New engine disaster need engine guru help!
 

Hi Guys,
I'm having a really tough time with a 454 I just had built and I'm in need of some advice. I picked up a 454 on OSO last year that didn't turn out to be what I was hoping so I decided to spend some money at our local machine shop and put it right. I've now had the engine out several times as it keeps bending valves after about five minutes of run time. The shop said all they did was disassemble and clean the heads but I didn't have this problem with the engine before I had it rebuilt. I'm running out of ideas and I'm concerned that the machine shop or I might doing something wrong.

The engine is a Dart Big M block with Dart Iron Eagle 308 heads. It has a forged steel GM rotating assembly pistons are forged federal mogul forged and give the engine a 9.3:1 compression ratio. Valves and springs are the same as what comes in a Dart 308 from the factory with positive valve seals. The cam is a Crane 132561 with crane hydraulic lifters and crane 1.7 roller rockers. Ignition is a thunderbolt IV V8-HP and timing is set consevatively at 10 degrees BTDC for break in purposes. The carb is an edelbrock 1410 stepped up to richest jetting on the chart (12%), The engine is in a Pachanga 22 with regular Stainless Marine exhaust and still has the original vernalift mufflers in place. The fuel tank has about 60 litres of 91 from last october that was stabilized and about 100 litres of fresh super and a can of SeaFoam additive.

When I first fired the engine I immediately brought it to 2000 rpm to break in the camshaft and the engine fired right up and ran for about 10 mins. Lifters took a couple of minutes to completely pump up. After about ten minutes the engine made a nasty mechanical noise (valve touching piston). I pulled the engine and returned it to the machine shop and it had bent the exhaust valve on number 1. They repaired it and I reassembled and installed the engine.

The next attempt was this week. Fired the engine up again and ran it at about 1600 rpm to finish the cam break in. I set the timing at 10 BTDC for 30 total timing and took it out for a drive. The engine backfired through the carb once as I tried to pull it up on plane then pulled up nicely to 2800 rpm. I varied the throttle over the next minute or so until the nasty sound returned and the engine started missing. I limped back to the dock and pulled the boat. this time I lost #1 exhaust valve again and cylinder had 0 lbs of compression. # 5 also kissed this time and was down to 90 lbs of compression. The machine shop said that there was a lot of gummy build up on the valve stems and said it must be the old fuel in the tank causing the problems. I have a tough time with that as I've had many engines with a little bit of last years fuel in the tank run through it just fine.

I'm really lost at this point and my patience is wearing very thin. The shop assures me that the valve clearance is fine but I'm having trouble believing them at this point. I'd appreciate any good advice as to where to look next. Thank you for any light you may be able to shed on this for me.

Sounds like it might not have enough valve guide clearance. When it starts to heat up the valve hangs open and the piston makes contact with it.

I'm about 99% sure that you have the timing chain installed incorrectly.

first place i would start is your valve springs. the springs that come on heads are a generic spring because not every head builder can make a spring to match every cam on the planet. get the right springs to match your cam. check your guide clearance. do you see and heat evidence on your valve stems?

Get to a other machinist NOW!

You either have too little piston to valve clearance or the valve is hanging up as already submitted.

The part I'm having trouble with is that the guy took it back apart and then reassembled it without fixing the problem.

This is a perfect example of why folks need to establish a relationship with a QUALITY, performance based, machine shop!

Good luck.

I'm betting the machinist never "degreed" the cam.

I had asked yesterday if maybe the cam was off a tooth and he showed me the lifter position with the timing marks and said it was almost impossible to get that wrong. When it's at zero is apparently exactly where # 6 changes valve openings as well. He told me that you can see that it is set up properly if it moves one valve on #6 immediately when you move off 0 one way and the other valve on #6 if you move the other. Can you tell me how the could have installed the timing chain wrong? I have used these guys several times in the past to build 350's and even once to build a vintage Jaguar XKE engine and this is the first time I've had any issue with them.

Sorry forgot to add that they clayed the top of the piston after the first incident and there was 300 thou of clearance.

There was no evidence of heat on the valves but there was a lot of kind of gooey carbon build up for an engine that had run for such a short time.

That sounds like a lot of valve to piston clearance.

Here is my thread about the issues I had with #6 and #8 cylinder. Not the same but similar issue.
Maybe wrong Mark/Gen head gaskets?

Another valve meets a piston - Boatfreaks

Yeah 300 is ALOT of p to v. He probably had the lifter bottomed out.

You need to find a machinist who uses another method to determine the cam phasing. Watching the lifters move is NOT the way to determine if the cam is in right.

What was the engine temp, thermostat or not and if so who's t-stat housing are you running?

What diameter are the valves?? may be expanding and kissing the piston..did they fly cut the pistons? when you say .300 is that intake or exhaust...i would also get rid of the edelbrock carb and find a 800 cfm carb..if its lein all sorts of chit happens to the valve trane from the heat.

Im with griff. Timing marks may be lined up, but did he installthe crank timing gear correctly? If its one of the deals with multiple degree positions that need to match cam gear. Seems like the timing is off causing it to run hot and cause some major valve dragging combine that with the valves opening and closing out of time with the pistons.... Disaster.

They have told me that they double checked the cam timing today and it was okay. I'm not so sure that they have degreed the cam. I believe that they double checked that they have put the timing gear together in the right holes and I've not done this myself before so I don't know what to look for. Coolant temps were 145 to 160 while underway before it smacked the valves. The machine shop has told me that they believe old fuel gummed the valves up and caused them to stick. Fuel was purchased last October and was stabilized supreme (91 oct rating). I ordered the Manley severe duty marine valves to install on the exhaust side as well as the corresponding Crane valve springs. I have also purchased a brand new Holley 800 double pumper marine carb. I'm frightened to death that I'm throwing good money after bad here.

GO TO A DIFFERENT MACHINIST!!!!!!!!!!

You are dealing with a guy that's "in over his head".

This isn't a stock 350 going into a Monte Carlo.

Bad gas making the valves stick?????? Please!

As far as the bad gas goes, I don't think it's old enough yet, but you could drain it to be sure.
A short story on stuck valves, a friend bought a '98 GT Mustang, it had been sitting for a few years, drained the tank, tune up etc. Ran pretty good, the next day he went to the shop to work on it some more and when he turned it over it had 0 compression. Most of the valves were stuck in an open position. Pulled the heads and it was like syrup (ethanol) in the guides. Re did the heads and it runs fine.
Not to hi jack the thread just wanted to share.

You have,,,, pushrod, rocker arm, timing, clearance issues. Meaning you need to start from the lifters up, make sure the pushrods are the right length, rocker arm ratios are what you need, and 300 thousands clearance,,,not sure about that! What timing set is in it? Is it adjustable?
Just a few thoughts.

Make him dyno it before he gives it back again.

But I agree,,,, find another assembler

The machine shop should be able to show you a build sheet on YOUR ENGINE with how YOUR cam is degreed in. I mean, they had it apart a few times, right, AFTER piston:valve issues?
Did they REALLY say "look at that lifter start to move, that means it's degreed properly"?!? WOW!!! I mean, Shizz son... maybe if Smokey Yunick said it, but he's dead so everybody ELSE shows the build sheet!

The Piston to Valve clearance must be done with a SOLID/testing lifter or similar, or the hydraulic pumps down, does NOT push the valve to full "pumped up lifter" lift, and shows falsely high piston to valve clearance.
I don't care WHAT they SAY the static P:V is! When your engine runs, MULTIPLE valves are RIGHT ON THE EDGE and some are going into INTERFERENCE condition. Your engine isn't "Magically" doing this, it is a setup issue of SOME kind.

You should not have SO much gum on the valves/valveguides to stick a valve against valvesprings with 250-350 lbs range seat pressure. If the valveguides were too tight and valves get hot that CAN happen but geez. Again, they should know the valveguide clearance figures. Not where the money is, I mean what kind of oil was being used that so much built up? It wasn't just ONE valve, you've had multiples.
If they were that shizzy, why didn't they disassemble the heads, clean them, clearance the valveguides/valves?

This is a MACHINE SHOP'S JOB, to BUILD you an engine COMPETENTLY that does not have basic MECHANICAL INTERFERENCE ISSUES, whether it's "dirty sticking valves" or "cam degreed wrong" or "heads/block were shaved/decked too much so less P:V clearance than should be when lifters pump up" or WHATEVER.

Again, you have MECHANICAL PARTS running into each other during rotation. This is the MACHINE SHOP'S JOB, it is NOT a "tune issue" or a "gasoline issue" or an "operator issue".
We aren't saying the shop are bad people but if you are PAYING them every time for this, "Their Freshness Date Has Expired".

I did just this with brand new inconnel valves. It is easy to install the crank timing gear in the wrong keyway and that is what I did. You description is identical to what happen when I had the crank gear in the wrong keyway. I'm with griff and meangreen. Does your crankgear have 3 keyways and if so which symbol key is the keyway on? Should be a triangle, o and 0.

If his engine builder degreed his cam when he installed it he should of seen right away if the crank gear was in wrong.

My thought was the cam was never degreed. When I installed my crank gear wrong (many moons ago) was the last engine I built without degreeing the cam. A quick observation of the crank gear or of the dots line up will tell the tale.

I agree if the head gasket is wrong strange things happen with heat, as well if the lifters are slightly to tight it will take about that time to build full oil pressure, thus bent valve. But by the sounds of it are they trying to help solve the issue? Hope so its the right thing for them to do . Good luck.

Are you running a water pump or a crossover?
I also believe that this might have also contributed to my failures outlined in the earlier link.

It has an Edelbrock circulating pump. I checked the head gaskets when I was over there today and the coolant passages all seem to line up. They are adamant that the cam timing is set correctly and have pulled it apart and checked it. I'm honestly lost. They think it's due to the oily build up in the combustion chamber and resultant heavy carbon build up on the valves. The new Manley severe duty marine valves arrive tomorrow and they are checking all of the guides with the diamond hone. I just don't want this to happen again.

A machine shop not degreeing the cam on a performance engine? I'm with those who say find a new builder/machine shop. If the timing is out it would be obvious as soon as the cams degreed. Going off of valves opening when this one is closing etc, etc is bs. It doesn't take very long to check and be sure. Mechanical damage from piston to valve interference is based off of timing being off or the valves are sticking in the guides because they are to tight when the motor heats up. Gummy residue on the valves from old gas with in 5-10 minutes of run time?? Hmmm sounds interesting. I don't build automotive engines on a daily basis, but I do build racing motorcycle engines daily and have seen some old gas, methanol and nitro mixes. I've ran them on the dyno with the customer not knowing of the bad fuel and they run like crap, but don't cause mechanical failure. Unless it had a ton of water in the fuel and it hydro locked.

Long story short, two times and still the same problem = news machine shop. In my opinion.

My expierance,,the exhaust valve is a common one to stick and or smack a valve due its expansion when the valve is hot.. you really need to be their watching them this time when checking the piston to valve clearances..i like to see a minimum of .100 thou..

It would probably be in your best interest to get someone to measure the guide clearance, particularly on the exhaust valves. Check them for being concentric as well as several spots along the guide. I believe 0.0015 - 0.0017 is a good ballpark to be in, but you should verify that with some experienced performance marine engine builders. Lifter bore clearance is another measurement that is often overlooked.

I'm taking the engine to another builder to dyno it. The original builder thinks it's fine and I told him he better be sure because if it blows on the dyno he'll be fresh out of excuses. He assures me that he has double and triple checked everything and now thinks that maybe the oil was drasticvally overfilled because of a poorly calibrated dipstick. I guess we shall see.

I don't think he is going to run out of excuses sounds like he has a whole book of them!

Keep us posted on how it goes. Good luck.

This is the kind of nightmare I hope I can avoid. Have one guy build it, another guy dyno it. If anything goes wrong then finger pointing.

I would pay to have the second guy reclearance valves=heads after degreeing the cam, just my .02.

Wannabe

Please listen to X-wing.
and by all means,
Bolt on a degree wheel to the crank.
Find TDC thru the spark plug hole (with an adjustable TDC stop) - adjust it so that it touches the #1 piston about 10* before TDC and check it in both directions and zero your crank pointer so that the number is the same from both directions.
Pull a valve cover and borrow a 1" dial indicator on a magnetic base and find your intake centerline. It should be wherever your cam card says (or up to 4* advanced).

That is the ONLY way worth a crap to check the installed position. All it takes is pulling one valve cover, and a little bit of time. You can do it on an engine stand, in the bed of your truck, in the boat - it is really NOT a time consuming job.

Crank keyways can be "off" a little bit. Stock timing marks on the timing cover can be "off" a little bit. Cams can be ground "off" a little bit. Timing sets can be "off" a little bit.

Don't trust the freaking timing marks in a situation like this.

No "builder" who is worth handing a dollar bill doesn't have a degree wheel and some knowledge on how to use it.
It's really as easy as I said above.

MC

:popcorn:

WOW!!!!! A fresh set of eyes is whats needed. I agree with degreeing the cam. You can pick up a wheel from summit /jeggs and and a dial indicator for not alot of cash. Its not overly complicated.

I say that the ACTUALL V/P clearance is next to 0.000 Been there done that. SAME RESULTS

One other idea, I have seen people misadjust their valves with no oil in the lifters.The lifters pump up some of the valves may not even quite close. At that point you could get contact. Your piston to valve clearance would have to be pretty tight for this to happen. What was the clearance when the machinest clayed the pistons.

I always used the light spring method with a dial indicator + or - 10 degrees from TDC.

lets think this out,without knowing the part number of the pistons there is no way to know if they are flat top or have a small dome,im assuming they have a small dome to achive 9.3 to 1 compression ratio,this is assuming the heads are not angle milled.your cam is somewhat mild so there should be plenty of piston to valve clearance if the cam is installed correctly.three things could be causing your problem,1 valve to guide clearance not sufficent 2 cam installed incorrectly 3 weak valve springs not pulling the valve back on the seat causing contact with the piston.at this point if this engine was in front of me i would remove heads and check ALL valve to guide clearance,[2] degree camshaft to make sure it is installed correctly[3]check valve train geometry[4] check valvespring pressure on the seat[5]check piston to valve clearance useing a solid lifter so there is no bleed down.these are all things that a competent shop can and should do.even though this engine is close to stock all these things still need to be done.after 2 failures maybe it is time to find a different shop to do the work.hope this helps.

Fixed it
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