350 TBI Engine Height (1 Viewer)

[Tokamak]

I know V8 engine locating has been beat to death on this site but I cannot find the pros and cons for how high the engine sits.

I want to lock down the location and don't want to regret missing something important.

I've got an Alum 3 row Champion with a Taurus fan. The WP pulley is below the Taurus motor. I set the transfer case to just clear the body and in the picture the engine is level. In the current location I can move the engine forward another inch. 4in Hell Creek lift.

There is plenty of firewall clearance as far as I can tell.

Is there anything else I should consider.

Thanks for helping me figure this out.

 

[reddingcruiser]

The engine typically is set 3 degrees down at the rear. I have always set the center line of the motor mounts 19 1/2" back from the point where the rear of the front cross-member intersects the frame. This leaves plenty of room at the firewall and the radiator. As far as pros and cons - lower motor (within reason) equals lower center of gravity.

 

[Sharp38]

Another issue to consider with V8 engine height is the exhaust system. With most FJ chassis, you don't have clearance on the transfer case side for an exhaust pipe. Therefore, most installs run the passenger side pipe under the engine and Y into the driver's side pipe to exit to the rear. Depending on your suspension, give some thought to how you will route that pipe. Typically, it's under the pan with minimal clearance and as far forward as possible, but it must provide sufficient clearance over the front differential for articulation.

Don

 

[Cdaniel]

Keep your rear drive shaft angle(s) in mind. If you're centered between the frame rails you may have a problem. Many variables there though. Lift, angle of the drive train, CV shaft or not.

 

[reddingcruiser]

Keep your rear drive shaft angle(s) in mind. If you're centered between the frame rails you may have a problem. Many variables there though. Lift, angle of the drive train, CV shaft or not.

Yep, typical offset is 1" - 1 1/2" to the left.

 

[reddingcruiser]

Forgot to say it - nice, clean job. Obviously lots of TLC and $$$$.

 

[Tokamak]

Thanks for the input

engine typically is set 3 degrees down at the rear
I read about engine angles. Saw that 3-5 degrees was recommended. Is this to reduce the rear drive shaft angle?

Another issue to consider with V8 engine height is the exhaust system
I've been looking at the exhaust off and on but figured it would fit. Good call on clearance issues. I need to measure from the bump stops and estimate how much room I have. It would be nice to cross over in front of the oil sump but that may not be possible.

If you're centered between the frame rails you may have a problem
The AA Transfer Case Mount shifts the transfer case to the drivers side. The engine is centered in the rails. Will that right to left angle of the flange cause problems?

Thanks Redding, as far as money pits, this one sure beats RC Airplanes.

 

[reddingcruiser]

The "engine angle" concept has been around for years. There are multiple reasons offered for this, and if you go back far enough you'll find that it has it's roots in minimizing the height of the transmission and subsequently, the firewall and tunnel. To keep the carb level (close. anyway) the carb surface was angled to compensate for this. Some A/T oil pans are also angled to compensate. But on a TBI of TPI motor with a manual trans it makes little diff, EXCEPT to get clearance for the trans and t-case. If you have not already set your tub AND tranny hump on to check clearances I highly recommend it.

I used the ram horn manifolds and have dual exhaust. I'm not a fan of cross-over pipes. With the 700R4, the t-case sits far enough back for the passenger-side exhaust to pass next to the t-case, and everything is above the skid plate.

The engine should be offset, also. IMHO, the centerline of the engine and trans should be paralell to the centerline of the frame. For starters, it makes driveline angles easier to deal with.

As for your last comment, boy howdy. I've watched as $2000 worth of my balsa and fiberglass F4-U slammed into the ground when some moron switched on his transmitter and started playing around without thinking.

 

[Tokamak]

The 19 1/2" looks like a really good number. I figured out what you meant by the intersection of crossmember to the frame and right now I'm at 20 1/2" with about 1 1/2" fan to WP clearance. I'll move it 1" forward.

I've had the body off and on a few times now to get things adjusted and check for interferences. At the back the body clears the TC by about an inch at the closest point under the tank bump. The transmission fits under the hump.

The front pulley clears the differential by only 5 inches. The bump stop to axle on the passenger side is 6". I can raise the front of the engine 1 1/2" without hitting the transmission on the hump. The Firestien Motor Mounts weren't made to go that high so I'll need to play it by ear. I'll check the difference between the 3 degrees vs the 1 1/2 inches.

 

[srgould41]

Be careful on height or you could have hood clearance issues. I thought I had tons of room when I installed mine. I have a split hood and the support rod won't clear a full size air cleaner.


I lost two airplanes to people switching on their radios without a second thought or checking the freq board. The last one led me to quit flying. RC is still cheaper than my 40, just don't tell my wife

The front pulley clears the differential by only 5 inches. The bump stop to axle on the passenger side is 6". I can raise the front of the engine 1 1/2" without hitting the transmission on the hump. The Firestien Motor Mounts weren't made to go that high so I'll need to play it by ear. I'll check the difference between the 3 degrees vs the 1 1/2 inches.

 

[Tokamak]

Good point, I'll install the air cleaner and lay the hood in place and see what kind of clearance I have up there. I wasn't thinking about the hood, thanks.

Does anyone know what clearance I should be looking for from the pulley to the differential or do I space the bump stop to keep it from hitting.

When you get good articulation does the axle contact the bump stop?Or is it more of the opposite wheel dropping. I don't know how important this bump stop clearance is.

 

[srgould41]

I flipped my front springs to gain clearance between the diff and the oil pan and front pully's. This causes other issues of course. Your 4" lift should have your diff well clear of the engine... Strange that it's so close with your lift, but it's the reason why I moved my axle forward. My personal feeling is that when the axle is against the bump stops you would want at least an inch of extra clearance. Bump stops can compress and deform a bit in a hard hit. I don't think the axle should hit the bump stops while articulating normally (unless you are using air bumps or something). If they do then something isn't right. Others can chime in if I am off base on my thinking here.

Does anyone know what clearance I should be looking for from the pulley to the differential or do I space the bump stop to keep it from hitting.

When you get good articulation does the axle contact the bump stop?Or is it more of the opposite wheel dropping. I don't know how important this bump stop clearance is.

 

[reddingcruiser]

The bump stops limit and cushion upward axle travel. they also help prevent the shocks from bottoming out, which is a good reason to extend them after a spring lift or spring-over.

 

[Tokamak]

Well, the combination of lifting the engine, keeping the air cleaner in mind, then extending the bump stops to provide 1 inch clearance to the pulley after contact will be a good first adjustment.

I'll try that tonight and let you know what happens. I'll also check the minium travel of the shocks I got from Hell Creek with the springs. They may provide a reference for the bump stop.

Thanks for the comments and ideas.

 

[srgould41]

I agree with ReddingCruiser. I set my bumps so I had about 1/2" of shock shaft left with one side at full stuff and the other fully extended.

You might want to wait on the bumps until everything is back together so you have full weight on the rig and your suspension is where you want it. Now may be a bit too soon to worry about it with all the other work you have to do

 

[Tokamak]

The way I look at it worst case would be both sides compressed equally. Correct me if I'm wrong but the clearance from pulley to diff under full compression should be independent of springs or weight. Therefore the bump stop location is not dependent on springs or weight.

 

[reddingcruiser]

True with regards to the minimum pulley/axle clearance. But, actually, no with regards to total axle travel. Look at the bump stop as a fulcrum on a lever during articulation. Once one side of the axle comes up to the the stop, the portion outside the stop it will continue to travel in an upward arc as the opposite side drops down, to the extent the springs allow the axle drop. That's one thing you have to consider when determining your shock length, and the distance between the axle and bump stop.

 

[Tokamak]

Okay, I need to absorb all this and at least move the engine forward an inch. My main task right now is to lock down the location of the engine. We will visit the bump stop adjustment later.

 

[reddingcruiser]

Now that you've got our attention, keep posting pics....

 

[Tokamak]

Fan Clearance

I went out to the garage this morning armed with all the information I gathered from this thread yesterday. I moved the engine to (I think) 1/4" of its final location. I measured all the reference points necessary to repeat it from scratch. It will take 6 or 7 posts to document what I gathered.

By the way, I want to thank you for the discussion on the propeller mount issues. Now I can't stop looking at it and thinking about how I'm going to fab a transmission mount and put the $160 propeller on the shelf. Thanks again.

The first is the 3/4" fan clearance. I layed the hood on from body to bib and straightened the radiator for an accurate reading. Radiator is in stock location and the fan is a Taurus un trimmed shroud clamped in place.

The second picture is a chalk line stretched under the frame 1/8" in front of the crankshaft pulley. The rivet on the shock tower is a good reference.

The third is a measurement from the center of the crank shaft to the chalk line, 3 1/2". Used a socket to extend the center location.