Crane cam kit

[FLASHBK2]

I have a crane cam kit which is both cams and new(read much stiffer) valve springs. So far I've had the stock cam belt tensioner break and now have had cams jump time all in 4000 miles. I'm running the -10 cams. My questions are as follows: Anyone else running this combo successfully without problems? Anyone else experiencing the same problems? Anyone running crane -10 with stock valve springs without problems ? I really love how engine ran when it runs but 2 major failures in 4,000 miles and 2 months ......is driving me nuts !!! If you don't want to post please e-mail me jlavaresr@stny.rr.com. Thanks all !

[Spiderman]

Sorry I can't remember how has used these cams. But I do not think it is necessary to have the heavy duty springs if you are driving the car on the road.

[Sci-Fi]

Contact Powertrip, believe he mentioned staying with stock springs in another post.

[KR4MC Steve]

Originally posted by FLASHBK2
I have a crane cam kit which is both cams and new(read much stiffer) valve springs. So far I've had the stock cam belt tensioner break and now have had cams jump time all in 4000 miles. I'm running the -10 cams. My questions are as follows: Anyone else running this combo successfully without problems? Anyone else experiencing the same problems? Anyone running crane -10 with stock valve springs without problems ? I really love how engine ran when it runs but 2 major failures in 4,000 miles and 2 months ......is driving me nuts !!! If you don't want to post please e-mail me jlavaresr@stny.rr.com. Thanks all !

Bob Stocksum makes PT cam tensioners, because he says that the stock ones are junk with anything more than the stock cam (even with stock valve springs). He can fix you up, but I don't know the price.

Anyone out there rember the URL for his web site?

[FLASHBK2]

I'm presently running Bstockum tensioner and cams still jumped time........

[bstockum]

The "bstockum tensioner", is all MOPAR parts. This is the set-up that Chrysler put on the 2.4 when they first started building it.
It is the same parts used on the 2.0 engine since 1995 and on the Mitsubishi engine. This set-up was used very successfully on the Neon race cars for years. It is also the same set-up used on Hahns 2.4 race engine in his 9 second Neon. This is where the info came from in the first place. The only "non-MOPAR" part, is the aluminum spacer block needed to line it all up.
I have 12 people, that I know of running these tensioner parts and so far this is the first one we've seen the belt problems with. The 2.4 engine swap into the Neon is a very popular deal right now and they are racing and running those 2.4's very hard, many of them using this set-up.

The one thing I have noticed, ... is that it is possible to, "not pre-loaded the cam belt enough", ... BEFORE pulling out the retainer pin that is in the hydraulic unit. Setting the cams to the correct timing and adjusting the belt tensioner, .... I have found to be VERY trickey with the engine out of the car, ON THE STAND!! ... IN the car, ... is a LOT harder!!
This belt thing has givin me a fit! .... and I'm a pretty fair mechanic! ...

Because of all the turns and twists the belt makes, ... on its trip around the motor, .... If the engine is not in the right spot, ... or the slack is not completly out of the "water pump side", when you tighten the hold down bolts and pull the pin out of the Hydraulic unit. .... then the belt could have too much slack and the tensioner unit may be out of its' travel range and NOT hold the proper tension on the belt. This slack, ... is not released, until the engine is rotated around at least one full revolution.

These situations have been caught / noticed, ... after turning the engine over by hand, RE-CHECKING the belt, ... after adjusting the tensioner and checking the belt tension. This is where you will see if there is enough tension on the belt ... The retainer pin should slip right back in! You are setting this unit just like it was a solid tensioner. The internal movement is for when the belt grows over time. These proceedures are being learned as we go! ..... NO body has done this before on a PT! .... so yes, .... please! .... if anybody is having problems like this speak up!
The stock factory tensioners are breaking with alarming regulariy, .... so trying to find a fix is very important. This tensioner set-up is the one that Chrysler took off of the 2.4 after 1997 to save money on building these engines!

Are the Crane springs too stiff? .... This is a dificult question to answer. Valve springs are designed by the cam manufacturer to keep the moving pieces in contact with the cam at high speed, ... to prevent wear or breakage of the rockers, valves, lifters, ....... The other side of the equation is, ... can the belt and tensioner set-up handle the extra load and jerking of the heavier springs?

If you run the stock springs, .... with no forced induction, .... I have said the PT should be fine with the #10 cams, since the PT is limited to 6250 RPM.

What happens with an SC or turbo is a different story. The boost pressure is trying to "BLOW" the intake valve open, ... so if the spring is not strong enough to over come the boost pressure, ... the intake valve can "bounce open", rather than set down firmly on the seat!
(EXAMPLE):: The intake valve is approx. 2 sq in of area. So if you are making 10 PSI of boost, that boost pressure is acting on those 2 sq in, ... which is "pushing open" on the valve with 20 pounds of force. The PT seat pressure is about 45 lbs stock, so the spring has just LOST about 1/2 of its seat pressure, when running under boost! The boost makes it harder for the valve to close too.
Chrysler had very strong springs on their 2.2 Turbo III DOHC engine, a few years back. This caused belt problems back then.
That doesn't mean we automaticly have trouble here. The new belts and materials are better/stronger now. This is still an area we are looking at, as well as trying to figure how much valve spring tension is really enough!?!

Keep us posted! ... Bob

[KR4MC Steve]

Look at the time/date on Bob's post.
He must be in Western Europe or Western Africa right now

[bstockum]

That is strange! it's 11:55 now on the east coast, Hampton, VA.

now let's see... oh look at the bottom of the page

the time stamp is way off!

[FLASHBK2]

Yesterday when hand cranking engine via crankshaft bolt pulley I was encountering some great resistance about once per crank revolution. I assumed I was overcoming the compression but being unsure I pulled all plugs and cranked by hand again, today . It then moved steadily and easily. Here's another thing I noticed however.... there were wet carbon like deposits in the intake runners, somewhat gritty that smelled like gas . Having changed plugs in both cruisers 1 year ago I don't remember encountering this before..... bstockum,powertrip,mx5 any hypothesis?

[Rojin]