New cam install w/MPI

[Sasquach]

I decided to replace my stock 1V camshaft since it was such a weak link in my motor upgrades. What I have is a 4.0 head with Mopar MPI on the AMC 258 i6 / 4.2l 1V engine.
I have the head off and lifters out and am wondering how to proceed with the distributor? I have the engine oriented at #1 TDC with the cam gear marks lined up, should I pull the distributor out and just reinsert after the new cam goes in and #1 TDC again? or can I leave it in?(not sure the cam would come out though).
Keep in mind the distributor is computer controled.

Next question is With 4.0 valve train(springs) and my new Comp cams AMC 232 i6 -4 will I need to replace the springs? this cam is comperable to a stock 4.0 cam I think.

 

[Sasquach]

I answered some of my own questions, I'm gona mark the distributor and remove and reinstall #1TDC comp stroke. What I did discover is the timing chain marks line up #1 TDC exhaust stroke so that would have led to a bit of greif.
FYI my Jeep has 78K on it and the timing chain has over 3/4" of deflection and FSM say's to replace at greater than 1/2", 3/4" equals about 10 degree's of slop.
Read previously 10 degree's being the acceptable tolerance but I'm thinking much less.

 

[coldair]

I would replace the timing gears and chain your already there. What's the lift on that cam?

 

[coldair]

Ok this is the stock lift on a 4.0 cam
Duration @ 0.050" lift int./exh.: 188/192 deg
Valve lift int./exh.: 0.408"/0.414"

That comp cam has a valve lift int/exh 0.460"/0.476

 

[rlitavecz]

I decided to replace my stock 1V camshaft since it was such a weak link in my motor upgrades. What I have is a 4.0 head with Mopar MPI on the AMC 258 i6 / 4.2l 1V engine.
I have the head off and lifters out and am wondering how to proceed with the distributor? I have the engine oriented at #1 TDC with the cam gear marks lined up, should I pull the distributor out and just reinsert after the new cam goes in and #1 TDC again? or can I leave it in?(not sure the cam would come out though).
Keep in mind the distributor is computer controled.

Next question is With 4.0 valve train(springs) and my new Comp cams AMC 232 i6 -4 will I need to replace the springs? this cam is comperable to a stock 4.0 cam I think.

I am running the 235 Comp cam, just slightly bigger than the AMC 232 i6 . I also have the 4.0 head. The only valve springs that will fit this head without cutting come from Mopar and will cost you over $250 with the retainers and locks. They are beehive type springs and no one else sells them! I kept the stock springs...they are holding up just fine. I rev this motor a lot, but do not have a tach. I did have to change out the pushrods for longer ones from a 1995 4.0 engine. They measure 9.696"....about .100" longer than the stock AMC 258 i6 / 4.2l rods.

 

[coldair]

Lol ok that's the same cam I'm installing in my motor has been a long day. You will have to change springs, retainers

 

[coldair]

I am running the 235 Comp cam, just slightly bigger than the AMC 232 i6 . I also have the 4.0 head. The only valve springs that will fit this head without cutting come from Mopar and will cost you over $250 with the retainers and locks. They are beehive type springs and no one else sells them! I kept the stock springs...they are holding up just fine. I rev this motor a lot, but do not have a tach. I did have to change out the pushrods for longer ones from a 1995 4.0 engine. They measure 9.696"....about .100" longer than the stock AMC 258 i6 / 4.2l rods.

How many miles does your motor have on it with that cam? I called and talked to com cam about springs they said the stock springs won't work with the AMC 232 i6 they will have coil bind. I was told that there are no springs that will work unless you cut the head. this is what i came up with I didn't have to cut the head and I have more the .060 of clearance when the springs are compressed. P5249464 single w/damper1.42"OD .400"/.525" lift P4529218 valve locks pack of 8 $21.99
P4452032 valve spring retainers $9.99 a piece*they are from a 5.9 they are pricey though.

 

[Sasquach]

This is what's going in.
COMP Cams SK68-232-4 - COMP Cams Xtreme 4x4 Cam and Lifter Kits - Overview - SummitRacing.com

4.21V stock cam lobe lift = .AMC 232 i6
4.0 up to 95 cam lobe lift = .424
Comp cam AMC 232 i6 -4 cam lobe lift = .460/.476
My hope is to use the stock 4.0 springs and sounds like most people do.

 

[rlitavecz]

I have about 500 miles on this engine so far. Half of those miles are in the dunes and the engine has been run hard climbing hills. I didn't replace the springs because of the cost. I did check for coil bind and that is not an issue.

 

[Sasquach]

The 235-4 cam is 0.477 int./0.493 exh.
If your not having problems I would thing the AMC 232 i6 -4 would be fine.

 

[coldair]

I have about 500 miles on this engine so far. Half of those miles are in the dunes and the engine has been run hard climbing hills. I didn't replace the springs because of the cost. I did check for coil bind and that is not an issue.

That's good to hear I guess why would comp cam tell me that stock springs wouldn't work with my set up

 

[rlitavecz]

High RPMs can damage the cam, lifters, valves and seats if there is insufficient pressure. I would like to replace the springs, but I am too cheap

 

[Sasquach]

That's good to hear I guess why would comp cam tell me that stock springs wouldn't work with my set up

What engine did you tell them you had? AMC 258 i6 / 4.2l or 4.0? as far as they are concerned they are looking at one or the other and not a highbred, I am thinking outloud here but if you have the 4.0 head then that's maybe all they need to know since this is the valve train we are dealing with.

 

[Sasquach]

High RPMs can damage the cam, lifters, valves and seats if there is insufficient pressure. I would like to replace the springs, but I am too cheap

I plan on low RPM and that's exactly why I chose the cam I did, I did not want to lose anything on the bottom and wanted a smooth idle. The AMC 232 i6 -4 is that and for whatever reason their fuel injection cam replacement.

 

[coldair]

Ok here is why they said stock springs wormy work they recomend a spring with O.D. Dia. 1 I.D. Dia. 2 Damper Seat Load Open Load Coil Bind Rate (Lbs./In.) Titanium Retainer Steel Retainer Cup Seat Shims
1.476 1.062 Y 109 @ 1.800 317 @ 1.300 1.140 415 730 1730, 740 4704 4755
These specs I know I was forgetting somthing this is why I came up with the springs I have installed in my head. My Spring Specs: 1.500" outer spring w/damper - ID 1.080" - Seat load 110 @ 1.650 - open load 290 @ 1.AMC 150 - coil bind 1.110 - Rate (lbs/in.) 360

 

[coldair]

What engine did you tell them you had? AMC 258 i6 / 4.2l or 4.0? as far as they are concerned they are looking at one or the other and not a highbred, I am thinking outloud here but if you have the 4.0 head then that's maybe all they need to know since this is the valve train we are dealing with.

I told them I was building a highbred out of a AMC 258 i6 / 4.2l block and 4.0 head. The guy I talked to told me what spring rates they recommend and well that's where I came up with my set up. I know it's a little more spring rate then what they recommend but Im sure I'll be fine. I'm also running crower cam saver lifters too.

 

[tarry99]

I told them I was building a highbred out of a AMC 258 i6 / 4.2l block and 4.0 head. The guy I talked to told me what spring rates they recommend and well that's where I came up with my set up. I know it's a little more spring rate then what they recommend but Im sure I'll be fine. I'm also running crower cam saver lifters too.

I'll put my 2 cent's in here for what ever it's worth........I hear everyone talking about spring pressure and cam lift , cylinder head flow rates and I can only assume that most think that bigger numbers are better..........and in a wide open throttle, high RPM environment for the most part that holds true! ...........but how many of you are doing that?
Peak lobe lift is really not that important......the average lift at a given degree of crank rotation is. Why? because the motor only see's peak lift once per cycle but see's average lift twice per cycle ......once on the way up and once on the way down. This also hold true when looking at flow numbers. Throw away the highs and look at the average.
High spring rates are to control the valve on the seat at high RPM. That's it!
High spring rates are hard on your valve train IE: push rods, rockers, valve seats, valves , lifters, timing chains & cam shafts............Notwithstanding the cost of power to operate that action.
Point is if your Idling around at under 2000 Rpm all day reconsider what your doing.
In this off road trail riding , rock crawling environment Peak Horsepower and Peak Torque is just for bragging.
Decent low RPM Torque & Gears will get you up the hill and over the rock.

 

[Sasquach]

Thanks for that. It more or less validates what I'm doing.

 

[coldair]

Sasquach I would run the stock springs. I will be using my motor for all around rock crawling, freeway speeds (75 mph) with 4.10 gears and my T-18 I will be seeing 3100 RPM

 

[Sasquach]

That's my plan since my cam is so close to the stock 4.0 camshaft that it's reasonable to think the 4.0 head package would be fine.
This and the timing not wandering around 10 degree's with the worn out chain I'm hoping it will run great.