Logo
Results 1 to 25 of 25
  1. #1
    Join Date
    Nov 2008
    Location
    Long Beach, CA
    Posts
    215

    Default Indmar 383 Hammerhead CYL Head replacement options

    Hey guys working on my buddies 2008 Malibu VLX. Its equipped with a Indmar 383 "Hammerhead". The boat is raw water cooled and operated in salt water. Although it it religiously flushed after every use, the Salt and lack of Zincs has taken its toll on the Aluminum Cylinder heads it came equipped with and they are in need of total replacement after 704Hours of run time.

    I know it vortec based GM 350 and is currently equipped with GM FASTBURN aluminum heads. I personally would like to replace the heads with a good set of iron heads as I think they will endure the salt a little better and I hate so see a great set of aluminums get destroyed.
    I need to call indmar and determine the valve lift to ensure what ever replacements will have adequate spring travel as this is a full roller engine right now.

    What are your opinions and what are my options in doing this?
    How much Power will be lost? Enough to have to re-prop?


    Wil

  2. #2
    Join Date
    Dec 2006
    Location
    Chaumont Bay, N.y., USA
    Posts
    5,218

    Default Re: Indmar 383 Hammerhead CYL Head replacement options

    Ayuh,.... There's lotsa Vortec iron fast burn heads out there, by 'bout everybody that sells heads,....

    Jegs or Summit list quite a few,....
    Any Grease is Better,... Than No grease at All....

  3. #3
    Join Date
    Nov 2008
    Location
    Long Beach, CA
    Posts
    215

    Default Re: Indmar 383 Hammerhead CYL Head replacement options

    I realize there are many Iron heads that will work, I would like to know what the expected power loss would be going from an aluminum to iron.

    thanks for the replies.

    will

  4. #4
    Join Date
    Dec 2006
    Location
    Chaumont Bay, N.y., USA
    Posts
    5,218

    Default Re: Indmar 383 Hammerhead CYL Head replacement options

    Ayuh,.... All else bein' the same, maybe 5 to 7 hp,.... Should be Unnoticeable,...
    Any Grease is Better,... Than No grease at All....

  5. #5
    Join Date
    Nov 2008
    Location
    Long Beach, CA
    Posts
    215

    Default Re: Indmar 383 Hammerhead CYL Head replacement options

    sweet. sounds good to me.

    I found the cam specs on the engine so I just have to get heads with springs that are compatible with a .528 lift cam now

    thanks, will

  6. #6
    Join Date
    Mar 2009
    Location
    Portland, Oregon,
    Posts
    9,189

    Default Re: Indmar 383 Hammerhead CYL Head replacement options

    Indmar is calling this a 6.2L but is also calling it a 383.
    A new 6.2L is actually 377 cu in, while a first over reman (4.030" bore) is a 6.3L or 383 cu in.
    According to their info, this is a production engine and is apparently new!

    I was trying to learn about which pistons are being used, but I'm coming up short.
    Do you guys know what they're using????

    They may have gotten away from the GM full dished style pistons and have incorporated a Q/E with a higher C/R.
    If so, you will probably want to stay with the aluminum cylinder heads and of the same combustion chamber volume.
    The aluminum cylinder heads will carry more heat away from the chamber, thus reducing detonation potential.

    As for salt water and the aluminum heads.... it's a bit late to do a closed cooling system for a cast iron cylinder block, but you will definitely increase aluminum cylinder head life if you were to.


    .
    Last edited by RicardoMarine; 01-23-2015 at 09:52 PM.
    Rick ... aka Ricardo..... AQ series Volvo Penta repair
    Portland, Oregon
    28' SDN F/B w/ twin Volvo Penta 5.7L DP's

    Please... no PMs! Post your questions on the forum.

  7. #7
    Join Date
    Nov 2008
    Location
    Long Beach, CA
    Posts
    215

    Default Re: Indmar 383 Hammerhead CYL Head replacement options

    I will snap a picture of the piston before re-assembley.

  8. #8
    Join Date
    Mar 2009
    Location
    Portland, Oregon,
    Posts
    9,189

    Default Re: Indmar 383 Hammerhead CYL Head replacement options

    Any pictures yet?

    .
    Rick ... aka Ricardo..... AQ series Volvo Penta repair
    Portland, Oregon
    28' SDN F/B w/ twin Volvo Penta 5.7L DP's

    Please... no PMs! Post your questions on the forum.

  9. #9
    Join Date
    Nov 2008
    Location
    Long Beach, CA
    Posts
    215

    Default Re: Indmar 383 Hammerhead CYL Head replacement options

    NO not yet, replacement cast iron heads should arrive tomorrow. We will be getting new head bolts, top end gasket set, oil, filters, and tune up parts together this week. Friday we will pull the boat out of storage and start prep and reassembly. Hopefully have it fire off by sat afternoon and change the oil a couple times and dip it in the water on sunday for a test and tune. I will snap photos along the way and let you guys know how its going.

    Will

  10. #10
    Join Date
    Dec 2006
    Location
    Chaumont Bay, N.y., USA
    Posts
    5,218

    Default Re: Indmar 383 Hammerhead CYL Head replacement options

    Quote Originally Posted by buick430 View Post
    NO not yet, replacement cast iron heads should arrive tomorrow. We will be getting new head bolts, top end gasket set, oil, filters, and tune up parts together this week. Friday we will pull the boat out of storage and start prep and reassembly. Hopefully have it fire off by sat afternoon and change the oil a couple times and dip it in the water on sunday for a test and tune. I will snap photos along the way and let you guys know how its going.

    Will
    Ayuh,.... Don't why yer buyin' new head bolts,.... Clean 'n reuse the old 1s is what I do,...

    Can't wait to see the pictures,....
    Any Grease is Better,... Than No grease at All....

  11. #11
    Join Date
    Mar 2009
    Location
    Portland, Oregon,
    Posts
    9,189

    Default Re: Indmar 383 Hammerhead CYL Head replacement options

    Quote Originally Posted by buick430 View Post
    NO not yet, replacement cast iron heads should arrive tomorrow. We will be getting new head bolts, top end gasket set, oil, filters, and tune up parts together this week. Friday we will pull the boat out of storage and start prep and reassembly. Hopefully have it fire off by sat afternoon and change the oil a couple times and dip it in the water on sunday for a test and tune. I will snap photos along the way and let you guys know how its going.

    Will
    OK....... with all due respect, I have a few questions:

    This engine was OEM with the aluminum cylinder heads, correct?
    You do or don't know what the combustion chamber volume was?

    You are replacing with cast iron cylinder heads.... correct?
    What is the combustion chamber volume of the replacement heads?
    You do or do not know which piston profile was used in order to see if the combination is correct?

    I'm just curious as to how you determined the compressed head gasket thickness (if other than GM f/d pistons), and if this new combination will work correctly!


    .
    Rick ... aka Ricardo..... AQ series Volvo Penta repair
    Portland, Oregon
    28' SDN F/B w/ twin Volvo Penta 5.7L DP's

    Please... no PMs! Post your questions on the forum.

  12. #12
    Join Date
    Nov 2008
    Location
    Long Beach, CA
    Posts
    215

    Default Re: Indmar 383 Hammerhead CYL Head replacement options

    Bondo, head bolts are being replaced because they are badly corroded and several required significant enough of force to remove from being seized in the head that they could have stretched or twisted. Its cheap insurance and will ease in the assembly, and its just not worth the pain in the ass of having to take it all apart if a bolt breaks off in the block...all for $38.00....

    Rick: Original heads were 62cc combustion chamber. The replacement Iron heads are the same size and combustion chamber configuration. The gasket set to be used during assembly was obtained from calling indmar and talking to the techs there, They use felpro head gaskets during assembly, I ordered the set through them. came with head gaskets, exhaust, intake, distributor, valve covers, injector o-rings, valve stem seals, and a couple others. I didnt see the need to determine the compressed gasket thickness as this is what they used OE.

    will

  13. #13
    Join Date
    Mar 2009
    Location
    Portland, Oregon,
    Posts
    9,189

    Default Re: Indmar 383 Hammerhead CYL Head replacement options

    Quote Originally Posted by buick430 View Post
    Rick:
    1.... Original heads were 62cc combustion chamber. The replacement Iron heads are the same size and combustion chamber configuration.

    The gasket set to be used during assembly was obtained from calling indmar and talking to the techs there, They use felpro head gaskets during assembly, I ordered the set through them. came with head gaskets, exhaust, intake, distributor, valve covers, injector o-rings, valve stem seals, and a couple others.

    2.... I didnt see the need to determine the compressed gasket thickness as this is what they used OE.

    will
    Will, I have no dog in any fight here. I'm just curious and learning.

    1.... The GM Vortec chambers are either 64cc or 65cc. You must have used A-market heads.

    2.... Knowing which pistons the Indmar 383 Hammerhead used as OEM would have been rather important to me.


    On the 25th, you were going to snap a picture of the piston before re-assembly.
    Were you able to do that?
    I'm just curious as to which piston profile was used in order to obtain the HP number claimed, and yet ward off detonation potential.

    Typically higher horse power and torque can't be safely achieved with the GM full dished piston since it cannot offer a quench.


    .
    Last edited by RicardoMarine; 02-04-2015 at 10:25 AM.
    Rick ... aka Ricardo..... AQ series Volvo Penta repair
    Portland, Oregon
    28' SDN F/B w/ twin Volvo Penta 5.7L DP's

    Please... no PMs! Post your questions on the forum.

  14. #14
    Join Date
    Nov 2008
    Location
    Long Beach, CA
    Posts
    215

    Default Re: Indmar 383 Hammerhead CYL Head replacement options

    Rick, no worries on all the questions. I'm learning too.

    the information I gave is really all that was given To me by the speed shop I obtained the heads from. I did confirm 62cc volume on the original aluminum through GM. Keep in mind the originals were GM performance parts fastburn heads.

    I know I said it would be back together last weekend and pictures would be posted but I'm not doing this for a living and my real job that pays the mortgage (active duty CG) kinda got in the way... I won't make any promises of when it's all going back together but I promise I will take a picture or two along the way.

    Im not sure how they did it but this engine really does make exceptional reliable power on 89 gas. Im sure indmar has done there homework and I hope these heads produce no noticeable difference in performance.

    Will

  15. #15
    Join Date
    Nov 2008
    Location
    Long Beach, CA
    Posts
    215

    Default Re: Indmar 383 Hammerhead CYL Head replacement options

    Wel got it all put back together and after a few oil changes got it in the water and run. No noticeable power loss if any. the real test will be when the ballast bags and tanks are filled (around 2k lbs). As promised I took a couple pictures of the pistons for rick. Thanks for all the help with project.

    willClick image for larger version. 

Name:	IMG_1198.JPG 
Views:	40 
Size:	95.7 KB 
ID:	10688Click image for larger version. 

Name:	IMG_1196.jpg 
Views:	35 
Size:	51.5 KB 
ID:	10689

  16. #16
    Join Date
    Mar 2009
    Location
    Portland, Oregon,
    Posts
    9,189

    Default Re: Indmar 383 Hammerhead CYL Head replacement options

    Quote Originally Posted by buick430 View Post
    Click image for larger version. 

Name:	IMG_1198.JPG 
Views:	40 
Size:	95.7 KB 
ID:	10688Click image for larger version. 

Name:	IMG_1196.jpg 
Views:	35 
Size:	51.5 KB 
ID:	10689
    Unfortunately, these are thee dreaded "full dished" pistons!
    IMO, these should never be used in a SBC Marine Engine, let alone the 6.2L (377) or 6.3L (383).


    .
    Rick ... aka Ricardo..... AQ series Volvo Penta repair
    Portland, Oregon
    28' SDN F/B w/ twin Volvo Penta 5.7L DP's

    Please... no PMs! Post your questions on the forum.

  17. #17
    Join Date
    Nov 2008
    Location
    Long Beach, CA
    Posts
    215

    Default Re: Indmar 383 Hammerhead CYL Head replacement options

    Yea I pretty much saw that response coming. As you can see there's no sign of detonation and the boat has obtained most of its hours in conditions that would be ideal for detonation. (Heavy ballast weight and being operated at or just above planning to produce a massive wake for the wake skate). I trust Indmars R&D and them knowing what these boats are used for.

    Will

  18. #18
    Join Date
    Dec 2006
    Location
    Chaumont Bay, N.y., USA
    Posts
    5,218

    Default Re: Indmar 383 Hammerhead CYL Head replacement options

    Quote Originally Posted by buick430 View Post
    Yea I pretty much saw that response coming. As you can see there's no sign of detonation and the boat has obtained most of its hours in conditions that would be ideal for detonation. (Heavy ballast weight and being operated at or just above planning to produce a massive wake for the wake skate). I trust Indmars R&D and them knowing what these boats are used for.

    Will
    Ayuh,... 'n that was with aluminum heads,...

    Now yer goin' to iron heads,...

    Be very careful, as yer in a more likely situation for detonation, Now,...
    Any Grease is Better,... Than No grease at All....

  19. #19
    Join Date
    Nov 2008
    Location
    Long Beach, CA
    Posts
    215

    Default Re: Indmar 383 Hammerhead CYL Head replacement options

    I didnt check the advance. its all computer controlled. I know with the cast irons it would be more prone to detonation, but Im gonna keep an eye on it all and hopefully the knock sensors can pick up on and and adjust the timing as necessary.

    will

  20. #20
    Join Date
    Mar 2009
    Location
    Portland, Oregon,
    Posts
    9,189

    Default Re: Indmar 383 Hammerhead CYL Head replacement options

    Kim, Bill and myself have warned about Detonation potential. My reason for the warning is the silly GM full dished pistons.
    The GM full dished pistons do not offer a quench surface... so that is strike one against them.


    I trust Indmars R&D and them knowing what these boats are used for.
    I too trust Indmars R&D.... and while these pistons were able to work with the aluminum cylinder heads that the Indmar Engineers chose, you now have cast iron cylinder heads that will not heat-sink as the aluminum cylinder heads did.

    With no quench, ignition advance must be held back in order to avoid ignition induced detonation.
    Detonation is not as audible as is pre-ignition, and is often difficult to detect with any significant warning.



    (Heavy ballast weight and being operated at or just above planning to produce a massive wake for the wake skate)
    Since this is a Wake Board boat, the operator will very likely be running at a more detonation prone RPM.
    If he runs it on 89 octane gasoline, his chances of detonation may increase some.


    Even though the EST ignition system may adjust the advance...... I'd want to double check the progressive and TA to help insure that he avoids detonation.


    .
    Rick ... aka Ricardo..... AQ series Volvo Penta repair
    Portland, Oregon
    28' SDN F/B w/ twin Volvo Penta 5.7L DP's

    Please... no PMs! Post your questions on the forum.

  21. #21

    Default Re: Indmar 383 Hammerhead CYL Head replacement options

    My 383 Indmar Hammerhead (2005) has under 500 hrs. For the last two years the engine has emitted a slight grinding noise. I asked that this be checked after winter storage this year. No electronic diagnosis was done; nothing was disassembled; the filter was not opened to look for shrapnel. I was just told to buy a new engine for $10k or a new boat for boat for $100k. Any suggestions where I can pull the boat to a very highly qualified mechanic for electronic diagnosis and new engine if necessary? Somewhere between Cleveland and Washington, DC preferably. Thank you.

  22. #22
    Join Date
    Sep 2008
    Location
    Maryland - USA
    Posts
    6,824

    Default Re: Indmar 383 Hammerhead CYL Head replacement options

    hooking up a scantool won't do you much good for a mechanical issue....unless its bad enough to impact performance....

    Try calling Indmar and see where the closest dealers are...and then call them and discuss the issue....they are likely busy this time of year,

  23. #23
    Join Date
    Mar 2009
    Location
    Portland, Oregon,
    Posts
    9,189

    Default Re: Indmar 383 Hammerhead CYL Head replacement options


    Will, I realize that this thread is fairly old by now, but I also see that Deep Creek recently woke it up!


    BTW, the pistons used are a bit different from the typical GM Full Dished pistons found in the SBC.
    These have larger top band, and only single valve reliefs.
    However..... these are still very Un-Suitable for Marine use!


    Quote Originally Posted by buick430 View Post
    Yea I pretty much saw that response coming. As you can see there's no sign of detonation and the boat has obtained most of its hours in conditions that would be ideal for detonation.
    As Bill says below, the Fast Burn Aluminum cylinder heads have been helping to avoid this.

    (Heavy ballast weight and being operated at or just above planning to produce a massive wake for the wake skate). I trust Indmars R&D and them knowing what these boats are used for.
    Indmar should be setting these Engines (cast iron block w/ aluminum cylinder heads) up with Closed Cooling Systems...... Period!

    Will

    Quote Originally Posted by bondo View Post
    Ayuh,... 'n that was with aluminum heads,...

    Now yer goin' to iron heads,...

    Be very careful, as yer in a more likely situation for detonation, Now,...
    I agree!
    Rick ... aka Ricardo..... AQ series Volvo Penta repair
    Portland, Oregon
    28' SDN F/B w/ twin Volvo Penta 5.7L DP's

    Please... no PMs! Post your questions on the forum.

  24. #24

    Default Re: Indmar 383 Hammerhead CYL Head replacement options

    Quote Originally Posted by Deep Creek View Post
    My 383 Indmar Hammerhead (2005) has under 500 hrs. For the last two years the engine has emitted a slight grinding noise. I asked that this be checked after winter storage this year. No electronic diagnosis was done; nothing was disassembled; the filter was not opened to look for shrapnel. I was just told to buy a new engine for $10k or a new boat for boat for $100k. Any suggestions where I can pull the boat to a very highly qualified mechanic for electronic diagnosis and new engine if necessary? Somewhere between Cleveland and Washington, DC preferably. Thank you.
    Do you have anymore details on where the noise is coming from? A grinding noise can come from several places and not be internal engine related. Could be something as simple as a starter not disengaging due to corrosion. A bad alternator bearing??? A bad engine is usually going to result in a knock.

  25. #25
    Join Date
    Nov 2008
    Location
    Long Beach, CA
    Posts
    215

    Default Re: Indmar 383 Hammerhead CYL Head replacement options

    Sorry For the late response, I have been busy with work and trying to catch fish on my own boat. Back to the Malibu, we had an issue with a hole in the oil pan so the engine had to come completely out to replace the pan. With the exception of that fiasco, the engine is still running great with close to 200 additional hours on it. I agree that it should have been a closed cooling system from the get go as this would have prevented this hole ordeal.

    Deep Creek, Im sure you have either fixed the issue or gotten rid of the boat by now. If not, you need to find another mechanic that will do a full diagnostic and give you a more specific reason as to why the engine needs replacing. The hammerhead 383 is an expensive engine. That being said as long as the block is not damaged, it can be rebuilt far cheaper than replaced.

    Will

Similar Threads

  1. Replacement options
    By jpar5184 in forum Pleasurecraft Marine PCM Forum
    Replies: 0
    Last Post: 03-07-2013, 10:38 AM
  2. Crusader discontinued 8.1 and no replacement -Options?
    By rmm in forum Crusader Marine Engine Forum
    Replies: 3
    Last Post: 12-01-2010, 08:04 PM
  3. older 9.9 powerhead replacement options late 70's
    By joeboo in forum Mercury Mariner Outboard Forum
    Replies: 8
    Last Post: 09-25-2010, 07:40 PM
  4. Replacement hatch options
    By makomark in forum Miscellaneous marine engine topics
    Replies: 0
    Last Post: 01-02-2009, 11:05 PM
  5. Blown 1987 OMC 350 help replacement options
    By Nathan Swensen in forum OMC Sterndrive and Inboard Archive
    Replies: 5
    Last Post: 03-06-2006, 09:56 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •