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Turbo Engine Re-Build

24K views 170 replies 7 participants last post by  CrucialProspect 
#1 ·
New to the forum here, but always referenced it’s material. Little background info, I have a built and stripped down ‘04. Been running an ancient hp performance twin 50mm turbo through a built mvb 4r70. I’ve raced this car off and on for 10 years, and just two years ago I’ve decided to take it off the street completely.

Figured I would run a cold compression test at the end of the season. I figured if it was getting tired, I’d go ahead and do some upgrades. Engine was originally built in 2008. Kellog crank, Manley rods, -18cc diamond pistons, ported pi heads. Since then I’ve put on trick flow 38cc to bump compression, and a secret sauce set of bump sticks. I’ve only had 15psi through it, and it has been dead reliable for 6 race seasons.
Originally I had 190psi cold, within 10% all cylinders. Now I have 170psi average, with cylinder 4 at 125 psi and cylinder 8 at 135psi. I believe that’s all I need to convince me.

I hope to be able to keep crank, rods, heads and cams. I may change pistons for higher comp (I’m running 114 octane) if they don’t mic round anymore. Also, I’m tossing the block to go to the aluminum block for weight savings.

Since I’ve been out of the engine building game for this long, what is some current advice/tips/tricks? This engine was built when the terminator was the best out there, and cams were all re-grinds. I know the game has changed and the aftermarket has a solution for every problem. The same suggestions would be welcome for bearings, rings, gasket brands, etc. there are some upgrades I’d like to do such as mmr’s billet timing guides and maybe adjustable cam gears, but a lot of others that I probably don’t need. And as much as I respect other engines, It will stay twin turbo 2v 4.6!
 
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#99 ·
Little FYI. When you file your rings, make sure there are NO edges on any sides of the side of the ring you filed. You want to make sure after you install the rings in the ring lands that they move in and out freely, no hangs or snags. I too filed my top and 2nd rings at .028 but I’ll be around 35+ psi.
 
#100 ·
What are some pointers for locating ring opening position on the pistons? I had planned on the top ring at 12 o’clock and second ring at 6 o’clock. I just figured to keep them from being online, and keep the gaps away from the wrist pins, but didn’t know how important that was.

Are the support rails, oil scraper, and both oil rings as important in positioning?

Also, are the gaps in the oil scraper, rings, and support rail important? I noticed the rings above and below had a minimum gap of .015 called out, but none on the actual oil ring. Also, the support rails are compressed, so it’s pretty hard to measure them.

Good advice to file all corners on the rings, don’t need any sharp edges to score up the sleeve, or piston.

How hard are the rings to install? I planned on using a flat billed ring expander, but didn’t know how easy these were due to the material and thickness. Thanks for all the help so far!
 
#101 ·
There are multiple ring positioning preferences. There are a few things to remember. Once the engine starts all the rings rotate and at different speeds. Best advice is put it together with the ring gaps evenly spaced on the top two and 180 apart on the oil rails. Do not line up the expander parting line with any of the oil rail gaps. Use one of the billet piston ring compressors sized for your engine's bore size. If you call total seal they will make it to any bore size you want for about $35 or $40 if I recall correctly.

Using a tapered bilet ring compressor with some lube, the pistons will literally slide in with the push of your thumbs at 3 and 9 o'clock on the pistons. Keep the ring compressor flat and square to the block deck.


Ed
 
#102 ·
Thanks Ed. I would like to point out another potential issue I have yet on the main studs. The larger inner studs have a tapered thread, in which the nut engages the larger portion as it’s torqued down.

The issue I have is just a few threads of engagement on the stud itself. Simple fix, you would un-thread the mainstud to get the nut to fully engage the thread, but then you would be loosing the integrity of the stud threading into the block.

Which is the lesser of two evils here? I was able to get the nut torqued down, but it’s only threaded 2/3 the way on the nut.
 
#103 ·
Because pictures are worth a thousand words... Fixture Motor vehicle Automotive exterior Gas Vehicle

You can see the longer studs at the center, the nut has cleared the smaller 8mm thread, but has only 4 or so threads on the 10mm section.
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If this is indeed a problem like I deduce, would it be safe to back out the main studs a few turns in order to maximize thread engagement of the nut, while not sacrificing the thread engagement depth in the block itself. And if so, what's the best way to do so? Should I loosen all the mains and side bolts, run them out a few turns and re-torque to specs in sequence? Or would doing one single stud at a time in any particular order suffice?

Also, is there any reason the shorter 8mm studs on the caps have washers and not the 10mm studs? Would simply removing the washers on the 10mm studs gain sufficient headspace for what I need?
 
#104 · (Edited)
You need to have washers under both the inner and outer nuts. The reason you have the minimal thread engagement with the nuts is the hole depth in the main web. Someone drilled and/or tapped it deeper than it was specified in the Ford design docs for the block. I would remove the nuts and put washers on all studs. Spin the nuts down finger tight and then, using an Allen wrench back the stud out until it has two threads of stud above the top of the nut. With two threads of stud above the nut, begin to tighten the nuts once again in Ford's recommended sequence. You should be OK.

If you want, you can play with ball bearing sizes looking for a size you can drop in each stud hole to provide a positive stop for the stud as you initially install the studs in the block. The ball bearing is not used to provide an object to torque the stud against. It is only intended to provide a uniform positive stop as you hand install each stud so you don't need to back each stud out however many turn are necessary to get your two threads above the top of the nut after torquing.

The total thread engagement with two threads above the top of the nut is precisely what you want to shoot for. It will give you more than adequate thread engagement in the block. Something to consider is, if the stud wells have had the threads chased to the bottom of the stud well using a cutting tap, whoever did that potentially took material out of the block if they used a cutting tap. That potentially weakens the thread in the block. If they did you will be able to tell as you torque the nuts on the studs. The torque wrench will not come up to the torque value with a positive crisp click. The torquing process will have a spongy feel to the fastener coming up to its torque spec.


Ed


p.s. Always use ARP UltraTorque and do not get it on the underside of the washers
 
#105 ·
Good advice with the bearings, sounds a lot like I’ll be loosening all the studs and re-torquing them! I didn’t figure I’d get it right the first time, it seems like without knowing where they bottom out on a positive stop you’d never know where the threads would land on the nut. I also have to dig through my old parts to make sure my oil pickup stud will thread onto the end of the one main studs. Thanks again!
 
#107 ·
Let see now, what was it that Forrest Gump said,??

Oh yea, "Engine building (sic) is like a box of chocolates, you never know what you will get"


Ed
Interesting he said chocolates, like no matter what, it's still gonna be pretty good!

On a side note, is anyone still using plasti-gage to check bearing tolerances? By using math on the crank and rod journals and bearings it seems obsolete, but I just wasn't sure this old school trick is still being used.
 
#112 ·
To show that I actual read other threads and am not the only star in the universe, I recall others with similar questions and can state these facts.

I believe the called out tolerance from one thread, quoting Mr. Mihovetz “keep that sh*t tight” .001-.0015. While I have no experience with the aluminum blocks, the cast blocks called out a different tolerance. I also used a slight film of 30w motor oil, as per the Hypand rebuild book during the tolerance process.

At this point, I know I’m having to loosen all the main studs to gain more thread under the nut. I also have another plastigage set that reads lower tolerances. The red I used is .002 to .006 and the green is .001-.003.

I think this would be a good opportunity to pull the crank back out of the block, clean off all oil on the bearing surfaces, and re-check tolerance using the finer plastigage. I feel like I had 2 fatal flaws this past time.

1. Thin film of oil on bearing tolerances while checking, there is an opportunity for it to skew results.
2. Because I was unaware of the tighter aluminum tolerances, I used the cast specs to select the plastigage.

My only fears now are these studs have been torqued twice now, this will be the third time to re-check, and 4th time to final reassemble. I have a fear that there will be an amount of stretch that plays in a factor.

My other fear is the use of assembly lube versus straight weight oil, there will be an amount of turning to be done with the crank in terms of timing and torquing rods, and it may be a few weeks before is time to crank and fire, so I want the insurance of the assembly lube. At the same time, I don’t want a quart of it clogging everything up when it’s time to break in.

Sorry for the novel, but although I have experience with building engines, I’ve never built one to the high precision and tolerances of this caliber (if that’s not already obvious) I hope these questions aren’t redundant and I’ve been searching all the build threads to answer what I can! I hope erring on the side of caution will do me better in the long run!
 
#113 · (Edited)
You want to shoot for a 0.0018" to 0.0025" clearance, Matt. While you can run up to 0.003" relatively safely you begin to change the delivery of lubricant to different parts of the engine.

Think of the oil system as a controlled leak. Whenever you increase clearance at one of the leak points you increase oil flow at that point at the expense of oil flow elsewhere in the engine. This can be mitigated by the use of something like a GT500 pump (which I would recommend no matter what) because the pump has such a significant capacity reserve that a small increase in flow at one location will not impact others, the pump just flows that much oil.

Here is a pretty good video from Melling on the effect of bearing clearances on oil flow, click here=>
Once the rings are seated be sure to use Prolong. When you assemble the engine put a drop, no more, of Prolong on each cam bearing journal and smear it around the journal.

Ed
 
#115 ·
Ed, I've got that pump from boundary already as per your advice, just wanted to see if my game plan seems good or unnecessary.
I had forgotten you were using that pump, Matt. You are good to go. The extra clearance on #3 won't make a difference with that pump. A good place to be is over 0.002" and under 0.003". The rule of thumb is 0.001" per inch of journal diameter. Our mains are 2.650 diameter journals.

Ed
 
#116 ·
Re-torqued studs today with at least 2 threads showing, trust me I was holding my breath the whole time!
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So not the mains are tackled, until I have to do the pickup tube. I'm going to attempt to brake clean, and atf wipe a cylinder, apply total seal quick seal and try my hand at installing rods. I plan on using the green plastigage dry first, then cleaning off and assembly lube and install. Wish me luck!
 
#118 ·
Ed, I know you said one end of the rod should have a heavier chamfer on the big end. I just can't differentiate. I'm going to go with implicitly sake and make sure all the labeled numbers on the rod facing forwards.
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Material property Rim Circle Auto part Electric blue

Also like you stated, I plan on putting top ring at 12, second ring at six, the top oil rail at 10 expander 7 bottom rail at 4 and support rain at 2. Should give me even space between all rings.
 
#121 ·
Quick seal applied, hazy green, so it's clean!
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Lesson learned, install the very bottom ring first, (the one that's a pain to install) the dimple I believe faces down to keep it from rotating. The dimple locates in the wristpin hole.
Next the expander ring, because as I've learned, the inside has a taller ledge, next install the two rings above and below. Once all 4 rings are in, it's almost impossible to reposition the opening in the rings.

Once the top two rings are installed (2nd ring has a dot that faces up) and the top ring can be installed both ways. Line everything up, lightly install in piston compressor with a small dab of 30w oil and tap in. The was a small audible pop when the piston was fully seated in the bore, piston rings sealing against the cylinder wall.
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Using plastigage, the bearing tolerance was measured at .002. Removed plastigage, used assembly lube on the bearing faces, and torqued to 60ftlbs.
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#122 · (Edited)
TotalSeal top rings usually have a dimple on them (like your second rings) indicating the topside of the ring, Matt. Make sure yours either do or do not and proceed accordingly. When installing rods, I prefer to use a rod bolt stretch gauge and record the torque necessary to hit the rod bolt stretch that ARP recommends for the bolt you are using. While the torque only approach will work the stretch approach guarantees everything is as it should be. A rod bearing oil clearance of 0.002" is correct. Remember the 0.001" clearance per inch of journal diameter guideline.

Be sure your pistons and rings are generously lubricated in and around the ring lands or you will damage the ring lands at first start.

While there is no shortage of sage explanations about the optimum way to position the rings on the piston at assembly the simple fact of the matter is that they rotate in service and will be different than they were when you assembled the engine. Given that, then you want to assembly the ring s to the piston in such a manner as to not line up ring gaps making it as difficult as is reasonably possible for combustion gasses to have an easy in line exit path to the crankcase. Given that there is no optimum orientation the following pic is probably as good as any;

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When you install the oil ring spacer ring (the tough one to install) try starting one end in the oil ring groove an then "wind" the rail into place. As the end of the ring comes up to the skirt on the piston take a tin can lid off a can of pet food or other tin can and place it between the oil rail and the piston to protect the piston from the sharp edge of the spacer ring as you "wind" it into the oil land.

Ed

p.s. Keep the oil rail support ring's (the tough one to install) gap away from the pin bore. In the pic above the correct position for that gap would be 12 O'Clock not 9 or 3 O'Clock. Putting the gap in the pin bore defeats the reason for using the support rail in the first place. Additionally in the which way is up discussion, dimples on spacers and piston rings usually indicate the top side. Contact your ring manufacturer and ask him how he wants you to place the dimpled oil rail support ring, he has provided you.
 
#125 ·
Still have a v6, waiting on the last two top rings from Gibtec, but everything good up to this point!

Got the cobra engineering timing studs and the cobra engineering remote oil mount installed.

Need to make my last order to summit racing, I decided against the .036 head gaskets and opted for .040 due to ship time. Should put me a tick under 10.3:1 compression. My last setup used .030 and lower boost, I plan on taking up that extra space and filling it with more boost rather than static compression.

Also need a rear main seal yet, any suggestions? They seem very vague on make and model, quite an interchange!

After I get the last two rings, filed, and pistons installed, I’ll move into the boundary oil pump and pickup tube. Other than head gaskets and a rear main, it’s ready to be buttoned up and installed!
 
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