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Just Some Dude in Jersey
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Discussion Starter #804 (Edited)
So was the vibration of the alternator the overall vibration problem?
I'm pretty sure that the vibration I'm feeling in the car is due to the CPS touching the front suspension. Or possibly the shorter motor mounts are affecting the drive line at the u-joints.

My car didn't have the vibration before this engine and FI set up and the shortened motor mounts. I had already modded the cowling to handle the extra height of the FI manifold, but then Norbert yelled at me for not using the super rare nobody-knows-about-them shortened mounts, so I got them and put them in. Now I think they're causing multiple problems.

My plan this week/end is to swap out the shorties and put my normal size motor mounts back in.
 

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Brackets have been added on the GM alt. and they help, but you do need to slot them for adjustments.
 

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Because the belt will wear and stretch.
Yup! Belts are supposed to be tightened again after about 50 miles.

In fact, old school rally cars used to carry a spare alternator belt taped to the rollcage. But proper prep meant to put the spare belt on the engine first, wear it in for 50 miles, then remove it for your spare. Otherwise you would have to stop during the rally to re-tension the belt. Once it has initially stretched, it’s good for thousands of miles.
 

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Just Some Dude in Jersey
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Discussion Starter #811
Written for Facebook: Today I tackled the job of swapping out the special, machined shorter, motor mounts and reinstalled my only 2 year old previous mounts to fix the problem of my Motronic FI's crank position sensor(CPS) pressing HARD against the front suspension and causing the consequent engine vibration I was feeling in the car.

The Back Story: When I test fitted the FI system manifold on the engine, I only had 1/8" between it and the cowling. I knew about this potential problem, so I cut relief slots in the lip of the cowling's drainage channel, at the manifold, and pounded it upwards to give me 3/8" of clearance. But then my German buddy Norbert(RIP) chewed me a new asshole for doing that and asked why I didn't install the super rare, nobody knows they exist, specially machined down by 12mm, motor mounts. So I waited until he got them for me and sent them and I installed them. I progressed with my build, Norbert passed away before ever really getting to drive his GT with freshly installed FI, and I finished my project. I noticed and got very nervous about the CPS sensor pressing so hard against the front supsension crossmember, then I drove the car for the first time with the fully properly functioning FI and felt a lot of vibration in the car. I searched for the cause and it was almost assuredly vibration of the engine transferring through the sensor and to the suspension/body. Holy ****! That can't possibly be good for the sensor to have 100's of pounds of engine pinning it against the suspension, I gotta fix that!

I thought about installing 1/4" of shims under the motor mount on the right side and made an attempt at it, but I failed. I was going to then go nuclear and cut a chunk of the suspension crossmember out where the sensor was touching and then have reinforcement plates welded to the sides of the suspension. But then Charlie said "Why don't you just put the previous motor mounts in?" Duh. Yeah, that's a better idea. I had made cowling clearance before I finished the install, so I should have the same clearance if I put them back in.

It took me 5 hours.

Goddamn Opels! Gordo's Murphy's Law: Every job on your Opel, no matter how simple, always requires every tool you own, all your neighbor's tools, 2 tools that you have to go out and buy, and one that they haven't invented yet. Cursing, throwing tools, and flipping your car the bird helps, too.

Now I have almost 5/8" of clearance at the CPS, but now there is NO clearance at the cowling where the FI manifold is. WTF! But it's all okay. I started the car, no vibration. As Opel GT motor mounts do, they had started to partially collapse and bend to one side, so to "rejunenate" them a little I flipped the 2 year old very healthy mounts 180* so that their bending to one side was now bent the other way. I knew that the engine would likely sit a little higher than when I started this FI project, I just wasn't expecting them it to sit 3/8" higher. No worries, engine heat and driving will start to squash them down and I'll get my gap back. The pics show the cowling and FI manifold clearance before the swap, and the CPS clearance before and after.

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Just Some Dude in Jersey
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14,123 Posts
Discussion Starter #812 (Edited)
After my Opel Work Nap, I realized where some of my previous cowling/manifold gap went: I forgot to install my OGTS sway bar brackets between the frame and the engine crossmember. This will push the crossmember and engine down 1/8"-3/16". That will be more than enough peace of mind clearance at the manifold/cowling gap.
 

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Just Some Dude in Jersey
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14,123 Posts
Discussion Starter #814
I lifted the engine with the hoist a whole 1/2"(until the manifold hit the cowling) to take the weight off of the mounts and maybe get them out. Nope, not enough. Then I took out all the crossmember bolts, but left the sway bar attached. Nope, not enough. Removed the sway bar and managed to get the previous mounts back on. But then had difficulty getting the crossmember bolts back in, it was cocked towards the rear and I couldn't figure out what was holding up the show.

Then I realized that I still had the bolts in the mount tower "wings" screwed to the sides of the engine compartment!

Dumbass!

But knowing that I'm a dumbass didn't help. Neither did knowing that those bolts were still in place. Those bolts are hard to remove/install in a totally stripped engine compartment, they're really hard to mess with in my fully assembled car. Nope, no way was I going to take those bolts out. That's why it took 5 hours. C-clamps and various pry bars, plus the enlistment of my tenant got the job done.
 

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Opeler
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After my Opel Work Nap, I realized where some of my previous cowling/manifold gap went: I forgot to install my OGTS sway bar brackets between the frame and the engine crossmember. This will push the crossmember and engine down 1/8"-3/16". That will be more than enough peace of mind clearance at the manifold/cowling gap.
The crossbar will not drop after inserting sway bar brackets. Crossbar is actually recessed for the thickness of the sway bar brackets. This is the reason that it is recommended shims to be installed when the sway bar is not present. You may make custom shims to drop the crossbar but they should be at least 1/2" thick to get may be 1/4" clearance and that would change drive train angles.
Permanent solution would be to remove the crossbar and cut the recess. The recess should be reinforced with welded oval 1/8" plate. Big job but it will pay off.
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Just Some Dude in Jersey
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14,123 Posts
Discussion Starter #816
YAHOO! YIPPEE! My engine swap and fuel injection is PERFECT! I fixed my vibration problem due to the too short motor mounts I was using and went for a nice long drive on highways and all sorts of things and the engine worked perfectly! I've driven GT's for 40 years and have tried all the carburetors, and now FI, and this is the best running engine set up I've ever had. I'm going to pronounce my engine swap and Fi install MISSION ACCOMPLISHED!!!!! Wheeeeeeeeee!
 

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Opeler
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759 Posts
YAHOO! YIPPEE! My engine swap and fuel injection is PERFECT! I fixed my vibration problem due to the too short motor mounts I was using and went for a nice long drive on highways and all sorts of things and the engine worked perfectly! I've driven GT's for 40 years and have tried all the carburetors, and now FI, and this is the best running engine set up I've ever had. I'm going to pronounce my engine swap and Fi install MISSION ACCOMPLISHED!!!!! Wheeeeeeeeee!
That’s so great to hear!! Congratulations! What makes you deem this the best set-up ever? Smoothness? Power? Reliability?
 

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I think you’ve arrived, I’ve been reading and cheering for you the whole way! Congratulations!!! I’m very happy for you. What a learning experience, now you’re one of the FI go to’s on the site 🤙 Way to stick with it!
 

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Just Some Dude in Jersey
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14,123 Posts
Discussion Starter #819
That’s so great to hear!! Congratulations! What makes you deem this the best set-up ever? Smoothness? Power? Reliability?
It's the smoothness and, more importantly, the consistency of the way the engine runs. Always the same, no strange sounds cropping up from time to time that make me think I'll get stuck on the side of the road.

I never wanted power, I just wanted an engine that ran reliably and consistently. Happenstance gave me a 2.4, but it was beat and unreliable, so a rebuild happened, then it turned out after 2 years that it was made with too much compression and I should have been running race fuel and the head/block wasn't milled flat enough and #1 had a chronic semi-blown head gasket situation, so a new engine that I had bought to put in my wagon project that I cancelled, then problems, problems, problems.........almost all of them due to factors caused by other people. So far, it seems as advertised: simple, reliable FI. This engine set up isn't as powerful as my previous engine and single side draft, maybe that's due to the lower compression and 2.4, instead of 2.5 displacement. The SSD set up was very stable and FI-like, but it wasted gas trying to run an engine that needed race gas with just premium. I can tell right off the bat that this engine is burning the fuel VERY efficiently.

It's all really too soon to make any big judgements about anything, but so far I'm very encouraged. :)
 

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Very happy to read all this
 
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