Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 27-08-2017, 08:59   #16
Registered User

Join Date: Sep 2016
Location: Chesapeake & southern new jersey
Boat: Eastward ho 24, Downeaster 32, scarab sprint 18
Posts: 405
Re: Volvo penta Md7a reseating valves ,and replacing valve seals only 2? A few questi

Thanks so much. Just took my injectors apart had a tiny straw and some choke cleaner, I sprayed in all the holes, nothing seems clogged they seem pretty basic and robust. looks spotless inside in and the spray comes out pretty even out of the nozzle. I think they are good to go. But thanks for the reference! Gonna put new valve seals on the intake side(don't add to exhaust correct? Theyere only 7$ I was tempted to add them to the exhaust side too?)bolt it back together and adjust the valves, I believe that process is in the manual..see if that stops the smoking.thanks everyone for the input again.
__________________

Eastward ho 24 is offline   Reply With Quote
Old 27-08-2017, 09:19   #17
Registered User

Join Date: Nov 2014
Posts: 1,188
Re: Volvo penta Md7a reseating valves ,and replacing valve seals only 2? A few questi

Quote:
Originally Posted by Eastward ho 24 View Post
Seems there's 2 diff head gaskets for the md7a
head gasket 840270 is 1.3 mm
The other is 840910 is .8 mm
Any input on which would be the better option?
Both gaskets, 840270 and 840910 which were for MD7A & MD7B have been superceded to gasket # 3809167.....used in both engines.

DougR
__________________

DougR is offline   Reply With Quote
Old 27-08-2017, 09:20   #18
Registered User

Join Date: Jun 2017
Location: Subic Bay Philippines
Posts: 539
Re: Volvo penta Md7a reseating valves ,and replacing valve seals only 2? A few questi

Originally they only came out with seals on the intake valves, but nearly all models after that have seals on both as does most every other modern engine manufacturer, The thing to check is :

1) Some valve guides have a recessed grove at the top to help locate and secure the seal in place on the guide

2) So do the top of your valve guides(inlet and exhaust) look the same in that respect?

3) Im sure if you are taking the head to a machine shop they will INSIST on replacing the valve guides (if they are any good!) as they do wear and cause oil smoking problems and premature wearing on the valve seat,(Valve guides are really universal and easily found and cheap!) most machine shops can adapt another guide to fit as well

4) I see no reason for not placing the seals on the exhaust valves and especially so if the valve guides are not replaced

Cheers Steve
Captsteve53 is offline   Reply With Quote
Old 27-08-2017, 09:53   #19
Registered User

Join Date: Feb 2013
Location: Rio Dulce, Guatemala
Boat: Seafarer36c
Posts: 5,547
Re: Volvo penta Md7a reseating valves ,and replacing valve seals only 2? A few questi

Seals on the exh side are not always a good thing. You get more valve guide wear and the oil helps with cooling. I would not do this to an old engine design.
Ecos is offline   Reply With Quote
Old 27-08-2017, 16:31   #20
Registered User

Join Date: Nov 2014
Posts: 1,188
Re: Volvo penta Md7a reseating valves ,and replacing valve seals only 2? A few questi

Any chance that the high smoke levels might be the result of worn or broken piston rings?

DougR
DougR is offline   Reply With Quote
Old 27-08-2017, 22:17   #21
Registered User

Join Date: Jun 2017
Location: Subic Bay Philippines
Posts: 539
Re: Volvo penta Md7a reseating valves ,and replacing valve seals only 2? A few questi

Posted comment from one of our largest engine rebuild shops in NZ and race conversion shop regarding all engines AND VALVE GUIDE SEALS:

QUOTE:

"but exhaust seals are regularly fitted on "modern" engines and retrofitted on older engines. Although exh valves/guides cannot pass as much oil as intakes can, it was found that the venturi effect of the the exhaust gasses rushing out of the Cyl head can pull oil past the exh guides. So now it's considered correct to fit exh seals to engines that originally did not have them". END QUOTE

As Doug R correctly points out your rings (especially oil control ring) could be worn causing the smoking, but as likely will be as earlier post regarding worn out valve guides (especially if no oil seals)

Cheers Steve
Captsteve53 is offline   Reply With Quote
Old 13-05-2020, 05:15   #22
Registered User

Join Date: May 2020
Posts: 3
Re: Volvo penta Md7a reseating valves ,and replacing valve seals only 2? A few questi

Quote:
Originally Posted by Eastward ho 24 View Post
Here's a better pic of the mystery port to no where I sprayed some we in it and it's actually art of the raw water passages in the head but yet on the exhaust it's just a knock out plug...? Any ideas here's a better pic all the screws and straws are water passages that drain into that hole. Now I've been running the motor with that manifold for 2 yrs with no over heating problems so I'm kinda at a loss here.
Hi Eastward ho - I sent a message via a different way to you regarding this problem -New to how the forum works sorry.
My exhaust manifold has that main hole seemingly block too and yet it is not in the motor side.

file:///Users/yvonnemcgill/Desktop/Documents/2020%20Pandour/2020.05.02%20Volvo%20penta%20MD7a%20cooling%20syst em%20cleaned%20and%20serviced/2020.03.20%20Pandour-no%20water!/Engine%20(Exhaust%20manifold%20removed)%20showing% 20salt%20build%20up.jpg
__________________

Pandour is offline   Reply With Quote
Reply

Tags
penta, seals, volvo

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Need Volvo Penta MD7A Reverse Gear Clarification/Help Please esarratt Engines and Propulsion Systems 14 05-06-2016 14:03
For Sale: Volvo Penta MD7A Engine and Transmission Coral Sea Classifieds Archive 1 09-09-2015 20:12
Want To Buy: Volvo Penta MD7a Fuel Injection Pump mahonrig Classifieds Archive 0 18-09-2014 14:01
Volvo Penta MD6B VS MD7A weephee Engines and Propulsion Systems 1 09-01-2014 06:03
Reseating Stringers Me-and-Boo Construction, Maintenance & Refit 7 11-11-2011 10:03

Advertise Here


All times are GMT -7. The time now is 05:26.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2020, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.