Hood clearance issue on 2800CS with M30B34

[thehackmechanic]

An old friend of mine is having a look at a 2800CS with an M30B34 engine, injection, and intake from an E28. He said that as soon as he unlatched the hood, it jumped up, indicating that the hood wasn't clearing the engine. Is there a known clearance issue with this conversion or something special that needs to be done with the engine mounts? I've only read about the clearance issue with the stock brake booster.

--Rob

 

[HB Chris]

Could it actually be the firewall seal causing the jump? New ones are pretty tall and stiff.

 

[teahead]

have to get some clay/play-doh and put it on what you think is the highest part of your engine compartment.

 

[Thomas76]

He'll have to dig a little deeper. Any of the seals could be pushing up. If anything on engine one would think dents, paint chips, ect would be obvious on hood.

 

[ChrisWrench]

Depending on where the idle control valve is located it could be hitting on it or the hose clamps attaching it to the intake manifold.
Check cold start injector and hose clamp
Check hood light clearance to the engine
check the position of the hood bar and if it is hitting in front of the manifold or if torsion bars are moving while the hood is closing.

Good Luck

 

[rsporsche]

having had a b34 in my car for as long as i have owned it, i'm betting on the firewall seal as HB Chris describes. i have the CSi / L-jet C tube manifold, not the log manifold. i have had the issue with the new type firewall seal and i bent my hood latch lever inside the car trying to lock the hood down.

 

[bavbob]

Seal comes pointing straight up and then bends with time. If straight up, then it is at least a contributor.

 

[Rek]

If the hood/bonnet was touching the engine it would create an almighty noise.

 

[eriknetherlands]

If the hood/bonnet was touching the engine it would create an almighty noise.

and you would see rub/scratch wear marks, as the engine rotates right to left and back under acceleration. The underside of the hood would have a spot without paint in that case. And the engine part being the culprit would have (dust)pieces of paint on it.

 

[OCCoupe]

There was a thread some time ago about installing a b34/b35 using the b34/b35 intake manifold. They had to cut the top of the manifold and reduce the height to eliminate interference with the hood.

 

[Dan Wood]

If I was concerned about hood clearance, I would remove the hood vents and use a borescope or even the phone camera (video) to see if there is any interference.