Potters Engine Saga

[Robert Kenney]

I wanted to post an up date on tim potters engine. For those who are not familiar with the saga.

This ihon thread documents a bit of the deal and some of the research.
http://www.forums.IHPartsAmerica.com/gas-engine-tech/1024-sv-series-timing-Mark-variation.html



The engine was supposedly rebuilt by a portland based engine re-builder. From day one it has been plagued by problem after problem. After working through the head gasket leakage he was never very happy with its performance. Low manifold vacuum, bad gas mileage <10 -11 mpg very soggy low rpm power. I was never satisfied with its idle quality as it seemed to have a limp or two. One thing it seemed to point to was retarded cam timing. The cam while bigger than stock it was still not any bigger than the average rv cam.

It all came to a head after the engine developed a series miss and loss of power while driving up the grapevine a couple of months ago. A vacuum gage showed some serious problems with severe fluctuations in vacuum.

This week end some dedicated scouts west members helped tim yank the motor with the intent of giving it a complete tear down and diagnosis in my shop. We pulled the heads to have a quick look... to say we were surprised would be an under statment...

First thing is broken valve spring on #2 intake..

Second was a 1/4 inch wide notch burned into the exhaust valve on #7 (picture below) that cylinder was not working very well.

third, the same valve and 4 others that I pulled for a look had severe seating surface wear grooves that would not have been there at only 17,000 miles, even 150,000 miles would show less wear if ground when the heads were really rebuilt.

Fourth, and probably the worst, all eight cylinders had severe scoring from inadequate ring end gaps from the start. They most likely didn't bother to even check.

Fifth, we checked the cam timing and like we thought it was installed 6 degrees retarded. I guess we need another offset cam key.

Tim asked that the heads and block be milled to achieve 9-1 to match the cam. I will need to cc the chambers to verify them but the block was never touched. In fact the factory size stampings were still fresh and had been media blasted but never machined. Pistons .040 in the hole ( below the deck)

I will update with more info after the tear down as low oil pressure was another issue. I hope the crank is ok.

 

[Michael Mayben]

While I fully expected some obvious engine build issues, I didn't expect anything of this magnitude. The back and forth regarding this motor was a worst case scenario involving way too many cooks in the kitchen and unfortunate selection of executive chefs. And to make it worse, the stew was brewed by long distance with "trust" involved.

Most likely too much water and time under the bridge now, but this confirms what others have alluded to regarding xxx...things are not always what we perceive.

I know yawl are documenting this to the max...that will serve yawl well as tim pursues the proper course of action.

 

[Robert Kenney]

Mm,

we got photos and photos and more photos. when I tear the short block down I'll take more as I doubt we will have any good news.

I intend to build this back with better than new clearances not service limits along with balancing the ra and adjusting fits to work with the performance upgrades like compression.

I know the exhaust guides are loose and all of the exhaust valves have checking and pitting along with the question of whether they will have good margins once they are refaced enough to rid them of the grooves.

Believe me tim is not happy but what can he do.

 

[Tim Potter]

mm,
believe me tim is not happy but what can he do. The guy's who made the deal probably won't give a shnizz.

Just to confirm....tim is not happy.

the only thing to do is to document this with photos and expert analysis of the condition of the engine which will tell us what was done and wasn't done to begin with and the results of the poor workmanship which shows itself.

People should know that I paid $1,250.00 for the heads and almost $2,500.00 for the long block to the company that did this work based solely on trust and recommendations from people that I believe also had faith in this builder.

Once we have all of the evidence, I will approach the builder and let them know what we have found and let them decide what they want to do about it, if anything. The thing is that I am probably beyond the warranty period on this engine but, at the same time, it has not been right from the beginning, starting with the blown head gasket on initial startup.

The other thing that really sticks in my craw is that in every conversation I have ever had with them I was reassured again and again about how meticulous they were in the machining and assembly of this engine. Even paying special attention to every detail because they knew I had already been through so much trying to get a good engine for my Scout. The only thing they ever told me that I had a hard time swallowing was that they had not degreed the cam, they only used the timing marks. I often thought how could they have paid so close attention to every detail and not degreed the cam? how is that even possible? Now it seems that everything I was told was a lie and the condition of the engine seems to prove it.

One thing I am certain of is that the good people that also had faith in this builder will be paying close attention to this thread and I'd even bet that the builder will too. It will be interesting to see what they have to say.

 

[RobertC]

Robertk -- curious question

you can answer in one of your info / pciture replies

given the condition of the one valve -- what shape are the valve seats in?

Thanks.

 

[Robert Kenney]

Robertc,

the valve seats of all of the valves I have pulled thus far are worn badly. The seat on the burned/notched valve while not notched becaust it was rotating shows worn also. I have rebuilt many heavy duty engines that have been beaten for in many cases 150k miles and they have shown close to that wear.

Gleam from it what you will but I smell somthing fishy.

 

[Michael Mayben]

I seriously doubt those heads were ever touched machining-wise except for a superficial cleaning. What ya see is typical high milage/normal valve and seat condition.

And there is no way of telling "which" heads were used because of all the swappin' and shufflin' of boneyard core parts that went on. Since they assembled the long block, I'm certain they thought the tracks would be covered.

Again tonite...I related the pottermotor story up to this point to a friend who had done considerable business with xxx at a point when they were a somewhat decent operation (many years ago), but cut them off in the late 90's after a business relationship that went bad.

 

[Robert Kenney]

Re: Potters Engine Saga No Good News Inside Either

Saturday tim came over with the 345 loaded in the back of his terra for a further teardown.

Unfortunatly we found some major issues there also

after pulling #1 piston out we removed the top compression ring to see where the end gap was. It was .015 after 17k miles and having gone through the scoring event. Usualy during breaking in and bedding of rings of a properly built engine the gaps open up .005 during the first 1000 miles then the opening slows way down and the next 15k May see another .005. That leaves us at .005 initial build but the scoring event would have worn the ring a bunch. The gaps were most likely at <.005 at initial build. So they butted and scored during the first drive or hill.

Fyi the IH spec is .010-.020 compression ring end gap new, .015 -.018 is where I would set this engine up given the bump in compression and cam lift. It will generate higher combustion temps and expose the top ring to a higher peak temp under a heavy foot and needs to built for. Higher combustion temp = larger ring gap per inch of bore.

All 8 pistons had crown damage and severe skirt scoring. Definatly some metal transver and galling to go along with the ring event. The bore sized were originaly very nice with less than .0003 variation across the board and an initial piston to cylinder clearance of .003-.0033. The scoring took .0007 out of the bores so depending on the replacement piston size and where they clean up we May or May not have to go .040 over. Would be nice to not bore again for cost reasons.

Tim originaly sent his pistons and rods out of his Scout (78? 79?) to the builder with the pistons hung. They had been lightened on the big end by removing the square protrusion. Tim knows they were all this way. Correct me if I am wrong but all 345 and 392 's built buying this time (1978) would have had the new generation of rod that IH redesigned to fix a rash of rod failures. Anyhow all 8 rods were not the same. 2 were the later improved design and the other 6 were the earliy desigh with the beam that was parralel all the way to the big end. See photo for comparison. One of the earliy rods had never been touched. I won't put the mixed up mismatched rods back, they need to all be the late model rods and tim agrees.

Help with 6 rods would be great???

Cam bearings look like they have been sanded and none wore correctly. One center bearing was installed out of square so it got wiped pretty bad. Oil holes were very marginaly lined up with one 1/2 blocked the other 1/3 blocked

the crank and bearings looked good but upon measuring the main bearing id and the crank od they were at .0035 clerance with the max IH spec being .004 that probably caused his low oil pressure.
We will set it up at .002 rods and .0025 mains bad news that May require a grind. I will need to look at a bearing catalogue first. At least new bearings. No I won't reuse bearings.

We cc'd the combustion chambers and got 77cc's. Put the motor at 8.5-1 with composite .040 thick hg and the pistone in the hole .046-.050. Will need to bump it .5. "0" decking will put it at 9.3-1 so we will see how bold we are. 9.3-1 will work on pump regular but barely. May need to take some total timing out of it to like 33-34 degrees.



So up to date the parts in the scrap bin are:
pistons 8
rings
valve springs 16
exhaust valves 8
exhaust guides 8
main bearings
rod bearings
cam rearings
rods (6)
gasket set

 

[Michael Mayben]

At this point this can't get any worse.

This pile of shit needs to be crated and locked up as evidence after the attorney provides a security seal for the crate. I'd not touch anything, I see recourse here no matter what the time frame is. The thieves that operate xxx must be slapped severely.

And nearly nothing is usuable anyway...you'd be much better off to start with a runner motor that has not been into, those are a dime a dozen. Or the core supplier we use up here has many core blocks/heads/cranks on the shelf right now...xxx to have indicated that they could not "locate" core parts was totally irresponsible. The largest core supplier west of the rockies is right there in the portland metro area. What they meant was...the core supplier will not do business with them based upon past history regarding "money".

And I've spent this weekend working with yet another 392 that xxx did the heads on (or at least they were paid to do the heads). Based on some rather odd valve train noise and lifter bang that comes and goes (this is a motor with no drive time and about 10 hours run time), I'm suspecting now that the installed valve height is all over the place, luckily they did not do the other machine work on this engine.

 

[Robert Kenney]

at this point this can't get any worse.

This pile of shit needs to be crated and locked up as evidence after the attorney provides a security seal for the crate. I'd not touch anything, I see recourse here no matter what the time frame is. The thieves that operate xxx must be slapped severely.

And nearly nothing is usuable anyway...you'd be much better off to start with a runner motor that has not been into, those are a dime a dozen. Or the core supplier we use up here has many core blocks/heads/cranks on the shelf right now...xxx to have indicated that they could not "locate" core parts was totally irresponsible. The largest core supplier west of the rockies is right there in the portland metro area. What they meant was...the core supplier will not do business with them based upon past history regarding "money".

And I've spent this weekend working with yet another 392 that xxx did the heads on (or at least they were paid to do the heads). Based on some rather odd valve train noise and lifter bang that comes and goes (this is a motor with no drive time and about 10 hours run time), I'm suspecting now that the installed valve height is all over the place, luckily they did not do the other machine work on this engine.

You are right there is nothing else to take apart.. Only whether or not the block will clean up with a lite hone and the crank will be usable without having to go 20/20. It is 10/10 now.

I really don't know how tim will handle the deal but first priorities are getting his Scout back on the road.

Can you look up the bearing recommendations eg recommended journal diameter and installed bearing id, I can't find my m77 book?? That will determine the serviceability of the crank as it stands @10/10

 

[Tim Potter]

I have little to add to Robert's analysis of what was found except that I am having a difficult time accepting what has happened here. Although, there seems to be little that can be done except start over.

Just a point of clarification. I have kept meticulous records on this engine and in fact it has 13000 miles on it. The heads have 17000 miles on them.

As for attorneys and such, all I have ever wanted is a good sound engine for my Scout that performed really well. I have tried every way I can to accomplish that thus far and, failed again and again.

The problems with the top end were one thing but the bottom is something completely different. There are three major failures in this motor that are the fault of the builder.

1. Cam installed retarded 6 degrees, they should have degreed the cam and did not.

These are two 3336 cam gears notice that the teeth are off about 3/4 which translates into the 6 degrees we measured. If they had taken the time to degree the cam many of the problems internally would never have been found. Even with the latest problem, I'd have pulled the valve cover, found the broken spring on #2 and fixed it. But because the valve timing was always suspect, the engine cam out and got disassembled. I guess I should be thankful they screwed it up.

2. No valve job done on the "new" heads I bought. Valves were maybe lapped and reused. And, get this, they had two opportunities to do this work. One when I originally bought them and again when I returned them for inspection. Neither time did they touch the valves.

3. Compression rings too tight. Scored the cylinders, and wasted the pistons. I really don't even know what to say about this. It's just stupid and really falls to the guy that assembled the engine like this. I can not understand how a professional engine builder let this happen. They had to know what the probable outcome would be of the rings being too tight. Even if the engine had stayed together for many more miles, the internal damage was still slowly killing it.

Setting up the main bearings at the end of the service limit does not make any sense to me. I am more inclined to believe that it's a grinding mistake on the crank than a plan.

Swapping out the rods I sent them from my 1980 engine and putting in 6 early rods is completely unacceptable. And, it puts me in a really bad situation now because I have to also buy rods along with everything else that has to be replaced.

Ok, that's all I'm going to say. I'm disappointed in what I got but. Will now concentrate on doing it right......one last time.

 

[Robert Kenney]

To all would be respondents to this thread.

This is an on going situation for the engine owner and the engine builder. We prefer that any direct references to the company be kept out of this thread. If the time presents it's self that the builder decides to post his or her name here so be it. That is not my nor tim's mission here so please respect these wishes.

We do how ever welcome an open and factually based discussion here.

Our mission regardless of any agreement between the two parties is to get tim back on the road and give some insight on failure analysis and cause and effect.

 

[Tim Potter]

I just want to say that I had a very nice long talk with the engine builder today. He has had an opportunity to inspect pistons, rings, rods and a valve and, although we do not completely agree about what happened in this engine, there are areas that we do agree upon and we have further agreed to work together to in the effort to build another one.

This supplier and, long time supporter of the IH community has been gracious and cooperative though out and has expressed a willingness to help offset the costs of a new engine by means of providing parts. This is completely acceptable to me given the circumstances and I am grateful.

I really do not want to go into this in any further detail at this time as I think we have done as much here as possible to correct the situation to our mutual satisfaction.

 

[Michael Mayben]

Thank you for the update tim.

If/when yawl start on an engine build, then create a new thread for that, I'm locking this one down to further posts.