Astro van cat conversion

[Snowy Rivers]

I used to work for a Mopar dealer back in the early 70's
Them suckers always had issues with "Dieseling"

I had a Chevy 454 in an 86 dually 4x4 and it was stock low compression.

That beast would run on when hot....I just got in the habit of shutting it off in gear.

I am not sure what to say...

I posted all the specs I have on the build.

Run the numbers and see what ya get.....

I ran numbers until I was dizzy.....The pistons are the stock type.....The one outlier is the Vortec heads at 64cc
The stock 400 heads were crap even when new......

The 400 came out in the early days (1970) with 9.6:1 ratio....No stock type stuff available in that config....

The later 400's were all 8:1 (Trucks)

The Vortec chambers are a radical departure from the older SBC heads of years past.

This is my first SBC build using Vortecs.....The buzz is that they are the real deal....??????????????

 

[m1west]

I used to work for a Mopar dealer back in the early 70's
Them suckers always had issues with "Dieseling"

I had a Chevy 454 in an 86 dually 4x4 and it was stock low compression.

That beast would run on when hot....I just got in the habit of shutting it off in gear.

I am not sure what to say...

I posted all the specs I have on the build.

Run the numbers and see what ya get.....

I ran numbers until I was dizzy.....The pistons are the stock type.....The one outlier is the Vortec heads at 64cc
The stock 400 heads were crap even when new......

The 400 came out in the early days (1970) with 9.6:1 ratio....No stock type stuff available in that config....

The later 400's were all 8:1 (Trucks)

The Vortec chambers are a radical departure from the older SBC heads of years past.

This is my first SBC build using Vortecs.....The buzz is that they are the real deal....??????????????

I will do that, I used to know how with a calculator, that skill got lost to time.

 

[Snowy Rivers]

I found an enhanced online calculator that has all the variables.....

Here are the snapshots of the data I got after inserting all my numbers.
These numbers seem to agree fairly close to what I have scared up off the net by others who have done this build.
The Silvolite pistons have a big chamfer on the OD at the crown......This has got to drop the numbers a tad.

The piston spec says 22cc dish....but does not say anything about that big chamfer.

Still ...the numbers are going to be close


I fooled with the camshaft numbers quite a bit (Intake closing and LCA ) and the changed to the COMP ratio do not wiggle very much.

We have non alcohol premium fuel available at the card lock....
Really....I think this build can work pretty good.

IT IS going to be about as close to max comp ratio as I want to go....

 

[Snowy Rivers]

I run the numbers on the comp ratio calculator again using the specs of the stock Vortec cam used in the truck.
The Intake closing is 21.5 ABDC....Dynamic ratio went up to nearly 9.6:1 and the cam I am thinking about shows 9.03:1

Makes sense...The earlier the intake valve closes the more effective stroke there is...hence, a touch more comp ratio...

All these numbers make up the basis of how well a collection of parts is going to work together for sure.

My kingdom for some 1960's White pump premium fuel..
Back then some of the Oldsmobile 455 engines had 13:1 Comp ratio...Just talking about that much will melt pistons today.

 

[m1west]

Duration effects how long the intake valves are open, lobe centerline effects when the exhaust valve closes, thats why a short cam for torque and tight lobe centers give you a lot of grunt, and raise the dynamic compression down low where it will rattle if you get too carried away. Ive seen street cars run 11 to 1 static with a big cam of around 300 degrees @ .050 run on pump gas. it works because the intake valve is open when the piston is coming up pushing it back out of the intake at low rpm then at high rpm the intake charge velocity stops the reversion and the speed of the flame front at 8000 rpm burns the fuel before it can detonate.

 

[Snowy Rivers]

YUP
That's the way I learned the theory....a long time ago.

This engine will likely never see much past 4500.

More likely 4000-4200......
I do not want to screw with machining the valve guide height and changing valve train hardware .....since the RPM is pretty low.

The Vortec heads flow well in the .400" to .450" lift area.

The stock L31 cam is like .414" Int and .428" Exh LIFT
The Duration is like 191 intake and 196 exh......

Trying to find a cam that does not have a mile of lift is tough.....

The ones I mentioned earlier have relatively close to stock lift......

Hot Doggers want 6K on up as far as revs..

The 400 was not meant for much over 5K
I think 5200 was stock Red line.

Just a good stump puller with a good bad AZZ sound to it.
The one cam I have in mind is supposed to pull good in the 1600 to 4800 range IIRC

The choices are skimpy when ya want a moderate lift and a good thump at idle.....

Get the heads worked over, cut the guides down, new springs, retainers and such....sky is the limit....

The Vortec heads use a self guided rocker arm.....the stock ones are in perfect shape.

I need to get a set of standard length push rods....the 400 uses a flat tappet cam and the L31 Vortec was a hydraulic roller.
The roller cam used shorter push rods.....

I really do not like the roller set up's for the Gen 1 blocks.....I have used them.....good old hyd flat tappet will do.

Just need to use oil with the ZDDP additive so the cam lives....

The stock valve springs are really benign as far as pressure on the seat.....4500 RPM engine does not need UNGODLY springs......
The only things I want to do to the heads other than clean them....buff the valves clean, lap them to their seats and replace the guide seals......and drill the steam holes so they will talk to the 400 block...

Plenty good for a long time

 

[m1west]

it doesn't cost much more for a custom grind at CompCams, have done it many times. And now that I mention that, if you call them and give them your engine specs and tell them where you want to make the power, they will help you with a cam profile that will do the job.

 

[Snowy Rivers]

Sweeeeeeeeeeeeet.....
Thank you for the info.

I have never used that company before.....

Do a grind that will have the stock lift, the duration @.050 and the LCA to give it a bit of thump at idle (Cool factor)

I will look them up and see what can be done....

Sounds like fun....

 

[Snowy Rivers]

OK
I called Comp cams and we hashed out a cam profile....Basically all they wanted was for me to buy a ready made street cam....

I called Howards cams.
I ran some numbers by them.
I think we have a plan
Hydraulic flat tappet cam

Lift 416/430 (Almost exactly the same as a stock Vortec L31 (Pickup with 5.7)
Duration @.050" 213/223
LSA 106

Will speak with authority (Bit Choppy at idle
4000 RPM all in and all done...

Sounds like a perfect match for the application.....

More study to be done...but we are getting closer.

 

[Snowy Rivers]

Trying to get the distributor interested in ordering the cam seems to be a different story.

Called up Isky cams and bounced these same specs off them.

NO PROBLEMO....$350 FOR CAM AND LIFTERS...

The Isky tech fella was sure this cam is gonna make gobs of torque and will fit the RPM range well....

 

[m1west]

OK
I called Comp cams and we hashed out a cam profile....Basically all they wanted was for me to buy a ready made street cam....

I called Howards cams.
I ran some numbers by them.
I think we have a plan
Hydraulic flat tappet cam

Lift 416/430 (Almost exactly the same as a stock Vortec L31 (Pickup with 5.7)
Duration @.050" 213/223
LSA 106

Will speak with authority (Bit Choppy at idle
4000 RPM all in and all done...

Sounds like a perfect match for the application.....

More study to be done...but we are getting closer.

What did they say about fuel octane requirement?

 

[Snowy Rivers]

We touched on the subject briefly....But the guy seemed most interested in selling me something they had ready to go....
I got a tad pushy at that point and told him I was interested in a custom grind to do a specific job based on the combination of parts that we had.

He then went over the numbers I gave him and he said "Oh, that's not possible"
I asked WHY ???
He seemed at a loss for comment for a short...."We don't have the masters" was his reply.

The cam grind I am looking at is very similar to several of the 420 rule circle track cams.

The difference is the duration mostly.

Howards cams response to the same questions (I described the build, type of machine, gearing, weight yada yada yada.
The fella said "No problem" We discussed the probable manners the engine will have and power band as well....
1500 RPM to about 4200 then fall on it's azz.

Torque should be great....the throttle response quick...

Howards cams will not sell direct....I called the distributor and we discussed the package, but the guy said he would have to call me back with the price. HAVE NOT HEARD YET.....

I called Isky and they were polite, fast and to the point.
YES WE CAN DO IT...BE ABOUT 3 WEEKS....$350 for the package and they deal with me direct over the phone and email.

We discussed the engine manners as well......I asked about the fuel requirements.....MAY NEED PUMP PREMIUM depending on how aggressive we get on timing......but should not be a real worry...

This Franken mutt combination of block, heads, rods, cam grind and such is going to be a crap shoot me thinks.

Too many variables that I have no way of sorting out other than REAL TIME TEST.

The short block is all stock 400 SBC ...so no worries there.
The addition of the Vortec heads to this soup mix should be a real plus as they are not known for detonation issues.
The L31 5.7 these came off of runs 9.4:1 comp.
The odd duck cam grind is another crap shoot, but the 106 LSA and resulting valve overlap....MAY BE A PLUS

I called up a buddy that has a computer program (Bench dyno) that has served him well and is usually real close to what he sees in the dyno room.

We plugged all the data in and it looks good ( I am always somewhat skeptical of these types of software) but I have known this fella a long time....He has been building engines many many years.....still has his shop open....locals swear by him.

I am not going to hang my azz out on a limb and make rash statements on this mutt.....but I am not real concerned so far.

When Isky said it should work sweet.....Those folks were here when I was a child.. .They should know wasssup....
Time to move ahead......

Always use the new cam as a paper weight...... if it turns out to be a turd....

 

[m1west]

We touched on the subject briefly....But the guy seemed most interested in selling me something they had ready to go....
I got a tad pushy at that point and told him I was interested in a custom grind to do a specific job based on the combination of parts that we had.

He then went over the numbers I gave him and he said "Oh, that's not possible"
I asked WHY ???
He seemed at a loss for comment for a short...."We don't have the masters" was his reply.

The cam grind I am looking at is very similar to several of the 420 rule circle track cams.

The difference is the duration mostly.

Howards cams response to the same questions (I described the build, type of machine, gearing, weight yada yada yada.
The fella said "No problem" We discussed the probable manners the engine will have and power band as well....
1500 RPM to about 4200 then fall on it's azz.

Torque should be great....the throttle response quick...

Howards cams will not sell direct....I called the distributor and we discussed the package, but the guy said he would have to call me back with the price. HAVE NOT HEARD YET.....

I called Isky and they were polite, fast and to the point.
YES WE CAN DO IT...BE ABOUT 3 WEEKS....$350 for the package and they deal with me direct over the phone and email.

We discussed the engine manners as well......I asked about the fuel requirements.....MAY NEED PUMP PREMIUM depending on how aggressive we get on timing......but should not be a real worry...

This Franken mutt combination of block, heads, rods, cam grind and such is going to be a crap shoot me thinks.

Too many variables that I have no way of sorting out other than REAL TIME TEST.

The short block is all stock 400 SBC ...so no worries there.
The addition of the Vortec heads to this soup mix should be a real plus as they are not known for detonation issues.
The L31 5.7 these came off of runs 9.4:1 comp.
The odd duck cam grind is another crap shoot, but the 106 LSA and resulting valve overlap....MAY BE A PLUS

I called up a buddy that has a computer program (Bench dyno) that has served him well and is usually real close to what he sees in the dyno room.

We plugged all the data in and it looks good ( I am always somewhat skeptical of these types of software) but I have known this fella a long time....He has been building engines many many years.....still has his shop open....locals swear by him.

I am not going to hang my azz out on a limb and make rash statements on this mutt.....but I am not real concerned so far.

When Isky said it should work sweet.....Those folks were here when I was a child.. .They should know wasssup....
Time to move ahead......

Always use the new cam as a paper weight...... if it turns out to be a turd....

Those tight lobe centers are going to cause a lot of cylinder pressure down low where things like to detonate ( not a plus ). The exhaust valve closes sooner trapping more air fuel charge, not overlap, thats duration and that cam is also short in duration. The idol is going to be so choppy that you are going to have a hard time idling it under 1000 rpm. The wrong person at comp cams must have answered the phone. The cam in my truck is a custom roller, that I designed and had no problem getting it done. Maybe the supply chains are effecting the cam manufacturer also.

 

[Snowy Rivers]

Never know.
All I know is the guy did not seem to be interested in even exploring anything to do with a custom....

I was totally open to suggestions.....BUY WHAT WE HAVE was his answer.

It is not a done deal yet....Plenty of time to work through details before dropping the hammer ($$$$) on anything...

The science of cam tech can/will drive you nutz.....

 

[Snowy Rivers]

Spent the better part of the last 30 minutes chatting with the cam dudes.
Opened up the subject of detonation with this engine combination and the cam grind that we are looking at.

Cold air really stomps out detonation.....as does humidity.
This same concept on an engine in the heat of summer probably would be an issue.
The cam boys are pretty sure that things will be fine with this combination..
May need to keep total ignition advance down a bit though.....??????

Premium fuel is certainly a fall back plan if need be.
We have 89 octane regular with 10% alcohol
The premium is alcohol free....

Other than build it and see wassssup....I don't know what else can be done to peek into this subject and gain anything more....

 

[m1west]

Spent the better part of the last 30 minutes chatting with the cam dudes.
Opened up the subject of detonation with this engine combination and the cam grind that we are looking at.

Cold air really stomps out detonation.....as does humidity.
This same concept on an engine in the heat of summer probably would be an issue.
The cam boys are pretty sure that things will be fine with this combination..
May need to keep total ignition advance down a bit though.....??????

Premium fuel is certainly a fall back plan if need be.
We have 89 octane regular with 10% alcohol
The premium is alcohol free....

Other than build it and see wassssup....I don't know what else can be done to peek into this subject and gain anything more....

You could always retard the cam if it won't run on premium, but thats going to move your power band upward in rpm too

 

[m1west]

Really other than the sound you might be better off with a stock cam ( cheaper, better drivability ). Those old machines came with six cylinders making 150 hp and they did fine.

 

[Snowy Rivers]

Yes they did have 6 cylinders in them.
The cats I drove the one season grooming had the 391 V8 (Mine had been fitted with the 391) the one 2100 I drove... the shop had retrofitted a 428 in it....They had issues in the spring with it overheating.
The stock radiator was not enough to cool the 428 well in warmer weather......

I think the worry about detonation at this time is not a big deal......
We will certainly find out.....

I would love to just grab an off the shelf cam....My concern is that the Vortec heads are designed for the low lift.
Trying to stuff a bigger cam in always requires cutting the valve guides down (Height) machining the spring seat to a larger diameter, new springs, new retainers.....This adds $$$$$$ to heads that given a cam with the lower lift will work sweeeeet.

I spoke earlier this afternoon with another cam grinder and we beat this subject all the way to hell and back.....this shop had the same general opinion as to the manners of the engine.....Decent sound, real punchy in the mid range with buttloads of torque and fall off fast after 4200....
At this juncture...I'm in...rock and roll time......

We can paint it CAT YELLOW with crackle black valve covers.

Ah yes...the trials and tribulations of trying to hatch a mutt....

I have built a lot of engines over the years....but I will be honest...very honest....This mutt is a big guess.....Should be fine...KEY WORDS...SHOULD BE.

 

[Snowy Rivers]

I am still snooping around for info on the "FrankenCam"
I spoke to the boys at Bullet cams in Ms.
I explained the project and the ideas.
We discussed the cam specs.
The fella sifted through Cam masters they already have.

He can do a cam with 408/429 lift....213/222 @ .050" with 106 LSA
Price for the cam $235

We discussed detonation, RPM, power band and such.....

Pretty much the same opinion on the manners of the engine.....

Their lead time is about a month out.

The fella was very attentive to what I had to talk about....and made several recommendations that will be useful..

We also discussed oil for the engine
Rotella T diesel oil 15-40 with a bottle of ZDDP additive....easy to get....Reasonably priced
Only use US made lifters from a couple outfits (Good quality) with good hardness on the lifter base.

*******Anyone building an engine with a standard flat tappet hydraulic cam...******

Be sure to use the ZDDP ADDITIVE in your oil during break in and at every oil change.

The newer cars/trucks mostly use roller cams now so they could reduce the zinc in the oil.....Zinc and other products raise hell with the catalytic converters....so it has been removed.

Some special racing oils have the ZDDP in them and are fine....
Without the zinc a cam can go away quickly....wiped out lobes and such.

And the saga continues.....

 

[Snowy Rivers]

A couple items showed up...more to follow.
Flex plate bolts are here as are a set of Mahle brand rings in .030"OS
A new pioneer flex plate should be here tomorrow.
A piece here and a piece there.....

I have have never had to gather so many small items for an engine build before....Usually have a complete to work with.
Still need the oil filter adapter, push rods, timing chain and sprockets......
Gaskets and such
Did grab a rear main seal the other day.

Going to use one of the one piece pan gasket....this looks like a sweet deal....
Need the oil pump, pump drive shaft
Vortec compatible 4bbl intake manifold.
NEW LARGE CAP HIE distributor....
OMG
We need the Vortec style long reach spk plugs.
I think I will custom build the plug wires to fit exactly.... Go with the 8mm with the metal shields on the plug ends
The ready mades always seem to have one that's an inch too short and one that needs to be wrapped around the distributor 5 times to work

Once this FrankenMouse is done....then it will be time ti dig into the TH350 tranny and get it all spiffy.

I have not done a TH350 since the mid/late 80's.....The 700R4 came out and they were a real bag of worms.....

Going to set the tranny up as a select shift (Manual control)

 

[Snowy Rivers]

Not a great deal going on...
Getting a tad bit done on the engine....
A very real need exists to be able to hold those VORTEC heads in the mill to drill the steam holes through the decks.

Sat down and sketched up a couple brackets to bolt to the ends of the heads and allow the head to be adjusted to flat as well as a 30 degree angle.

Take a bit of machine work....very little materials other than what I had in the short stock rack.
A couple pillow block bearings, a couple short chunks of 1-1/2" shafting.

I looked into a head fixture designed for the task....ahhhhh nooooooooooooooooo...$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$....
Waste of $$$ to buy this type of tooling for a one time job ..(Or so)

With the holidays coming up.....time to get work done is sketchy....

 

[mlang2005]

cant you just rotate the mill head?

 

[Snowy Rivers]

Not really....The mill head does tilt, but not to the extent I need.

I want the fire deck facing up and parallel to the table.....One set of steam holes (4) are drilled at 90 degrees to the deck, and the other set (4) are drilled at 30 degrees.

I could make a little drill jig and do this job with a hand drill.....just a bit too sketchy though....

The procedure involves placing the head gasket on the head and marking where the steam holes are located... Between the First and second...second and third...third and fourth cylinders where the bores a siamese'd

The job is not hard, but one needs to be careful to NOT break the drill off in the head ....or miss the water jacket....

Piccy of the block shows the holes....Note...the white line on the upper hole....the steam hole is actually just below the line...

The line is pointing at a head bolt hole

I was not a fan of the 400 when it came out in 1970....The idea of the Siamesed cylinders seemed waaaaay too sketchy....but these engines did what they were designed to do.....Torque monsters....I owned a GMC pickup 4x4 with one...it was a great truck....

 

[Snowy Rivers]

Freight is a tad slow with the holidays coming up and the weather.

Finally got the new Pioneer Flex plate for the 406 SBC today
Looks sweet...
So we have a flex plate and a set of factory bolts to fasten it to the crankshaft

Slowly the parts are stacking up....

 

[Snowy Rivers]

Merry Christmas.
This past year has seen a lot of good things come to pass on the FrankenCat project.
It might seem slow to some....but we are heading in the direction I had envisioned pretty much from the begining.
Sure....there has been twists and turns along the way, change orders galore.....And this is expected when you try to do a roll your own...

Wishing all the folks a Great Christmas holiday.....and soon it will be 2022.....
Be safe....

 

[Snowy Rivers]

Not much to report.
Weather has been wretched.....absolutely no way I'm trying to work outside..

Did fool with the Blazer body the other day....Noticed that the rear hatch lift cylinders were unhooked......
Ordered some new ones....
The stick laying in the back on the floor was a good hint that things needed attention......

Been beating off a case of this Covid crap.....
Just about done with that stuff....Pretty well back to normal now.....Still tire out a bit...

Looking forward to getting back to work on the cat.....

Be safe troops.

 

[PJL]

Wondered where you've been. Glad you beat back the Rona.

 

[Pontoon Princess]

 

[Snowy Rivers]

I LIKE THE PURPLE.......

Yeah...The Rona is certainly no fun.......I had this crap back when it first came to town in early 20.

Was getting over it when I found the 2100......
This time was just annoying...more like a nasty cold......Sadly it takes about 3 weeks to beat it off and get back to par.

The weather has not been conducive to wanting to be outside or to do much.

The only thing we have been doing on a regular basis is "KEEPING THE HOME FIRES BURNING"

We heat the ranch house with several pellet stoves located though out and feed them ground up hazelnut shells.
We go get the shells in a large dumpster straight from the plant (Dry) and barrel the stuff up and store it in the barn.

Grind it up and then dump the stuff in the stoves.......

It is a cheap biomass fuel.....I am no tree hugger, but heating 2300 sq feet for about $150 for the season.....With extra left to start the next season (The dumpster is 3 yard cap. $30 to fill it.

The labor is minimal....at least compared to hauling and stacking wood.

We don't have natural gas here.....Propane, oil or electric .....the house has an electric furnace $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$......NO WAY
Pellets are priced waaaaay too high.

We have done the nut shell thing since 1991/92 .

So about all we have done these past few weeks is pack in shells to feed the stoves and vegetate trying to be rid of the Rona

WE rent the lower level of the house to a lovely lady.
She is all fully Vaxed....somebody at her work dragged the Rona in a passed it around her work.

So then our gal had the crud and shared it with us......

Here are some pix of yesterdays haul.
We generally make 4 shell hauls....Weather has been just miserable wet with no let up.
We did a haul Wed. and then again yesterday.......We are full up now at around 50 barrels....

Yesssss...Nursing Rona and sitting by the warm fire.....

Thanks for the good thoughts troops.

With any luck I want to get back to work on the new engine for the 2100 soon

Some videos that may be of interest.
When I am not manufacturing snow cat stuff.....The stoves and related items get my attention .

Came home one night, stove off and house full of acrid smelling smoke....Electrical control in the stove had died and melted...
New control not available (Stove is 1993...same as house)

Screw it...built my own controller with way more safeties, fuses and protection than factory....Anything not right and the stove shuts off.....

The nut shell crusher "Munchy"

If you can't buy it.....MAKE IT
Shot of the inside of the new controller on the big stove (Last piccy on Right)

Having tools to build things with makes life a lot more fun...

The control modules in the panel are all rated at 20 amps and the max they see is about 1.5 amps fused at 2 amps

This is off the shelf heavy industrial stuff......not the cheap azz made overseas tiny circuit board crap.
Any issue can be diagnosed and a part replaced within a few minutes......Even at 2am with snow blowing sideways and me half asleep and not a happy camper....

All in a days work eh ????


JUST AN FYI

The Munchy can handle the material about as fast as you can scoop it in.
Going slow for the video.....

Munchy was hatched out of necessity when the plants all switched to half shell only from the outflow from the cracker.

Sketched up an idea and built it......
Its crude....but works well....

 

[vintagebike]

Leonardo da Vinci or Thomas Edison reincarnated.?👍