Big Valve Stroker Motor

[Maize583]

I dropped off the head and the two valves I brought home at Sperry Engines today.

I also dropped off the rocker arm studs and pushrod guides so they could be machined into the head. I am having them cut it down 0.400" inch to accept the studs.

I will have to wait until I get the motor together to order my pushrods. I will have to measure them to get the correct length once the motor is together.

I also dropped off the main bearings, a set of rod bearings, a set of rings, the new ARP rod bolts, the new dampner, the flex plate and bolts so the rotating assembly could be balanced. I already balanced the pistons and rods so all that is left is to balance the crank with the weight on it.

I am also having him cut 10mm off the snout of the crank to fit the new style balance/pulley.

He is going to deck the block to 0.010", with the Mopar Performance head gasket of 0.043", that will give me a quench height of 0.053". Mopar suggests a quench of a minimum 0.040" to a maximum of 0.060". This should put me just in the middle.

With the new larger chamber, quench at 0.053" and 18cc pistons. I should have a compression ratio of 9.08:1. I should be able to run 87 octane gas running around town, and change to 91 octane when pulling under load.

The shop said they should have everything done in about 2 weeks. So once it gets back, I will be posting the progress of the new build. I will actually be getting to put it back together. YEAH!!!

Once the old motor is out, I will have the Doug Thorley header coated in ceramic and also the intake manifold. I will have to show the new setup to use the 2000 style intake, on the 94 configuaration..and still use all the 94 accessories so you don't have to mix and match.

I feel like it is Christmas around the corner. I am getting stoked to get it back and start putting it together.

I need to start working on the adjustable MAP sensor, so it is ready to go.

[Maize583]

I took the week off this week to try to get caught up on a bunch of work around the shop.

I got both motors out of the Speedster. The one motor needed to have 4 crank bearing replaced and new pistons. The othe motor was good to go with a re-ring while it was apart.

Now that I have the front end back together, I need to line up the new lift gate that has been sitting in my garage and paint this weekend.

I had to fabricate a new frame rail as it was smashed in. I then had to tie that into the rebar. I did get everything lined up perfectly with the rebar and headlight buckets.

I bought some euro from Kolak last summer and also his direct wiring harness for them. I had to do some fabrication with the adjusters to get them to fit properly, but that was par for the course.

I put the front end from a 98 on my 94 to allow the driving lights to be mounted under the bumper. I also looking into getting a Safari bar and some PIAA driving lamps. I am going to use the existing lights on low, and then hook PIAA driving lamps into the high beam circuit.

Anyway, the bumper will be painted this weekend and the front end will be complete. I still have to mount the trans cooler to the backside of the grill support, and align the lights.

[Maize583]

Well. The assembly has started.

It looks like I will be keeping the Jeep a bit longer. The wife said I could either look into a newer vehicle, or modify the snowmobile motor. Since my company motto is "because stock s*%#s...." guess which I opted for.

The sled will be getting an overbore kit and should be pushing around 172hp.

I am fixing up the Jeep a little. I bought black leather seats and center console from Puma. I got new black carpet floor mats and will be getting new black carpet. I am going to dye the top of the dash and carpet inserts in the door black. I have the driftwood interior now and my driver's seat is starting to show its age.

This morning, I helped out my neighbor in his shop. I did the plumbing work for him. After the flood damage, he had all the walls torn out so he decided it was a good time to convert the galvanized pipes over to copper and plastic.

This after noon, I assembled the head and took readings off them. I included my very sophisticated engine tag to show the head numbers for the lifts.

Here are the specs on the valve train springs using the Australian fine wire springs.



Here is the head with most of the valve train installed. I do not have the rocker arms on it for obvious reasons. I may put them on just to shoot a picture for the 'cool factor'. LOL.











Here is all the stuff with the machine work finished. I still have to radius the underside of the block for the rod clearance. Other than that, it is ready to be put back together.

I'll have some pictures of the rods and the pistons later next week. I am heading to Wisconsin tomorrow for Fish Fest. A bunch of snowmobilers get together each summer and have a party. I won't be home until Sunday night.

Have a GREAT weekend. I know I will.

[SilverXJ]

I seem to remember seeing your build before.. perhaps it was on Naxja. I also thought that you didn't go with the Aussie springs for some reason. If so, what was it? What cam will you be using? I dodn't remember seeing it on your posts or I may have missed it. Where are you getting your MP head gasket from? I would like to get one, but can't find another one. Lastly, I seem to remember Dino's numbers were are 25", not 28, so that may be where your measurements are quite different. Nice build so far!

[Flash]

You said you needed to grind the lower side of the block for rod clearance????????............what crank, and stroke, are you running?

Whats with the duel valve springs............How high are you planning on spinning this 4.0L?/stroker?

And yes, what cam are you going to run in this?

Also did you have the valves mover closer to each other, or just enlarged the seat, to accommodate the larger valves?


Flash.

[Maize583]

I am using dual springs not because I am planning on reving the motor high, but because it cuts down on valve train harmonics. If you will observe the spring pressures in my last post, closed pressure = 100lbs, open = 235lbs. That is pretty close to stock pressures. Stock springs were rated at 105lbs closed, and 245lbs open.

I am using a Comp Cams cam (I have the number at home, but not with me at work) that has been nitrated and cam saver lifters that have been machined with a small area of the side of the arc removed to allow more oil to pass to the cam lobes.

I am going to clearance the underside of the cylinder sleeves to allow for .100" clearance. I am using a 1988 4.2L crank and 94 4.0L rods.

I got my MP head gasket from Summit Racing.

I did not have to move the location of the valves at all. I opened up the quench area and deepened the pocket for the valves. I expanded the size of the combustion chamber to 65cc's. There is actually more room now with the bigger valves, than there was in the stock configuation. The valves have way less of the valve head shrouded by the sides and back of the chamber.

The thickness between the intake and exhaust runners is more than on my 455 Pontiac heads so it should be plenty of material.

[gradon]

Man--I wish I could get that much accomplished in 22 minutes! The head looks good. If I ever take mine apart, I will go with Mopar's 1.97"in and 1.60"ex swirl-polished stainless steel tulip valves, advance the 30ab cam, and use the thinner Mopar .043"HG(what I ordered, but was given a .051" fel-pro). I also might consider those crower RRs in future since $267 is a lot cheaper than the $400 I found the Yella Terras for. Tomorrow you'll have 2000 miles on it.

[dwg86]

DO YOU HAVE PART NUMBERS FOR THE STUDS AND GUIDE PLATES?

[Alex22]

If I had to guess I would call them Oldsmobile guide plates. I was test fitting a set on my head the other day and they looked like they would do the trick.

I didn't read the entire thread yet, but I can say that the reason the flow numbers are off from Dino's and most of the rest of the published numbers is because there was no intake or exhaust adapter used during the test. If you have time you might want to re-flow the heads and use play dough to make a nice radius, descriptions of how to make it should be in the Superflow manual. I have seen a difference of 25cfm @28 inches at high lift when the clay fell off. I see you made the exhaust ports very large, how large are the primarys on the headers?

Its a nice looking stroker.

[Maize583]

If I had to guess I would call them Oldsmobile guide plates. I was test fitting a set on my head the other day and they looked like they would do the trick.

I didn't read the entire thread yet, but I can say that the reason the flow numbers are off from Dino's and most of the rest of the published numbers is because there was no intake or exhaust adapter used during the test. If you have time you might want to re-flow the heads and use play dough to make a nice radius, descriptions of how to make it should be in the Superflow manual. I have seen a difference of 25cfm @28 inches at high lift when the clay fell off. I see you made the exhaust ports very large, how large are the primarys on the headers?

Its a nice looking stroker.

The exhaust ports aren't really that much bigger. They flare out at the end to match up with the Doug Thorley header. It is a smooth transition, and it flares out towards the end to equal the wall diameter of the header. I wanted to keep the water jackets at least 0.250" thick to prevent cracking.

The guide plates are actually from a Magnum motor. The part number from Summit Racing is CCA-4842-6. They run $12.95 for 6 of them.

The rocker studs are part number CCA-4542-16. The are also from a Chrysler small block. They are $68.95.

The cam I am using is Comp Cams part number 68-232-4, with a .462 intake, .478 exhaust.

It didn't really matter to me what the maximum amount of flow was. I was mainly concerned with the improvement over stock in the flow numbers. Ultimately, the dyno will tell the final HP numbers.

[Alex22]

If I had to guess I would call them Oldsmobile guide plates. I was test fitting a set on my head the other day and they looked like they would do the trick.

I didn't read the entire thread yet, but I can say that the reason the flow numbers are off from Dino's and most of the rest of the published numbers is because there was no intake or exhaust adapter used during the test. If you have time you might want to re-flow the heads and use play dough to make a nice radius, descriptions of how to make it should be in the Superflow manual. I have seen a difference of 25cfm @28 inches at high lift when the clay fell off. I see you made the exhaust ports very large, how large are the primarys on the headers?

Its a nice looking stroker.

The exhaust ports aren't really that much bigger. They flare out at the end to match up with the Doug Thorley header. It is a smooth transition, and it flares out towards the end to equal the wall diameter of the header. I wanted to keep the water jackets at least 0.250" thick to prevent cracking.

The guide plates are actually from a Magnum motor. The part number from Summit Racing is CCA-4842-6. They run $12.95 for 6 of them.

The rocker studs are part number CCA-4542-16. The are also from a Chrysler small block. They are $68.95.

The cam I am using is Comp Cams part number 68-232-4, with a .462 intake, .478 exhaust.

It didn't really matter to me what the maximum amount of flow was. I was mainly concerned with the improvement over stock in the flow numbers. Ultimately, the dyno will tell the final HP numbers.

Oh ok, you kept the head at 5/16-18 for the rocker stud pedestals and used the guide plates with 5/16 stud holes. The Olds guide plates had 3/8 stud holes in them. Did you have to modify the Chyrstler guide plates at all?

~Alex

[Maize583]

The guide plates did not have to be modified in any manner. They were a "drop-in" fit.

[SilverXJ]

Why did you go with the CompCam 68-232-4 over the 68-231-4?

[Maize583]

Why did you go with the CompCam 68-232-4 over the 68-231-4?

The lobe seperation on the 231 is 111, the lobe seperation on the 232 is 113. The loss of idle quality and vacuum for the fuel injection system would not allow the use of the 231. The 111 lobe seperation is bit to lumpy for the computer. Comp Cams does not recommend that cam if you use the factory computer.

My plan is to keep the factory computer, use my adjustable fuel pressure regulator, larger injectors and adjustable MAP sensor to adjust the fuel curve demands.

[SilverXJ]

Are you generalizing that, or is that just for your particular build? I.e. the lobe separation issue.