Install DOHC cylinder head

[AQ171C270SP]

LONG STORY but will make short. timing belt went.Lost 15 cogs on a fairly new one. as of today have not found the cause of the premature belt failure. Don advised to remove head and check for damage.I have removed the exhaust and riser and plan on taking the head off in the next couple of days. My problem is the manual SELOC does not go into detail on reassembly if the crank and cams have been rotated.When my belt broke the engine was cranked over. I want to know how to reinstall the belt and what position the valves should be in,I dont think I can just line up the marks I want to verify that valves are in the right position,so when I bring the engine to TDC I dont do any damage Thanks Ps its an AQ171C DOHC with an SP-A outdrive.another question is if the motor has damge such as bent valves and or piston damge is there any other motor I can swap.I would like to put another motor as the volvo AQ171c parts cost are out of this world

 

[dubs283]

Re: Install DOHC cylinder head

if you post engine make/model, s/n, etc - someone may post a link to the service manual for download

otherwise, check ebay for an OEM service manual, i.e. merc/volvo/omc

throw the seloc in the trash

 

[AQ171C270SP]

Re: Install DOHC cylinder head

Anybody have a suggestions, or hints on what position valves should be in when reinstalling the head for correct timing belt install so I dont damage them again on intial start or attempt at start. Thank you

 

[cr2k]

Re: Install DOHC cylinder head

Seloc and Chalmers manuals are excellent for leveling your workbench.

If you intend to work on your boat you need a factory book.

 

[HT32BSX115]

Re: Install DOHC cylinder head

Anybody have a suggestions, or hints on what position valves should be in when reinstalling the head for correct timing belt install

Howdy,


You would install the head with the camshaft in the #1 TDC position along with the #1 piston in the TDC position. This is pretty standard for any interference engine.

Doesn't the Volvo service manual outline the procedure?

EDIT: yeah.....Seloc and Clymer manuals are pretty good for starting your wood stove......not so good for anything else......

 

[AQ171C270SP]

Re: Install DOHC cylinder head

I must rephrase my question. I know that marks have to be tdc.My question is this. is it possible to have marks line up with the valves in wrong position? will the marks line up on compression stroke,then again on exhaust ? the manual does outline procedure but only if you are repacing a good belt that was not broken and an engine that was not disturbed after belt removal. In a perfect world I would have no problem doing it that way, But as I stated in an earlier post this engine was cranked over after the belt lost cogs, so the crank was turned but the cams were not.OR------------should I turn the engine by hand bring #1 piston to top dead center and turn the cams one at a time and just line up the mark and-------------------HOPE FOR THE BEST lol I dont want to do any unnecesary damage. Also remember I have 4 four valves per cylinder so I dont even know as of yet which ones are exhaust valves and which ones are intake to gat them in proper position

 

[6meter]

Re: Install DOHC cylinder head

I don't know about the volvo motors but my Chevy DOHC timing chain and gears had marks on both chain and gears. Marks should line up, with crank at TDC. The other way it was done was a mark on each side of the head for the cam gears and the crank at TDC and the belt goes on any which way. Just food for thought, no other responces.

 

[EddiePetty]

Re: Install DOHC cylinder head

I must rephrase my question. I know that marks have to be tdc.My question is this. is it possible to have marks line up with the valves in wrong position? will the marks line up on compression stroke,then again on exhaust ? the manual does outline procedure but only if you are repacing a good belt that was not broken and an engine that was not disturbed after belt removal. In a perfect world I would have no problem doing it that way, But as I stated in an earlier post this engine was cranked over after the belt lost cogs, so the crank was turned but the cams were not.OR------------should I turn the engine by hand bring #1 piston to top dead center and turn the cams one at a time and just line up the mark and-------------------HOPE FOR THE BEST lol I dont want to do any unnecesary damage.

....once the belt is off, the crank doesn't care what stroke it was on as long as the timing marks at zero. The cams, on the other hand, normally have their timing marks set for TDC compression on #1 cylinder.
And to answer your question, only the crank marks will align on EVERY revolution. The cams align on every OTHER revolution.

 

[Don S]

Re: Install DOHC cylinder head

I posted this manual link this morning, must have hit the wrong button because the post isn't here. But here is the OEM manual.

http://www.4shared.com/file/64741910/25295432/230_250_251_131151171.html

 

[mr300z87]

Re: Install DOHC cylinder head

I have been working on Nissan interference engines for a long time and when the timing belt breaks it usually bends valves. I have set from a V6 that broke a timing belt with a bent valve in each head. After you put the belt back on with the marks lined up spin the the engine by hand to make sure there is no resistance. Good luck. Also try looking at a Hanes manual for Volvos I bet the set up is similar.