Performance Boats Forum banner

1 - 13 of 13 Posts

·
Registered
Joined
·
4 Posts
Discussion Starter · #1 ·
I've did several searches on this, and came up with a majority vote on not installing 1.880 exh valves intothe 049 oval port heads due to the chances of hitting water. Always thought putting big valves in the 049's was the right thing to do.

Are the chances still there if you go with a valve seat with the same OD as the exhaust valve, or at least close, i.e. .010-.030 bigger?

Example of dimensions
Seat OD - 1.88 + ??
Seat ID - 1.5625
Seat Depth - .3125

If the majority of the vote is against this, what's my alternative? The cast iron is not tempered below the exhaust valve now. Wouldn't this beat the seat up really bad? You could tell when milling the heads that the head material got really soft there.
 

·
Registered
Joined
·
4 Posts
Discussion Starter · #2 ·
Sorry, didn't realize this was my first post. Used to search the HB forums alot, but that's dead now right? Anyway, I'm Joe from KY, and really need some good advice. On a budget, so no fancy stuff for me :(
 

·
Registered
Joined
·
4,288 Posts
I'm not the sharpest tool in the shed when it comes to this stuff, but I thought hardened seats were pretty much a must with unleaded fuel.
 

·
Premium Member
Joined
·
5,488 Posts
2.190 & 1.720 in my 049's ...10 years ago Brandywine Cylinder Head Services in Pa didn't want to go any bigger >River/Lake daily Jet Boat.
 
Joined
·
283 Posts
2.190 & 1.720 in my 049's ...10 years ago Brandywine Cylinder Head Services in Pa didn't want to go any bigger >River/Lake daily Jet Boat.
2.19 % 1.88 in my 049's and never had a single issue and this motor is going on its 12th season! Why wouldn't you put big boys in them?They make great power ported with big valves!:)devil
 

·
Registered
Joined
·
389 Posts
I have a set of 049 and 781 with the 1.19in and 1.88ex and never had a problem ever. They work extremely well in that head. If I were you I would I put them in. That's just me
 

·
steelcomp was here
Joined
·
26,529 Posts
I've did several searches on this, and came up with a majority vote on not installing 1.880 exh valves intothe 049 oval port heads due to the chances of hitting water. Always thought putting big valves in the 049's was the right thing to do.

Are the chances still there if you go with a valve seat with the same OD as the exhaust valve, or at least close, i.e. .010-.030 bigger?

Example of dimensions
Seat OD - 1.88 + ??
Seat ID - 1.5625
Seat Depth - .3125

If the majority of the vote is against this, what's my alternative? The cast iron is not tempered below the exhaust valve now. Wouldn't this beat the seat up really bad? You could tell when milling the heads that the head material got really soft there.
I just finished a set of 049's with 2.25/1.88 valves, no seat inserts. Typical marine use is well below automotive use in terms of running time, so I think the consensus is that unleaded set wear isn't as much of a concern. Keeping up on valve spring maintenance is helpful, since there's nothing harder on a seat than a waeak valve spring. You can add fuel additives if it's a concern based on personal preferences. In asnwer to your question above about seat size, you usually don't want the 45 to be on the edge of the seat. The ID is usujally dictated by the head.

ETA:
Heads flowed >[email protected] intake, and [email protected] ex with just a bowl blend, nothing else. That's good for an honest 600hp on a 496.
 

·
Registered
Joined
·
39 Posts
Joe I'm in the same boat, the machine shop called me yesterday expressing concerns of hitting water, he said after cleaning the 049 castings up, he noticed a lot of core shift in the castings which he said would elevate the chances of hitting the water jacket, he is uncomfortable with changing the seats,as it may trash the castings, he said even if he didn't hit the water jacket, this could leave a thin supporting structure for the new bigger .188 seats, which could be prone to cracking... so now what?:)bulb Need to make a decision quick, plans for the engine are a tunnel ram 468 going in a 21 daytona jet.. like to get over 550 ponies on a solid flat tappet. Only want to do this once. Any one try any of the Pro Comp Electronics heads on Ebay? Recommendations?
 

·
Registered
Joined
·
5,180 Posts
I bet their are more with the big valves then the smaller stock ones out there now.
 

·
steelcomp was here
Joined
·
26,529 Posts
Joe I'm in the same boat, the machine shop called me yesterday expressing concerns of hitting water, he said after cleaning the 049 castings up, he noticed a lot of core shift in the castings which he said would elevate the chances of hitting the water jacket, he is uncomfortable with changing the seats,as it may trash the castings, he said even if he didn't hit the water jacket, this could leave a thin supporting structure for the new bigger .188 seats, which could be prone to cracking... so now what?:)bulb Need to make a decision quick, plans for the engine are a tunnel ram 468 going in a 21 daytona jet.. like to get over 550 ponies on a solid flat tappet. Only want to do this once. Any one try any of the Pro Comp Electronics heads on Ebay? Recommendations?
Reccommendation? Don't.

Oversized valves don't require installing seats, and neither does a marine application. Installing seats requires machining away more material than just doing the oversized valve job and does increase the risk of hitting water. Just doing an oversized valve job shouldn't be a problem. Worst case, find another set of castings you're more comfortable with.
 

·
I'm No Expert
Joined
·
3,142 Posts
Sorry, didn't realize this was my first post. Used to search the HB forums alot, but that's dead now right? Anyway, I'm Joe from KY, and really need some good advice. On a budget, so no fancy stuff for me :(
Joe, That forum is no longer online but there is an archive of all the posts at http://www.riverracer.net/ and it is searchable.
 

·
Living in a cage of fear
Joined
·
16,464 Posts
Oversized valves don't require installing seats, and neither does a marine application. Installing seats requires machining away more material than just doing the oversized valve job and does increase the risk of hitting water. Just doing an oversized valve job shouldn't be a problem. Worst case, find another set of castings you're more comfortable with.

This has been my experience. Although I have no where near the experience or knowledge that Scott has, I can't count how many heads (049 and others) that that I have opened up for 1.88's. Both marine and street / strip deals. Just open up the bottom angle, rough grind contact angle (45*?) to re-acquire correct tip height, blend bowl, finish grind seats.

Seat inserts were avoided due to water, as well as running into the intake seat with the edge of the exhaust insert.
A weak spring, incorrect timing, will do more damage than strictly unleaded fuel, IMO.

Just my humble .02 I would not worry in the least about hardened inserts.
 

·
Registered
Joined
·
383 Posts
anytime you start cutting or boring (this is why they make sonic checkers) you are at the mercy of the casting gods, If they ruin a piece of a engine because of a casting flaw, don't blame the machine shop, most of them have good equipment and know what there doing
 
1 - 13 of 13 Posts
Top