Valves Collide with Pistons ....
 

Starboard motor began not wanting to idle ...found wet plugs and 2 cylinders no compression ...Pulled the heads and found 2 valves open and slight impressions in Pistons ...head shop is inspecting the heads today ...we couldnt find any source for the water ..the Exhaust and risers had showed no signs of leaking esp inside ...no trail of water towards head ...any thoughts ?


These are stock 454 mags ...

Re: Valves Collide with Pistons ....
 

What kind of exhaust? How are your flappers on or in the tips?

Re: Valves Collide with Pistons ....
 

Stock merc manifolds and risers ...Formula Silent Thunder ...I was thinking maybe need to check inside Flappers ? Outside are fine ...

Re: Valves Collide with Pistons ....
 

these are jasper Motors installed June 03 ..25 hours MAX ...run 46-5000 WOT. I have been doing some Prop tuning but really only at WOT a cpl of times and only one extended run ...10 mins max ....I dont hammer these motors ....usually 3000-3600 ...

Re: Valves Collide with Pistons ....
 

Which valves were open? If an exhaust valve hangs open, it will suck water into the cylinder which sounds like what you have.

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Same ? as above about which pistons. Also didn't they make a heck of a noise. I had a guide hang up (Salt and sitting...) and it was pretty loud, thought I really broke something.

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Joe ... 4 and 5 ....the exhaust valves were hung open ..not sure if they were bent or what ....

Sutphen ...Stock bravo's ...not really any change in speed ..This motor has NOT got hot ...After a simular episode with port motor this spring I watch temps very close ....

Re: Valves Collide with Pistons ....
 

I had the same thing happen on the SBC I built for the Minx. For some reason, the brand new crane hydraulic lifters wouldn't collapse down when I originally set them. I had to set them like solids.

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these mag motors have roller lifters but standard rockers ...I am thinking about going to roller rockers ....you know we never found the source for water in the port motor last spring ...it did get hot though ...but we tore it all apart ..did the heads ..new gaskets and since then has been fine ....

Re: Valves Collide with Pistons ....
 

hoping to hear something from Dover Head today ....Talked to Jasper Motor and warranty ran out in June ..they claim 18 month on their website but these "hi performance" motors only have 1 year ...what bothers me is 2 different Valves and seaperate heads ...

Re: Valves Collide with Pistons ....
 

Mike,

Sorry to hear you have a problem again. I don't think this is from the internal flappers ... they were burnt out in my 311 and I never had this kind of problem with my stock motors.

Were these your original heads and were they magnafluxed before re-installation?

What material were the valves and were they new? You should be using severe duty stainless for the intake side and Inconel for the exhaust. Doesn't really sound like you ran it hard enough to hurt them, even if they weren't severe duty.

Were the valve guides new or reconditioned (knurled)?

I have two complete sets of aluminum roller rockers with only two hours on them. Let me know if you are interested in them.

Wish I could be more help to you on this! Good luck and please post your findings when you get this sorted out.

Chris

Re: Valves Collide with Pistons ....
 

I believe the Jasper motors are long blocks ...boat was new to me in April ...this motor was installed June of 03 ... I agree on the internal Flap but really dont know for sure ...usually try to not slam on the brakes ..the only one time was when the port motor got hot 1st time out ...shut it down as soon as I saw the temp peg ....

Re: Valves Collide with Pistons ....
 

one bent Valve ..one with some rust 2 valve seats need replacing but going to replace them all with a different type .......everything else is ok ....

Re: Valves Collide with Pistons ....
 

Could it have been reversion? What's the cam specs with centerline?
Are you running OEM merc risers or aftermarket risers?
Any water in the oil?

Re: Valves Collide with Pistons ....
 

I am not sure of cam specs but would assume 454mag specs would be pretty mild ....I think the manifolds and risers are Siera's ...and yea there was some water in the oil ....

Re: Valves Collide with Pistons ....
 

The motor was put back together and ran it for almost 2 hours on the stand with no problems ...Put the motor in the boat and my mechanic ran it for another 2 hours in the river with no problems ...65 mph at 4500 rpm ...( gota get those props tuned) ..I picked up the boat ..ran 5 miles to the house ....came off a plane and Same motor Stalled (star) ..cranked it up was running on like 3 cylinders ...shut it down and Idled back to shop ...talk about frustration .....

Re: Valves Collide with Pistons ....
 

I had a water in the oil issue recently. When I re-did the heads springtime,I put aftermarket risers (sierra) on just as a precaution. Boat ran fine but spun a brg later in the season. Replaced the cam upon rebuild. Ran the engine @ high idle to break in the cam and everything was fine. Idles it the next day and had milk. Had the bore scope in the cyl and h20 around the valves etc. Long story very short...took the exhaust off one side to the other and no more milk. It turned out to be the design of the riser on the aftermarket riser. Take a merc riser and compare, you'll notice the differance.

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shop just called .....no compression in one cylinder again ...dont know if its the same one ........now they want to repull the motor and gon into the bottom end .... If we have piston/valve contact again ....what in the bottom end would cause that ?

Re: Valves Collide with Pistons ....
 

Dollars to doughnuts the previous owner went "cheap" and did not spec marine grade.... hence the rust meaning NOT SS valves. That is why the valves hung up.

I suggest you have the heads on both engines redone.

Wannabe

Re: Valves Collide with Pistons ....
 

Jasper Reman motors ....Stainless Valves ... I would think a spun bearing would let the piston contact the head and would let you know it ...the first time was just a slight ring where Exhaust Valve tapped the piston ....might know this afternoon if it same symtoms

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I would agree with all of these guys, the problem is in the cyl. heads, exaust manifolds. Guides are causing valves to stick. Could be because water is getting to the head causing corrosion. These are old engines, exposed to salt water for a long time. Taking apart the bottom ends will just cost a lot of money.

Re: Valves Collide with Pistons ....
 

Patriyacht has a good point! I would never imagine in a million years the design of a stock riser would cause a problem. Took me a few weeks to figure it out after changing intake,exhaust gaskets... pressure testing this/that. Came close to winterizing the boat in July!

Re: Valves Collide with Pistons ....
 

My father in law boats around Long Island. His boat sits in the water all summer. After 3 years, he had to replace the exhaust manifolds. They were already leaking. It makes you wonder how long the rest of the engine will last.

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Offthefront, did you check the valveguide to valvestem clearence. I've heard of valveguides cracking also.

Re: Valves Collide with Pistons ....
 

head shop inspected the heads ...replaced 2 valves and all exhaust seats ...they will have to go back this week ..I am sure we find something else ...

Re: Valves Collide with Pistons ....
 

I've been watching the two threads on this situation and have to admit that it's a bit of a muddle. The worst situation is that after 25 hrs, the valves are hitting the pistons of what should be a very mildly built motor. Sorry, but I don't think the problem is in the bottom end. Nor do I think a stuck valve or reversion caused the valves to hit the pistons. The way us old timers used to check valve to piston clearance with high compression (domed pistons) was to put the pistons at TDC with the valves fully open and check the clearance. This way, you could float the valves or have a timing chain let go and not grenade the motor. Obviously, the valves shouldn't be full open with the pistons at TDC unless something unnatural happened. I'm puzzled as to how a relatively low compression motor cold have valves in several cylinders stick full open and hit the pistons. Having said that, the many folks here that know more than me can enlighten me. Moving on, this is supposedly a Jasper long block. Is it a maranized long block? What's the cam and it's Lobe Separation (LSA)? Sounds like reversion or water getting into the cylinders (risers) could be another problem. I believe Offthefront said it ran fine on the hose until he took the boat out on the water. Were the exhaust manifolds pressure checked? Without seeing the motor as it was disassembled it's hard to comment further, but the valves hitting the pistons in several cylinders really puzzles me. Keep us posted. Lou

Re: Valves Collide with Pistons ....
 

ok .. first time only one valve hit piston ...the other was stuck open but did not contact the piston ...this time its the same piston ..same valve ....the other side seems ok ...I went by the shop today and they showed me the lifter and you can see where the pushrod has walked around in the lifter ....so either the lifter is not pumping up or spring tension bad or bad adjustment ? I dont know ....If I knew .. I would be doing the repair and not them ...

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If the valve is sticking, the push rod would bounce around because there is no spring pressure on it. That is not your problem.

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Mike-- Patri Yacht is correct. If the valve is stuck in the guide partially open, there will be play in the pushrod until the cam tries to open the valve further. Then something's got to give which would show as a chewed up seat in the lifter. What you're describing is the result of your problem and not the cause as he suggests. If water is getting in the cylinders, it would explain warped/stuck valves. It does not explain the valves hitting the piston. I know this is frustrating not to mention expensive. We've all been there and are just trying to help.

Re: Valves Collide with Pistons ....
 

Offthefront, as I said in one of my post. I have the 365 mag's and the aftermarket risers made no differance w/the old cam. As soon as I changed to a new cam (same spec) I had problems with water. It was plain to see with the bore scope I was having a problem with water in the exhaust. And yes, the stem of the valves were pretty rusty by just running the garden hose thru the engine. This was driving me up a f'in wall. The design of the riser was at fault.

Re: Valves Collide with Pistons ....
 

Cig ...your loosing me ..you went to a new cam with same spec's and then had problems ? the valves are SS ...also this valve was brand new ...So I dont see how corrosion could do it ...so soon ...they did just the EM's last time but pluged it with clay ...only 5-6 lbs .. to me thats not enough ...

Re: Valves Collide with Pistons ....
 

What are the valves? If not severe duty, and if engine is run out of tune (lean for instance) you can get this result. It will trick you because the exhaust valve will get hot and start to move, then start sucking water and then you get the result you have, or worse the valve head pops off. If its not that, then the risers most likely. Do you run the 3" spacers by chance? I could never keep that crappy system from leaking... terrible design.

This time put in top of the line manley valves for starters. Once running again, read the spark plugs in primary and secondary circuits of the carb. and determine state of tune.

BTW, all valves are stainless. But there is a large difference between high quality and regular grade, as wannabe was saying. You want one piece, severe duty, with no necking of the stem. Preferrably 3/8" stems.

BT :cool:

Re: Valves Collide with Pistons ....
 

A stuck open intake will draw water in the cylinder.

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Actually, if the risers were leaking the water in the cylinders would cause severe damage due to increased compression and or hydrolock. The fact that no major damage is done indicates the valve is already bent before the water infiltration. Therefore the water is being freely pumped into and out of the cylinder via the bent exhaust valve. Your valves are weak and your tune suspect... (nothing personal :p )

BT :cool:

Re: Valves Collide with Pistons ....
 

Blue Thunder/Cuda-- Good input on water ingestion/reversion and whether this Jasper long block contained marine components. But I'm still not hearing why a number of valves hit the pistons. I'm willing to bet you could open those valves to the point where there was coil bind and still not hit the pistons. Maybe the valve heads warped to the point where they weren't square to the valve stem? I apologize for sounding like a cynic but I'm just wondering if there's an automotive cam and valves in that motor. It definitely sounds like water is part of the problem cause or is the result of some other problem(s).

Re: Valves Collide with Pistons ....
 

Only ONE valve (exhaust) has kissed the piston . #5 I believe ...same one two different times ....Jasper knows it was a marine motor ...I would think they build it to spec ...talked to them today and they want us to check timing gear/chain for wear ( i dont see how with 20hrs) or damage ...we will check it .... Valve warp ? from the revervsion ? .... there is one scary thought in my mind is maybe it IS something I am doing comming off a plane ....My mechanic took the boat out and ran it for over an hour with WOT runs and had no problems ....I ran it 15 mins @ 4000rpm and it broke ..When I come off a plane I dont slam on the brakes but I dont take a mile to stop either ....I ease off plane and then throttle all the way back ...maybe I need to keep 1000+ rpms till boat settles ? I cant believe its that sensitive and also have silent thunder so there is no full blast from wake in the rear ...also all he plugs are out of the bottom of the platform wich menimizes water in box .....

By the way I dont take any of this personal so keep em commin ...mike ..

Re: Valves Collide with Pistons ....
 

Mike--Here's what I'd do. I'd put #5 at TDC, pull the spark plug and pump it up like I'm going to do a leakdown test. Then I'd remove the valve spring for the exhaust valve and replace it with a soft sring so you can check the clearance to the piston with the valve at it's normal maximum lift (you'll need a dial indicator). The results of this will hopefully explain why that exhaust valve has TWICE hit the piston. I agree that it's unlikely the timing gear/chain is the culprit with 25 hours but you have to check for everything. Who knows, maybe the keyway was broached wrong on the timing gear and the cam is way off (advaced/retarded). Now since we're concerned about water ingestion/reversion, did Jasper confirm that the cam is a Marine cam with appropriate Lobe Separation Angles to avoid reversion? I don't think with a Bravo setup that you should be extra vulnerable to your wake coming back up into your engine though the thought crossed my mind ( post #31 ) after you said it ran great on the hose until you took it out on the water. Which takes me back to confirming that you've got a Marine cam in that motor. Personally, I'm extra careful coming off plane. After making sure my wake doesn't catch up to me, I put both motors in neutral, bring the rpm's up to 1500-1800 to get a little water pressure to try to minimize any steam pockets,etc. Probably overkill but it's worked for me so far. Good luck! Lou

Re: Valves Collide with Pistons ....
 

If it's only #5 having the problem, did they check guide to stem clearance on that valve? If it's too tight, it could bind and cause the valve to hang open when it gets hot. I think the wrong cam or bad timing chain would affect all cylinders, not always #5. When you put the heads back on after the first repair, did you put them on the same sides you pulled them from? If so, concentrate on the head first. If you swapped sides and #5 went bad again then I'd look elsewhere.
Just my $.02 :)

Re: Valves Collide with Pistons ....
 

I have seen a several problems with valves hanging in apparently stock motors. It seems that there is always some water vapor in the area of the exhaust ports. It seems that it is very important to make sure that the exhaust gasket and exhaust manifold do not overlap any part of the exhaust port on the head. If it does it can cause any eddy of trapped water vapor that will dry out the oil film around the exhaust valves causing either accerated valve guide wear or seizure. We fought a similar problem with a 502 for months after replacing the exhaust with merc replacement. After trimming the gasket to match exhaust port and matching the exhaust manifold to gasket the problem never returned. Don't really know the science in this but it seems possible.

Mark

Re: Valves Collide with Pistons ....
 

Mike, just trying to help you out. I replaced the cam because it was worn, once the new cam was installed the reversion problem started. I only ran the engine in the driveway but had I ran the boat WOT in open water, I'm sure it would have been a simular problem to yours. It drove me nuts for weeks on end and with help from Marc @ BAM he helped to steer me in the right direction.
I wish I had a pic of the top of a merc riser to show you the differance. I can get a pic of the aftermarket riser if you want. Alot of good advice here on this thread for you to follow. Hope it all works out for you.
Stan