Engine/Transmission (1994 - 1998) Revs way rough in neutral, why??

[pwknapp]

Blew my motor up last March and had it rebuilt at ATS. Rebuild had some oil problems and Clint at ATS stepped up and installed one of his project motors with most of the bells and whistles. Problem is the rebuild and this project motor runs way rough when revved in neutral, almost to the point of backfiring. Cleans up fine when under a load. Both motors had my P7100 tuned by Scheid and a 3k gsk installed by me. Clint has the timing turned up to 26. 5* where he says it runs the best. I'm just wondering what is causing it. Anybody got any ideas????????

 

[Andy Redmond]

Not trying to step on ATS's toes without knowing the entire story.



Most folks that run timing advanced beyond the data plate stay in the 15-17 deg. range.



If a drastically thicker head gasket were used maybe 20 deg. or so? Do you know how to retard it to 15. 5-16 deg. ? Does it have your vendors "blessings"?



Good luck

Andy

 

[Piston Slapper]

My dad has a 95 with lots of fuel, we got it timed at 22 degrees. It loves it. Could it be a little lean on fuel for all that advance timing? Delivery Valves maybe not getting it enough fuel at low rpms. Dad's 95 did this with the 370 injectors and stock pump. DV's cleared it up. We got it now where the 370's are saying slow down!

 

[Jim Fulmer]

Paul, I like what Andy says... I run mine at 20 with an O-Ring in the head and a . 020 gasket... . so does Piers!



Jim

 

[pwknapp]

The head is ported and o-ringed, don't know what size gasket, custom cam matched with the head and 370's. DV's are original with the 215 pump and have nearly 450k miles. Maybe it's time for some fresh ones and a timing kit to zero in on what it likes the best.



As always thanks for the input.



Paul

 

[Joseph Donnelly]

If you hit the pedal a little too hard, the P pump delivers way more fuel than the engine can burn while revving in neutral at zero boost. You are basically flooding it. I'd back down on the timing as others suggested. Better driveability especially cold, less hammering on bearings, etc. I got best mileage around 15. 5 deg. at 2000 rpm.