New engine trouble, need help.

I have a newly rebuilt engine in my 1999 Jeep Wrangler. I went all out, having it bored and stroked to 4.7L, balanced, and a new specifically custom worked head to accommodate a Comp Cams 8,000 - 4,800 rpm semi radical camshaft.

Everything was carefully and meticulously assembled and installed along with a new starter, alternator, and water pump.it took my brother and I six months of cleaning, painting, etc. to prepare the Jeep for the new engine.

When he started it to properly break in the camshaft I recorded the moment with my phone. We are both in our 60s and have been modifying cars for many years and we have never heard an engine sound like this. The first half of the video is mostly a loose serpentine belt and fan noise, but from the 14 second mark the sound shows up quite well.

We have checked everything we can think of. If anyone has heard that sound before and can identify a likely cause I would really appreciate your feedback.

 

nothing I can ID, but after working jet engines sounds are all scrambled to me...

I see you had serpentine running accessories, I would remove that, eliminate as much as possible.
next valve cover removal get a good look at top end -
Have you tried a stethoscope to try and isolate area as much as possible.

 

I tried without the serpentine belt. The stethoscope is a good idea. I suspect the starter may not be disengaging from the flywheel. When I first removed the engine the starter was very loose and had scarred the teeth on the flywheel. I've just never heard a sound like that. acceleration just makes it faster, not louder. Thank you.

 

Welcome! I think some older running cars sound worse. If the starter/solenoid is suspect the pinion gear will have unusual wear too. Perhaps a swap to eliminate a variable. Sub'd for the engine noise resolution and hoping its not the timing chain rattling or whatever.

 

Thank you. The timing chain is a possibility. It's new, but maybe not the one required by the Comp cam. I will eliminate the starter possibility today.

 

there is only 1 timing chain for the 4.0 I doubt comp cams would spec a different component without BIG letters and notices on their cam install instructions.......

With cams the subject, you said heads were done - could there be a lift valve spring height issue?
Anyway removing the valve covers will tell - yeah I know everything is SO clean I hesitate knowing the likely mess....

OLD school trick, using a wood dowl (wood brooom handle) place one end CAREFULLY by ear lobe touch other end to various engiine areas - you will be surprised a t the ability to isolate noises
thats cheap easy fast and you will give a thumbs up....

PS Harleymick any reference to real motorcycles?

 

Thanks for the info. I had the head done specifically for the camshaft with 1.94 intake and 1.60 exhaust valves and heavier springs which were recessed. They are Chevy small block. Gotta try the broomstick!

ps 2001 Dyna Wide Glide chromed out, looks new with 32,000 miles.

 

anything new to report?
distributor, timing chain or valve train ?
forget to tighten XYZ ?

 

No, the engine fires right up and runs without a miss, no hesitation with quick acceleration. It's just that damn metal hitting metal sound that gets faster with acceleration but not louder. It sounds like the front rocker arm is hitting the valve cover, but it's not. It makes the same noise without the valve cover on it. I really appreciate the suggestions though.

 

did the stethoscope broom stick give any insite?

OK listen #3* - soinds like tin more than a casting sound meaning timing cover, valve cover, water pump,

dist**, oil pan - SO broomstick sound ck is it - top, bottom, front or rear.... going on to long without fix


*poor old fart hearing
** a dist gear issue W jeep not uncommon

 

At my age my hearing isn't what it used to be, but the broomstick idea made me order a mechanic's stethoscope which will be here Thursday. I was so sure it was the valve cover I tried it with it off and no change. I did notice that the front pushrod was not pumping much oil compared to the others, do you think that could be the problem? Is there a way to test the distributor? The engine actually runs great and seems very strong except for that damn sound. I really miss my Jeep.

 

wait for stethoscope, check eng oil see if flakes chips are present....

 

Since the pushrods are the originals and fit the current geometry, where could I find quality replacements at a decent price? The dribble of oil coming from the front one makes it suspect.

 

The oil is very clean. I cut the filter open. could I switch two of the pushrods to see if that is the problem?

 

Sorry, I just found some patience I will use!

 

Update: Titan did not tell me not to install the main girdle on the crankshaft with the Stroker engine and the bottoms of the rods have been hitting it. It appears the rods are a much harder metal than the girdle so I'm hoping it will be OK. Will find out this weekend.

 

Problems resolved and it sounds great. If anyone here has a Comp Cams 68-232-4 camshaft in their Jeep, what should the initial timing be set on?

UPDATE - I talked to Comp Cams tech support. Although the ECM controls the timing on acceleration, it should idle between 10 - 12 degrees before TDC.