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My Twin Turbo Build

18K views 72 replies 4 participants last post by  eschaider 
#1 ·
Hi Ed,
i need some advice on phasing my cams, this is for a 4.6 teksid with heavily ported B heads 4.75 stoker, forged internals, adjustable primary and secondary sprockets, twin turbo in my Nash Metro. Cams are Comp Cams
106-403-9 ...specs are exhaust 116 CL duration 232 deg and intake 112 CL with 234 deg duration.

the car was running before an unfortunate oil pressure problem it was a slug off the line but really flies when it gets moving, any suggestions as to advancing intake or exhaust and by how much? thanks JT
 
#4 ·
Thunderbolt,

If you have a first name I'll use it or if you prefer I'll use your screen name.

I am not going to be able to get to your request until later this evening. Some of the items Todd has identified are important to how you phase the cams. For example PTV clearance. Todd calls it valve reliefs, I call it Piston To Valve (PTV) clearance, they are similar and they will determine the limits you have to work within when phasing your cams. I will touch more on that going forward.

Your comments about the car being a slug off the line indicate you are lacking in low speed power. Some of that is inherent with turbochargers because it takes time for them to spool up unless you are doing a drag race type start. Which turbos are you using? Do you use an automatic or do you use manual trans like a TKO or T56? If you use an automatic what stall converter did you buy. I am unfamiliar with Nash Metro weights. My guess is your Nash Metro is somewhere between 2700# and 3000#. Do you know what it weighs. What rear end ratio are you running?

Until your engine gets into boost it is more like an n/a engine than a supercharged engine. My first blush instincts are that those cams are not only installed on a pretty wide centerline but they are pretty big cams for one of our engines used on the street. Which actually begs another important question, is this a street car or is this a race car?

Like Todd suggested we need a bit more information to begin the noodling out process. Let us know what you know :)

Ed
 
#5 ·
HI Todd and Ed I'm jonathan, I'm a New Zealander but i live in the philippines...im the only one here running a Mod motor, its primarily a Drag car that is a bit streetable.

Ed i did read your Cam article and found it extremely interesting thank you!

the car is a tube frame unit with the steel body as decoration, weight is 2400lbs empty +me @225. tire diameter 28.5, rear end gear is 3.80 trans is a Powerglide from BTE in louisiana it has trans brake and has a 4500 stall converter.

engine is Teksid 4.6 now 4.75L (small stroker) ford motorsports forged crank, Manley rods and Pistons...pistons have valve reliefs on one side only, i will try to measure PTV today, Compression 8.5.

Heads are lincoln B which we ported and polished extensively. intake is a sheetmetal unit i made myself as i could not find one to buy.

cams are a weak knowledge area for me what i bought are these Comp Cams 106-403-9 ...specs are exhaust 116 CL duration 232 deg and intake 112 CL with 234 deg duration, Grind XE270AH-114... i bought these with little knowledge as they were advertised as being the best for a turbo car.

Turbos are GT35 with ceramic bearings. I am aware of the turbo spool issue and have been working slowly on that...thinking of activating the ALS system on my MS3pro or adding nitrous to launch.

Some History, i got bored with the same old formula BBC or SBC with a carb that everyone seems to run around here and wanted to show them that Ford modular is a viable deal! i got a junk yard 96 lincoln Mk8 engine and built the car around it.

I left it completely stock apart from injectors and ECU (MS3 pro) and twin turbo....it went surprisingly well and was running great but i got scared adding boost beyond 10 psi with the powdered metal rods etc, at the same time i was building my race engine with internals mentioned above....right or wrong i went with the B heads and spent a lot of effort improving them and building my intake which turned out pretty good except i think it has too much volume (too long too inflate).

i built the car with mid or low 8s in mind despite the short WB it handles great straight as an arrow but embarrassingly my best time so far is 11.3 .....but trap speed was 142mph , we did dyno the car prior to the oil starvation issue and it was making 590 RHP with about 12PSI of boost (weak waste gate springs prevented further improvement).

After reading your Cam article i see that I have probably bought the wrong Cams :weep: (lucky they are so cheap ha).

If I'm honest my the Race engine i build did not perform much better than the stock MK8 engine, so any advise you can give with either recommending better cams or making the best of what i have already would be greatly appreciated.

thanks in advance jonathan
 
#6 · (Edited)
Jonathan,

I am going to summarize your car profile, if I misstate or otherwise overlook something please feel free to jump in and correct me;

Car weight (w/driver) — 2625 lbs
Tire Diameter — 28.5 inches
Trans — 2spd P/G with stock first gear(?)
Converter stall — 4500
Rear end — 3.80 ratio (rear end type?)
Engine — Teksid block
Crank — Modified Coyote for Teksid use
Rods — Manley 5.933 length
Pistons — Manley 8.5:1 c/r (intake valve reliefs?)
Heads — Ported Lincoln "B"
Intake —Fabricated sheetmetal
Cams — Comp XE270AH-114
Current Phasing — unstated
Turbos — Twin Garret GT35's w/ceramic bearings
Eng Mgmt — MSPro or is it the MS3Pro Ultimate?
Fuel — ?? Gasoline?


A couple of follow on thoughts on your car;

As a tube chassis car I am surmising it is a race car and not a street car. The Nash Metropolitans were short wheelbase cars that I want to say were around an 85" wheelbase. Short wheelbase cars in general and less than 90" wheel base cars in particular become increasingly unstable as power levels and performance levels increase. Instead of being like a long slender arrow with good aerodynamic and directional stability the short wheelbase cars increasingly become directionally and aerodynamically unstable at higher vehicle speeds. Those are a lot of words to say, be careful as you push on the vehicle's performance envelope.

Another challenge with short wheelbase cars is how hard you can launch the car. Because the short wheelbase reduces the leverage the front wheel weight has available to resist wheel stands, short wheelbase cars need to rely increasingly on mechanical devices like wheelie bars to control the vehicle at launch. Longer wheelbase cars can benefit from the increased lever length of the longer wheelbase to resist the pinion's predisposition to climb the ring gear at launch.

Last rain on your parade vehicle commentary; The directional stability of a long wheelbase car is largely attributable to the aerodynamics at speed. The greater the ratio of wheelbase to vehicle track the more stable the car is at speed. One of the best examples of this is a dragster and a funny car. The funny car drivers will talk about how they have to 'drive' their car to keep it in the sweet spot on the track. The dragster drivers will comment on how little effort (comparatively speaking) they expend keeping their care in the sweet spot.

All this worry wart stuff is just to say proceed cautiously as you turn up the wick on your car's performance. You are likely to have a handful to work with as you go down track.

A couple of additional questions revolve around the fuel you will be using, which I suspect is gasoline, the rear end the car is using and the MSPro engine management system you are using. Your ring and pinion ratio does not seem to be an 8.8" r&p or a 9" r&p. What have you chosen to use as your rear end? MSPro systems are very impressive. Are you using the MSPro, MS3Pro or MS3Pro Ultimate system?

Your observations about manifold volume and what you called time to inflate and I would call throttle response are spot on. Smaller intake volumes will produce improved throttle response and high end performance. For a drag race car (other than high end performance) the difference is not as great as for a road race car but it is still measurable. To the extent you can skinny up the intake volume you might want to take on a winter project that sections your plenum and allows you to experiment with different plenum volumes by changing a spacer that would raise or lower the plenum floor or roof depending on how you built the manifold. If the volume is attributable to the runner length, your ability to tune this metric is all but impossible without a manifold redesign.

The "B" heads can be modified to have impressive port volumes and very good performance. The GT500 style head is something you might want to explore going forward. The GT500 design has two significant improvements over the earlier "B" style heads. While both intake and exhaust ports offer better shapes and dimensions for high flow applications the intake port's short side radius is substantially improved over the "B" head design because of the raised and straightened intake port. A second benefit is the casting. When Ford designed the FGT and GT500 family of heads they were intended for performance oriented use on supercharged applications with a factory warranty. The original "B" heads Ford offered were designed for a n/a Lincoln Continental driven as a luxury daily driver by a senior citizen. The GT500 castings are substantially more robust than the original Lincoln "B" heads and will last longer in a supercharged race environment.

I'll begin to work on the cam phasing question you originally raised this evening and have a first look for you by sometime late tomorrow afternoon. BTW if you have any pics of your hot rod I am sure the guys on the site here would love to see what it looks like.
:gotpics:


Ed

p.s. there is no reason to limit the boost on your built engine to 10 psi or so. A good initial starting point would be somewhere in the high teens / low twenties. Additionally if in fact the car is a race only car and your racing association rules allow it, methanol is the preferred fuel.
 
#7 ·
hi Ed thanks for the reply,
Engine management is MS3 Pro..an ongoing learning curve for me but I'm getting it figured out.
I'm running 100 octane gasoline but have Fast fuel injectors installed 160lb-hr each so can run methanol which is available here, i did wire in a GM flex fuel sensor but have not activated it yet I'm guessing when the time comes i will have two tunes one for street with gasoline and one for race with Methanol.
The cams were installed in Std position i wanted to see how it would run before advancing or retarding anything.

I do realize that my choice of car is very un orthodox this is because i just like the unusual and a challenge :laugh: i will definitely take your advise on sneaking up on power and speed...I used to run a big block austin Healy and that was a handful until i finally got it to stick.

i cut down a ford 9" and installed a back brace and Yukon aluminum pumpkin with strange gears and solid spool, strange 31 spline axles strange 4 piston brakes, front end is strange struts and brakes, make my own 5 link rear end that has quick disconnect coil overs so i can drop it far enough to change the tires.

The chassis turned out very well car runs straight and true, i did do a sneaky stretch of the wheel base to 90" ...i did not want to destroy the appearance of the car so i moved the the fender wheel arches forward and aft respectively rather than stretching the whole car.
The car has almost exact same weight on all 4 corners and its grip is outstanding so far, but that will no doubt change if and when i can make more power off the line.

with regard to head choices...it was more of lets see what i can do with what i have already and now having build a special manifold for B heads I've kinda tied myself to that early decision...also a pair of B heads can be bought for $150 where as GT 500 are $$$$.

After studying your cam article i would appear that one of my biggest issues is the Cam choice, if you are able to give guidance on phasing what i have to produce a significant improvement then great, but if they are really totally unsuitable i will have to bite the bullet and buy new ones!..maybe i can use the old ones in either my studebaker Hawk or 56 F100, both of which will have ford Modulars:)

Oh the low boost i mentioned was just to protect my first engine which was a completely stock Mk8 engine...i did not want to grenade a good teksid block with those powdered metal rods, remarkably it held up very well.
 
#10 ·
It is impressive Jonathan! That is the color my mind painted the car. I think it was one of the most popular colors for those cars. I love the way you maintained the original dash appearance and extended its functionality. Why am I not surprised to see mil-spec style aircraft electrical connectors for the wiring harness :)

BTW very nice fabrication and build. Your attention to detail is impressive. The ride in that little missile will be nothing short of stunning. I am guessing the car weighs in somewhere around 2300 / 2500 lbs? BTW your manifold does not look as big as I expected from your description. I suspect you are pretty close to the mark with your design.

I noticed you are still using the OEM COPs for ignition. Does the road, you might want to consider something like the Mercury Marine IGN1-A smart coils. The OEM ignition system can fall a little short of the mark power wise when igniting supercharged mixtures. The OEM coil has about 20 mJ of energy and the IGN1-A coils are around 108 mJ. While I don't think the coils are currently costing you power (unless they are used and potentially tired) they will as you turn up the wick. If I am not mistaken the MS3Pro has the ability to drive the IGN1-A coils as part of its standard feature set.


Ed
 
#11 ·
Jonathan,

There are two pics that didn't make it into your post #8. Try reinserting them. When you start to get around four or five pics in a post the bulletin board software gets clunky.


Ed
 
#12 ·
Hello Ed,
thank you very much for your favorable comments, High praise from someone with your experience and knowledge!

I wanted to maintain the cuteness of the car but still make it functional as a race car, it actually has great manners on the street just gets a bit hot in the cockpit as we always have 32deg C + here and getting stuck in traffic can be misery.

Im using MSD 82448 COPs for ignition and i needed coil drivers for them (DIY autotune Quadspark units) as the MS3 pro only has a 200 milli amp per channel max capacity so yes i would need the coils with built in igniters.

by the way the intercooler had to go due to the install of a huge radiator so i am now using water Meth for induction cooling.

jonathan

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Nash metropolitan Tire Vehicle Car Hood
 

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#13 ·
The water / meth combination will certainly cool but with the high ambient temps I suspect it will be hard to keep the charge temps below 65 or 70˚C. If you have built the fuel management system to pull charge at elevated charge temps, which I suspect you have (and should do), then the MS3Pro is taking timing away at the ambient temps you experience over there and that will cost you a significant amount of power.

Whoever did your cage was quite a good fabricator. The tubing angles by the front roof posts mirror the OEM window pillars very closely while the remainder of the cage, for the most part, is nicely hidden behind the original sheetmetal.. Your are right about the car's appearance when all the sheetmetal is on the chassis it has the classic Metropolitan look with a hint of something no one would suspect — although the big feet in the back definitely hint at it.


Ed
 
#14 ·
Hi Ed I'm happy to say that I build the cage myself and since folks have seen the car i have been getting work from other local racers for cages and chassis, i Now have one full time worker and have trained her to be a a great welder fabricator, she's also an excellent Mechanic:).

About the only job i didn't do in house was the forward facing headers...they were made by Carlos Garcia in Los angeles, very nice work, fast and fairly priced CGFABRICATIONS.

The original design of the car (stock appearance) and lack of space meant the turbos were sucking air from behind the radiator which was not good and to make it worse i was getting significant under hood head build up so a few months back we louvered the hood and flipped the turbo intakes upward so the will suck air straight thru the hood...waiting to test it all out when i can get my engine re assembled.

As i recall previously on the dyno induction temp under boost with hood off were about 180F and with meth on it was instantly cool to touch the intake so about 60F

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we made some nice Bezels with mesh grilles for the air intake unfortunately can't find the picture...will have to make water drains in bottom of turbo intake and some make remove before flight bungs to keep out dirt and water.
Tire Hood Light Automotive tire Car
 
#17 ·
I have spent the last few days considering the final tune of the engine, one of the options was a switch to methanol and the HP numbers are very impressive but for two reasons i think i won't go for methanol at this stage;
I don't think my 90 inch wheel base Nash will hold more than 12 or 1300HP and also after doing a lot of reading of other threads here i was a bit shocked on how much methanol will be required and it will need a minimum of 16 injectors @ 220lbs and wow!

So i think ill stick with Gasoline but as per Ed's advise ill upgrade my ignition system and i have bought 8 Mercury mating IGN-1A smart coils and also my fuel pump seems to be low on pressure at higher boost so i will upgrade that too 250 GPH with 100 PSI.
 
#18 · (Edited)
Jonathan, my day job has gotten out of control this week but, I have slowly gotten my arms around it again. If you can send me a PM with a couple of days when you are not flying (and we are both awake), we can use a product called Teamviewer to meet and interactively explore some of the build models before you actually spending money on parts. It is easy to throw away alternatives in a simulation rather than real parts in real life. :)

In the FWIW bucket, Teamviewer is a commercial screen sharing tool for business that is free to use for hobbyists. It has screen sharing and audio among other features that make it attractive for this type of collaboration. You can explore their product and what it is about at Teamviewer.com.

As a passing thought, methanol is not a good fuel for a street driven vehicle. It is great for a race car. Ethanol in one of its variants from E85 to E99 is a much better street vehicle choice because it will be less aggressive about attacking fuel system components and deliver most (maybe 80% or so) of the methanol performance w/o the headache of dissolving your fuel system and going to the gigantic injectors.


Ed
 
#19 ·
Hi Ed, thanks for helping me with the engine simulations 😁, takes a lot of guess work out of it for sure, truly amazing tool.

I have downloaded Teamweaver app to my laptop and will be in touch soon to coordinate a time.

The engine is in final assemble stage at the moment awaiting final Cam phase decision.

Thanks Jonathan
 
#20 ·
Hi guys not much physical progress last two weeks as I've been away working although a lot of learning has happened on my part Thanks Ed!!

just got back Home and have gifted my 5 year old Mazda pickup (3.2 turbo diesel 6 speed auto) to my son, so i bought a new Ford ranger it has the same new 10 speed auto of the F150 but with a little 2 litre Biturbo engine the turbos work sequentially !! 210HP & 368 ft lbs torque quite impressive go Ford :)

hope to get back working on the Nash in next few days
 
#21 ·
Hi guys well progress has been very slow with lots of interruptions... I had an oil starvation issue some time ago which damaged my cam journals so i had my machine shop clip the top of the heads then line bore the cam journals, (since found clip in shells Available hahah ) this of course lowered my cams in the heads and created some geometry issues.
so i got a 9/16 end flute and made a sleeve to align and protect my lifter bores, not having a mill i used my Bench drill press and measured each bore individually then the process began, it took about 3 hours to do all 32.
I then had the valves tipped to be all the same exact length so this gave me good clearance compared to a compressed lifter on base circle,

have done all that I'm now doing the cam Phasing, this is my first time to do this (before the cams were just installed straight up dot to dot.

Ed was kind enough to run some Dyno simulations for me and the required centrelines for my cams came in at 115 exhaust and 110 for intake...i was able to get the Lh exhaust set at 115 ok but the Intake is at 111.25 Im using the MMR sprockets and gears but just can't get it to 110deg (similar to Cloyes) I could get it to 110 deg by filing ether the Key or the keyway of the gear..any preference for that?

CAMS are comp cams XE270AH-114 106 403-9

my current numbers

INTAKE
IVO 2.5deg BTDC (@.050 lift)
IVC 46.5 ABDC (@.050 lift)
@50 thou before max lift 74.5
@50 thou After max lift 148
so 222.5 divide by 2 = 111.25 CL

EXHAUST
EVO 130.5deg ATDC (@.050 lift)
EVC 2 deg BTDC (@.050 lift)
@50 thou before max lift 154.5
@50 thou After max lift 75.5
so 230 divide by 2 = 115 CL

Im just a bit worried i have messed up here because I have read Ed's cam phasing posts with interest and the rule number one for Boosted engines is 5-10 deg Negative overlap...clearly in the above scenario I have 1/2 deg of overlap and thats at .050 lift so there is way more than that seat to seat.

Guidance Please :)

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#22 ·
Jonathan, the -10˚ overlap target is primarily to help PD blown engines. As you tighten up the overlap number, the idle vacuum will drop low enough that vacuum sensitive components will begin to not work. The most significant of these is the idle bypass diaphragm. When it fails to open the boost bypass valve, the blower overheats. The overheating will eventually cook the seals and cause physical contact between the rotors themselves and also the case damaging the blower.

For turbo cars the overlap target produces different challenges. With the excellent low lift flow 4V heads have when both the intake and exhaust valves are open at the same time the engine can exchange exhaust gasses and incoming charge. The exchange direction depends on which side (intake or exhaust) has the lower pressure. One direction you supercharge the atmosphere and the other you dilute the incoming charge with the byproducts of combustion — exhaust gases. There is evidence that small amounts of exhaust dilution of the incoming charge can have positive benefits. Generally speaking for performance engines less is more.

With respect to the 110˚ C/L target and the 111.25˚ closest result you can achieve wit the MMR sprockets, I would not worry. The difference is all but indistinguishable. I definitely would not file the keys or keyways to hit the target. The upshot of filed keyways is down the road unhappiness. You want to maintain the most intimate fit possible between the key, its keyway in the cam and its keyway in the sprocket at all times. If you really want to clean up the 1.25˚ difference I would attempt to find some of the now out of production Cloyes 9 way adjustable secondary sprockets from Jegs, Summit or other retail sources including eBay. For a small change like you are chasing sometimes you can get the results you are looking for by swapping sprockets side to side. The production tolerances for those gears tend to be rather generous.

BTW very nice looking porting job on the heads Jonathan. That is a lot of effort you put in there. Very good looking job!


Ed
 
#23 ·
Hi Ed thanks so Much again for the great explanation and giving guidance that I’m on the right path.

I also have another option on the intake at about 108.5 CL I believe that may give me tourque a bit earlier....

Not thrilled with MMR gears ...no instructions at all.

I have a lot of work in those heads and figured it was worth saving them.

I hope to finish the can phasing today as I’m off to work Monday, I find it difficult to pick up where I left off on return.

Jonathan
 
#24 ·
... I hope to finish the can phasing today as I'm off to work Monday, I find it difficult to pick up where I left off on return.

Jonathan
Glad to be able to help Jonathan.

I know the challenge in restarting a semi-complete cam phasing job. I don't recall if I gave you one of these worksheets but if I didn't her it is now. It is pretty straight forward stuff but provides the cookie crumbs sort of path to allow you to see what you have done and where you were headed when you set the tools down at the last break. It uses MS XL as the engine to run the sheet.

Ed
 

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#25 ·
Hi Ed thanks for the worksheet we did a bunch of them but here is the final rendition.
in the end we were able to make it within 1/4 degree of 115deg CL exhaust and 110 deg intake :)

i made an error and filed too many teeth from my primary chain adjuster so I came up with a simple 5 minute fix...a piece of T6 thick wall aluminium tube 3/8 long slid over the push rod ...works great whew !!
View attachment 169313 View attachment 169315
 
#26 · (Edited)
Great job on bringing the cams to heel, Jonathan.:)

Here is a more robust alternative to the spacer on the ratcheting device, from Joe Goffin's thread. It is easy to do, very robust and just plain clean, click here => Primary Tensioiner Fix. The length is 0.200" or 5.08 mm.

When you disassemble the tensioners be sure to keep all the 'little hardware' from the bottom of each piston well paired up with its original tensioner. It turns out Ford uses different valving on the right and left tensioners.

Ed

p.s. In addition to being side specific, there is also a top and bottom to the valving be sure to put it back top side up if you take it out.
 
#27 ·
Hi Ed thanks for the compliment.

Ok I will definitely try Joe Griffins Fix....when I studied the Damage to my Cam journals the front journals of the exhaust (drive cams) left and right bank were significantly damaged as compared to the other journals and i believe it was from the overtightening phenomena of the tensioners with chain stretch at high RPM.

Oh well i won't have that problem again.:)
 
#28 · (Edited)
The over tensioning of the chains is definitely a significant contributor to the problem, Jonathan. Their is also another reason the front journals on the exhaust cams get beat up more. It is attributable to the tug they get from the primary drive chain. The front journal on each exhaust cam has to sustain the continuous tug from the primary drive chain to drive both cams on that head. You can substantially improve and extend the life of the cams and cam saddles in the heads with the use of an oil additive called ProLong <= clickable. You can buy it in gallon jugs for about half the cost per ounce/ml or less, that you pay in the 12 oz bottle. I think a gallon is about $65 on Amazon.

I first ran into this additive several decades ago at a track somewhere on the east coast. I watched the demo in the manufactures area and was mildly impressed but suspicious. I bought a bottle just to try in the car. That afternoon on a qualifying pass we blew a hose end off the oil line to the filter somewhere in second gear. Amazingly the oil didn't get under the tires! Once what had happened became apparent, at the end of the track, I was convinced the engine was dead.

We began the tear down when we got back to the pits and discovered two things I never experienced before. We pulled the blower off and began to disassemble the top of the engine expecting the worst. My first surprise was the fact my fingers could not hold a push rod or grip a roller lifter to pull it out of its bore, I had to use a set of pliers. The lifters were not stuck, they we just so slippery my fingers could not grip them. After the pan came down I began the job of breaking the rod bolts loose to push out the pistons and see just how badly we had killed the rods and crank. The first bearing came out looking brand new. In fact every rod and main bearing looked the same! I was astounded and became an instant believer in ProLong after that experience.

The only downside to the additive it is you can not use it in a new engine until the rings are seated - it's just too slippery. If you put it into a new engine you will likely never seat the rings. Seat the rings first, put in the Prolong and in particular for OHC engines it will provide an extraordinary protection for the cam and cam saddles in the head. The use of the additive is even more beneficial if the car sets for days or weeks between firings. The slippery just doesn't go away!

Ed
 
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