Author Topic: '84 Dodge Rampage Build Thread  (Read 818149 times)

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Offline SteveM

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Re: '84 Dodge Rampage Build Thread
« Reply #1395 on: April 21, 2016, 10:11:43 AM »
I'm closing in on the To-Do list items for The Ohio Mile.

Last night, a friend and I set up our "Jackstands and String" wheel alignment fixture, made some small adjustments, and are pretty happy with the results.

In just over a week, we will see if we've been able to make any improvement in the 1-mile speed of the Salty Frog.



1/2 of the Rampage Brothers

Offline SteveM

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Re: '84 Dodge Rampage Build Thread
« Reply #1396 on: May 02, 2016, 03:43:30 PM »
Bad news - we were "One and Done" at Ohio this past weekend.  The Rampage pulled great in 1st gear, 2nd gear, 3rd gear, then felt a little bit soft in 4th gear, and had no power in 5th.  It might have actually slowed down in 5th gear.

In any event, the engine is dead in its current configuration.  We burned up a piston in cylinder #3.

Here are a couple of videos (one from in-cab, another from the starting line)....

https://www.youtube.com/watch?v=F-rNLGyGnWA

https://www.youtube.com/watch?v=VqI_K3aafso&feature=youtu.be
(Run starts about 2:25 in this video)
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Offline SteveM

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Re: '84 Dodge Rampage Build Thread
« Reply #1397 on: May 02, 2016, 03:45:47 PM »
and some pics of the damage....







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Offline Polyhead

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Re: '84 Dodge Rampage Build Thread
« Reply #1398 on: May 03, 2016, 10:44:27 AM »
That's a shame.  Looks like maybe a valve floated and kissed a piston as well.
Ben 'Polyhead' Smith
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Offline SteveM

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Re: '84 Dodge Rampage Build Thread
« Reply #1399 on: May 04, 2016, 08:50:12 AM »
Yeah- there was definitely contact.  I haven't figured out why.  My first thought was that maybe some molten aluminum got behind the valve head and stuck it open.  There is almost no clearance in these VW diesel engines.

Steve.
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Offline tauruck

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Re: '84 Dodge Rampage Build Thread
« Reply #1400 on: May 04, 2016, 10:42:32 AM »
Sorry you lunched a motor Steve. :-(

Tough break brother.

Offline SteveM

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Re: '84 Dodge Rampage Build Thread
« Reply #1401 on: May 04, 2016, 12:30:00 PM »
That's the way it goes in our chosen hobby.....

My challenge now is to see if I can pull it all together (machining, custom parts, etc) in time to go to Bonneville this summer.

Steve.
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Offline Crackerman

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Re: '84 Dodge Rampage Build Thread
« Reply #1402 on: May 04, 2016, 02:07:59 PM »
You might turn some valves reliefs into those pistons as well... Maybe next time it won't hurt hard parts. Be sure to check your rods for bend too.

Offline Polyhead

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Re: '84 Dodge Rampage Build Thread
« Reply #1403 on: May 04, 2016, 10:04:48 PM »
You might turn some valves reliefs into those pistons as well... Maybe next time it won't hurt hard parts. Be sure to check your rods for bend too.

tough deal on a diesel.  The last thing you want to do is anything that will lower compression, especially true of a small diesel.
Ben 'Polyhead' Smith
  KE7GAL

Offline Crackerman

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Re: '84 Dodge Rampage Build Thread
« Reply #1404 on: May 05, 2016, 01:57:25 PM »
No, this is not always the case. The most powerful, fastest and quickest light truck based diesel engines in the u.s. drag racing right,now are sitting around 12 to 1 compression (power service dragster and scheid diesel dragster) 3000 ish hp 6500rpm and much more than 100 psi of boost.
The same principals are applied to sled pullers. (actually, pulling methods were applied to these engines.)


If I am not mistaken, that vw idi should be sitting somewhere between 19 and 21:1 comp ratio. Yes, it's easier to start, and helps the precup warm up and run without as much smoke while cold.

Losing a whole point of compression will not hurt much in the cold start department(esp if glow plus are still utilized) and may even result in MORE hp, as timing can be added without detriment to the peak cylinder pressure. Another benefit of added timing is cooler exhaust temps. Diesel is a slow burning fuel, start burn sooner, more energy released in burn (to a point) it will also cool off sooner, not torching exhaust valves or exhaust edge of piston crown.


Steve, higher hp cummins guys bevel the top of the piston side.
From top Of top ring land to top edge of piston crown, .010 to .015 taper is cut. It allows for,more agressive heat expansion without sticking piston in cylinder. Also it retains stock bore. (egt over 2000 dg can be had of fuel is kept off the piston)


Are you allowed to run straight water injection? Or is that out of class rules?

What egt, boost and iat levels we're you seeing at max?






Offline Sporty Dan

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Re: '84 Dodge Rampage Build Thread
« Reply #1405 on: May 07, 2016, 05:04:15 PM »
If that was a gas motor I would say that it leaned out on that cylinder, but with it being a diesel I'm not sure what would cause that. It definitely got way too hot and melted the edges of the piston though.

Offline SteveM

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Re: '84 Dodge Rampage Build Thread
« Reply #1406 on: May 16, 2016, 04:40:48 PM »
As always, thank you for the great responses, guys. 

I just returned from a business trip to Europe.  It was maddening to not be able to respond to this forum from my phone - for some reason, the TapaTalk app did not want to play nicely with the forum software.

Re:  Compression - the factory VW 1.5L IDI engines were 23.5:1 static compression.  Through the use of a 1.9L "AAZ" cylinder head, mine is a much more boost-friendly 17.5:1 compression.  The 1.9 heads have more volume in the pre-combustion chambers pressed into the head.

I am still using Glow Plugs, wired to a Ford type starter solenoid.  I usually hit the plugs for 15 seconds or so before firing the engine.

Beveling the top of the piston, above the top ring, is an excellent idea.  I think that's what killed my engine.  VW recommends extremely small piston-to-wall dimensions.  Even though I had my block bored higher than the VW-recommended spec, it is still very small (less than 0.002" total piston to wall clearance).  I will definitely be increasing the clearance, and will talk to my machinist to see if he thinks he can machine an accurate bevel above the top ring.

The EGT's I was seeing were at or above 1600F, and running 40-45 psi boost.

Water injection is allowed, and I'm using a SNOW system, with a #3 (I think) nozzle.  I'll have to check that when I get home.

Steve.


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Offline SteveM

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Re: '84 Dodge Rampage Build Thread
« Reply #1407 on: May 16, 2016, 04:42:38 PM »
Since 1mm oversized 1.5L VW diesel pistons are essentially unavailable, I have decided to order a set of 1.6TD pistons, which are the same diameter, but have a different wrist pin height and diameter.

To make up for the difference in pin height, I have ordered a set of custom connecting rods from Pauter Machine.

At this point, it will be a bit of a scramble to get it put back together in time for Bonneville, but that's my goal for 2016.

Steve.
1/2 of the Rampage Brothers

Offline Crackerman

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Re: '84 Dodge Rampage Build Thread
« Reply #1408 on: May 17, 2016, 11:32:25 PM »
Nice, if the rods are longer that will set you up with a better rod ratio.

Offline SteveM

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Re: '84 Dodge Rampage Build Thread
« Reply #1409 on: May 18, 2016, 12:16:03 PM »
Yes, the rods are longer by necessity, but not a whole lot longer.  Just over 1/8" increase in rod length.

I brought an old piston into my day job to let one of the machinists "test machine" a taper above the top ring groove.

Steve.
1/2 of the Rampage Brothers