mumzer

sacott...how does one mount the front block off plate on the lower housing? i cant see how this block off plate could be installed and sill allow the lower housing snout/power steering bracket to mount up....

thanks...

TonyG

Scott..

Pretty funny how none of your engines have had bolts come loose or things break....

Because John Milledge and I had a good laugh about how the opposite is true. In fact, after I told him that I had no balance shafts, he asked me if I had broken the a/c tensioner (with a smug tone) yet. "I said yes, how did you know?"

We both discussed about the necessity of making sure all the fasteners are locked down and using custom tensioners for the accessory drive belt.

So either you know something we don't, or your cars have the exact same type of vibrations (or the machine ship the John Milledge uses does't balance engine properly... which I would find impossible to believe).

My entire reciprocating mass was balanced with the flywheel and pressure plate. And there are still vibrations. They not the result from imbalance, but rather from the nature of the 4 cyinder firing order (the 2nd order vibrations).

The vibration is noticable in my car. It's pretty easy to notice since the factory setup with the balance shafts is silky smooth (unlike a 4 cylinder engine)... thus it doesn't take much to go from silky smooth to to feeling like a normal 4 cylinder.


I don't regret removing them for my application, but I woudn't do it for a stock engine.

TonyG

Under Pressure Performance

We have two different kits. If you delete the power steering, then the complete kit is $175.00 - If you want to retain the power steering, then the kit cost is $275.00 which includes a modified lower pump mounting housing. There is a $100.00 core charge for the housing which is 100% refundable upon receipt of your good usable core. All prices do not include shipping.

The kit includes everything you need for installation including necessary factory O-Rings, stainless hardware, shaft removal components, and a bottle of Loctite 574 (enough to do a total rebuild of your engine)

Hope this helps.

David Floyd

I had an ac tensioner break on a stock engine, so deleted balance shafts can't be the sole cause of this problem.

Under Pressure Performance

Tony, you wrote...

"Pretty funny how none of your engines have had bolts come loose or things break....

Because John Milledge and I had a good laugh about how the opposite is true. In fact, after I told him that I had no balance shafts, he asked me if I had broken the a/c tensioner (with a smug tone) yet. "I said yes, how did you know?""

Well, part of what may be different is that none of the engines that I am referring to have A/C, (no A/C on race cars) but I have sold many of these kits over the years and I have not heard of anyone losing/breaking pieces. That is not to say that is has never happened without my knowledge, but I have not had any complaints so far.

As I have mentioned in a previous post, in a solid driveline configuration there should be attention to certain areas which could be prone to failure, but these areas should be addressed regardless wether or not you run the balance shafts - For example, the oil pickup tube comes to mind.

It is also worth noting that there are more four cylinder engines in the world that do not run balance shafts, than there are those that do. Of course I do not mean for that to be an answer to any question, but I only offer it to demonstrate that there are many engines that run for many miles without parts falling off.

As I discussed in a previous post, there are several factors that determine how much internal dampening and engine has, which has a direct effect on how much of the vibration you feel.

More likely than not, your vibration is the result of reduced rotating mass, which will not mask the inherent 2nd order harmonics as well as an engine with more rotating mass.

You also wrote...

"We both discussed about the necessity of making sure all the fasteners are locked down and using custom tensioners for the accessory drive belt."

Again, we are not having this problem, but then again, we are not running A/C. As far as I know, those running this kit with stock engines with A/C have not been losing parts either.

"So either you know something we don't, or your cars have the exact same type of vibrations (or the machine ship the John Milledge uses does't balance engine properly... which I would find impossible to believe)."

All things are possible. Unlikely, perhaps, but impossible, not necessarily.

"My entire reciprocating mass was balanced with the flywheel and pressure plate. And there are still vibrations. They not the result from imbalance, but rather from the nature of the 4 cyinder firing order (the 2nd order vibrations)."

Yes, these vibrations are inherent in virtually all inline four cylinder engines. The problem of rough idle and harmonic vibrations are nothing new in the four cylinder world - For example, virtually all mid-eighties Mazda four cylinder engines could easily be mistaken for small tractors. The Toyota, Hyundai and Ford engines of the same vintage had similar problems, even more so when coupled to automatic transmissions, as automatics usually idle a bit lower in gear and vibrate quite a bit, still, they held together.

You wrote...

"The vibration is noticeable in my car. It's pretty easy to notice since the factory setup with the balance shafts is silky smooth (unlike a 4 cylinder engine)... thus it doesn't take much to go from silky smooth to to feeling like a normal 4 cylinder."

Absolutely. The only thing I will add is that the balance shaft removal has less of a negative effect on stock engines with full weight cranks, rods, pistons, flywheel, and clutch, even less noticeable when the factory (stock) engine and transmission mounts are used. Generally speaking, you will notice very little difference on a totally stock engine if you remove the balance shafts. That said, the more you move from stock, the more pronounced the effect, but in an all out race car, the 2nd order harmonics are the least of the noises and vibrations you feel.

You wrote...

"I don't regret removing them for my application, but I woudn't do it for a stock engine."

While I understand your point, the ironic thing is that the harmonics are much less pronounced when the balance shafts are removed on a stock engine.

Are you still running the factory engine/tranny mounts, or do you have your driveline solid mounted?

Thanks for your input and insight, as always it is appreciated.

Thanks for reading.

mumzer

crap...i figured...i wish you had made this clear when i bought the parts as i do intend to retain power steering....oh well...i have a tig machine and plenty of aluminum lying around...do you turn a plug and tig it into the bore of the lower snout?

thanks

the_jester

i am new to the 951 but i happened to come into a 86 951 with only 40k miles. but it needs some engine work, which i am almost done with, i was worried about getting the balance shafts lined back up, but now im thinking of just getting rid of them, if i can cut some rotational mass. im not worried about a little vibration. just a coincidence that i also own a eclipse that had the shafts removed

mumzer

by the way.... i still need to oil the turbo off the upper shaft housing....do i sinply leave the bearings inplace and tap the oil source as per the stock 951?

968 block, so i will tapping and running a -3 braided oil supply line.

thanks

Under Pressure Performance

mumzer,

I always ask if the power steering is going to be retained when someone buys a delete kit. How recently did you buy the kit from me? Quite honestly, I do not recall your order based on your forum username - Did you email or call in your order?

In regard to the lower housing, you can machine a plug and weld it to accomplish the same goal. Sorry if there was an oversight on my part, but I make it a habit to always ask about the power steering.

mumzer

scott...we talked at some length about this item and turbo choices...at the recommendation of alan coleman to whom i believe you supplied a custom turbo.

i cant recall the timing, but it was quite a while ago...you were out of stock on the balance shaft parts at the time, and it took quite a while for me to recieve the parts.

im not worried about it...i can simply cut up a shaft and make a plug that uses the stock seals.

what are you reccomendations on turbo oiling with the kit...the o ring is of a size that seems to require the bearing be left in place...is this correct?

or must i pull the bearings and take the oil supply from some where else?

thanks

Under Pressure Performance

The kit includes the appropriate shaft spacers. You leave the shaft bearings in place. The turbo is oiled using all the factory connections.

Going back to when you bought the kit, didn't you mention that you were thinking of removing the power steering? I only ask because if I knew you were going to keep the power steering I would have told you about, and sent the other kit. Either way, we will make things right and get you on the right track. If you have your housing off, feel free to send it to me, with one of the end covers I sent you, and I will make things right.

Hope this helps.

mumzer

thanks scott...im really not worried about it...i appreciate the offer.

thanks for the clarification on the bearing placement.

jonathan

trymorris

Have an 84 na I class racer I bought about 4 years ago. The shafts were not connected
before the start of last year and I don't know how long it ran that way before I bought it. Noticed a leak on the fuel rail. It had several fatigue cracks around the mounting legs. Did rod bearings before last season and found the oil pickup tube cracked almost all the way thru. It's failure would have been ugly. The vibration occures at several specific rpm ranges, one I believe is in the high 2000 or the low 3000 rpm range, about where you are on highway driving. The other is in the 5000 range. If you race and spend all your time up and down the rpm range and well above 3000 rpm, it may be ok but you would want to check or reinforce things like two failures above often. Also heard that the bell housing reference sensors can be ruined by this vibration but have no experience.

M758

Personally I don' t thing the risks of cracked fuel rails (could result in fire and burned car or worse) or broken pick-up tubes (could result in motor blow-up) are worth the 2-3 hp gained from no balance shafts.

Now If you are re-balancing and lightening all the other parts of the engine then it may be good thing to do. The shafts do cancel the secondary harmoinics so changes to reciprocating and rotating masses will change those secondary harmonics and therefore the balance shafts should be adjusted to compensate properly. Of course how much is big mystery. It is not THAT hard to figure out, but you would need and engineering analysis to figure it out. In that case no shafts may be better.

Under Pressure Performance

Fuel rail failures on the early cars have nothing to do with the balance shaft removal. The fuel rails on the early cars are known for failures and even split at the seams.

In addition, pickup tube failures are far from isolated to removing the balance shafts. The pickup tube failures "can" be accelerated by the combination of removing the balance shafts AND solid mounting the driveline, but these failures still would eventually occur with the shafts all other things being the same. Part of the problem is the design of the pickup tube, and another issue is the material work hardening over time.

There are many myths and misconceptions regarding balance shaft removal, and these myths are constantly perpetuated by theory and speculation. I have tore down and built enough of these engines to know that the removal of the balance shafts will not directly "cause" such failures, but will accelerate any inevitable failures. To prove my point, take a brand new pickup tube and have it Rockwell tested, then take one from an average mileage 15-22 year old car and test it too - Or, take a brand new pickup tube and put it in a vise held at the flange and try to bend it (it will bend) - Take a used one (15-22 years old, average mileage) and it will crack at the flange.

You can greatly reduce the likelihood that you will have a pickup tube failure by replacing your old piece with a new one - Regardless if you plan to run balance shafts or not.

Does that mean you MUST replace your pickup tube if you want to eliminate the balance shafts, no, but it does mean that regardless if you remove them or not, the "cause" of the failures is not the removal of the balance shafts, but rather an inherent aging condition who's failure is accelerated by removing the shafts. Heck, for that matter, if the shafts are retained, you may never experience a direct failure of the pickup tube, but then again, it will not guarantee that you won't.

Since its inception, there have been several posts in the forums regarding low or loss of oil pressure - In each instance I would reply to the person directly and tell them to check the obvious, then if all checked out I would give them the bad news, cracked oil pickup tube. At first many do not want to hear what I have to say, but I am batting right around a thousand on my diagnosis of this problem - Oh, and it is worth noting that NONE of the failures I am referring to were the result of the balance shafts being removed, they all had the balance shafts installed.

Thanks for reading - Hope this helps.