355 engine fails leak down test

I am a relatively Ferrari novice, but I am building a sports car which uses the chassis of an Ultima and will look a lot like a 330/P4 and be powered by F355 running gear.

Today I have driven 450 miles to collect an F355 engine, but sadly i have returned empty handed. In my toolbox I had a leak down tester and an endoscope.

Having spent 4 hours making up an adapter to get the leak down tester to screw into the oddly pitched 355 plug threads, I set about running the test. The engine has done 19,000 miles and has been removed from a car which had a tree where the passenger seat was previously fitted.

So to the test results:

7 of the 8 cylinders gave minimal leakage <5%

The 8th cylinder leaks about 50% of the pressure from one of the exhaust valves when the piston is at TDC on the firing stroke. This is obviously not good, but I have read referrals to carbon buildup on valves causing problems of this nature. How big an issue is this? Should I run a mile and get an engine elsewhere, or is this a common, easily fixed issue?

The engine was last run about 1 year ago and has not run since. It cannot be run now as the car is in too many pieces. The seller is a bit lacking in terms of coming to a constructive resolution, and is as such unable to respond beyond saying it sounded OK when we ran it a year ago. This would have been static and not under any kind of load. How does the carbon buildup issue manifest itself in terms of symptoms of engine running?

I'm not bothered by anything which is not an internal part of the engine, and I think I am mechanically savvy enough to remove the cylinder head, get the guides and seats reworked and rebuild. I am however a bit scared of potential costs. Can someone give me an idea of the parts cost to do this (gaskets, valves etc.)
Many thanks for any opinions.

At £7k inc all ancilleries should I buy or run? Douglas Valley have a similar mileage bare engine (no loom ECU, alt, A/C pump/PAS pump - half of this I don't need) at £5750. I would prefer to avoid a lemon.

Advice much appreciated.

 

Thx Guys,

Mark, you are right, that was the purpoe of my call. ES do sell rings for £125/set although I also had an endoscope down the plug holes and all looks OK. Sadly it is hard to see the seats of the valves, but generally all looked to be in order.

 

Well, I bought it.

I've stipped the throttle bodies and manifolds off, and stuck the endoscope in the back of the exhaust valves. One of them has a small white lump on it and a similar tracking mark as if the edge of the valve has cracked and the sodium has leaked out. It looks white, but the contrast of the endoscope is poor so it may just be some contamination. Whatever its right on the valve seat, so could prevent the valve from closing properly.

So to investigate further I need to remove the head. Does anyone in the SE of the UK (ideally nr Gatwick) have the tool to undo the head bolts?


Thanks

 

I was hoping you'd have one Mark!

Seriously however, thats a fair bit cheaper than the genuine item!

Gives me a course of action if no-one has one to lend....

Cheers,

Arnie

 

Interestingly my last car revved to 9750rpm and produced 300bhp from 2093cc and was normally aspirated. It broke a few times nmainly due to issues with the dry sump system, but as an amateur built engine it never showed any signs of serious wear when stripped and examined.

The 355 engine has both good and bad news.

I've taken the head off the left bank and:
The cylinder in question had a piece of silicon contaminant stuck behind the exhaust valve, and this was the cause of the leak down failure.

The bads news is that sometime in its life the engine has suffered an ingestion ( a small maybe 3mm x 1mm x 1mm piece of steel is the only evidence, which is enbedded in the head) such that the top of the piston is peppered, and both the squish area of the cylinder head adjacent to the exhaust valves and teh corresponding part of the piston crown is also badly pitted.

So a replacement piston and a bit of welding to the head is required.

I'll be taking this up with the supplier on Monday.

I'm going back out to the garage to remove the sump and for a much closer look at the other bank now just to be sure all is ok over there.