V8 won't accelerate

danny · 2004-12-16T21:33:55+00:00

I've recently had a 2nd hand engine fitted to my 110. It has 34k miles, but is an old V8 - 1975. It wouldn't start on the carbs it had fitted so my mechanic swapped them for my carbs, off my 1984 V8 and it started straight away.I went and collected it today, but hadn't gone far up the road when I found it wouldn't accelerate - it would pull strongly then just run out of steam, either hesitating or backfiring. I took it back to the mechanic who checked the timing - it had gone from 4 degrees to TDC, so he corrected that and also reset the dwell. He also swapped the dizzy cap and rotor from my old engine. He surmised that as the engine had been standing for quite a while it might take a while for the valve gear to operate freely and that I should replace the missing air filter when I got home.You could rev it freely up to maximum revs when stationary and it checked fine with a timing light, but when I went home, the same thing happens, but with no backfires this time. It pulls strongly in first through the rev range, and in 2nd it gets to about 30mph before holding back, but 3rd is impossible beyond 35 (the old engine would pull to 50mph easily) and in 4th power fades at 35-50mph depending on the road. I've found that if I back off the accelerator and lightly reapply it picks up speed only to fall back at the slightest incline.The engine sounds fine, very quiet, and when I got home I noticed in the dark that the HT lead from the coil was arcing, so I swapped it out, and put the air filter back, but with no change.It idles fine, starts first time and revs freely and there's no smoke visible, but it loses power when under load - any ideas?Thanks in advance.

Dec 16, 2004 20 Replies

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Rich 21 years ago

You go on about going back to SU's as apposed to Strombergs what about the Weber 500 as sold by RPI on their web site??? has anyone got on and what are the thoughts on them??

Rich

"improvement",

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