Cam and Engine Build Choices

[Robert Kenney]

Good pictures Mark,

1) need to measure the bore to know for sure but in general if after cleaning the carbon at the top of the bore you can feel the lip even if barely it probably has more then the allowed wear/taper.

2 the bad cam bearings are hard on the rocker assembly. Both sides need a complete tear down and cleaning.

3) lifters and cam are toast by the lack of a outer ring with no wear. Must have dishing and that would indicate lobes are done.

4 good thing on those e heads is I see exhaust seat inserts. They will handle unleaded fine.

You're off to a good start for sure.

 

[Eagle-Mark]

Appreciate the feedback Robert! I knew I was going to get it, yours seems promising and that's what I see here is a good motor to rebuild.

Block is coming out in the next couple days so I will have more information.

Hearing the heads are a good choice and I already have them is encouraging!

Bore and pistons or hone and re ring will be decided by machinist.

Will tear down rockers, thoughrough inspection, then pictures for advice here. But I see no bad wear. I see barly wear. Tops of valves look like no wear!

Cam and lifter were going to be replaced with a performance cam anyway. Yes they are dished, but no critacal damage. So the performance cam recomended ealier in thread from IH only? Comes with lifters or I have to order them with it! But what about valve springs? Use the IH springs? Other?

One thing we haven't talked about is oil pump. Is the oil pump rebuild kit I see here on IH only site what is recomended?

 

[Eagle-Mark]

Pictures later tonight but I got another question... Got the oil pan off and the block out of the truck. All the rods are number stamped! Does that mean this has been rebuilt before?

 

[Robert Kenney]

So the performance cam recomended ealier in thread from IH only? Comes with lifters or I have to order them with it!

Yep the same one and just clarify that you want lifters too. Ihon specs there own lifter (johnson's) because of the issues we have found regarding face contour on the other brands.

But what about valve springs? Use the IH springs? Other?

Use the comp set that Jeff sells http://www.IHPartsAmerica.com/store/comp-961-16-p-vt.html . think I mentioned it before but who knows .

one thing we haven't talked about is oil pump . is the oil pump rebuild kit I see here on IH only site what is recommended ?
[/quote ] you have the double sump ? if yes then you need that rebuild kit . if not then you can get a new pump and I believe Jeff sells it.

 

[Robert Kenney]

pictures later tonight but I got another question... Got the oil pan off and the block out of the truck. All the rods are number stamped! Does that mean this has been rebuilt before?

Not necessarily. Still have "IH" bearings in it?? It is probably a factory deal.

 

[Eagle-Mark]

Ok the suspense is killing me as my son dismantles the engine.

Cam is out and doesn't look to bad but definatly has wear. Front cam bearing has failed and is missing the top layer on about half! Taking off the rear cam retainer plate now to see how bad the rear is...

 

[Eagle-Mark]

Rear cam bearing complete failure!!!

 

[Robert Kenney]

pictures!!!

 

[Eagle-Mark]

pictures!!!

I feel like I have been spanked...

front cam bearing.

Rear cam bearing.

Cam.

 

[Robert Kenney]

I feel like I have been spanked...

Hope you know it is all in fun. Nothing to serious here..

Wow it sure did shit them didn't it? I would say by the look of those bearings, they are factory originals. Shells will be stamped IH. Same on the rods and mains.

Had to use your nice photo to make a few points for reference.

 

[Eagle-Mark]

hope you know it is all in fun. Nothing to serious here..

I always take it as fun! Unless I am really told bluntly... Sometimes people mistake me because I am to blunt sometimes but if I'm on a forum it is always for fun! Even as serious as this thread is, it's fun for me!

Wow it sure did shit them didn't it? I would say by the look of those bearings, they are factory originals. Shells will be stamped IH. Same on the rods and mains.

So the rods are stamped with numbers? Mine are and I thought that was a sign of a past rebuild?

 

[Robert Kenney]

I've seen them on first time poppers many times. I have never opened up an IH that was not marked. Doesn't mean they were never built unmarked but I have yet to run into one.

 

[Eagle-Mark]

Well like I said they were all marked 1 through 8. Rod bearings and main bearings all have an IH emblem on back side and marked std. No signs of crank damage. No signs of rod damage. No signs of block damage. No signs of valve damage. No signs of rocker damage but I have not taken them apart yet. Pistons show a little skirt wear but from my experiance machinist usually say they look good the way they are but have to mic the cylinder bore to determine if indeed it needs a bore.

So overall we have all good parts to rebuild. Actually if it weren't for cam bearing failure and resulting oil pressure loss this motor would probably have gone another 100 to 200k miles.

Now comes the nickel and dime damage...

edit: went back and saw your notes on my rear cam bearing! Thanks! What your saying about the gasket not being there is critacal? Sign of origanal engine or good IH rebuilder? From everything on here it looks like an origanal.

 

[Eagle-Mark]

I've got a couple weeks before I need to order a cam! Wish a few guys would give opinions on all the cams listed in the IH only store. I looked at details and I could efi tune any of them so thats not an issue.

The one that says 1500 rpm up seems apealing because the others are 2000 rpm and up. Truck has 3:73 gears and a manual trans. Will be a street only and tow rig. No need to figure in for cam use. I do want this thing to scream hp while towing aas where we live within 5 minutes driving it is all mountains on the interstate.

Really looking for power 2000 to 3500 for towing.

I May teach my kid how to port and polish. Truck already has duel exhaust. Don't know what else to add? So I am looking for cam choice? Cam timing? What port and polish will help and hurt?

 

[yotakid85]

I am the son in this case, Dad just told me he was posting stuff so I thought I would check it out! I appreciate all your guys' info and all I am really looking for is a cool dd and a bad ass tow rig! And like I said thanks for all the info and im really looking forward to this rebuild

 

[yotakid85]

This is a picture of the tow rig and the wheeler by the way!

 

[Robert Kenney]

I've got a couple weeks before I need to order a cam! Wish a few guys would give opinions on all the cams listed in the IH only store. I looked at details and I could efi tune any of them so thats not an issue.

The one that says 1500 rpm up seems apealing because the others are 2000 rpm and up. Truck has 3:73 gears and a manual trans. Will be a street only and tow rig. No need to figure in for cam use. I do want this thing to scream hp while towing aas where we live within 5 minutes driving it is all mountains on the interstate.

Really looking for power 2000 to 3500 for towing.

I May teach my kid how to port and polish. Truck already has duel exhaust. Don't know what else to add? So I am looking for cam choice? Cam timing? What port and polish will help and hurt?

I've installed and driven most of them. 345-392's the 392's with some good porting and 9-1 will like to be installed straight up (110 not 106) this helps with the upper rpm band and maintain reasonable cylinder pressures for pump gas.

A good point of reference is what you have for a cruise rpm? Larger cams will give you better hp but with a sacrifice in low end. Also should have a compression bump.

If you cruise at 2300-2700, stick with my initial recommendation. Higher and go to the next bump stick. I don't recommend it however seeing as the rig is real heavy and will have a narrower power band with the sv's asthmatic breathing potential.

I must remind you that I am quite conservative with cam choice. I don't want to risk recommending a bigger cam just to have you be unsatisfied with the low end.

Porting the exhaust will help as will some deshrouding of the valves in the combustion chambers. Let me post a picture to show you what I mean

 

[Eagle-Mark]

Ok I'll wait...

they will be a good reference as I am going to teach the kid how to do his first port and polish and port match. He's got loads of spare time till collage starts in fall...

Edit: he's in the 2300 to 2700 rpm range. 3:73 manual trans and stock tires, May go to a skinny 33.

Double edit: what is recomended for compresion boost? Shave the heads?

 

[yotakid85]

Im not trying to get crazy rpm's but just enough to winde it up to get over the passes and hills while towing

 

[Eagle-Mark]

How about cc measuring the combustion chamber during this?

 

[Robert Kenney]

Been really busy lately so have not got around to the picture I promised. But after more thought regarding your build and application here is what I suggest.

Mark you sound like you are experienced enough to accomplish the porting but heads can also be ruined just as easily. Other then blending you won't gain much at your expected rpm range

the exhaust port ceiling where the air tube goes should be smoothed. Eg remove the hump so the roof is flat and contoured.

The valve bowls should be smoothed and blended seat to port.

The intake short side radius needs special attention. The bowl to port should be free of corners and as large a radius as reasonably possible. Posting a basic port drawing to show what I mean.

As an exercise you could cc the cc's.

could be used to dial you in on cr.

Depending on the operational altitude a compression ratio bump will help. I don't recommend head milling but do recommend "0" decking to accomplish the desired cr. You'll be very near 8.6 with a composition gasket and 0 deck. Steel hg, leave the piston in the hole .020 at tdc.

 

[Eagle-Mark]

Thanks Robert! I had a port and polish thread on bp and the info there was basiclly the same. Port and polish is a waste of time. No real noticable gains in hp or tourque on these engines. This engine and it's purpose will probably never see 4000 rpm and has no purpose over that. I am using 4000 rpm as an extreme example as well.

But will take your recomendations into account and May do that mild work as we have the engine apart and it's a learning opertunity to my son. I have done about 10 sets of heads in my life. None IH and all with positive results because of my learning opertunities from others at a younger age.

So I will have to watch and see what gasket comes in iho gasket kit. I will be purchasing as much as possible there but that depends on machinist here that we are dealing with as he has hands on this engine.

Because of IH experiance he has no problems using the isky cam, lifters and springs sold and recomended here. He would like to use his bearings and pistons if we need a bore.

Again a big thanks to you. And to Jeff he's lucky to have you here!

 

[Eagle-Mark]

Another question on compresion. 0 deck and composite head gasket = 8.6 to 1. Any reason to go higher? Still want the option to run readily available 87 octane fuel...

 

[Robert Kenney]

Still don't know your native altitude. I don't recommend more than 0 decking and a comp hg to run 87 pump gas.

Run what ever piston you want, just make sure it is a stock compression height slug and not decompressed one. Silvolite is about the only one I know that fits the bill.

All I can do is give you what I feel is the way go. Beyond that it is your call.

Hope you and your son enjoy this project together.

 

[Eagle-Mark]

I'm not going to hold you to anything, you can stop the disclaimers, all is well!

we are having a good time on this, especially me! Knowing his age (18 two weeks) it;s lucky I get any time with him, so doing an engine (second one, we did his toyota engine at 14) is good times!

Altitude here is 2000 to 24000 feet and just outside town we go up! Not real high but two mountains in between us and montana are both around 6,000 feet.

What's all this talk of a decompression piston? It it just that, a piston that lowers compression. I am not looking for that at all.