Need some help on a motor build

[DBD]

Originally Posted by johnmiller66

I've heard rotella is a good oil for flat tappet cams also.

IMHO, nope. the diesel additives dilute the effectiveness of zddp and nowhere does shell claim it's the right oil for flat-tappet cams. lots of other choices. only comment on the subject as folks get heated about this pretty quick...

[dfrank]

Originally Posted by DBD

IMHO, nope. the diesel additives dilute the effectiveness of zddp and nowhere does shell claim it's the right oil for flat-tappet cams. lots of other choices. only comment on the subject as folks get heated about this pretty quick...

I heard they actually even reduced the amount of zddp in the shell rotella due to epa reasons.

[jjzepplin]

I have built hundreds of engines with flat tappet cams and never lost a lobe. That truly would suck! I have done the break-in with rpm meters and stopwatches though. I have always used Comp cams. I haven't built an engine in ten years or so though. Not sure when this oil thing came around. I use liberal amounts of cam lube and engine assembly lube. I never let them sit for more than a day before I start them. Seems a lot of guys lose lobes after the engine has sat for a while. I bet the lube all flows down off the cam and boom. Any way-if you can use a roller cam go for it. Can't lose there.
The last engine I built is still kicking hard. Comp 4x4 Extreme cam by the way. 14 years old and no smoke and smooth as glass.
Good luck with your engine! Should be nice. Just break it in right with lots of cam lube!

[Captainfab]

To my knowledge Rotella does not have enough ZDDP. The ZDDP was removed from gas engine oils because it was contributing to the failure of catalytic converters in less than 100,00 miles. Some of the medium and heavy duty trucks began using catalytic converters as early as 2002 and all trucks had them beginning in 2008. So now all diesel specific oils no longer have sufficient ZDDP for gas engines.

Originally Posted by johnmiller66

I've heard rotella is a good oil for flat tappet cams also.

There are several gas engine specific oils formulated with sufficient ZDDP for flat tappet cams.

[GASoline71]

I have used and installed lots of Lunati flat tappet cams (including the Voodoo series) and have not lost one yet. As long as they are installed with the right lube, and broke in properly, they work great. The only cam I have ever lost due to a wiped out cam lobe was a Summit Racing house brand camshaft.

Gary

[johnmiller66]

I bought the comp xtreme 4x4 cam. 12-235-2. 447/462 lift. With a 4.04 bore, 348 stroke, 64cc cyl head volume and a .023 deck clearance what head gasket thickness would I need to get proper compression for pump gas? I have the flat top speed pro forged pistons with valve relief.
Thanks.

[johnmiller66]

I'm coming up with 10.4/1 with a .040 compressed head gasket. I should be in the 9.5/1 range shouldn't I?

[dfrank]

Originally Posted by johnmiller66

I'm coming up with 10.4/1 with a .040 compressed head gasket. I should be in the 9.5/1 range shouldn't I?

Are you using iron or aluminum heads? You need 9:1 max with iron heads to run on 93 pump gas and 10:1 max with aluminum heads to run 93 pump . What heads are you using?

[johnmiller66]

062 vortec.

[dfrank]

Originally Posted by johnmiller66

062 vortec.

I never dealt with those. Are they aluminum or iron? I am guessing iron.

[dfrank]

Originally Posted by johnmiller66

I'm coming up with 10.4/1 with a .040 compressed head gasket. I should be in the 9.5/1 range shouldn't I?

Ok I just ran the compression ratio's. You are right at 10.4:1. If use a .080 compressed head gasket it will put you around 9.5:1cr and a .100 compressed head gasket will put you around 9.1:1 cr. I would go with the .100 compressed head gasket that way me may be abke to run on 89 octane pump gas but idk for sure. http://m.summitracing.com/parts/cgt-c5245-098

[johnmiller66]

They are iron.

[johnmiller66]

I recalculated on Summits website using the exact specs for my pistons.
Bore 4.04
Stroke 3.48
Cyl head vol. 64cc
Deck clearance with strait edge and feeler gauge. .023
Piston head volume. +6.10
Compressed gasket thickness. .050
Comes out to 9.55:1
I feel much better about that. Someone please confirm the calculation.
JM

[DBD]

I'll take a look at this tonight but you DO NOT WANT an .073 quench!!! So hold off on the gasket order.

[johnmiller66]

Man, I was kind of feeling good again about this setup. Now this quench curveball. I'm lost again. Lol! So I take it that .073 quench is to much space between the top of the piston and the head at tdc.

[DBD]

ok, I got a minute at work.

a couple of things to start. doing a 'top' of an engine is always hard because nothing's planned...you kinda have to work with the cards you're dealt with pistons, deck height, etc. kinda like assembling the puzzle with some pieces that don't fit and you can't change

the big deal is always premium fuel - if you go over about 9.5 you'll need premium. over about 10.5 or so and you're pushing even that. its all about how much power you want in a daily driver and how many miles you drive. folks will debate those numbers, but they're pretty good based on my experience.

quench is a Big Deal - it has a major impact on power and detonation sensitivity. around .040 is ideal, anything over .060 and we start having higher detonation sensitivity. high cr + high quench is Bad News - .073 quench + 9.5 CR is not a good combo IMHO.

so in your case your calcs look good and you're around 10:1 with an .028 compressed gasket. you have two choices. 1, run that cr and recognize that you need premium fuel on every fill. you'll need to be real careful and get the timing right, but I'm sure you'll be OK. Or...you sell your vortecs and buy a set of 76 chamber heads. what you can't do is just stuff on a thick gasket to get the CR you want.

I feel bad I didn't do the cr calc once we had the piston numbers - I just figured you had already looked at 'em. it's job one on a top.

[dfrank]

Originally Posted by DBD

ok, I got a minute at work.

a couple of things to start. doing a 'top' of an engine is always hard because nothing's planned...you kinda have to work with the cards you're dealt with pistons, deck height, etc. kinda like assembling the puzzle with some pieces that don't fit and you can't change

the big deal is always premium fuel - if you go over about 9.5 you'll need premium. over about 10.5 or so and you're pushing even that. its all about how much power you want in a daily driver and how many miles you drive. folks will debate those numbers, but they're pretty good based on my experience.

quench is a Big Deal - it has a major impact on power and detonation sensitivity. around .040 is ideal, anything over .060 and we start having higher detonation sensitivity. high cr + high quench is Bad News - .073 quench + 9.5 CR is not a good combo IMHO.

so in your case your calcs look good and you're around 10:1 with an .028 compressed gasket. you have two choices. 1, run that cr and recognize that you need premium fuel on every fill. you'll need to be real careful and get the timing right, but I'm sure you'll be OK. Or...you sell your vortecs and buy a set of 76 chamber heads. what you can't do is just stuff on a thick gasket to get the CR you want.

I feel bad I didn't do the cr calc once we had the piston numbers - I just figured you had already looked at 'em. it's job one on a top.

You must have better gas or something up in Washington if you can run 10:1 cr on iron heads. My experience in PA has been at 9:1 cr you need 93 and over 9:1 you need vp 110. I tried 89 and it just ran like **** and constantly pinged. Now we can run 10:1 cr on 93 with aluminum heads but anything over you need the vp 110. I am not doubting your experience. My guess is just that you probably have better gas up in Washington which is interesting. I have also found down here that BP has way to much ethanol content in their gas. Anytime you run bp gas you need a lot more shot from the accelerator pump and I think that is the reason people are now complaining about a hesitation off idle when it ran perfectly fine before.

Op, I agree that your best is to probably sell your vortec heads and buy heads with a larger chamber. I think these world products sportsman 2 heads would be a perfect match and they aren't very expensive. http://m.summitracing.com/parts/wrl-012250-1 these heads would put you at a 9.24:1 compression ratio with a .028 compressed head gasket. I have a set of these heads on now and they are great!

[DBD]

If there's trouble running 10:1 cr on 91 octane...then the timing curve is too aggressive or there's a build issue. i'd like to know the specifics of the engine and the timing curve, mechanical and vacuum, and how it was tuned.

my truck has been all over the US and runs a 355 at 10.4:1 with ported 487x iron heads with full ignition advance. I used to run a '69 LT-1 with 11:1 on premium pump gas, although I had to back off the vacuum and mechanical advance a bit. ive built engines used all over the us (and 2 in Europe) that all run on premium pump gas and were pretty much all in the mid-to-high 9's.

so I'm not misunderstood, I didn't recommend other heads - I'd run the vortecs with the .028 or so gasket.

[johnmiller66]

If it comes down to this combo not being quite right I will just sell the shortblock and rebuild the one that's in my truck to be more compatible with these vortecs. I really have my heart set on running those for some reason. I don't have much in the shortblock so it shouldn't be to hard to move if it comes down to that.

[DBD]

Originally Posted by johnmiller66

If it comes down to this combo not being quite right I will just sell the shortblock and rebuild the one that's in my truck to be more compatible with these vortecs. I really have my heart set on running those for some reason. I don't have much in the shortblock so it shouldn't be to hard to move if it comes down to that.

I really don't see an issue here - promise the combo is fine, it's just going to take premium fuel. It's a pretty decent performance engine; I'd run it!

[dfrank]

Originally Posted by DBD

If there's trouble running 10:1 cr on 91 octane...then the timing curve is too aggressive or there's a build issue. i'd like to know the specifics of the engine and the timing curve, mechanical and vacuum, and how it was tuned.

my truck has been all over the US and runs a 355 at 10.4:1 with ported 487x iron heads with full ignition advance. I used to run a '69 LT-1 with 11:1 on premium pump gas, although I had to back off the vacuum and mechanical advance a bit. ive built engines used all over the us (and 2 in Europe) that all run on premium pump gas and were pretty much all in the mid-to-high 9's.

so I'm not misunderstood, I didn't recommend other heads - I'd run the vortecs with the .028 or so gasket.

Internally balanced 383 stroker, kb hyperputic aluminum dished pistons, scat 4150 forged crank, speedpro 214/224 at .050 lift, scorpion racing carbide tip lifters, world products sportsman 2 heads, holley 750 ultra double pumper with 72 primary jets and 80 secondary jets with no rear power valve 33 front squirter and 31 rear squirter, msd 6al-2 cd ignition box, msd pro billet distributor, msd blaster 2 coil, 18° inital and 36° total no vacuum advance and tuned on a dyno with 450hp/470tq running right at 9:1 cr hopefully to be 500hp/540tq once I swap the heads and cam.

[DBD]

Impressive power from heads that flow around 250 cfm - are they ported? Do you recall what the quench was?

I can't see any reason that engine wouldn't run easily with full advance easily on premium gas - the initial seems kinda high, and no vacuum advance if it's a street engine can cause all kinds of issues...but I've built stronger engines that had no issues at 10+ CR.

[dfrank]

Originally Posted by DBD

Impressive power from heads that flow around 250 cfm - are they ported? Do you recall what the quench was?

I can't see any reason that engine wouldn't run easily with full advance easily on premium gas - the initial seems kinda high, and no vacuum advance if it's a street engine can cause all kinds of issues...but I've built stronger engines that had no issues at 10+ CR.

Yes the heads where ported and had a valve job done on them. I can't remeber what the quench was. It was 2 years ago. I do run premium gas which is 93 up here. Only sunoco has 91. 91 would probably work.

[storm9c1]

Iron Vortec heads can be pushed a little higher than conventional heads. Aluminum even higher.

On my setup running iron Vortecs, a roller 264 cam, on my 383 with 9.8 compression, it needs 91+ octane to pull a load up a hill without pinging. Max timing is about 28 degrees checked w/o vacuum advance hooked up (but I do run vacuum advance). I had to completely customize the mechanical curve and vacuum advance (vacuum advance needed a hard stop at 10 degrees, or was it 8 degrees, I can't remember). I'm possibly leaving power on the table to protect myself from detonation, since it's a tow rig, I never spin the thing faster than 5000 anyways, so it's torque I'm after and I have plenty of it. So there are ways out if you end up with a higher compression ratio than you want. I wanted 9.0:1 with this setup but got 9.8:1, I can't remember why I had to go with 9.8, but I think it was the aforementioned quench issue as well... long day at work, my memory isn't serving me well today, LOL.

[johnmiller66]

New question for you guys. I've had this motor finished for a while but just got it on the run stand yesterday. I put a new quickfuel carb on it and set the timing to about 34 degrees and plugged the vacuum advance. It fired on the first hit and did the 20 minute recommended comp cam break in. It runs like a top and sounds really good.
Now for the problems. I put a melling select oil pump in it and am getting about 55psi idling and close to 80 at 2k rpm. Is this too much on a fresh motor? Next thing is that both head gaskets are leaking a bit externally. The oil is not milky at all. It has a bit of oil that is running down both sides of the block but I've been under the impression that head gaskets don't leak oil so it has to be coming from under the intake. True? Next thing is that I need a recomendation for new head gaskets as I will probably have to pull this thing back apart. I need an .028 thickness. It has Chevrolet performance head gaskets now which are leaking.
Thanks for any ideas.