Experts.. what would you do? Engine?

[gsmith660]

+1 He has done a good job so far and the goal is to not do a rebuild but I would replace the manual tensioners with the oil fed tensioners some people say the man. ones are the best but they require periodic adjustment for chain stretch.

[911lvr]

Good morning everyone. First thanks for the kind words. im trying! Second I was able to get a partial set of the factory service manuals. The last 4 books. I bought them last night. There is no bentley for my year so I was happy about this! Third, help me understand something. The Tensioner upgrade is almost a 1000.00. I have the manual ones that dont ever fail. It seems like they dont have the oil feed and of course require manual adjusting where the others do not. Given my goals and what you know about my engine so far, Im kind of leaning towards not doing that up grade an just saving the grand to put towards another motor in a year or so. Sure adjusting them is a pain in the butt but only requires time. Plus the way I see it, Then engine will probably be out again in a year. Thoughts??

Last here are the pics of the rails and sprockets that were requested. Thanks as always.

[911lvr]

Excellent, my time sert repair kit showed up today for the transmission mount holes. Looks like I will be fixing that soon and checking one more thing off the list.. progress is being made!

[preston_brown]

As you stated, if you are planning on getting a new motor in a year, adjust the existing manual chain tensioners and then call it a day.

[911Freak]

Great pics and good news on finding those manuals!

I'm thinking your chains might be stretched and need attention, that left side tensioner looks adjusted pretty far out, almost touching the inner case and the right side tensioner sprocket is very close to the underside of that ramp. hmmm... Maybe one of the more experienced guys will chime in on that before making any decisions...

Sprockets look good!

I see your point on the tensioner investment issue. When I bought my SC one tensioner had collapsed so it was a no brainer for me, got 'r done.

$1k is a commitment (you could move those Carrera tensioners over to your new motor if/when you buy it)

BUT considering those chains might need replacing (look stretched out to me) I'd want to be 100% confident in my chain/tensioner funcionality & reliability before I button her back up with those solid tensioners in there... There isn't much of a margin for error with an interference engine...
- JMHO -

[911lvr]

I agree with the interference engine. I don't want valves slapping into pistons! That would really be bad.

I was kind of hoping to buy an engine that already had the tensioners. However, I do under stand that it wouldnt be a waste of money to get them.

Since I dont have the service manuals yet does anyone know for sure how I could measure or tell if the chain is stretched beyond the service limits?? Any help would be greatly appreciated.. im so close to putting this thing back together and getting it running.

Thanks everyone.

[911pcars]

Originally Posted by 911lvr

I agree with the interference engine. I don't want valves slapping into pistons! That would really be bad.

I was kind of hoping to buy an engine that already had the tensioners. However, I do under stand that it wouldnt be a waste of money to get them.

Since I dont have the service manuals yet does anyone know for sure how I could measure or tell if the chain is stretched beyond the service limits?? Any help would be greatly appreciated.. im so close to putting this thing back together and getting it running.

Thanks everyone.

Chains don't stretch. They get longer due to wear. Inspect the distance between the idler arm and the chain box (drivers side). If too close, something is worn. Inspect the chain wheel sprockets. If worn, the sprocket OD effectively decreases and allows more slack in the chair which must be taken up by the tensioner.

If all looks good, I'd replace the mechanical tensioners with the turbo versions of the self-contained units. Used, but working versions are around and should be more affordable than new. These should work for a long time. In the meantime, save your pennies for the pressure-fed versions. They should last even longer. Of equal importance are the late (post '81) idler sprockets which have a wider bearing surface (description should be in one of your rebuilding books).

Have you read the books yet? If so, they should have recommended NOT using mechanical tensioners. If not adjusted accordingly, they will either cause excessive wear if too tight or cause excessive wear if too loose. YMMV.

Sherwood

[gsmith660]

Yes that one chain does look like it needs attention and WOW that is outragous for the oil fed tensioner kit it used to be just under 500 not that many years ago!

[911lvr]

Hmmm..That is not what I really wanted to hear right now. So if the chain has to be replaced, then im back to splitting the case open and doing a total rebuild. ARGGGGGGG @#%$^@#^@#&% im going to get a beer.

[911Freak]

No, you don't have to split the case to change out chains. They can have links that allow you to change them w/out splitting case. There are several threads on this. +1 on the reading up on all of this. As Sherwood mentioned you can use the regular pre-Carrera tensioners. I have 1 good tensioner (non-oil fed style) for the left side you can have. I also have the right side but it needs a rebuild. You can have them for price of shipping. PM me if your interested.

Change out the ramps might not be a bad idea when you do tensioners, they're not to expensive.

[gsmith660]

No no no the sky is not falling you can replace chains without splitting the case our host sells the chain with a master link in it that allows you to change it without splitting the case now have that beer and breath in through the nose and out through the mouth balance young grasshopper.LOL


You beat me to it 911freak thats funny!

[gsmith660]

I have to check but I think I have a set of 930 tensioners but I have to look at the part numbers but if you change that chain and I think I would change both while you are at it you can use the hard tensioners for now just remember you have to pull those covers every so often and check the tension.

[911lvr]

Thank you both very much. The beer is helping along with the great advice on the board. Im going to search for the threads mentioned. If either one of you is ever in Atl look me up and ill buy you a beer for sure!

So in a nutshell, I can cut the old chains off, replace with new chains with a master link chain and replace the ramps since they are cheap. Make sure the timing is right before cutting it off and somehow locking it in place. I guess ill need the master link tool as well. off to do research and drink my beer. you both have pms. thanks

[911pcars]

Originally Posted by 911lvr

Thank you both very much. The beer is helping along with the great advice on the board. Im going to search for the threads mentioned. If either one of you is ever in Atl look me up and ill buy you a beer for sure!

So in a nutshell, I can cut the old chains off, replace with new chains with a master link chain and replace the ramps since they are cheap. Make sure the timing is right before cutting it off and somehow locking it in place. I guess ill need the master link tool as well. off to do research and drink my beer. you both have pms. thanks

Just to review and repeat; read the books.

You'll need to retime the cams; difficult to ensure sprocket is correctly reinstalled during an R&R. You'll also need some special tools to R&R the chain sprocket and confirm the timing. However, the mech. tensioners will come in handy to preload the chains during cam timing adjustments.

BTW, way back, did you perform a compression test? If so, the results?

Sherwood

[gsmith660]

get the flywheel lock and the cams will move slightly so you will need to mark the cam location prior to removing the chain so you can put it back in the same location what ever you do DON'T move any motor internals while the chains are off.

[911lvr]

Originally Posted by 911pcars

Just to review and repeat; read the books.

You'll need to retime the cams; difficult to ensure sprocket is correctly reinstalled during an R&R. You'll also need some special tools to R&R the chain sprocket and confirm the timing. However, the mech. tensioners will come in handy to preload the chains during cam timing adjustments.

BTW, way back, did you perform a compression test? If so, the results?

Sherwood

I just finished reading my 101 projects book ( only tensioner replacement and not the entire chain) and my rebuild and modify engines book from Wayne as well. I read a tech article here on Pelican and then about 20 threads relating to replacing the timing chains. I feel like I have a pretty good idea about how to go about it but I have a few concerns. Mainly the retiming of the cams. that does tend to make me a little nervous. I really dont want to have pistons hitting valves.

When I replaced the timing belt on my Audi (quad cam) it had this cool little tool to lock the cams in place so they wouldnt move. I see where there is a tool to lock the flywheel in place thus securing the crank but I didnt find anything like that for the cams? Does it exist? I just like the added insurance.

thanks

[911lvr]

Originally Posted by gsmith660

get the flywheel lock and the cams will move slightly so you will need to mark the cam location prior to removing the chain so you can put it back in the same location what ever you do DON'T move any motor internals while the chains are off.

Flywheel lock - check. When you say mark them do you just use a paint pen and put a line on the sprocket and one on the case for ref?

[gsmith660]

Any way you can mark it to make sure the cam doesn't move

[j911brick]

By all rights,if you replace the chains you should also replace the sprockets. Sprockets and chains learn each other and wear together. But if you don't split the case and replace the inner ones it won't be the end of the world.

Don't worry about the cam timing. Its easier than it looks. Once you do a couple its no big deal. Forget about marking the cams and forget about the flywheel lock. It won't work.

[gsmith660]

Excuse me explain please.