View Full Version : engine mounts in a '90

10-09-2003, 12:25 AM
Hey guys, how difficult is it to put in new engine mounts on scale of 1-10. Do it on airplanes all the time but those are sometimes a little easier to get to. Hmmmmmm, Lycoming powered SC?..........

Michael Mattix
10-09-2003, 06:16 AM
Really? I have not changed any mounts, but from the Lycoming description, I would say you have to work in General Aviation, right? I am just saying that because I have an A&P license and have touched a few lycoming's and continental's also. But, I will have to say, working on those or turbine engines has my vote over choosing to work on these SC's! Ha, ha! BTW, I just had my engine mounts changed, I didn't want to take it on. Cost me 190 USD in labor. The guy said I got a good deal because it took them over 8 hours to do it. But, I went with them because they gave me a fixed quote and I trusted their work. Not like most other places. And forget the Lycoming powered SC....go with an Allison 250 (small turbine engine used in over 60% of the world's helicopters)! They did it on what has the name of "Y2K" motorcycle. Jay Leno bought the first production model for like 150k, I think. I have a magazine that has the article about it. It's hilarious.

Randy N Connie
10-09-2003, 06:25 AM
go to the search button at the top of page and type in.

motor mount change from top

This post has some good info.


10-09-2003, 10:05 AM
You are clear for takeoff...


check it out, nuthin' like runnin' a 55mm MAF at 10,000 feet LOL!


Michael Mattix
10-09-2003, 10:49 AM
Oh my gosh that's great! What kind of plane did that go in? Did it have an STC for it or is it experimental? V6 or V8?

10-09-2003, 11:17 AM
Darkside, didn't mean to hijack your thread but...

Originally posted by Michael Mattix
Oh my gosh that's great! What kind of plane did that go in? Did it have an STC for it or is it experimental? V6 or V8?
I posted these pics back when we were on EZboard. It's actually an engine out've a Super Coupe, the aircraft is a BD-4.

If you go here (http://bd-4.org/index.html?/builderlist_sheet.php?id=16&session=&user=Steve%20Craigle) there are more pics.

Oh yeah, if you wanna lose sleep then get ready to start lookin' for some "missing SC engines" because as the story goes...
(taken from here (http://bd-4.org/newsletter21.html))

A Roots Super Charged BD -
My daddy always told me to finish what has been started before looking for something else. He didn't know how many people there are out there trying to get me into trouble. It all started when Tim McGinnis called me and complained about wanting more power than the 3.8 titer Ford V-6 normally puts out (180 - 190 hp). I assured him that 180 hp is the right amount of power for a BD-4 but that didn't help. I then went on about higher compression pistons (10 : 1), and turbo-charging for more performance at altitude. As an after thought, I mentioned the Ford Thunderbird Sport Coupe and it's super charged V-6. I wasn't sure about exact power output but did know that the engine is a variation on the very 3.8 liter engines that we are currently building up and using. I tried to find one of these supercharged engines when I was looking to buy my V-6. The salvage yards around here told me they were impossible to find and would cost about $7500 for a run-out engine. I gave up at that point and bought my 1986 V-6.

Tim called me back after a few days and had located 8 new (< 200 miles) SC engines. We thought of buying two of them but ended up buying all of them at a discounted price Tim and I each bought two of them and BD-4 builders Dave Dotson, Denns Love, Steve Craigle, and Rick Graf each bought one.

This engine has timed port fuel injection, hydraulic roller cam system. Roots supercharger (will boost 20 inches to 50 in Hg at sea level), intercooler, unique crankshaft, rods, and pistons, distributorless ignition, cast aluminum oil pan, and 8.2 : 1 compression. It is all computer controlled and has "get home" modes built-in (not sure if they are sufficient for airplane safety). it puts out 210 hp at only 4000 rpm (276 fl lbs) and 156 hp at 2600 rpm (315 ft lbs). The peak power at 5800 rpm must be around 270 hp (245 ft lbs). With a torque curve like this (peaks at a low rpm) this engine might work out fine with just direct drive and a constant speed prop.

The weight of the engine with everything on it (air conditioning, power steering, cast exhaust, 3 heavy belt tensioners etc. comes out to 480 lbs. I think we will be able to get d down to < 500 lbs firewall forward. That is about 40 lbs more than I have now.

Steve Craigle has been pioneering the work so far. He has deciphered the wiring diagram and is planning to buy a Northwest Aero Products PSRU.

These engines were taken out of 1990 Thunderbirds so that new modular V8's could be installed for testing.

Most people use 4000 rpm for cruise with the regular 3.8 liter V-6. Normal cruise power (75 %) on a 180 hp Lycoming is only 135 hp. I am afraid we will have trouble loading up the 3.8 SC unless we find a good variable pitch prop.


10-09-2003, 11:29 AM
Based on posts here....and a decent set of tools, I removed
as little as possible....it was still 8-10 hours.
Scale of 1-10......7.9.
Good luck!

10-09-2003, 07:53 PM
Originally posted by tganley
Based on posts here....and a decent set of tools, I removed
as little as possible....it was still 8-10 hours.
Scale of 1-10......7.9.
Good luck! Yup. The higher than average rating has to do with working in cramped spaces requiring extensions, having to remove parts which require finesse to reinstall (the IC tubes), and the fact that some of the bolts are very tight and can result in broken sockets and rounded off bolts.

10-14-2003, 04:56 PM
i just changed mounts with the heads off for a head gasket replacement and it was easy but if engine is together and you must do it i would rate it a 9 or 10 it is a tite area and will require alot of disaccembly of the other **** around them or you could try dropping the cradle under the engine to get them.Both my mounts were broke and im glade i did it when she was apart,made it alot easier.