Guys with "built" (forged) engines
 

How many of you guys with forged bottom ends just tossed the pistons and rods in with little to no machining?

i have been interested since i have been hearing from most here that they havent balanced the engine internals and have been using it for XX years.


i would love pistons and rods in the short term but the balancing and machining costs in my area cost more than the parts which breaks the budget. on the inverse im not going to toss some gang parts in and blow shit up in a week.

Matt

Bad idea, unless you are in cuba, and have no choice. Gotta plan for the machine work as well.

I consider this notion a complete waste of time. Do it once, do it right, do it white.

the bore and balance is cheap compared to everything else

I just threw SBC parts in my motor and it ran. I did not even bolt anything down.

I remember there being a thread on what machining is reccomended, but i cant find it with the search.

if you have done machining what have you done, what is needed and what is gravy?

if you just do a bore/hone and a full balance thats not too bad... but the builders here are slinging all of this crap around about high boosted street builds.

A simple crank balance and polish should cost $120-$150 up here in Canada. Then it's up to you how much further you take it. You can balance everything or match it as closely as possible by weighing everything. A bottom end done like that should spin to 8k without any problems.

Ignore what all the "builders" are saying. Just bore/hone, balance/polish the crank and balance your pistons, rods and rings as closely as you can my mixing and matching. You can tKe it one step further and take material off the underside of the piston in tiny amounts to match it perfectly. Anyone charging you more that $30/hole and $150 for the crank is charging too much n

the balancing quotes i have been getting are in the area of $350 and bore/finish coming in at $45 per hole ($180 total)

polishing the crank is necessary, or is that gravy?

so if i essentially wanted pistons and rods so i can toss some real boost in it with a stock VVT head i would be looking at:

-pistons
-rods
-bearings
-head gasket

-balanced
-bore/hone

everyone here is trying to add line-hone @180$, knife edging at $250 (iirc) and some weird tempering and crap to the block.

-Matt

I got bore/hone w/ torque plate and line bored for $325, was told knife edging was overkill for a street car.

Also, so long as you're doing all this get:
new water/oil pump (with fancy gears, of course)
full engine gasket set
arp head/main studs
belts/hoses
coolant re-rout

Then, once again while you're in there:
headwork
valve seals
fancy valves/springs (I'm trying to resist doing this)

And you'll be 4-5k in the hole with the rest of us!

the "while your in there" thing is the whole reason i made this thread.

headwork, fancy valves and random useless shit like that pushes most builds to the 4-5k range.

i want to take my GOOD VVT engine and just put basic pistons and rods in. keep costs low for other things that fail when im racing this summer.

lol @ Canadia
lol @ spinning a Miata to 8000rpm. I'm just a layman, but I've seen my engine beat the turbo to death with vibration at <7k and would never go higher with this motor.
I agree with the cost/benefit ratio. Hit the big stuff that make the engine reliable and take that last $1000 you'd spend on removing material and porting to the suspension fund because I promise you'd get more bang for your buck out of half a set of Xidas over 10hp from a p&p.

Lol @ Hustler, I've been revving my engine to 7800 for 4 years straight, with no broken pumps, valves, throttle bodies, NOTHING. The VVT engine does in fact, like to rev.

Just do a basic balance, matching things up with a decent scale as best as you can. For a street car, full balancing and blue printing is a little over kill. Get the cylinders bored and honed. Maybe polish the crank if it needs it. Take a dremel to the cylinder head. Just do a gasket match and knock as much of the casting marks out as you can, nothing serious. All that takes is time and a few cans of brake parts cleaner to get the shavings out. You don't even have to remove the valves to do that one.

I'm going to get berated for admitting this, but I only put rods in my car. I blew a headgasket, decided to pull it, put a new gasket in and eagle rods. I reused my stock pistons, bearings, headstuds, etc and did no machine work at all. I just put it all back together and I've got probably 10k on that motor that's seen up to 18psi without any complaints so far.

I actually have a few questions that are somewhat similar to this. I'm looking to do a budget build. (I.E. student budget) Ive got a torn down 94 block that im looking to build. What are your thoughts on forged rods, everything else stock and a complete rebuild?

I dont have a turbo as of yet. but I'm looking for a trackable 240 hp down the line. Thoughts, Suggestions? Should I hold out for some pistons while I am at it? will stock 94 pistons hold to 240 safely?

Edit: ^sort of to the extent of what hes done. Except with machinework and a homebrew balance job.

Lol @ you, actually. There is a confirmed intake camshaft harmonic that will destroy the #1 intake valve seats if you run the motor at 7500+ for any sustained period of time. There's a local CSP car that destroyed 4 heads last year due to excessive sustained RPM - they dropped the rev limiter down and stopped hammering the intake seats out of #1 immediately.

My limiter is set at 7400 for a reason.

You must hone the motor, that's not optional. It is HIGHLY recommended that you bore the motor, unless you are having custom pistons specifically created to match your bore sizes with the proper wall clearances. Start with a running motor and nothing else is needed, IMO - neither of my built motors had any additional balancing done beyond matched pistons/rods.

I have datalogged WOT sessions of 110 seconds. Literally WOT for 110 seconds on 5th gear. Several of those were at 7500-7600. Granted, only one such datalog. Do I stay at 7500+ for more than a few seconds each time? No, I shift. I first installed my MS in July of 2006. 5 years later and this engine is still here.

How many times have I gone above 7500? If only twice per day (way more), then in 5 years, and if only lasts 1 second every time, that's roughly sixty minutes spent above 7500rpm.

Maybe the USDM engine is different, maybe you track guys alter something but don't share, I don't know. My own engine has exactly Z E R O failures in the 5 years of being MSed and being pounded a little too much.

We all know the story about Bill's car.

First, it was "overheating" each time.
Then it was the VVT that was switched on at the setpoint with the TEC2, rather than progressively retarded and destroyed the head.
The the Hydra was fitted and now its the sustained high-RPM operation that causes the failure.

So what is it?

IF the bores are in very good condition you can get away with new rings and a HONE.
Said hone can be a DIY job using a brush hone. The hone is needed for the new rings to seat.

www.brushresearch.com

There is some technique to it...

You NEED to hone the engine at the least

Was said 'sploding head with aftermarket valves/springs? I have +1mm supertechs all around with the single spring and titanium seats. I was told that'll do 8k without problems by a cam shop and I believe FM as well. Hammering through the head sounds like a lash adjustment issue to me. Either that or they cut the seats too much.

IMO if there is no loss of cylinder wall material you can get away with a hone, get the crank polished, and have the head and block mating surfaces checked. That should come in pretty low on the price range to have done or like others said hone it yourself and have a shop check the head, block, and polish the crank.

For balancing if you shop around you can find a good price I would think. The shop balancing my rotating assembly (including clutch/pp/flywheel harmonic balancer) is getting $200. I really feel getting everything balanced is important for an engine that is going to be pushed hard but if it is just a toy that won't be tracked then you could pass on it.

It was the RPM, not valve lash or something else. It was always the number 1 intake valves - same failure mode in 4 different heads with lots of stuff changed except the RPM.

It's the sustained RPM.

-Jason Cuadra did 15 seconds of math and dispelled the idea that the rapid snap from full advance to full retard was increasing the cam RPM enough to pound the seats - IIRC he said that at most it was a 150rpm increase
-Once they fitted the Hydra and had another failure, someone spoke with the old owner of Integral Cams, who said that there's a harmonic on the VVT intake cam at 7500.
-Bill dropped the RPM to ~7400 and hasn't toasted another head that I know of.

Maybe the EUDM VVT cam is different - I know the JDM VVT motors have higher compression.



You can get away with just a hone - assuming the wall clearances are still within spec. You cannot just hone and slap slugs into a motor without confirming wall clearance.

If your building a motor its worth doing everything you can to make sure its right, I'd much rather over build than build twice. Its cheaper that way and less time involved.

This is only on the VVT head, FYI. '99 intake cam can be spun past 7500 safely AFAIK.

The USDM VVT intake cam harmonic is one of the big motivators for me to get a set of "mild" cams into my motor - I could really, really use another 400-500rpm in 5th to avoid 5-6-5 shifts at a few tracks.

It's Canada.

And because your turbo system can't handle the resonance above 7k RPM doesn't mean the engine can't. I'll happily rev my motor to 8k+ with the Rotrex, and NA motors will run up there all day long.

As for the head work, I agree. If I were to do my build over again I would have done the same stuff to the bottom end but on a 1.8L and throw a VVT head on it and call it a day. You can very quickly start spending too much money because "well I'm doing X already so I may as also do Y and Z while I'm there"...

My head has supertech valves, stock BP springs, my own cams and MazComp SUB. Plus porting/polishing.

Sav: re: "mild cam" - you may want more duration but with more gentle closing-acceleration profiles. You might want to talk to Dema Elgin at www.elgincams.com

Having said that, the problem may not lie in the cam profile...

Did the dude who lost several heads, try stiffer or dual springs, or lighter valvetrain parts? Because a "resonance" is in the mass (valve+lifter) and spring combo, and is excited at a particular RPM (e.g. 7500). You increase the resonant frequency by reducing mass or increasing spring rate; dual valve springs break up the resonance into 2 smaller ones.

Maybe you could do what Rebello does on some heads, which is to shim up the springs to get a bit more RPM capability.

Side question whil i have a thread started... do the VVT oil pump gears have the same issue as the earlier pumps which suggest using billet gears to avoid shattering at high power levels?

I just keep running into new info here lately! I have experienced the hammered valve seats twice on my '99. The top end is all OEM except for some porting. I even decided not to rebuild that head again thinking something was wrong with it. I never could figure out what the hell was going on, and people looked at me like I was some sort of freak when I brought it up! And ... I've been running a 7500RPM redline with the need to ride it occasionally for autocross!!!

Jason, why a more gentle ramp-down? To deal with the harmonic?

AFAIK aftermarket valvetrain parts are not legal in CSP, so I don't think he tried anything because he couldn't.

Again, only affects VVT heads.

I saw that you mentioned that.
What do you suppose is happening in my case then? I keep having to install smaller and smaller shims until the cam wants to hit the edges of the bucket. It's always the worst on #1 followed by #3, and always only the intake side. The harmonic issue is the closest thing to an explanation that I've heard. :vash:

No

Is a hone required if you are just replacing rods and rod bearings (reusing pistons and rings)?

What you know is indeed true, not allowed.

I vote for absolutely minimal machining if you are pinched for cash. Hone for clearance on the pistons, polish the crank only if it needs it, make sure the pins fit properly, and I'd even vote for just a valve lap to confirm seat. Spend your money on getting a good tune.

I spent too much on balancing, line hone, bore and hone with deck plate, valve job, et al, then the fucking asshole knocked the thrust bearing out of place during assembly and the whole thing got scrapped.

If the cylinder walls are in good shape. Are the pistons stock?

Didn't know the VVT block pumps were more resistant. Is it worth swapping my 2001 oil pump into the 1994 block I'm going to be using soon?

any chance you could have a brass valve seat or something like that machine fit into place that would resolve this issue?

i know that they do that for better sealing, but being softer i dont know if it would just fuck up faster....

Whoever told you this is wrong - there is absolutely nothing about the VVT motor/pump that would make it less susceptible to oil pump failure.

From what I've been told, it's not a good idea to remove/spin the pistons in their bores if you expect the rings to continue to seal. If you disassemble the motor, expect to hone and re-ring.

Balancing the crank, flywheel and pressure plate as a single unit will smooth things out.

+1... But my engine is definitely "overbuilt".

Polish the crank unless you choose to knife-edge.

Clean up and port match the head. IMHO polishing the runners is counter-productive. I prefer to have the turbulence in the runners over the risk of boundary layer effects...

Keep in mind your turbo is nothing more than a force multiplier. The stronger and more efficient the foundation, the better gains you will see when you add the boost.

- L

There is another factor that has be looked at with Bill's car, the amount of time spent above 7500rpm. I don't know many road racers that will lay on the limiter for multiple seconds. I drove a CSP at Nationals last year and there were multiple times I laid into the limiter for long periods of time. A few times I even short shifted just to "save the motor" after reading about Bill's problems. The owner of the CSP car I drove has since changed to a 5spd and 4.1 and dropped the limit down to save the motor (all though after 1.5 years of abuse, the motor is still healthy with no leak down issues).

Don't reuse hi-mileage rings. Put new rings and hone it.

Pat found out the hard way. See his thread on m.net.

I'm of two minds.

First possibility: Resonance in valvetrain *at* the ("fundamental") frequency it opens and closes at 7500 RPM; solution, stiffer or shimmed or dual springs, and/or lighter valvetrain parts (e.g. shim-under-bucket).

2nd possibility: Resonance in valvetrain at 2nd or 3rd harmonic meaning, a multiple of the frequency it's opening and closing at, at 7500 RPM. The amount of excitation at the 2nd, 3rd, or higher harmonics, is a function of the aggressiveness of the profiles.

When your valve starts to open, this sequence occurs:
1- first part of lobe comes in, to gently reduce the lash to zero
2- valve is accelerated open
3- valve is at maximum opening *velocity* - it's opening wider and wider, and halfway up the lobe
4- velocity may be maintained for a bit
5- lobe/spring begins decelerating valve - spring actually does the deceleration, and lobe/lifter interface unloads a bit
6- valve reaches peak opening, this is zero *velocity*, and peak deceleration
7- valve continues its deceleration so that it begins to close (deceleration is actually acceleration in the closing direction
8- valve reaches constant closing velocity, and it's closing more and more
9- lobe profile begins to decelerate valve to soften its landing on the seat
10- valve reaches some low-ish velocity before it contacts the seat

The problem with banging seats I believe starts with too much peak deceleration in steps 5 6 7, so that the lobe loses contact with the lifter. This is float.

This is like a ski or motocross jump. If the ground drops away at an acceleration greater than 1G, gravity (or the spring), can't accelerate the skier/rider/valve down fast enough to keep contact with the ground. And the landing will be hard if the bottom of the hill on the other side.

The lifter loses contact all the way until the point where it's supposed to be closed, so the valve isn't decelerated in order to land gently on the seat.

So you can see that the acceleratoin/decel peak numbers are proportional to RPM. There will be a point where these peak numbers exceed the spring's capability to accelerate the mass down.

There's also a more serious, complicating factor. The spring coils oscillate up and down, and if this frequency coincides with the RPM, the spring actually momentarily stops applying force to the valve, at the worst time.

There's a youtube vid of it...

Going back to the harmonics. If it's not the frequency directly from 7500 RPM, then it could be the harmonics (multiples) of this fundamental, which is a function of how sharp the accel and decel ramps are on the profile.

Thinking about it some more, it seems not very likely; but lower peak decelerations around peak lift I think would still help, and so would landing velocity. A higher rev limit requires a softer landing and reduced peak deceleration at the top of the lobe, for a given RPM, so that you can run at higher RPM.

I also suspect that the purported cause, the term "harmonic at 7500 rpm" is a misnomer, the problem is probably "resonance" at 7500 RPM. Again I think stiffer springs is the easiest solution. Resonance moves up as the square root of the increase in stiffness or reduction in mass.

e.g. 21% stiffer springs, will increase the resonant frequency by 10%

I wanted to say this, by I also wanted to avoid being the physics nazi. :bowrofl:

Would 110k KM be considered high? I was planning to do just rods next off-season. I don't want to skip the minimum required steps, and I also don't want this to turn into a high end (dollar) build.

If you pull the slugs out of the cylinders, you must hone and install new rings. The rings get microscopic peaks and valleys as do the cylinders during break in. If you take the pistons out, you will never get them exactly lined up and you will have bad compression. Can you install rod bearings without removing the slugs?

100km is considered "high" IMO. If you remove the pistons and rings, you must hone and re-ring.

You can do rings, pistons, and all the machine work on a bottom end for under $2k including parts. Head refresh adds a bit of cost, assembly adds a bit more.

100k KM is not really that much. It's 62,500 Miles. 100,000 Miles on the other hand is 160,000 KM and that is getting up there.

dgmorr, if you know how do a leak down and a compression test. That will tell you a lot about the health of the motor. If it's healthy, just keep it at or under 250whp until you decide to build a motor. Throw some M-Tuned rods in, bore/hone, polish crank, OP gears and pistons of your choice. Don't need to go too crazy. While the head is off, check the valve guides for stickiness or looseness and if you feel like it replace the valve oil seals.

I said 100 kilometers, not 100,000 kilometers. The point was that if you are removing the pistons from their bores (which you are doing to install rods), you must hone and re-ring.

Valve seals are outrageously cheap, incredibly easy to replace, and you would be a fool to leave the old ones in place, ESPECIALLY if you have the head off the car.

I still want to know who told you that VVT oil pumps were stronger, BTW.

Points taken, thanks for the info.

The downside to stiffer springs is at some point you start beating the shit out of the cam lobes instead of the seats. Cams and springs, like a lot of stuff in an engine are (or should be) designed as a system.

I agree with your suggestion to talk with Dema about it. I'd also maybe try to pick TurboTim's brains as well... Jesel makes some pretty cool valvetrain stuff.

Gotcha. It looked like you said Miles.

My valvetrain was chosen by Maruhas recommendations. They use the BP valve springs on pretty much all of their cams up to 8.5mm lift. Apparently the spring works out perfectly for cams around that lift and can rev 8k+ without float when used in conjunction with solid lifters. They were fairly cheap too which was nice. In addition I bought some MazComp SUB lifters and used supertech lash caps at $4/ea. And my cams were custom grinds costing around $400 and have supertech SS 1mm over valves. All in all my head aside from the port work was extremely cheap. I also replaced the guides, shims and seals.

"Stock" Motors. Factory parts only.

The above makes the Trackspeed Engine seem like such a deal.

My motor "went" on Monday. Not sure the details yet but sudden loss of power under boost, misfire, increasingly blue smoke until about 2km later is was a nice cloud and then stopped. Still cranks. Haven't touched it in 3 days except to see if the turbo seals went and oil got into the intake - which it didn't. Since the car and I are fighting I don't want to see if for a few days until I'm ready to talk nicely to it.

I keep debating dropping in a $1000 dollar used motor or rebuilding mine slowly or buying a Trackspeed built motor.

I've rebuilt single cylinder 2 stroke bikes, modern 4-stroke motocross bikes and ATV's 8 times. Including gearbox and bottom ends. Still I'm not that confident in rebuilding a 4cyl. car motor.
With my rebuilds I did everything except the re-bore of 2 motors (the rest were nikasil lined and in good tolerance) What does the shop have to do for me and what cost and what can I do all by myself? Do I absolutely need to know how to use Plastiguage for example or other new to me procedures?
Part of me wanting to do my own build is to get the experience and say I built my own engine!
If I had more income Trackspeeds engine would be bought today. I may just save up over the next 6 mos. for that gem anyways

Tips, thoughts ?

ps goals are about 300 +/-20 whp..

I kind of wish I'd gone with TSE engine.

landrew.... its just a (physically) bigger engine.

Set your rings proper, get proper clearances with proper machine work and it will be fine.

Singles have cranks on real bearings, and no rod bolts or main caps. Crank bearing on multi cylinder engines seem to be named odly to me, bushing seems for fitting, that's a whole new area for me.

Being from Canada what machine services and costs did you have to pay for and how much if you dont mind telling?

Are you still a 1.8 or 1.9L now, and how do you like the 2871 .86?

TSE is on my list if/when mine/I does/do something stupid. CA sales tax is gonna suck...