The Idea to lower the engine and transmission has been on my mind for a couple of weeks now and will be posting a thread on the lowering question soon.
Unless one of the members visiting this thread has some experience on the subject and want to put their 2 cents in.
The blower without the snout is 16 ½” long without the snout and the blister is roughly 24” wide.
I should be OK as far as falling inside the blister (a scoop)… it is the snout I am unsure of at this point… if the snout becomes a problem I will use a jack shaft to lower that part of the system. (Pain in the a$$ though)
Lowering the engine I believe will make for some altered geometry on the suspension and axels as well, but I am unsure of how much an inch or two would throw it off???
Maybe some mental giant will step in an offer me some knowledge.
Thanks for the input.
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12:33 PM
Scoobysruvenge Member
Posts: 550 From: Richmond Virginia Registered: Apr 2009
Here is an example of a short snout that could be used for a jackshaft setup, They come on 3800 Eaton M90 blowers are readily available and cheap.
The jackshaft, and mounts would need to be made custom, but so is almost every thing else I’m doing here.
I did not have a chance to go look for a 3.1/3.4 balancer this weekend, but hopefully I can get to it this week with all the extra daylight we now have from DLST kicking in.
On a side note I have the Oliver rods in hand and am ready to take my crank and the rods to the machine shop.
I am waiting to make sure I need no more measurements for a for the blower project before I drop it off.
Should be in the next couple of weeks.
I will take some pics of the 6 rods I purchased for less than 150$ on Ebay… they are new have new Carr bolts and have been Teflon (or something similar) coated and made by Oliver… the retail is over 200$ a piece.
I am expecting something to be really wrong with them and have crawled all over then with a mic and can find nothing wrong. (We will see if my machinist finds something)
My machinist suspects that there is nothing wrong with them and that a rule change in IMSA made them obsolete for that class of racing and thus eventually liquidated being an incomplete set of 6 made them even harder to unload.
They are a strange set of rods they are identical to a stock SBC rod in big end and little end widths, the pin hole is standard only difference is 1.880 Honda journal size on the big end.
This may be another reason they were purchased for so little… Hell the rod bolts cost way more than I paid for all 6 at auction.
Wish me luck, I’m probably going to need it.
Pics soon
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02:18 PM
fieroguru Member
Posts: 12240 From: Champaign, IL Registered: Aug 2003
Lowering the car, increases the axle angle (and a large # of people do this). Lowering the drivetrain, increases axle angle (a few people do this). Moving the engine further forward (about 1") also increases the axle angle (a few people do this as well)... I did all 3 on the same car with SBC and put 45K miles on it w/o issue.
So with great confidence you should be able to do 2 of the 3 w/o issue as long as you check for tripod binding from full compression to full extension.
Now I am lowering the rails of the cradle 1" to further lower the engine, but also rotating the transmission (raising the differential) to keep the axles at thier current angle.
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02:21 PM
Mar 16th, 2010
Scoobysruvenge Member
Posts: 550 From: Richmond Virginia Registered: Apr 2009
With a little time to burn last night I set to work on lowering the blower plate…
I have an 1 ¼” I could remove from the sides of the plate, but I decided to be conservative and remove a 1/4” from each side of the plate.
Having done this several times it went quickly…
The plate cut down a ½ inch and ready for a test fit.
Putting the plate on and setting the blower on top shows the new height…
A closer look at the room on the under side…
Looking at the room with the blower ramp in place…
You can see that I can still go lower, I really only need 3 inches…
Some shots of the blower on top…
Taking some measurements…
You can see that I am below 8 inches already and will be able to go a little lower by narrowing the plate some more.
A closer look at the runners and plate…
Now for the evil monkey in the closet… The lower I go from here I have to worry about the clearance between blower intake and the plenum it’s starting to get close…
Laying a piece of 3” OD pipe shows I’m still OK, but any lower and I will need to measure carefully…
I can cut down the runners at least an inch no problem they are 3” tall now 2” as long as it can still be welded.
Welding with the TIG poses problems as you must have ample room to rod and gun in there to weld it.
I took some shots of the rods…
Thanks for looking
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07:00 AM
Mar 17th, 2010
Scoobysruvenge Member
Posts: 550 From: Richmond Virginia Registered: Apr 2009
For less than 20 dollars I will try to machine the face of the pulley ring off my balancer.
I will then separate the ring from the balancer I bought on ebay and machine it down to two grooves and the face.
The idea here is to weld these two pieces together.
This may be easy, hard or impossible…
I liked Fieroguru’s idea using the 3.4 balancer, but the weight is different as is the diameter (6 ¼ vs 6 ¾”) if this attempt to mate the two together fails I will be using the 3.4 balancer.
If I weigh the stock balancer before I modify it I can remove the weight I gained by removing some material from the balancer… I will then have the exact balancer I need for my engine instead of something close.
That is if it works…
Thanks for looking
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08:23 AM
fieroguru Member
Posts: 12240 From: Champaign, IL Registered: Aug 2003
You might be over thinking the harmonic balancer... Across the years of SBC's with essentially same design - even if you just look at 350's, I can show you about 5 different shapes, sizes and weights of balancers. Same for the 60 degree V6 family - even between the FWD and RWD versions of the same engine... My SBC had about 45K on it with a non-stock balancer and my 4.3 has about 15K on it running the 3.1 balancer.
I agree you need some type of balancer, but the difference between the 3.1 and the 3.5 balancer is probably a non-issue and converting the 3.1 to 8 ribs will be much less involved than the welded 3.5 combo.
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04:12 PM
darkhorizon Member
Posts: 12279 From: Flint Michigan Registered: Jan 2006
The conundrum that the balancer poses for me is the how and why of the thing…
I agree that the 3.1 balancer is ideal for this swap, but it really bothers me there is very little published material on the subject of balancer math and its effects on the engine.
The second issue I have is that I will be going down to 1.880 Honda journal size on the crank…
This change in my opinion requires some extra attention in the form of a good balance job, some quality machining and installation of the rods and mains…
These things I have a handle on but, the last piece of the puzzle… The balancer is a mystery.
Let me remove say three pounds from your crank and see how much more quickly it will turn RPMs
Also the size of the balancer pulley sets the speed on the accessories… Not a major issue, but an issue none the less.
The size of the balancer also drives blower speed.
The 3500 crank also is a forged unit and the 3.1 a cast item, a large weight difference between the two.
The General is not one to give up on a part just because it has some age to the design and if GM could have gotten away using some surplus dampers they probably would have.
Those are the cons…
Now for the pros…
The crank will be heavily modified in that considerable weight will be removed from the journals as they will go from 2.25 down to 1.880”
The rods are over a hundred grams lighter per rod vs the stock rods… There are 453.5 grams in a pound, that’s over a pound in weight reduction just going to the Oliver rods.
So the rotating assembly will be far from the piece it started as so in theory the balancer will need to be different as well.
Taking all this in to account I was getting more confused than when I started… so I reached out to a SME (subject matter expert) at ATI balancers named Chris and this is what I got…
As stroke increases so must the weight of the balancer…
When the weight of the crank goes down the weight of the balancer must go up.
The larger the diameter of the crank pulley the less slip a blower will experience.
He could give me no exact numbers for my engine as the program they use is for their balancers, but he did give me a way to ball park it.
#1 use the largest diameter pulley available to reduce slip.
#2 record the weight of the crank before machining and after covert this into a percentage and increase the weight of the balancer by the percentage difference.
Let’s say the crank weighs 20 lbs and after machining it weighs 18 pounds this is a difference of 10%
Now let the stock balancer weigh 5 pounds. Increase that weight by 10% and we have a balancer that now weighs 5.5 pounds
#3 figure the stroke increase… I am going from 84mm to 89mm which is roughly 6%... now divide by this number by two… this figure is now 3%... 3% of 5 lbs = .15 lbs
Add the weight increases together and add to them to the balancer…
The new balancer weight is 5.65 lbs
He told me the formula was a little on the heavy side for weight, but should be very close…
He also stated that it is better to be too heavy rather than too light.
So here I am… The blower slip is a definite concern, but I could get away with the smaller 3.4 unit at the expense of a little more slip.
The 3.4 unit looks heavier but I will not know until I have one in hand… This does seem to follow the lighter the crank the heavier the balancer.
Anyway thanks for keeping me honest.
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08:56 AM
Mar 22nd, 2010
Scoobysruvenge Member
Posts: 550 From: Richmond Virginia Registered: Apr 2009
With honey do’s and the arrival of spring I had a busy weekend, but managed to work in some shop time and this is what I got done…
The blower discharge plate I cut and milled out turned out to have a slight bend in one corner… it was bad enough that I decided to abandon the piece and make a new one.
Leaving this new piece allowed to leave me some material for mounting the discharge plate to the blower plate if the discharge tube needs support.
I clamped up some ¼ 6061 in the mill and went to work…
With a new plate made and a quick check to ensure it was perfectly (relative term) flat I had a new piece to work with…
I made quick work of the discharge hole…
A cleanup of the mill and it was time level and index the blower plate mounting holes…
After an hour or so I had it just right…
I recorded the measurements hole to hole…
Then clamped the blower plate up in the mill and made the holes for the blower mounting bolts.
With the blower plate finished for now it was sadly time to wrap up.
As it happens… thanks for looking. With honey do’s and the arrival of spring I had a busy weekend, but managed to work in some shop time and this is what I got done…
The blower discharge plate I cut and milled out turned out to have a slight bend in one corner… it was bad enough that I decided to abandon the piece and make a new one.
Leaving this new piece allowed to leave me some material for mounting the discharge plate to the blower plate if the discharge tube needs support.
I clamped up some ¼ 6061 in the mill and went to work…
With a new plate made and a quick check to ensure it was perfectly (relative term) flat I had a new piece to work with…
I made quick work of the discharge hole…
A cleanup of the mill and it was time level and index the blower plate mounting holes…
After an hour or so I had it just right…
I recorded the measurements hole to hole…
Then clamped the blower plate up in the mill and made the holes for the blower mounting bolts.
With the blower plate finished for now it was sadly time to wrap up.
As it happens… thanks for looking.
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07:05 AM
Scoobysruvenge Member
Posts: 550 From: Richmond Virginia Registered: Apr 2009
why have you not removed the blower drive snout and shortened it to move the blower body forward over the engine to give you more room at the rear the snout is very easy to shorten
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11:11 AM
Scoobysruvenge Member
Posts: 550 From: Richmond Virginia Registered: Apr 2009
OK! I got three retaining walls (roman stacks) and their attendant planting beds in. A couple of my BIG H/Ds out of the way; you commin' up for air soon Scoob? How's those wounds from the 'Cat o' Nine' doin', healin'up? You know we need a vicarious 'garage fix' don't ya?
Hi, this is Scooby's brother. I bought the Fiero and the 3500 from him and plan to do the swap. I have another project in front of this one that needs to be done first. I'll start a new thread when I begin the swap. In the meantime I've tried searching this forum for information on what I need to buy or modify/fabricate to physically put the engine in the car but haven't had much luck. Could someone provide a link or where I could look to find that info? Thanks.
