|
77 Firebird Engine Mounts
Having problems getting the engine to sit in the frame.
We removed a '69 400 from this '77 Firebird. The '69 engine had unusual engine-to-cushion brackets. There were two heavy bars, (1/2 inch plate, about 3/4" wide) one on each side bolted to the engine, with the brackets that would go around the rubber mounts bolted to those plates. I understand this to be an aftermarket "adapter" to allow the older blocks which don't have 5 motor mount bolt holes to install in the '70-up Firebird chassis. The engine going back in is a '73 455 block; five bolt holes on each side for motor mounts. I'm installing engine-to-cushion brackets of unknown origin; but probably from a '73 full-size car. They attach directly to the block, with no heavy bar between them and the engine.
We don't have another Firebird to look at; if we did we could probably see what is wrong with our mounts. DO THE FULL SIZE PONTIACS USE DIFFERENT ENGINE-TO-CUSHION BRACKETS THAN FIREBIRDS? WOULD USING THE AFTERMARKET "ADAPTER" MOUNTS REQUIRE RE-POSITIONING THE FRAME CUSHIONS? It really seems like the driver's side frame cushion is too far to the rear, and too far towards the center of the car. If we moved it forward and outward, the engine would straighten out and probably drop right in--but I don't know if there are bolt holes in the frame crossmember to bolt the frame cushion through. I'm thinking that the frame cushions were installed out-of-position when the '69 engine and the adapter mounts went in. DOES ANYONE HAVE PHOTOS OF THE ENGINE MOUNTS OF A '70's FIREBIRD THAT THEY CAN POST? We have a '77 Chassis Service Manual, but it only shows an illustration of "Typical" engine mounts; and there isn't enough detail. |
The 2nd gen bird mounts (block bracket) are different than full size cars.
I don't think there is any difference front to rear but big car mounts make the engine sit too high in the cross member. Difference is in pin location going through the bracket. One is a lot higher/lower than the other. Engine should set in all the same...just be too high with the big car mounts. Does sound like someone moved the cross member mounts to make room for using the adapters. |
Pics of the engine brackets and the mounts on the crossmember might help us.
There are L & R side engine brackets,are you sure you have a matching set? :noidea: Bret P. |
No need for pictures. the full size car mounts will not work, actually they do work but they place the engine quite a bit higher up than correct firebird mounts. you will know you have the wrong mounts because of two things: enourmous amounts of clearance all around the engine and the second thing is that you cannot ....or should not close the hood as the carb air cleaner stud will damage the bottom of the hood putting a dent in it.
do a search because I posted this info a few years ago in the 70-73 firebird section with pictures. |
I too have experienced this, yee ha. I believe your engine brackets are wrong for a "F" body. I tried to get the "B" body brackets to work on my car, just couldn't stretch that subframe that extra half inch or so...LOL
|
RESOLVED. THANK YOU all for posting.
Yes, the full-size engine-to-cushion brackets are too tall for Firebird. That was our only problem; the frame cushions were positioned properly. Found a set of Firebird brackets at my second-favorite salvage yard; they're blasted, painted, bolted to the engine and the engine is in the frame. TOUCHDOWN! I have photos and measurements of the adapter brackets, full-size brackets, and Firebird brackets; but it'll take me a few days to get 'em posted here. Maybe someone else can learn from my bad experience. How a person could get the full-size car brackets to work in a 'Bird is beyond me. I didn't think there was any way on earth to position the engine so that the through-bolts would go in. WE sure couldn't! If I understand correctly, the full-size cars and the "A" body (Tempest, GTO) use the same brackets; but the Firebird uses shorter ones. |
In, Running, and semi-successfully Test Driven: Sorry, I have to unload. Ten LONG days of thrashing; I'm taking today off and trying to recover!
My 70-year old carpenter Father-in-Law, his 16-year old never-held-a-wrench-in-his-hand-before step grandson, and I (almost) finished the "engine installation". Installing the engine nearly killed us with the "Might As Wells"; and we are severely over-budget for both time and money; although there was nothing we did that didn't need to be done. The old engine yanked out easily enough except for one header bolt that needed persuasion. Grandson learned what a "blue wrench" is. With the engine out, we can see that there's thirty years of oil sludge built up on everything--frame rails, crossmemember, suspension and steering linkages, so we might as well drop it back off the jack stands, push it outside, and powerwash the engine compartment. Engine out; we already know the radiator is going to be inspected and cleaned by my favorite radiator shop. F-I-L looks at the A/C condenser; wonders if we might as well have it cleaned because "someday" he wants to re-install all the A/C stuff that had been recklessly removed by Previous Idiot Owner. We remove condenser. At that point, I'm stupid enough to suggest that we "might as well" yank the evaporator too. Evaporator comes out easily enough. At that point, we see the giant mouse nest; F-I-L tells me that he's been pulling fluff and crud out of the ductwork ever since he got the car. Mouse nest removed...and we can see the heater core. I guess if we're having the radiator, condenser, and evaporator cleaned...we might as well yank the heater core, too. Woof. What a job. Might as well pull the passenger front seat and console for working clearance. The rubber motor mounts look worse for wear (and oil leaks) so we might as well pop the cushions out. I'm thinking I have a set of polyurethane inserts; but the part number turns out to be for Chevrolet clamshells; I don't know why they wouldn't be the same for Pontiac but that's not what Energy Suspension says. New rubber mounts are in-stock at the local NAPA; and about nine bucks each. I know that replacing the rubber cushions means dropping the lower control arms for bolt access. We might as well install new control arm bushings; and since the lower arms are the hard ones to access, upper arm bushings are really no more trouble. We bead blast the arms, the knuckles and dust shields, repack the wheel bearings, and thank God that we don't need ball joints! We might as well install new front brake hoses while we're in there. We had to pop the inner fender out to get to the heater hoses. Might as well pop the other one out, bead blast 'em both and paint 'em. About this time, we start looking at the rubber cushions holding the radiator support. They look terrible. We might as well change all six subframe bushings now that the weight of the engine isn't an issue... Rad shop calls. Radiator and heater core are done, evaporator and condenser are junk; and they've both been discontinued according to NAPA, CarQuest, and the local independent parts store. How parts for a Firebird/Camaro can be unpopular enough to justify disco is beyond me. We might as well hit the junkyard and see what we can find. As it turns out, I locate a one-year-newer ('78) T/A that still has enough pressure in the A/C system to hiss just a bit when I touch the schrader valve. $150 for all the A/C parts under the hood; we might as well take everything including the compressor brackets (but it's a 403 Olds engine). At this point, we've toasted 50 lbs of beads through the bead blaster (probably more); every bracket and small part has been blasted and rattle-can painted. The kid has been worth his weight in gold. Admits that working outside in the sun blasting parts "Sucks", does what he's told, doesn't complain; never snivels at having to actually work. MOST impressive. We tried to treat him like a man, and he responded very well. God knows, he now understands "Project Creep"; and how things don't go right but still have to be "dealt with". He doesn't actually have the skill set (yet) but he understands the concept of gently brutalizing (Beating or abusing stuff in a way that does not ruin) stuck/seized/uncooperative parts using torches, hammers, prybars/alignment bars, and other Implements of Destruction. Previous Idiot has broken off a section of the 1/4" fuel vapor return tube. I might as well bend and flare another section of tube; and we might as well replace the rubber fuel hoses. Engine back in (THANKS for the advice on engine mount brackets!) and running. The shaker hood scoop used to rub the back of the hood hole; changing engine mounts and using a stock intake manifold instead of the P4B has put the shaker nicely centered in the hole. Test drive was both happy and sad. The engine runs STRONG. Woof! That thing has SNORT. But the Q-jet is lean at idle. I can block the air bleeds with two fingers, or close the choke and the idle RPM picks up a lot. I think it's lean throughout the RPM range; we can only get 1/2 throttle before the engine rattles. Carb is from our core engine, a '73 455. We get the carb sorted out and this thing is going to ROCK--but--we were TOTALLY out of time, the car immediately went onto the trailer and was towed back to F-I-L's home about 300 miles away. Even so, 1/2 throttle was enough to take out third gear on the TH 350 transmission during the test drive--multiple 30 mph to 75 mph acceleration runs in third gear to load the piston rings; each time followed by closed-throttle deceleration back to 30--40 mph. I guess we might as well build a TH 400. I've already got a '77 Pontiac short-shaft core; and I've scavenged a six-clutch sprag-style direct drum. |
sounds like FUN !
|
agreed, might as well have fun!
|
lol...so, you're saying its a typical car project then?
|
| All times are GMT -4. The time now is 06:07 PM. |