FF1600 Piston Failures

[CalTrumbo]

I am posting this thread to see if anyone else has had this problem.

I built two engines using the Jake Lamont book. The first engine failed after about 4 hours of running time (est.). The piston skirts broke off on one side each of the number one and number four pistons (car right-side skirt). I checked the piston cylinder wall clearance and it was 0.005" which is the upper end tolerance. I had the block re-sleeved and built another engine using the same method but left no stone unturned per the book. I used a test day to break in the engine (one to two hours of run time). I followed book here as well. On the track I never exceeded 6400 rpms and started out at 4400 and went up in increments of 1000 rpms for each 30 minutes of running. After getting it home I pulled the pan and once again found pieces of pistons in the pan. I am assuming they are the skirts. I put the pan back on and walked away (that was a month ago!!!).

I am hoping someone else has seen this and can point me in the right direction?

[bob darcey]

CT: That is curious. Failures with the Hepolite cast pistons are rare, but there has been some talk of a "bad batch" occasionally. Hepolites generally come as a 18649 or a 20552 model--there are minor differences, but the 20552 has a steel insert to strengthen the pin bosses. Do you know which piston models you were using?? Can you describe where they broke??

[Brian]

Not to be smart, but what method are you using to measure the piston - skirt clearance? I've seen that, but only after the skirts on the pistons had collapsed to about 10 thou clearance or greater, never with new pistons.

Brian

[Greg Mercurio]

Check the bores for taper.

[Rick Kirchner]

a phone call or short trip to Rollin Butler might be in order

[Scott Hanba]

Two years ago, I had a brand new motor with Hepolites in them. After 15 minutes of gentle break-in, had one break causing the rod to exit the block. There is a problem with some of these Hepolites. Next motor will definitely have Jay's pistons in it.

[EYERACE]

sounds to me for the trouble and expense you're going to, you've have come out ahead if you'd followed Carrol Smith's advice > "an engine is a part you take out of a box and bolt in just like one does with a coil" ......call Butler or Farley or any pro builder in the future.....at least send them what you have and let them lay hands on it for now

[CalTrumbo]

Thanks everyone for your comments. I agree there is something wrong beyond my skill set. I will plan to contact Rollin and bring the engine as is for him to look at. I also agree for the amount of money and time I could have had a pro build it but I would have lost out on the learning experience and the therapy of building something with your hands. One of the main reasons I got into vintage FF is to work on the car.

Fortunately I have a spare CF I can use for this season.

When I learn something new I will make sure to pass it on.

Cal

[mblanc]

sounds to me for the trouble and expense you're going to, you've have come out ahead if you'd followed Carrol Smith's advice > "an engine is a part you take out of a box and bolt in just like one does with a coil" ......call ..........'WHOEVER'

What a bunch of bunk!

We can all help with tons of chassis engineering expertise, extensive alignment procedures, nth degree of suspension analysis, but the best advice anybody can ever come up with regarding engines is ''call so&so" BS! -not just ripping on eyerace here, but seems this whole board has the same attitude on engines, just go spend the big $ with a pro, we don't even want to talk about it.

Completely ridiculous. Nothing magic in this engine at all. Sure, a great head is needed to make power, (were not talking about a guy with a homebuilt flow bench here) but the rest is pretty basic.

Why are we so willing to spend all the time and effort on lots of whizzy scales, platforms, and what did I read the other day regarding motion ratios, "Front is approximately 0.8- it's not quite linear, though. I have a pretty good polynomial approximation if you care."
Anybody that's willing to be able to think through those processes, could assemble a short block, and bolt a head on.

My point being, if half of the guys spent their efforts learning how to refresh their pinto/kent, instead of biatchin about the price, they'd be much further ahead. It's just pistons, rings, bearings, a spec cam, and a valve lap. Compare that to the thought processes involved in motion ratios, roll centers, shock dyno graphs, nth degree of alignment procedures, roll couple distribution, wing angles, chain tension, etc etc.

I for one am glad to see somebody that puts their own stuff together, Hooray for Cal, and the few others. Too bad he had problems. (Like nobody's ever had a problem from a pro built?) Could be he made a mistake, could have been the piston, but I think as a group, we all could do a whole lot better than "call 'insert yer fav engine builder here'".

What if thats what was said everytime somebody had a question on alignment?, hey, just call xyz prep shop, they're the experts, they can do that better alignments than you, and you'll not have to learn all that stuff. Quit wasting your time and money, let an expert do your alignment and setup. How boring, and un educating.

Apexspeed CAN be a good source for engine help too, .... can't it?

DON'T GIVE UP CAL

[Rick Kirchner]

It's not giving up, it's accesing the appropriate level of expertise (just like asking any quaestion on this board) when it's absolutely necessary.

Do you have a materials analysis lab at home or at work? Know how to identify the type of failure from the fracture site? Then know how to trace that back to a specific mechanical cause?

Whereas there have been problems with Hepolite pistons the probability of having the exact same problem occur in two different sets is probably pretty small, unless they were purchased from the same supplier who had sets from the same lot on the shelf.

In any case, an engine builder has probably seen dozens of these failures, can explain why, and put you well on your way to keeping it from happening again.

Anyone with the appropriate technical background can develop the needed expertise from first principals - but it's a damn sight cheaper to just ask an expert.

[EYERACE]

mblanc - no offense taken because i know that many of us do build our own engines and indeed as this thread brings out - some would prefer to build their own - when it's almost like therapy it's a good thing ...but when it's enough to drive one crazy, that's another thing. the point is: the crate engine makes life simpler and much more importantly.....the pro built with experience will have a few horsepower that the home built guy will spend a couple of years chasing before finding.

[EACIII]

Are you sure you are putting the pistons and rods in the right way, both have a front and back.

Ed

[John Merriman]

If I recall correctly, poorly manufactured batches of AE pistons - maybe made in some far-away land and not in Jolly Olde England - were one of the reasons Jay developed the forged pistons. But certainly there could be other reasons for the failures and all alternatives should be considered. (I think Jay could tell you if the pistons are the culprit if you have the part number and/or casting numbers) Pro-built engines are simply not for everyone - for various reasons and the options available to those who want to build up their own FF engines is, of course, one of the hallmarks of the class. But doing it right means getting all the machine work done by a qualified shop, obtaining parts from the best sources - in many cases fully prepped - and then, as Jake shared with the rest of the FF community, carefully assembling the thing. Tricks? Yeah, there are plenty of them too but most of 'em can be found if you work at it and study the deal enough!

[mikara]

Hi
Sounds like piston to bore clearance to high, measure piston at guegon height , make sure piston is on rod correct oil squirter to trust side ,asemable into engine ,bring to tdc and check how much the piston rocks,also make sure the the skirt is not hitting any thing ie crank counter weights
Michael






ote=CalTrumbo;135370]I am posting this thread to see if anyone else has had this problem.

I built two engines using the Jake Lamont book. The first engine failed after about 4 hours of running time (est.). The piston skirts broke off on one side each of the number one and number four pistons (car right-side skirt). I checked the piston cylinder wall clearance and it was 0.005" which is the upper end tolerance. I had the block re-sleeved and built another engine using the same method but left no stone unturned per the book. I used a test day to break in the engine (one to two hours of run time). I followed book here as well. On the track I never exceeded 6400 rpms and started out at 4400 and went up in increments of 1000 rpms for each 30 minutes of running. After getting it home I pulled the pan and once again found pieces of pistons in the pan. I am assuming they are the skirts. I put the pan back on and walked away (that was a month ago!!!).

I am hoping someone else has seen this and can point me in the right direction?[/quote]

[Jon Jeffords]

Were the con rods inspected to make sure they're not bent?

Look at whats left of the damaged pistons and their respective rod bearings to see if they show normal wear patterns.

[Chester Carter]

THE TYPE OF DAMAGE YOU HAVE DESCRIBED IS USUALLY CAUSED FROM SOMETHING INTERFERING WITH THEIR MOVEMENT. THE PISTON ITSELF DOES NOT HAVE TO ACTUALLY HIT SOMETHING. iF THE CONROD IS TOUCHING ANYWHERE THE SHOCK ITSELF WOULD BE ENOUGH. WITH THE ENGINE LAYING ON THE BENCH TUMMY UP LOOK AT THE BASE OF THE PISTON LINERS ON EACH SIDE OF THE ENGINE. THEY SHOULD BE RELEIVED IN SOMEWHAT OF U SHAPE ON BOTH SIDES TO CLEAR THE RODS AND BOLTS. ROTATE THE MOTOR SLOWLY AND MEASURE THE CLEARANCE AT THE CLOSEST POINTS. I LIKE ABOUT .050 CLEARANCE AT LEAST. THINGS HAVE A TENDENCY TO GROW WHEN SPUN AROUND VERY QUICKLY. WHILST DOING THIS YOU CAN COMBINE LOOKING FOR ANY INDICATION OF CONTACT WITH THE BLOCK AND OR ROD ASS'S. i HAVE ALSO SEEN THE FUEL PUMP CAM TOUCH THE PISTON WHEN CLOCKED WRONG, VERY SLIGHT CHANCE. REMEMBER A LOT OF THESE OLD ENGINES HAVE BEEN LINE BORED NUMEROUS TIMES LOWERING THE CRANK INTO THE BLOCK AND THROWING EVERYTHING THAT THE ORIGINAL ENGINEERS HAD PLANNED AWAY. A BORE GUAGE RAN ALL THE WAY TO THE BOTTOM OF THE BORE WILL ASSURE THAT WHOEVER INSTALLED THE LINERS DIDN'T OVERDO IT WHEN PRESSING THEM IN. ALSO MAKE SURE THE WRIST PINS ARE FULL FLOATING. IE MOVE FREELY IN ROD AND PISTON.
NOT ALL OF US ARE CHECKBOOK RACERS. OUR MOTTO IS WE MAY HAVE THE OLDEST CAR IN THE CLASS BUT NOT THE SLOWEST. I LOVE TO WHUP GUYS WITH PRO MOTORS.
CHESTER CARTER SF REGION

[LolaT440]

Why bring the engine to a pro? Well, If you get the roll center wrong or something, you go slow or burn up some tires.

If you are on a learning curve building an engine and make a mistake, it costs you a lot.

So doing it wrong twice could cost more than paying someone once to do it right.

[Mark H]

The machine work.
Relying on someone else to do the machine work is shaky at best. Unless you have $1000's of tools to check his work.
I build a street engine a month and have had zero failures. A race engine is not as simple as reading a Pinto shop book and putting it together,,,,sorry. I built 2 in one month when I started out and will never do it again! 99% of the machine shops out there can't or won't do the work to the tolerances we need and don't know the tricks to make them live at 7000 rpm.
And then there is the 5% more HP needed to win, forget about finding that out on your own. I hear bits and pieces of what is being done to these engines to get that power, now Ive been around for a while and these things still wow me.
If you just have to do it yourself get the block built to your specs by a race engine builder and do the rest yourself?

7000 rpm. for 30 min = 10,000 mi on a street engine.

[Scott B]

The book its own self made a recommendation regarding home versus pro rebuild. If you are new to building race engines, first time send it to a pro. When it is time for a rebuild, take it apart carefully and see how it is done. The refresh should be then close to the professional rebuild and as in an earlier thread you (the individual racer) will have the satisfaction of rebuilding your own engine.

Scott B

Crossle 32F

[se7en]

Let's start by using the dreaded word "assume".
Working with the bottom end only, I will assume that the machine shop you are using is competent and capable of doing a correct job. Beliving that you are assembling the bottom end correctly and EQUALLY, all things in this area are good ???? I guess it is time to work outside the box (bottom end). Now what would cause these two particular pistons (#1 and#4) to break only on the right side? But first, what resides on the right hand side of the item that sits on top of the block? The obvious answer is the cylinder head and attached to the cylinder head is the ...... INTAKE MANIFOLD/CARB. We are taking a long time to get to the crux of this discussion, but it is very important to visualize the components involved and their function. In short, I believe that #1 and #4 manifold runners are running too lean, causing the two pistons (#1 and #4) to "slap". From your original post, you ran the engine for approx. 4 hours, then discovered the broken pistons. You then had the block re-sleeved and reassembled it very carefully. You then ran the engine another ~4 hours with identical results to #1 and #4 pistons. Here it is, sir: because (1) #1 and #4 intake manifold runners are longest, (2) carb may be jetted too lean or not prepped correctly (a phone call to Jay Ivey Engines may be in order here 503 255 1123) and (3) engine timing may be off. Items #1, #2,and #3 together could lead to specific cylinder (#1 and #4) detonation, because they are linked to the two longest intake manifold runners probably causing #1 and #4 cylinders to run lean, causing detonation thus piston slap.
Just my $.02 cents worth (and 35+ years FF racing),
Ken and Jack Hi Josh!!!

[jdp526]

I found an excellent book 'Ford SOHC Pinto & Sierra Cosworth DOHC High-Performance Manual' by Des Hammill. He describes problems areas of engine in great detail along with all the proper steps in prepping each type of component in engine. He identifies several ways to set up engines with various parts available at the time book was written.

I picked up a 2.0L engine a couple of months ago at a self-serve salvage yard and I plan to rebuild it myself to be used in autoxing and time trials until I am ready to run the spec race engine in drivers schools/racing.

http://www.amazon.com/Ford-pinto-sie...6520540&sr=8-1

[Roger Eade]

I don't understand why a lot of you guys sleeve the Kent and Pinto blocks? this is something we would normally never do, we will use Ford Motor sport blocks for the Kent X flow, or get the blocks ultra scinic tested to check core depth and width when building big block cross flows (up tp 2 litre 190Hp ) and the pinto blocks sleeving is a no no, and one of the reasons is that there is not enough meat there when bored out to hold sleeves in place, it may be ok with a standad engine, such as you use for FC and CFC, but we trick them up somewhat, and they would just fly apart.

As for the piston failures, it could be as been said, too lean and to much advance, this will also cause erosion on the piston top, it might be slight for just 4 hours running, but it will be there so have a careful look, are the rods straight, around the right way, pistons on correctly, piston pin clearence ok, bore true, these things are easyally checked, make sure your clearences, piston to wall are correct, I have said before here these engines are not rocket science to build, and sure you may have one bite the tarmac once in a while, ther wouldn't be a pro builder out there that hasn't had that happen, and if they say its never happened stay away from that guy, I feel sure that you must have a buddy to give you a hand, to check over every thing, four eyes and two minds will often work wonders.
Roger

[John Merriman]

Roger, we sleeve them because the rules require the use of standard size pistons or, at most, the new .005" oversized forged pistons made by CP. If the cylinder bore is excessively worn and piston to wall clearances are too great, sleeving is the only option. Fact is, done properly it works just fine. Obviously there are pitfalls and poor machine work will result in potential failure as will the use of sub-standard blocks such as those once made in Ford's South African plant.

[Roux]

Cal, This is a sad state of affairs. I had a bad season once where I had a lifespan on an engine measure in minutes, not even hours, at speed. In my case both problems were traceable to my own mistakes. I have since had great luck in prepping my own engines and you should too. Get to the bottom of the problem and become meticulous (which I am sure you probably are) and you should be able to build a good one every time.

I think the Lean theory is interesting. Are you running the DFM and if so, does it still have the simultaneous opening gears on the two throuts?

If you bought the pistons from the same source then I fear that maybe you just helped the rest of us with weeding out the bad batch

Give me a call if you want to talk

Cheers
\
Steve

[Joshharvey]

A lean issue also is not always caused by jetting. You can have the correct size jets and still run lean. Check float level, but you still need to go one step further than float level. You can check your float level in the garage, but that does not guarantee that your float level is correct on the track. Make sure to check not only fuel pump pressure (1.5-2psi), but fuel delievery also (.25-.3 gal/min or 15-25 gal/hr).

Good luck!

[bob darcey]

Does anyone know how to identify the "bad batches" of Hepolites?

[CalTrumbo]

Wow! Great information and theories, each I will look closely at. I am very interested in understanding the #1 and #4 intake that Ken proposes and will explore further.

Thanks mblanc for your comments which were very encouraging. I am on a quest for knowledge because I love working on the engine. Even though this is frustrating at times, I enjoy it and I am even more determined to get it right. I am going to involve a reputable engine builder to help me with the postmortem dis-assembly and go from there. I may also spend twice as much as a pro-built engine before I am done but I will get the knowledge and over the lifetime of this hobby I should be ahead from a money standpoint (if that was all I am concerned about).

Thanks to Steve Roux for his continued support and encouragement. Steve sold me this car literally in a box (I can hear most of you cringing at that statement ). I did a frame-up restore and I now know the car inside and out, thus a great education.

I am grateful for everyones comments and thank you ApexSpeed for creating an awesome forum for discussion.

Cal

[Greg Mercurio]

Please post the findings of the post-mortem.

[CalTrumbo]

Will do. Probably not going to deal with it until this summer after my July event.

Cal

[Joefisherff]

Like you I suffered through a number of bizarre engine failures early on so I am empathetic to your situation. On one, I had a piece of the shiny chrome on timing chain come apart and lock up my oil pump which broke the cam which met with a rod and wiped out a block, crank, rod, piston, etc.. I had another where (due to my mistake) there was too much pressure on the rear of the crank and the thrust washer fell out leading to another failure. If you need some parts to get back on track let me know as I'm cleaning out my FF stuff. I've got quite a few pistons and would be happy to send you some out if that would help you get back on the track. Don't get frustrated.

Joe

[John Merriman]

Cal - pls send your email address to me - your profile email kicks back. Thx johnm63@gmail.com

[CalTrumbo]

I updated my email profile for APEX.

Joe,

Based on what was in the pan, I need a cam, 0.030" pistons and cam followers for starters. I will have to wait on the postmortem for the rest.

Cal

[Joefisherff]

I've got the cam followers, some stock pistons (where can your run .030 over pistons?) but no extra cams. Let me know what else you need and I'll send it out.

Joe