I'm forced to rebuild a relatively new small block 427 crate engine - really bad piston slap, no oil pressure - long story - not worth going into. Since I have to rebuild it and many of the parts are still good (at least we hope - it come sout and apart tomorrow) I want to make it more streetable. Right now the cam is supposedly a Crane custom grind hydraulic flat tappet, 244/252 with .515/.525 and 112 degree centerline. It seems too lopey to be that cam - won't know for sure until we get it out. Engine is 10:1 and dyno'd 547hp @ 5600rpm. Before it became to damaging to run, the engine idled so rough it shook your teeth out, and that was with it set at factory timing of 38 degrees, but with the idle bumped to 1200 rpm.

I'd like to go with hydraulic roller replacement cam, but anything else you guys can come up with that might help keep the car a little more comfortably streetable would be appreciated. I need to keep the new 700r4 (Bowtie Overdrive Extreme 3) w/2200 stall. Also, Currie built a really nice 9" rear end w/3:70's.

I need a motor that will make enough vacuum for power discs up front, and I want to be able to cruise with my wife and kids without having to set the idle at 2000 or rattle their teeth out. I'm hoping for 450hp or so at the end of the build.

The engine has lots of good stuff in it - World Products Block (4.125 bore), motown 220cc aluminum heads w/manley valves, scat forged crank, eagle h-beam rods, edelbrock victor single plane, blueprinted Holley 870, milodon 7qt, MSD HEI, Vintage Air FrontRunner (Steward high flow, mullins power, A/C, 140am alt all on one solid mounting rack with spring loaded tension idler). I'd like to reuse as much as possible because it's all pretty much brand new. I read in another post here about PolyDyne skirt coatings - that might reduce the clearance enough to use the existing JE's, which are supposedly slapping due to .005-.007 clearance. If the cylinders aren't too trashed, maybe a hone and some order proper clearance pistons will do the trick. Otherwise, I'll have to bore, which is okay cause the WP block's got plenty of metal around the cylinders.

I know it sounds goofy to take an engine like this and make it milder, but the original goal was a healthy street machine. I just got oversold on horsepower and didn't understand the ramifications on the rest of the "system". Any suggestions on cam and other things I can do to make it a solid, reliable street machine would be appreciated. Also, any recommendations on good engine builders close to Katy, TX would be appreciated. Thanks for any suggestions.

With an overdrive tranny and a 2200 stall lockup converter, you'll be spending a lot of time operating in the 1500 - 2500 rpm range. I had a similar setup in my Nova, a 406 and a 700R4, and use a Comp 280HR cam. It runs well from 1500 on up to 6000 rpm, slight lope at idle. The specs are 224°/224° @ .05, .560 lift with 1.6 rockers, 110 LSA. I got very good mileage on the road, about 16, and 11.70's @ 117 at the strip.

I was just wondering if the vibration problem could've been caused by the reason the engine had to come apart? I don't think you mentioned why you had to tear it down?

Well this may be hard to hear but my Personal Opinion, now mind you this is just my opinion, is that if you dont make this car run at least sort of hard its a wasted big inch small block. That cam you have shouldnt have idled like that if im not mistaken. And with all those cubic inches you have what alot of us would love to have but cant, and to see middle ground 383 power out of somthing of that nature hurts. Im not saying go all out, just talk to some cam manufacturers and tell tham what you have/want and i bet youll come out well ahead of 450 hp. and be able to run power accesories, pump gas, stable streetable idle, and all that stuff.

Guys - thanks for the input. Some clarification.

The engine was a crate motor from Bill Mitchell. We haven't torn it down yet and I'm just going off of what one of the engine builders @ Bill Mitchell told me (although he wasn't supposed to); said they like to build their motors "loose". Seems all their 427 blocks are machined for drag race application - looser bearing tolerances which means 5-7psi oil pressure at idle and .005-.007 piston clearance. I ordered a street motor so a 550hp street "kit" went into a block machined for a 675HP drag engine. I imagine the bearing clearances are gonna be ugly once we get them mic'd. Eventhough it runs clean and like a scalded dog from 2500-6000, the idle is radical rough and the piston slap is so loud it sounds like a gremlin with a ball peen hammer. The cam spec is what Bill Mitchell claims is in the engine - won't really know until I get it out, but I suspect it is something more radical than what they told me. Crane would not release the "special grind" specs to me - said it was confidential.

I would love to make big horsepower but the first thing I've got to do is tighten up the tolerances (bearings/pistons). Then I have to cam it so I have enough vacuum for the power brakes. I'm getting about 12" right now and we all know I need 18" to make it a safe street ride. I'm kind of stuck with the best of the best in HP potential coupled with a system that's set up for the street (power steering, power discs, Vintage A/C, etc). Bottom line is shame on me for buying a 550hp crate motor. I could have bought almost all the same parts and built it myself (with some help) for less than I paid for the crate. Live and learn...this lesson was about as expensive as they get.

Any additional feedback appreciated.

Not feedback but I'm interested in how this turns out. Your experience seems different than the fairly recent comparo that one of the mags did of the 427 vs big block. Of course, they may have omitted that aspect. Best luck to you.

I got the guys at Bill Mitchell to give me the specs after leaning on them some. I wrote them down at the time, but must not have kept them. I was fairly interested in that motor, but they would NOT put a roller cam in it. I wasn't going to spend that kind of money on a motor that had a hydraulic flat tappet cam. Anyways, I do remember thinking that the cam wasn't radical at all. Actually quite tame. I even had a few guys run the specs through desktop dyno. I think it was Dennis (DjD) that did it for me.

Here it is, I found the post I was talking about:

http://www.camaros.net/forum/ultimatebb.php?ubb=get_topic;f=4;t=006044#000000


The cam specs are:
Lift: .516 I, .525 E
Duration: 244* @ .050 I, 252* @ .050 E
LSA: 112*

FWIW and JMHO, I would leave it just the way it is EXCEPT drop in a CC 282S solid type cam!!!

The piston slap and bearing clearances WON'T hurt anything EXCEPT your feelings that you got screwed b/c you got oversold!! DON'T worry at all about the NOISE!!

I say this b/c look at how many guy's put noisy gear drives in their motors just to hear them sing!!!

Your's will sing naturally and even moreso with a mild solid cam in it!!! And just look at all the power you will end up with that is in the street rpm range by going with a small solid cam!!!

Run some straight 40wt, (maybe even 50wt), oil in her and set the solid lifters about three times in a week or two and then forget her until she starts clattering too much!!

But don't rev her up until she gets warm b/c of the heavy oil...

I think you have a heck of a motor and I would be proud to own it!!!

And again, jmho... pdq67

Thanks to all for the advice, guys. PDQ67, is 5-7psi idle oil pressure okay or not? I care less about the noise than I do about the detremental effects to the engine as a result of said noise. Your comments are exactly in line with the builder himself - loose doesn't matter if the engine makes the horsepower claimed and the engine hangs together. Regardless, the engine has to come out for pan removal, head removal (got a small coolant leak), and cam change. If I run a heavier single weight oil and the pressure comes back up, I'm totally cool with that. It's kinda hard to get all the issues prioritized, but I guess brakes are the most fundamental so I need more vacuum - 18" or so. That's really where the whole thing started - too much cam for power brakes. Then came the noise, then the drop in pressure and it just seemed like a rebuild opportunity.

Also, do you think the cam you recommend in conjuction with the Super Victor and flowed 870 make the vacuum I need? Thanks mucho for your input. I'll go slow. One thing for sure - I ain't giving this thing up. Too much good stuff here to let go of.

69ProTouring, I had the same beef about the roller cam, but went for it anyway.

BTW, the warranty isn't worth the paper it's printed on - it's just a marketing ploy. The "third party insurer" is not an insurer, insruance adminstrator, insurance agent - nothing. They are in Michigan and are not even recognized as remotely related to insurance provision by the Michigan agency that regulates insurance. If you ever did try to use the warranty, there are so many avoidance loopholes that it would be impossible. Also, there is a $4K cap on payout and a whole lot of exclusions that are hard to prove or disprove you adhered to.

I've gotten to know John Beck (BRE) in Phoenix via phone fairly well over the past year. My decision came down to an engine from him or BM. He kept telling me to forget about the warranty, doesn't mean jack if you're not committed to building the best each and every time. Again, that old hindsight thing, but it looks like it will turn out fine - just a little more work on my part.

Life,

I ran my homemade out of cheap and junk parts 301 for several years!! And I swear that it had .010" on the pistons!!!

Cheap, cast W/JCW, 1/8th over 283 pistons ran in a worn-out, dingle-berry hone job, stock bore, small journal, 327 block......

The Machinist that ground my 265 crank said he knew that I was going to run the dog-sh-- out of it so he ground it so that she had at least a half a thou. more clearance then max. stock on both the rods and mains!!

And he said that they run a lot better loose!!! He sure wasn't concerned about the cheap pistons at all!!!

Sure she used AND leaked oil, but when she loaded up my plugs from the wife dogging her around town, I just took her out on the road and held her in each gear until she blew them clean and quit missing up around say, 6000rpm!!! Started in first and went through this til third gear...

I used to run 40wt in her in the summer, (and 20wt in the winter), b/c I flat couldn't find 50wt back then at the local Western Auto Store before Walmart came to town...

And when she idled, she was down around 5/15 pounds. Depending on how cold it was.. BUT she NEVER KNOCKED!!!!

You got a good one so please don't play with her...

As my nephew say's, "if I'm lyin, I'm dyin!!!!"

pdq67

Sorry, Forgot about the cam!!! Yes, I bet a 282S type solid cam will be fine in that big a motor...

Should be, what?, a 1200 to 5400rpm, power-wise cam, but can go higher rpm-wise!!! Vs 2000 to 6000rpm power-wise in a smaller engine

pdq67

This is what I would do . . . just fix it. Then sue them in small claims court in YOUR state for the cost of fixing the motor ;) I bet they would settle rather than make the trip to defend themselves in such a hopeless case. Get video tape of the oil pressure gauge and audio of the piston slap to show in court. Also bring any evidence you have that there is a warranty - I don't think the judge would be too friendly to a company that won't honor their warranty. You got them dead to rights if what you stated here is 100% accurate and "provable".

Rebore the block if necessary and put new pistons in that fit nice and tight. Same with bearings, shoot for .002 - .0025 on the mains. that will keep oil pressure up where you want it. 5 - 6 psi at idle IS NOT EVEN CLOSE to normal!

As for a cam, the specs that BM gave you actually seem pretty decent for an engine of that size. The bigger the engine the smaller a cam will "act". Maybe the cam has super-agressive lobes or something that makes it so unruly.

If you want a hydraulic roller, I'd put in a hydraulic roller. I like the looks of the Comp XE288 for your combo - would work nicely if your compression ratio is between 9 and 10:1.

Specs for the XE288 are: 288*I/294*E advertised duration, 236*I/242*E duration @ .050" lift, .520"I/.540"E lift, 110* LSA, 106* ICL. Power band should be from anout 2200 - 5800 RPM in your engine with a dual plane intake. Idle would be much smoother with just a hint of a lope.

Life,
I think you should get the engine apart before trashing the builder. It sounds to me like there are other problems. "Race" pistons are installed with more clearance than "street" pistons but... it is because of thier material and shape...they expand more than the street type alloys and once warmed up to operating temperature they should not be noisy. Same goes with the oil clearances....at the most, some race engine builders open them up maybe .0005 or so...that a half of a thousanth ! That should not be causing low oil pressure. The cam that you mention should idle very smoothly in that large a cubic inch engine.
I am wondering if there is a balance problem...maybe the wrong flywheel ?? Also 38 degrees timing seems to be too much in my experience with that size engine with that mild of a camshaft.
I am curious to see what you find when you take it apart.

The teeth jarring idle might be having it in gear at idle with the idle set for out of gear with a low number converter. More car to shake when it's in gear. If it is a real rough idle I'd figure a cylinder or two is missing from ignition, low octane, or valve buggery. What sounds like piston slap might be a valve problem like busted rocker arm. I've found that before. If you haven't removed the vavle covers do so. You could see broken or cracked stuff or leaking seals and have a chance to adjust the valves to make sure things are right.
If it's just the cam I'd enjoy the ride at idle. Give it a major tune up instead of a rebuild. Then if it's broken you've gone by the words of "If it aint broken... don't fix it."

The information regarding the engine build comes from an assembler on the builder's shop floor (want to hear the tape?). I may be a little rusty on wrenching, but I'm not making stuff up and that is exactly where this went last time I tried to get some advice on a cam better suited to my street application. Furthermore, it's a crate motor. They are shoving them out the door as fast as they can make them. Like someone said numerous threads back, QC can be a problem in just about any crate motor (meaning high volume, same build everytime) over 350hp. I don't believe for a second that a volume production shop wouldn't look for some easy middle ground that would span a horsepower range over the same block. Regardless, they can run their business as they see fit. What I was supposed to get and what I got were two different things. A settlement has been reached and I'm covered. I'm not trashing the builder; I'm stating public record.

The engine is supposedly internally balanced and the fly is neutral. The engine has to come apart because of the numerous things that could be wrong. I'll know soon enough. The entire tear-down, balance tests, and mic measurements will all be recorded via photos and/or video.

All I wanted in the beginning was some help on cam spec's. I got that and more, and appreciate it. But it's starting to get personal again and I'm not up for that. I'll email the admin and request this thread be closed. Thanks to all for your help.

Mike,

Nobody is saying anything personal here about your situation.. I think there are two schools of thought going on and everybody is concerned AND wants to know what's going on so we all can learn from it.

First there are the guy's that run h-ll outta their "noisy" motors, (the noisier, the better), and don't really see all that much wrong except maybe the cam is too big, which is doubtful. Of course these are the guy's like myself that will say there's never too much cam, just not enough motor!!!

And second there are the guy's like you that want what you thought you were going to get which isn't a "balls-out" motor, which is fine!!

I have been mouthing about grunt motors for quite a while and can see both sides of this.

You are RIGHT b/c you are the customer!!! It is you who has to be happy in the end AND there is nothing wrong with you for wanting what you want..

I do believe you got over-sold which I hope is made right by B/M... And please come back both here AND at Team Chevelle and tell us what you find out about the low oil pressure and why it is sooo "shakey" for want of a better word??

And I hope that I have not came across as being by any means judgemental here or over at Team Chevelle b/c I, for sure, don't want to be thought of as have...

And kudos to Bill b/c he hit the .0005" right on the head!!

I've asked Gene, (427L88), to critique what I've said here so look forward to what he has to say about my mouthing..

I'm posting this over at Team Chevelle so we all are on the same wave-length...

Hope everything works out... pdq67

-Crane would not release the "special grind" specs to me - said it was confidential.-

very childish... graemlins/sad.gif

Yeah, I was kind of surprised, too. The specs are only a few keystrokes away for them.

I did understand the confidentiality part though - if it's the builder's special design and they said to keep it confidential, that's their call. We'll find out the truth about the mystery cam soon enough. Thanks.

pdq: thanks - I mean it - for all the help and pushing for information. Like I said, the project never would have gotten this far were it not for these forums. By the time my boys are teenagers, auto mechanics will be second nature to them. A big part of the credit goes to the Chevelle and Camaro forums for providing the information that kept things rolling.

I'd like to keep posting and will. I'll keep the builder out of it as much as I can, since they've already been to the woodshed with the AG in their home state. But you hit the nail on the head as far as oversold goes - they knew my application, knew their 415 would be a better fit, went for the extra $2K on the 427, and wound up shipping a mystery engine with problems. It all came right back on them.

It'll all work out fine and my oldest boy is working on a website for the car - we've got hundreds of pictures taken during the build and several hours of video (thanks to Mom). He's got the intro to the site done - a short clip of the both of them standing on either side of the 427 hanging from the engine hoist, ready to be dropped into the bay and shouting, We need more horsepower! That became their motto early on. Probably will stick. Thanks again for your help.

http://www.chevyhiperformance.com/chevyhighperformance/techarticles/p33037_image_large.jpg

Callies did some research on bearing clearances and their effect. The difference between 0.002" and 0.0025" is quite a bit. The additional 0.005" bearing clearance doubles the flow of oil, creating a lot more windage loss, less load capacity with only a small rise in temperature. In our road racer, we use .0018" - .0022" on the rods and .0020" - .0025 on the mains. Using 5W30 synthetic, we have had no bearing problems at all.
The rest of the story:
http://www.chevyhiperformance.com/techarticles/4380/

Thanks, Mike.

I appreciate your kind words and I'm like you with respect for these forums b/c my car sat for years gathering dust in my garage until I got into these and they helped me get the nerve up to tear into it!!! pdq67

The tear down is proceeding and everything will be mic'd by week's end. First piston out had .006 clearance. Can you say, "piston slap"?

Question: I have to replace the *brand new* pistons. With this block we can go to a max bore of 4.250; existing bore is 4.125. Machinist wants to use coated .030 over pistons, but I'm not sure about his selection - SpeedPro HyperEut's. Existing pistons have a slight reverse dome so we may have to keep that, but I would appreciate any opinion on tight tolerance pistons. Machinist wants .002 clearance max.

After teardown, we realized this engine is a mix of very high quality parts and some bin parts - just seems like it was put together by someone with a huge hangover. The windage tray was beat to crap with a ball peen hammer and punch before installation - probably to clear the 6" eagle h-beam's. The tray marks were not rod bolt scores as we first thought - they were punch marks. With the vanes hammered shut, the tray was useless. Rod separation between two rod's per journal was 1/16" in a couple of cases, 1/8" in others by my cursory measurement - machinist will get more accurate. Bottom line - fully torqued, the rods were so loose you could rattle them by hand. The bearings however looked fine.

I think we found the noise/lack of oil pressure culprit - loose, loose, loose engine. No biggie. I just can't figure out why it wasn't burning oil. Seems like the clearance would have shoved oil up into the chamber. Also, I can't believe we didn't spin a bearing. The wrist pin bushing was loose too - if you hold the rod and pull up/push down on the piston you can feel the play. The rods are killer eagle h-beams and the crank is a forged Scat. I've got to figure out a way to save these parts, but the rod-to-rod spacing on the journals may require either rod of crank replacement.

Cam provider has been narrowed to UD or Crower roller hyd - both have specs to provide enough vacuum and grunt to take advantage of this package. I like UD - they are ultra responsive and will do custom grinds I think, but the engine shop has done more work with crower. Existing cam is Crane hydraulic - no button - walked all over the place. #3 exhaust is a little flat, but not enough to cause the original racket. I'm using a Comp Cam's two-piece cover when it goes back together.

The heads are a work of art - cc'd, polished, stainless valves, big studs, rollers, etc. We're going to check for cracks, but they look brand new and every bit of the 220cc they are supposed to be.

appreciate your feedback - that's all for now,

Mike

Mike,

You should be able to turn the crank and use the appropriate bearings to get the crank/rod clearances to where you want them to be. You may even be able to get there with different bearings.

.007" clearance is perfectly normal for some forged pistons. Cast or hyperutectic is a different story but .007" is not necessarily a bad thing with some forged pistons. I just grabbed my Speed Pro catalog and there are forged pistons that spec .007" clearance so I am not so sure you have a problem there. Granted, a .007" clearance setup may be more prone to piston slap than tighter setups, but the noise should go away when the engine is warm.

On the rods, not sure if you are talking about side clearance or not but 1/16" is bizarre and 1/8" darn near an impossibly.

My point is this . . . make sure you are using a machinist you can trust. Be careful that you're not dealing with a shop that is just trying to make things sound worse than they really are so they can hand you a hefty repair bill at the end.

Eric, I'm still learning. The machine shop does all the work for a number of Houston area racers - G&G Performance. I'm still getting the lingo down, but I guess I'm talking about side clearance between rods where they attach to the crank journals - two rods per journal, right? Well, with the pan off, I took a small increment straight edge and pushed the rods on the journal as far apart as I could. The closest measurements I could get were in 32nds and like I said one set had a 1/16 gap and one set was just shy of 1/8 inch. Also, I could move the rods on the journals and make the "clack". We removed the front main cap and the bearing was clean and fresh could still see the dial mark. I may just have been luck enough to catch this engine in enough time to prevent real catastrophy. Anyway, Joe at G&G is going to mic and measure all. He does not like the .007 piston clearance and would like to see .003-4. Piston slap never did go away in the original build when the engine warmed up - in fact, it got worse. Thanks,

Mike

Maybe the noise was never piston slap to begin with . . . something is bad wrong with that rod side clearance - I'm betting that's your culprit since excessive side clearance will both make noise and cause low oil pressure.

I'm no expert either, just picked up a few things from my mistakes of the past :rolleyes:

Good luck and pls follow up so we know what the problem was for sure.

Go get youself a decent 6" dial caliper and a set of feeler gages that stack to about a 1/2". I have both and between the two of them I can get fairly close on alotta stuff, but not the mains and rods. They really need mic's and snap gages...

I can't see an 1/8th inch, wow!!! But the .006" and .007" on th piston seems OK..

Like I said, I'm almost positive that I shoved a .020" feeler gage down one side of my junk 301's cheap, cast pistons and she ran fine... She was noisy though...

pdq67