Installed a new crane cam today

I installed me new cam today and I have a few follow up questions...

#1 what is this 5th lobe for? I dont know if they were anywere else? I didnt notice when installing it. Its not like the rest of the lobs though its oval shaped but just different.



#2 the timing chain seems to be loser for some reason how do I tighten it up? because the chain is lose there is a little play in the sprokets so the timing marts dont line up perfect anymore unless you hold the chain still. There are 48 links in it to is that matters. I dont know why it is loser either.



#3 Because part of the oil pan gasket was removed can I buy just that one piece or will I need to replace the entire gasket now to?

Thanks
Chris

Put new timing chain in. You are already in there and they are pretty cheap.

Hickey said:

Put new timing chain in. You are already in there and they are pretty cheap.

Click to expand...

Napa online says $20 so I could do that, but what is making it not as tight though? Any ideas?

Mileage... Chains stretch... How many miles on it?

Do the 4.0 and 4.2 share cam designs ? if so the extra lobe could be to run a fuel pump.

Save yourself the hassle and replace the timing chain now, otherwise you'll just be doing it again in a few weeks.

The stretch comes from each of those little rivets getting ground down a little and the holes they're in rounding out a bit.

Bill

You probably just didn't notice the slack at first because you had the motor rotated such that one side wasn't tighter than the other as it is in your pic.

You also might consider degreeing in your cam- 2 degrees makes a world of difference...

xj_convert

xj_convert said:

You also might consider degreeing in your cam- 2 degrees makes a world of difference...

xj_convert

Click to expand...

How do I do that? I just followed my haynes step by step so there was nothing in there about that. Do I need any special tools?

Yes you need some "special tools"- a degree wheel, and a piston stop, both are pretty cheap. Rent or borrow a dial indicator. This won't be in a Haynes manual, as it is a performance thing, but it means everything. This could get really long, so I'll keep this simple:

You want to degree in the cam to make sure that the crank events are timed to the cam events perfectly. Why would they not be perfect? Because of manufacturers tolerances- there are no guarantees that the cam was ground exactly right, that your gear set is exactly right, etc. Small tolerance shifts can put you off by a couple degrees when added all up.

You correct this by using an adjustable gear set.

Crane or Lunati (look at the web sites) have excellent articles explaining degreeing a cam.

If you went to the trouble of installing a cam, you wanted performance, why not check to ensure that it is right on? Chances are everything is OK. However in my experience drag racing big blocks, I have personally seen gear set/cam combinations that were off by 4 degrees (huge in terms of cam timing).

Again before anyone gets excited, chances are it's OK, but why button it up to find that it "just doesn't have the power it should" Same reason to put a new chain set on it. I hate ripping apart something I just had apart.

xj_convert

The fifth lobe is for a mechanical fuel pump - the AMC I6 cam design is common through the 199-232-242-258 (with the need to go to the earlier timing set for the 1999-up 242.) If you check the literature, you may find it called an "eccentric" - which is precisely what it is. It is a circular lobe mounted off-center to provide action to the actuating lever of a mechanical pump.

Did you install a new timing set? I would highly recommend it with a new bumpstick. No sense in keeping old parts when you're deep enough to replace them.

A timing chain cover gasket kit should have that front oil pan rail section in it as well.

Degreeing a cam never hurts - I think Crane's article (on their web site) is about as detailed and thorough as can be had. If you do some looking, you should be able to find a timing set (I think Crane does this as well, but I'd have to check) that will give you three timing options - ZERO, 4* advanced, and 4* retarded. The use of the 4* advance will make a significant difference - it's something I illustrated in my chapter on camshafts. I've found that combinations of gearsets/camshafts are a lot more consistent if you get both from the same outfit - which is why I mentioned Crane. Once you mix brands, you become subject to a little phenomenon known as "tolerance stacking" - mainly because they're made in different plants!

Just a few more ideas...

5-90

what is a bumpstick??? never heard of that one...

bzdel2441 said:

what is a bumpstick??? never heard of that one...

Click to expand...

What you just installed... :twak:

How many miles are on that engine? Have you done anything else to it beside changing the cam? I also recommend like the rest that you get a new timing set. If you dont know what degreeing the cam is, leave it alone with the stock setup. Are you reusing the original lifters or did those get replaced too? When you are installing a new cam, it is highly advised to go with new lifters. Dont forget to break the cam in properly following Cranes recommedations. Probably something like running the engine at around 2 to 2.5k for about 20 minutes.

Good luck.

Forgot about that - usually because performance cams are bought as kits with lifters.

DO NOT install used lifters on a new cam, unless you've already decided that A) you don't like the cam you got and B) you don't mind doing the job again. I've seen cams wrecked in the first run by installing the old lifters on the new cam - it's critical that the new cam get a new set of lifters on installation. Hope you haven't installed old ones and bolted the head down already...

Bumpstick is an O-L-D word for camshaft - it's just a bumpy stick, right? I guess a lot of people just don't use that word anymore...

Y'ask me, I think that new performance cams should come with timing sets as well as lifters - it would simplify things. I wonder why they don't? If nothing else, offer the cam kits with a timing set as an option...

5-90

I am not sure how many miles are on the engine.. For sure at least. The odo says 270k but the engine is painted bright red/orange and is clean as hell so it has either been recently rebuilt or its newer.

I did also get the crane lifters to go with the cam. when you say replace the timing set do you mean replace the timing chain and sprokets? or is there somthing more to it? I guess while I have it all apart I will just replace the entire oil pan gasket with the once peice, and while I am at that I should just do the rear main to to make sure it prevent future leaks. This is so much more work than I ever though it would be...

bzdel2441 said:

I am not sure how many miles are on the engine.. For sure at least. The odo says 270k but the engine is painted bright red/orange and is clean as hell so it has either been recently rebuilt or its newer.

I did also get the crane lifters to go with the cam. when you say replace the timing set do you mean replace the timing chain and sprokets? or is there somthing more to it? I guess while I have it all apart I will just replace the entire oil pan gasket with the once peice, and while I am at that I should just do the rear main to to make sure it prevent future leaks. This is so much more work than I ever though it would be...

Click to expand...

The fun never ends

A timing set consists of the chain and both sprockets.

bzdel2441 said:

I am not sure how many miles are on the engine.. For sure at least. The odo says 270k but the engine is painted bright red/orange and is clean as hell so it has either been recently rebuilt or its newer

Click to expand...

If you're sure this engine was rebuilt before, you should use buy new head bolts and yes, if you are going to replace the oil pan gasket, it makes good sense to do the rear main seal at the same time.

Like I told you over there, you better pull it out, and put some assembly lube on those bearings before you spin it up.....or you'll be out one cam and bearings. Cam bearings are NOT easy, or cheap to have installed. Buy a new Timing set, and install it.......if it jumps a tooth on you it opens up all SORTS of problems.

Hate to be the bearer of bad observations but no one told him to change the oil pump since he has the pan all the way off... at 270k it is probably pretty tired and one of the most important components of the engine...

You'll regret it later if you don't do it now.


SORRY.


JC95

Storydude said:

Like I told you over there, you better pull it out, and put some assembly lube on those bearings before you spin it up.....or you'll be out one cam and bearings. Cam bearings are NOT easy, or cheap to have installed. Buy a new Timing set, and install it.......if it jumps a tooth on you it opens up all SORTS of problems.

Click to expand...

I just followed the directions the came with the cam. Crane said to just put oil on the berrings not teh lube. So I soaked them with oil as they went in. I am sure there may be a little grease on them as the lobes lightly went thought the berrings.

I will get a new timings set while I am in there and look into a oil pump to

bzdel2441 said:

I just followed the directions the came with the cam. Crane said to just put oil on the berrings not teh lube. So I soaked them with oil as they went in. I am sure there may be a little grease on them as the lobes lightly went thought the berrings.

I will get a new timings set while I am in there and look into a oil pump to

Click to expand...

"Oil" is not especially sticky. Every cam kit I have ever bought came with a can of assembly lube, which is thick, grey, molybdenum disulfide grease to protect the cam lobes and bearing surfaces during the initial start-up and run-in.

The oil you applied has probably mostly dripped into the crankcase by now.