Any idea on what cam (or brand) to purchase?

[iCEMAN]

My motor is a 401 and has roller rockers. Tore into it a little tonight to see why it keeps jumping timing. Turns out the dist and cam gear are toast and most likely the cam.

Need to replace the cam, however no idea what is in there now. From what we could tell, the PO put a motor out of a 75 J10 into it. However, can't find anything about a roller setup for that motor.

Any of you help me out here?

 

[LongHorn]

My motor is a 401 and has roller rockers. Tore into it a little tonight to see why it keeps jumping timing. Turns out the dist and cam gear are toast and most likely the cam.

Need to replace the cam, however no idea what is in there now. From what we could tell, the PO put a motor out of a 75 J10 into it. However, can't find anything about a roller setup for that motor.

Any of you help me out here?

No 401 ever came with roller rockers. What makes you think it's stock?

 

[iCEMAN]

No 401 ever came with roller rockers. What makes you think it's stock?

Sorry, didn't clarify. I know it isn't stock, however, in looking at Summit's website, they don't even list a cam for a roller 401 setup. Talked to the PO (Friend of my son's) and they have no clue what is in there either.

 

[LongHorn]

Sorry, didn't clarify. I know it isn't stock, however, in looking at Summit's website, they don't even list a cam for a roller 401 setup. Talked to the PO (Friend of my son's) and they have no clue what is in there either.

Are talking roller rockers or roller lifters?

 

[LongHorn]

Sorry, didn't clarify. I know it isn't stock, however, in looking at Summit's website, they don't even list a cam for a roller 401 setup. Talked to the PO (Friend of my son's) and they have no clue what is in there either.

With roller rockers you use a flat tappet cam.
I run a "Comp Cam".500 lift-.270 Duration
I would be willing to bet money ( I'm no gambler) that it's not a roller cam, that's big bucks.

 

[iCEMAN]

With roller rockers you use a flat tappet cam.
I run a "Comp Cam".500 lift-.270 Duration
I would be willing to bet money ( I'm no gambler) that it's not a roller cam, that's big bucks.

Longhorn, let me start by thanking you for your help. I am not as good as I had hoped with this stuff.

So, if I understand correctly, I can use a regular cam with the roller rockers and be okay? Agree with you, in looking at roller cams, they are about 3 or 4 times the price.

 

[LongHorn]

Longhorn, let me start by thanking you for your help. I am not as good as I had hoped with this stuff.

So, if I understand correctly, I can use a regular cam with the roller rockers and be okay? Agree with you, in looking at roller cams, they are about 3 or 4 times the price.

A roller cam is made of billet, it's a lot harder to stand up to roller lifters.

 

[LongHorn]

Longhorn, let me start by thanking you for your help. I am not as good as I had hoped with this stuff.

So, if I understand correctly, I can use a regular cam with the roller rockers and be okay? Agree with you, in looking at roller cams, they are about 3 or 4 times the price.

Yes, a flat tappet hydraulic lifter cam is what you need.
make sure you use new lifters if you replace the cam.
Also make sure you use a double roller timing chain set.
Look in my pictures there are a few shots of my 401V8.
Some of the roller rockers & the intake valley.

 

[CJ]

What color are the rockers (the anodize color)? Could give us a clue as to the ratio. If they are an orange color - they are Sharp rockers and could be a 1.5, 1.6 or even 1.65 (1.7). -->> Harland Sharp 1.7:1 Roller Rocker Arms - Jeep-CJ Reviews

As for the cam, how does it run now? Vacuum at idle? Power breaks? What do you want to do with it? I cannot say enough about the Lunati cam grinds and the low rpm torque grinds from comp cams are great also (I believe LongHorn runs that cam). For the ultimate cam, call Lunati and have them make a cam for you...

 

[My1stnicejeep]

Dont the stock timing covers hold the dist gear?And are known for having problems.
Im pretty sure they are known for eating the gears.Just something to look into.

 

[iCEMAN]

What color are the rockers (the anodize color)? Could give us a clue as to the ratio. If they are an orange color - they are Sharp rockers and could be a 1.5, 1.6 or even 1.65 (1.7). -->> Harland Sharp 1.7:1 Roller Rocker Arms - Jeep-CJ Reviews

As for the cam, how does it run now? Vacuum at idle? Power breaks? What do you want to do with it? I cannot say enough about the Lunati cam grinds and the low rpm torque grinds from comp cams are great also (I believe LongHorn runs that cam). For the ultimate cam, call Lunati and have them make a cam for you...

CJ, the rockers are a darker blue. Prior to the valve covers blowing off and the timing jumping, it ran great. Vacuum at idle was a bit on the low side. Power seemed fine.

 

[CJ]

Dont the stock timing covers hold the dist gear?And are known for having problems.
Im pretty sure they are known for eating the gears.Just something to look into.

The gears usually get torn up when a hardened gear and a soft gear are mixed. The factory gears will last for just about forever - it when people swap out dist. that the majority of the problem start...

CJ, the rockers are a darker blue. Prior to the valve covers blowing off and the timing jumping, it ran great. Vacuum at idle was a bit on the low side. Power seemed fine.

The 'valve covers blowing off'??? WT Hell do you mean?

 

[iCEMAN]

The 'valve covers blowing off'??? WT Hell do you mean?

Timing jumped. Blew the valve covers about a 1/4" up, the entire valve cover gasket got blown out. Oil breather on top of the filler neck blew off as well.

Checked the fluids. No gas in the oil, no cross contamination of the oil/antifreeze. Spark plugs look good.

Set the timing mark and #1 to TDC. Dist was pointing at the #7 plug. Gear on the dist shaft is concave. This led to where we are now.

 

[My1stnicejeep]

The gears usually get torn up when a hardened gear and a soft gear are mixed. The factory gears will last for just about forever - it when people swap out dist. that the majority of the problem start...


I know about the hardness of the gears as with the AMC 258 i6 / 4.2l I had the same problem.But I was under the impression that the timing chain cover is an issue.

 

[CJ]

I know about the hardness of the gears as with the AMC 258 i6 / 4.2l I had the same problem.But I was under the impression that the timing chain cover is an issue.

Not sure what you mean? The timing cover? Now I very rarely work on the I6...

 

[Buuushman]

Comp cams has a great cam finder program on their website. You download it, enter the info on your motor, and it will give you a range of cams to chose from depending on what you are using the engine for. It will even show you estimated H.P. and torque curves.