar items.

The advantage of a moldstar seat vs a steel alloy seat is heat transfer. The valve contacts the seat at a "margin". That's the 45 degree angle in the middle of a 3 angle valve job. The width of that "margin" can be .010" all the way out to .045" or more. The smaller the margin, the better the flow (in theory). The smaller the margin, the less space for heat to be transferred out of the face of the valve (fact). Heat transfer is based on two items. Contact surface area (margin width), and spring pressure. So with a moldstar seat you can run narrower contact areas because you transfer more heat out of the head of the valve. Since this sounds like a schnitzer 250hp rally motor setup, I think you'd be fine with nice steel alloy seats front and back. Nothing to trick going on there. Now if you were considering a 600HP turbo 10k rpm twin cam build, then I would reconsider.

Beryllium Copper(BeCu) and You.

BeCu dust and vapors are lung carcinogens. If you work with the material under coolant when machining, you're good if you have good common sense. Since you're not casting it either, then your safe. Unless you start grinding on your ports (valve guides or seats) and breathing in the dust, your risk for exposure is nil. Moldstar and Trojan are not BeCu and do not have these issues. BeCu is stronger than either but only marginally. True BeCu is utilized in a number of industries but is difficult to manufacture in the US due to health concerns. Items such as "no spark" tools, or bearing surfaces in mission critical parts are some of the uses for it. Ping used to make an ultra forgiving set of golf irons out of cast BeCu. I still want a set just for grins.

Sorry, oldguy, I'll have to disagree with you. Type 356 aluminum is not always at maximum tensile strength as cast. However, it will usually be, within 1 year at normal room temperature, because as you know, heat treatment of aluminum alloys for maximum strength is an aging process that is accelerated by elevated temperatures (up to a point).

When a heat treatable aluminum alloy is welded, the weld material and adjacent area are rapidly cooled by the large and cold thermal mass of the surrounding material. This rapid cooling (quenching) leaves the welded area in a condition of less than maximum tensile strength.

[aa/fd]

albim, you have it correct the a 356T6 casting is very effected by massive welding (gets soft) but the machinist/welder he is using is familiar with and services Cosworths, so I would imagine he knows the threshold at when it becomes dead soft and whether a trip to the heat treater (not good) is in order.

We always preferred a Timesert to welding up a plug hole, but that was our opinion.

Nice to see people will still install Beryllium seats they really cool the exhaust valve nicely.

[markmac]

The outline on this intake port is from the current slide throttle intake - which gives you an idea of how much material they take (took) out to open the port up. Quite a bit really. My head was flow tested many years ago and at the time he (engine builder) told me it flowed more air than any four cylinder head he had ever tested (including BMW M12, Hart 420R and any of the Cosy's). Top image is of a NOS Schnitzer head I used to own - untouched (shoot me in the head for selling that thing), bottom image is the head I am refurbishing now

www.alpinabmw2002.com