Desperately seeking Timing Marks

[brodie123]

Hi All;

Before I pull out the cam and crank, I usually find timing marks for the chain or gear.

This is a Mercruiser 3.7 inline 4 and has a different timing gear from our other boat.

I see that the pins face each other on every other rotation, but there must be a better mark for re-assembly. I was thinking of making a score mark on the chain and cam and crank gears prior to removal. Any suggestions here for proper removal/assembly to ensure proper timing?


Also, the cam has heavy wear marks where the seals sit for the water pump causing a leak. Otherwise the cam seems fine. Would a good machine shop be able to build it back up and machine it to proper specs? Cam replacements seem to run around $350+ and my budget is going towards a rebuild kit, machining etc. I prefer not to use sleeve if possible.

thx!!!

 

[brodie123]

Re: Desperately seeking Timing Marks

Sorry, I meant to post a pic.

 

[alldodge]

Re: Desperately seeking Timing Marks

This should help, it came from a previous post from achris

 

[Eric 3.7LX Alpha 1]

Re: Desperately seeking Timing Marks

I've read somewhere where someone has had the cam welded then machined back down.... I don't remember if it was breezeworks.net or here.

I have the speedi sleeves on mine and (knock knock) they are doing nicely.


edit....

Here's the OEM Mercruiser service manual#8 link will take you to the chapter on timing chain:
Boatinfo - Mercruiser Service Manual nr. 8 - 1985-1989 - Mercury Marine 4 Cylinder Engines

You can print the pages but can't download it.

 

[Bifflefan]

Re: Desperately seeking Timing Marks

Also, the cam has heavy wear marks where the seals sit for the water pump causing a leak.

Don't get it welded, that is a waste of money. Call this place, Murry Lake Marina. They have speedy sleeves for the end of the cam shaft in stock. It takes 2 of them and they are about $20 each. But it is a way better system than welding. Also look closely where the seals ride, sometimes it looks like damage but it can be polished off with a bit of emery cloth.
I put the speedy sleeves on my 470 about 5 years ago and they work great.

 

[achris]

Re: Desperately seeking Timing Marks

Use the new 'Gold series' sleeves. They have better abrasion resistance. I think they might also be a bit thinner....

Chris...