SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: J2 on October 24, 2016, 07:53:15 AM
-
Who's our local cylinder head expert?
I have the Iron Square port 990 heads. When I built the engine many years ago I had a full valve job done and the shims they used started to come apart within a few trips. Caught it early and went to Teague, they don't stock that sort of thing and sent me across the street to Jim Grubbs Motorsports. I know a bit about Mr. Grubbs and trusted what he sold me. Hardened shims.
Since these were not supposed to come apart I didn't look under the valve covers as often. Fast forward to last week, lost oil pressure, fortunately caught it with a few seconds of happening. Swam the boat to shore and hiked it up river to a friends place and got a ride to my truck.
Top of the oil pump shaft broke off. Pic is of the piece that found it's way to the pan through the screen and froze the oil pump gears. Pump moved back and forth with the piece stuck in between, no noticeable damage to gears. I'll go through everything to look for damage, I was lucky. Water was rough so no long runs, was going out the following morning to see what it would do, that would have smoked everything or it would have run right through the gears causing damage later.
So the question is why are these coming apart? Running Comp Cams springs 924-16 matching my cam.
Who should I consult?
-
I would investigate coil bind. If the springs are allowed to bind, it will hammer all kinds of stuff apart. What rotators, where does the Rocker arm contact the stem at full open and full closed, what rocker arm ratio, hydraulic cam or solid, lash, were the spring pockets machined, are they straight and smooth?
Lots of factors come in. Sure sounds like a fundamental issue.
How many shims showed signs of damage?...
-
I would investigate coil bind. If the springs are allowed to bind, it will hammer all kinds of stuff apart. What rotators, where does the Rocker arm contact the stem at full open and full closed, what rocker arm ratio, hydraulic cam or solid, lash, were the spring pockets machined, are they straight and smooth?
Lots of factors come in. Sure sounds like a fundamental issue.
How many shims showed signs of damage?...
Haven't removed the springs to see damage yet. Might have to wait until next weekend.
Hydraulic Flat tappet. Lash set per Comp cams specs Pro Magnum lifters, 1/8 turn, I know this sounds unusual, but it's what they need. Stem pretty close to center, will take a closer look and will take some pics. Teague 1.7 roller rockers. Spring pockets were straight and smooth last time I looked. Had a complete valve job when I put the motor together about 6 years ago.
Thanks
-
Haven't removed the springs to see damage yet. Might have to wait until next weekend.
Hydraulic Flat tappet. Lash set per Comp cams specs Pro Magnum lifters, 1/8 turn, I know this sounds unusual, but it's what they need. Stem pretty close to center, will take a closer look and will take some pics. Teague 1.7 roller rockers. Spring pockets were straight and smooth last time I looked. Had a complete valve job when I put the motor together about 6 years ago.
Thanks
Spring bind height is 1.175", you will need additional clearance above that, have the valves/seats been cut since the original build? How many shims are failing? (I know it's not apart yet).
The shims need to fit pretty well, they can't be allowed to walk around in the pocket.
Are you running the same head gaskets from the original build?
1/8 turn sounds funny, is that from the manufacturer?
GT
-
Just verified the 1/8 turn on the lifters "zero to 1/8 turn".
-
You didn't state the shim thickness required for you application, but here is what we use. Can be used with or without additional shims, available in different thicknesses.
Smilies are killing me. Lol
-
Cup
-
Who's our local cylinder head expert?
I have the Iron Square port 990 heads. When I built the engine many years ago I had a full valve job done and the shims they used started to come apart within a few trips. Caught it early and went to Teague, they don't stock that sort of thing and sent me across the street to Jim Grubbs Motorsports. I know a bit about Mr. Grubbs and trusted what he sold me. Hardened shims.
Since these were not supposed to come apart I didn't look under the valve covers as often. Fast forward to last week, lost oil pressure, fortunately caught it with a few seconds of happening. Swam the boat to shore and hiked it up river to a friends place and got a ride to my truck.
Top of the oil pump shaft broke off. Pic is of the piece that found it's way to the pan through the screen and froze the oil pump gears. Pump moved back and forth with the piece stuck in between, no noticeable damage to gears. I'll go through everything to look for damage, I was lucky. Water was rough so no long runs, was going out the following morning to see what it would do, that would have smoked everything or it would have run right through the gears causing damage later.
So the question is why are these coming apart? Running Comp Cams springs 924-16 matching my cam.
Who should I consult?
Kinda an odd looking shim bit... Like wrong shim. Should have something that looks like a flat washer that just fits around the guide and barely goes inside the spring pocket (to keep movement to a minimum) Valvetrain harmonics, coil bind, wrong shims... And a couple other reasons will cause shims to flake apart... Kinda just need to see what you have going on before drawing to a conclusion.
Sent from my iPhone using SoCal Jet Boats
-
Spring bind height is 1.175", you will need additional clearance above that, have the valves/seats been cut since the original build? How many shims are failing? (I know it's not apart yet).
The shims need to fit pretty well, they can't be allowed to walk around in the pocket.
Are you running the same head gaskets from the original build?
1/8 turn sounds funny, is that from the manufacturer?
GT
No valve work since original build. This is 4th season since replacing the shims, only thing I've had to replace except the intake gasket & pan gasket after the original shims started coming apart and yes same head gaskets.
The 1/8 turn always gets the head scratching going on when I mention it :sly:
I'm thinking about tinkering this evening to figure out which one or two or ...
Thanks GT
-
Kinda an odd looking shim bit... Like wrong shim. Should have something that looks like a flat washer that just fits around the guide and barely goes inside the spring pocket (to keep movement to a minimum) Valvetrain harmonics, coil bind, wrong shims... And a couple other reasons will cause shims to flake apart... Kinda just need to see what you have going on before drawing to a conclusion.
Sent from my iPhone using SoCal Jet Boats
It looks familiar which is why I say shim or shims coming apart. More to come, Thanks for your input.
-
Here's a few pics before I take it apart, won't be today. I found a couple of similar pieces near #2, close up pic.
Then there's the Mellings shaft that broke. I feel like this happened near idle, if I was running 6000+ rpm wouldn't that small piece run right through the oil pump? Shaft is part # 12770
Cylinders that I can see and the bottom of the pistons all look fine.
-
Don't take this the wrong way, but those retainers fit like crap.
GT
-
Don't take this the wrong way, but those retainers fit like crap.
GT
Good point, never thought twice about it. On a side note if I couldn't take it I wouldn't have posted the pics. Keep it coming :thumbup:
I know I've made mistakes along the way, but I still prefer to do it all myself. Thinking back, new springs, new rockers, existing retainers, hmm, guess I should have matched the retainers to the springs. Well shit I just realized the machine shop that did my heads put em together like this, less the inner springs for break in, then I put them in.
Another B.O.A.T. part to add to the list, my wife doesn't like my boat part list >:D
Looked up my springs on Jegs site and there's the retainers... only $58.
-
Good point, never thought twice about it. On a side note if I couldn't take it I wouldn't have posted the pics. Keep it coming :thumbup:
I know I've made mistakes along the way, but I still prefer to do it all myself. Thinking back, new springs, new rockers, existing retainers, hmm, guess I should have matched the retainers to the springs. Well shit I just realized the machine shop that did my heads put em together like this, less the inner springs for break in, then I put them in.
Another B.O.A.T. part to add to the list, my wife doesn't like my boat part list >:D
Looked up my springs on Jegs site and there's the retainers... only $58.
I would replace the retainers, checking the spring height with the new retainers and shim accordingly, those retainers are crooked/lose enough to cause some serious spring rotation and could very well cause enough harmonics to destroy the shims.
I'm sure someone else will chime in, that just jumped out and kicked me in the eye.
Good hunting, and good on you for doing it yourself and accepting the problems associated with failures like a man. Very endearing quality.
At this point, you can't over measure. I would even go as far too say the spring pressures should at minimum be verified, in all honesty, I would change them all out, but I'm a nervous Ned when it comes to crap like this. Just thinking they haven't really been hitting super square and a failure would be costly.
GT
-
Yeah... Springs wobbling all around on the retainers will cause some funky harmonics... And start chewing up shims. If it were me... I'd pull the heads at least and give them a good once over look... If you're not able to control the valvetrain... Then I wouldn't be suprised to find beat up valve seats as well.
Sent from my iPhone using SoCal Jet Boats
-
Yeah... Springs wobbling all around on the retainers will cause some funky harmonics... And start chewing up shims. If it were me... I'd pull the heads at least and give them a good once over look... If you're not able to control the valvetrain... Then I wouldn't be suprised to find beat up valve seats as well.
Sent from my iPhone using SoCal Jet Boats
I agree. Also inspect the valve stems for galling at the guide.
Unfortunately, the only real guarantee it will be right is if the heads are removed and gone through real quick like.
If you find one little seemingly insignificant thing or will be worth it in the long run.
As an example, a cracked seat could drop out, take out the valve, taking the piston with it, potentially killing the block.
I'm only able to put that together because it happens all the time.
Shouldn't be that expensive really, hell of a lot cheaper now rather than later.
GT
-
I agree. Also inspect the valve stems for galling at the guide.
Unfortunately, the only real guarantee it will be right is if the heads are removed and gone through real quick like.
If you find one little seemingly insignificant thing or will be worth it in the long run.
As an example, a cracked seat could drop out, take out the valve, taking the piston with it, potentially killing the block.
I'm only able to put that together because it happens all the time.
Shouldn't be that expensive really, hell of a lot cheaper now rather than later.
GT
☝️☝☝☝so true .....you'll be ahead in the long run
Sent from my iPhone using SoCal Jet Boats
-
I did most of the work before it got cold outside. Took it apart and checked everything out. Put it away until it got warm out a couple of weeks ago.
Replaced retainers, shims, oil pump & shaft. Got lucky, engine in good shape.
Ran it to test & tune on the trailer. Compression check is consistent with past results since 2013. Real happy about that.
Ready for a lake test and it gets cold again :mad:
Thanks GT & Six Oh Nine for your input!