Jump to content

 

Welcome to TheMalibuCrew!

As a guest, you are welcome to poke around and view the majority of the content that we have to offer, but in order to post, search, contact members, and get full use out of the website you will need to Register for an Account. It's free and it's easy, so don't hesitate to join the TheMalibuCrew Family today!

Sign in to follow this  
Ndawg12

07 Hammerhead 383 Knocking Noise

Recommended Posts

Ndawg12

If you've experienced this issue with the same motor/tranny/vdrive combo then you'll easily know what I'm talking about, but for others I'll try my best to describe it.

Once going into idle forward (no acceleration, 650rpm, ~3.5mph) I get a knocking/vibration sound that comes from the vdrive area. Even the slightest acceleration will make it go away, 700rpm. My dealer changed the ATF in the vdrive to straight 30W and that didn't help at all and then Indmar strongly suggested that I put the recommended ATF back in. Indmar said something about the Hammerhead being a "hotrod" motor with a different cam and that the relationship between the tranny and motor will make this knocking/vibration sound.

Ok, so it's normal (per Indmar) but I searched on here and didn't find much info on it or any members complaining about it, so I'm thinking mine is louder and more annoying than most. I'll try to shoot a video of it this weekend.

.....found the correspondence from Indmar:

If they put 30W oil in that unit you need to get it changed back to ATF. That transmission will not survive on 30W. The 383 engine does not idle as smoothly as your Monsoon did. The 383 has a big cam so it lopes a little. Some trans noise at idle that goes away when some load is applied is normal. All of the engine/tran packages do that to some extent but it is more noticeable on the 383 because of the hot rod cam.

Like I said, it's very annoying, especially with my OCD tendency, but if it is normal I would like to hear some others backup this claim.

Share this post


Link to post
Share on other sites
Brian Ferrell

I have the 08 and notice this most when pulling away from the dock at slowest possible idle speed. I used to have a pickup truck that went through ujoints about every 6 months due to some mods I did and lots of hard driving. The sound reminds me of a muffled version of the loose ujoint. Does that sound familiar?

Share this post


Link to post
Share on other sites
malibu2004

You're going to need to change that tranny fluid a bunch of times to get the oil out. I understand trouble shooting but to change oils doesn't seem very smart to me. Different viscosity for trouble shooting I could live with for a short time.

I would go with what indmar says before your dealer.

Share this post


Link to post
Share on other sites
G-Mack

08 HH with the same issue. My dealer eventually changed the v-drive/transmission, noise is still there. Indmar may not be far off the mark

Share this post


Link to post
Share on other sites
CanVLX

I have the same situation. I looked at the dampener plate when the engine was getting rebuilt and it seemed strong. So I have ruled that out.

When I winterized on the weekend I noticed that one of the anodes on the vdrive had broken off so I thought that may have been the culprit. I will be pulling that apart in the spring to try and retrieve the broken anode.

I am actually glad to hear that I am not the only one experiencing this sound.

Share this post


Link to post
Share on other sites
Ndawg12

You're going to need to change that tranny fluid a bunch of times to get the oil out. I understand trouble shooting but to change oils doesn't seem very smart to me. Different viscosity for trouble shooting I could live with for a short time.

I would go with what indmar says before your dealer.

That's part of what is confusing, the dealer is very reputable and say they've always done this to quiet down the noise and that Indmar suggested it to them. It didn't work at all and Indmar basically tells me it's a horrible idea....

I have the 08 and notice this most when pulling away from the dock at slowest possible idle speed. I used to have a pickup truck that went through ujoints about every 6 months due to some mods I did and lots of hard driving. The sound reminds me of a muffled version of the loose ujoint. Does that sound familiar?

Yes, and I checked the coupling from the vdrive to the shaft and the 4 bolts appear to be snug....

Share this post


Link to post
Share on other sites
wheelman

Friend just got used boat with hh and we noticed this first time out. You may have just saved him some time and money in the shop if it is normal.

Share this post


Link to post
Share on other sites
black06VLX

My boat does a similar thing with the 383 hammerhead. I noticed it more when I went to the 1273 prop over the old stock 381 prop.

Its basically like a chug/clunk type sound correct. Like something is causing a vibration at low speed and making stuff shake/shudder. Sort of like if the platform was moving up and down slightly? It could just be the lope of the cam being transferred down the shaft and its more noticeable with the larger diameter props.

Share this post


Link to post
Share on other sites
Bobby Light

I have it too in mine, it's normal.

Share this post


Link to post
Share on other sites
Ndawg12

Friend just got used boat with hh and we noticed this first time out. You may have just saved him some time and money in the shop if it is normal.

It's looking that way.

Had I known of this issue before I drove 1100 miles one way to pick up my boat then I may have passed on it and concentrated on 8.1L. It's good to know that's it's probably normal and I plan to have the boat a very long time but I'm not looking forward to convincing a potential buyer that it's normal.

Share this post


Link to post
Share on other sites
Bobby Light

It's looking that way.

Had I known of this issue before I drove 1100 miles one way to pick up my boat then I may have passed on it and concentrated on 8.1L. It's good to know that's it's probably normal and I plan to have the boat a very long time but I'm not looking forward to convincing a potential buyer that it's normal.

If you got an 8.1 repowering it would be nearly impossible since the block isn't made anymore

Share this post


Link to post
Share on other sites
Ndawg12

My boat does a similar thing with the 383 hammerhead. I noticed it more when I went to the 1273 prop over the old stock 381 prop.

Its basically like a chug/clunk type sound correct. Like something is causing a vibration at low speed and making stuff shake/shudder. Sort of like if the platform was moving up and down slightly? It could just be the lope of the cam being transferred down the shaft and its more noticeable with the larger diameter props.

Not sure if it is more pronounced now that I have the 1235 on there, but it certainly did it as well with the 537.

You could describe it like that, I'm sure we're talking about the same thing if it goes away with the slightest throttle bump.

Share this post


Link to post
Share on other sites
shawndoggy

I think you just bookmark this thread and point your potential buyer to it when your last kid heads off to college and it comes time to sell.

Share this post


Link to post
Share on other sites
black06VLX

Yeah its gone once you get above 1200rpm I believe.

Share this post


Link to post
Share on other sites
Ndawg12

I would if there's a way to advance the throttle

I think you just bookmark this thread and point your potential buyer to it when your last kid heads off to college and it comes time to sell.

:biggrin: 17 years and 9 months.

Yeah its gone once you get above 1200rpm I believe.

Maybe I should feel good about mine. Mines goes away with any throttle, like 700rpm+. I wonder if there's a way to advance the throttle so I don't ever have to hear it or would that have to be done via computer if at all possible....?

Share this post


Link to post
Share on other sites
black06VLX

Well I just used 1200rpm as an example. You are correct its gone with any input over idle and just in gear.

Share this post


Link to post
Share on other sites
malibu2004

The problem with increasing your idle is when you put it in gear the transmission will clunk because it's idling to high. That can then turn into transmission problems.

You could shorten the cable?

I would just turn up the stereo and call it good.

Share this post


Link to post
Share on other sites
dihrdskir

The problem with increasing your idle is when you put it in gear the transmission will clunk because it's idling to high. That can then turn into transmission problems.

You could shorten the cable?

I would just turn up the stereo and call it good.

A mate of mine had a similar issue with an oil pressure warning light on the dash. Covered it up with a business card. Problem gone

Share this post


Link to post
Share on other sites
Falko

I have the older 380 HH, and while that is a 350 based engine, the cam is lopey. I get engine shimmy down lower in rpms. I would imagine that rough idle beats on the damper a little bit making a thumping or clunking.

Share this post


Link to post
Share on other sites
mattm

Mine has been making that sound since day one. 540+ hours later it still does.

Share this post


Link to post
Share on other sites
Ndawg12

Ok, it's officially been confirmed as normal. But how do we fix it because it drives me :crazy:

Share this post


Link to post
Share on other sites
Falko

Get someone to make a phenolic buffered damper plate.

Share this post


Link to post
Share on other sites
jcon44

dynamat the whole tranny compartment... ear plugs, drink more, turn up the stereo... As always i am willing to help with any and all of these suggestions..

Share this post


Link to post
Share on other sites
mattm

Ok, it's officially been confirmed as normal. But how do we fix it because it drives me :crazy:

Turn the stereo up.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Sign in to follow this  

×
×
  • Create New...