Cam retaining problem

Performance mods and Advanced Stroker discussion.
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dvd_fuller
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Cam retaining problem

Post by dvd_fuller »

Hey guys, I have searched the best I can and I'm sure that this topic has been covered somewhere but I cannot find the answer anywhere.
I have used a comp cams 68-232-4 cam in a 2000 block. I know that the stock cam used a retainer plate to hold the came in but as I'm sure you all know the new cam cannot use this plate. I also know that a cam bolt spring and pin kit is often used to hold the cam in. how ever it seems that this kit is on back order :brickwall: ....everywhere... :brickwall:
I gave up on my search for this part after looking for over a month and decided to put the engine in anyways because I had also seen that not all of the 258's used the kit and managed to hold the cam in regardless. I believe that the distributor managed to hold it in place.
well now that my engine is running there is an awful knocking sound coming from the front on the engine at low rpms, this is notorious for the cam hitting the timing cover, due to ofcourse the lack of the spring and pin kit. I also have low oil pressure after the engine warms up (10-20 psi) but good oil pressure when cold (40-50 psi) which sounds a lot like a bad oil pump. if it wasnt for the fact that more often than the oil pump being bad this same thing can be caused by bad cam bearings.
so what I'm thinking is that my cam is walking forward allowing oil to escape out of the cam bearings causing low oil pressure, when the engine is cold the oil is thick enough to continue to give good oil pressure but once it heats up the oil thins out and escapes from the cam bearings faster. Does anyone know of another solution to hold the cam in place, or have an extra spring and pin that you would be willing to sell me? Or if you have any other theories on what is going on with my engine please say it, the more I know the better.
p.s. the guy that bored my engine seems to have known less about engine building than I though because he bored the block exactly to piston size, and I mean exactly. My genius self in excitement of getting the engine together forgot about skirt clearance and put the engine together anyways. lets just say I had to wiggle the pistons into the bore and tap down with a rubber mallet. I honestly dont know why I didnt think anything was wrong. I'm just letting you guys know this because there was a lot of metal in the oil after the break in, but I checked the crank bearings and they all seem fine.
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Re: Cam retaining problem

Post by Joshy »

Have a read through SilverXJ's build. Had a few issues with the cam/bearings from the cam walking til he replaced the spring and pin combo with a solid pin that gave .003-.008" (from memory) end play. You'll be lucky if you don't have to replace the cam bearings. Pistons should be a tight fit and would likely seize during break in if the bore was too small. I'd guess those bits of metal are from break in and buggered cam bearings.

Some other guys should chime in. Silver went through a few cams so his advice would be helpful
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Re: Cam retaining problem

Post by Joshy »

Ps. Welcome to the forum mate
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Re: Cam retaining problem

Post by Cheromaniac »

dvd_fuller wrote:I also know that a cam bolt spring and pin kit is often used to hold the cam in. how ever it seems that this kit is on back order :brickwall: ....everywhere... :brickwall:
I gave up on my search for this part after looking for over a month
Try the junkyards.
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Re: Cam retaining problem

Post by SilverXJ »

dvd_fuller wrote:I gave up on my search for this part after looking for over a month and decided to put the engine in anyways because I had also seen that not all of the 258's used the kit and managed to hold the cam in regardless.
The early 4.0Ls Didn't have the spring and pin either but they added it later. Aera has a document about leavign the pin out after a rebuild.. results in cam walk.
I believe that the distributor managed to hold it in place.
Oil pump drive and taper on the cam lobes should hold it in place. But doesn't all the time.
well now that my engine is running there is an awful knocking sound coming from the front on the engine at low rpms,
Cam walk.
I also have low oil pressure after the engine warms up (10-20 psi) but good oil pressure when cold (40-50 psi) which sounds a lot like a bad oil pump.
Your cam bearings are most likely trashed.
the fact that more often than the oil pump being bad
Interesting fact. Don't know where you heard it but the 4.0L oil pumps aren't notorious for going bad. Especially a new one.
so what I'm thinking is that my cam is walking forward allowing oil to escape out of the cam bearings causing low oil pressure,
Most likely what is happening is that the cam walk was damaged the bearings. The excess clearance on the cam bearings is what is now causing the low pressure.
p.s. the guy that bored my engine seems to have known less about engine building than I though because he bored the block exactly to piston size, and I mean exactly. My genius self in excitement of getting the engine together forgot about skirt clearance and put the engine together anyways. lets just say I had to wiggle the pistons into the bore and tap down with a rubber mallet. I honestly dont know why I didnt think anything was wrong. I'm just letting you guys know this because there was a lot of metal in the oil after the break in, but I checked the crank bearings and they all seem fine.
You ran it like that? If the block was exactly the size of the piston, no clearance your pistons would have seized. Something doesn't add up here.

As for what you need to do now.
1) pull the head, lifters and cam.
2) Check your cam bearings.
3) most likely you be replacing the bearings
4) If the bearings are damaged pull the engine and clean it.
5) Install new bearings
6) install cam retention mechanism.

Now, on the cam retention you have two options. 1) Use the bolt with the hole, a solid bar instead of the pin and spring, and set end play manually. Shoot for around .005" end play. You can modify a bolt to have a hole if you can't find one. Make sur eteh hole is centered and slightly larger than the pine. Have you tried Hesco for the cam bolt? 2) Get a stock cam or get a custom grind on the 99+ stock cam core. I used Jones Cams for the custom grind on my 99+ cam. Then use the stock camshaft retaining plate.
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Re: Cam retaining problem

Post by dvd_fuller »

Thanks guys
I was really hoping to not have to pull the engine again but it's looking more and more like that's what I'll have to do.
Surprisingly the engine didn't seize running like that. I guessi got lucky there.
I've tried hesco for the bolt and they also told me out was on backorder. I'll look around for a 4.2 in a junkyard
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Re: Cam retaining problem

Post by SilverXJ »

dvd_fuller wrote:Surprisingly the engine didn't seize running like that. I guessi got lucky there.
Not luck. The machinist probably did the job correctly. Pistons with the ring pack installed don't just slide into the cylinder. I recommend googleing piston installation.
I've tried hesco for the bolt and they also told me out was on backorder. I'll look around for a 4.2 in a junkyard
Why a 4.2L? The 4.0L had the bolt. Try the forums too. I'm sure someone had a bad pre 99 4.0L around some place. You will also need the correct washer. Might try the dealer. The part number is 83502890.
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Re: Cam retaining problem

Post by akadeutsch »

When I showed the guy at the junk yard what I had been searching for...the spring and pin. He told me I could have it for free. I did have to tear the whole front of the truck off to get it, but it was free.
dvd_fuller
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Re: Cam retaining problem

Post by dvd_fuller »

I went through 9 engines today. none had it but i did find a bolts that had a hole in them, just not deep at all. ill look for a different junkyard tomorrow
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Re: Cam retaining problem

Post by Cheromaniac »

SilverXJ wrote:
dvd_fuller wrote:The part number is 83502890.
Yup. That's the part no. of the recessed cam bolt/spring/pin kit.
The part no. of the correct larger cam bolt washer is J3173284.
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Re: Cam retaining problem

Post by SilverXJ »

Don't forget ebay.. look for a "cam bolt" or "timing bolt"
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