Volvo penta Md7a reseating valves ,and replacing valve seals only 2? A few questions.

[Eastward ho 24]

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.

[DougR]

Originally Posted by Eastward ho 24

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Both gaskets, 840270 and 840910 which were for MD7A & MD7B have been superceded to gasket # 3809167.....used in both engines.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

[Captsteve53]

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

[model 10]

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.

[DougR]

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

DougR

[Captsteve53]

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

[Pandour]

Originally Posted by Eastward ho 24

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