SC engine job - first startup and problems
 

6 months after taking out the SCs engine for syncros, cams change and new rings I finally started it up last night. It runs on the right bank only, but idles easily. There is an unhealthy honking noise, almost as if a manifold was loose, and my preliminary theory is I somehow messed up with the left bank cam timing completely. Not that i can understand how that could have happened. Worse is there is oil dripping from base of cylinder #2. Actually while idling it felt as if cylinder #2 was moving slightly which of course is impossible. I only ran the engine for maybe 20 seconds total and decided to pull the engine out and inspect

I had the engine out in about 3 hours and hope to know more within the end of week.

contact
 

Trond, please contact me regarding your order, my e mail to you failed last week
Mike Bruns JBRacing.com

One of the cams is out 180 degrees.
Bruce

Bruce; I believe you must be right. The non running must be timing off by 180 degrees. I did align the stamped dots on the cams both up, and intakes on 1&4 open 360 degrees apart.

What worries me and made me pull the engine again is the oil leak.

I was suffering broken leg and on painkillers when assembling and must have screwed up.

For the oil leak, check the torque and check for a base gasket, you should be able to see it. I guess you didnt open the center case so all cross bolts seals will be intact so it has to be the base gasket but 20 seconds of running its hard to diagnose.
Bruce

Parts
 

Trond, Your custom base shims shipped on Tues. for your 930
Mike Bruns

Mr Bruns; I do not have a 930 and I did not order anything from you., I hope you sent it to someone else !

Mistake
 

My mistake, I have a customer in Norway, Trond Retterholt with both a 930 and an SC
Mike Bruns

Found the problem to be I had forgotten to make up the left bank cylinder stretch bolts !

Cam timing was correct. 1.7 mm at Z1 on alternating cycles as per DC13 spec

I am currently re-checking everything else but have only found this fault and expect new start up late next week. I am using the opportunity to replace more small stuff in the engine bay

How does forgetting to torque the rod bolts prevent one side of the engine from running? Rod bolts are the only "stretch" bolts in the engine.

i didn't just forget to tighten them, the cylinders were so loose they were actually moving. But you are right, I would have expected it to to fire myself. So i am checking my work.

I had hoped to find one cam 180 deg wrong, but they appear to be timed correctly, the two sides opening every second revolution,opposite order.

I hate to just bolt it back in and try but thats what it looks like

good luck. I too just finished my own inaugural rebuild. Out of fear that I may have a similar experience I'm having the motor dyno tuned before going thru the effort of putting it back in the car.

finally got the engine back in after checking everything. I found no mistakes, loose bolts or mistimed cams so tonight it should start. Took the opportunity to replace more hoses and small bits so not too bothered but it has been hard work wrestling around with engines while on crutches.

and we have lift off !

hooked up the wiring and fuel lines, turned the key and the engine started right away and it runs beautifully. no leaks. I let it run maybe 1/2 minute at around 2000 rpm and will take it on the road tmrw after I get the driveaxles installed and the wideband O2 sensor calibrated. Then off to load it up as much as possible to seat the rings

Great fun and looking forward to tuning it in again with the new cams.

I would run it at a hgh idle for at least 15 minutes and check for leaks. What was the cause of the crank stopping on rotation? Was it a rod bolt?

the engine never stopped by itself, I stopped it. I assembled the engine over a longer period in the middle of which I had a motorcycle accident and was out of business for 4 months. Something slipped and I forgot to tighten the cylinder stretch bolts on the right cylinder bank.

Just came back from the first run with the 'new' engine. I drove to a 2 mile hill, while loading the engine as much as possible below 4000 rpm. Then I did the hill 6 times accelerating in 5th between 30 miles and 110 miles per hour at full load. Then some pulls in 3 gear to about 5500 rpm before heading home for an oil change.

It is run in.

And very happy with the Dougherty DC13 cams and RS style light flywheel/Sachs Powercluch. It snappier than stock with driveability not suffering as far as I can tell.

Good news that the only oversight was loose cylinder head bolts. That at least only cause inconvenience, not any permanent damage.

Had a good day mapping the megasquirt to the new cams. Using Tunerstudio it is a blast. 2 hours and it is close to perfect !

Given the narrow heads and cis plenum I believe the DC 13 cams must be perfect. More character than with stock cams and the car feels noticeably quicker with a hint of coming on the cam at 3200 rpm but still strong from 2000. Also holds on slightly longer. Very happy ! Just as the (cam)doctor prescribed.

Nice work Trond!