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View Full Version : RB25DET SWAP, what to do with this motor...


Turb0wned
07-07-2013, 01:06 PM
I finished my RB25 swap into an S14. I'm not to happy with a few things I would like the members on the forums opinion please. I bought the motor locally so I have the 30 day warranty and can still exchange it.

If I do exchange it I might just jump on the series 2 they have for the same price only because it's newer. What do you think? Ok to the point of this thread.

First, head sounds like crap. I understand that the motor has been sitting for god knows how long but I didn't get any better after running for about 15-20 mins with brand new oil. NOTE VIDEO AT THE BOTTOM OF THE POST.

Second, did a compression test with the motor warmed up and at WOT with all spark plugs removed. Yes I did use an Advance Auto Parts tester though. Not to happy with these numbers but I could have OCD.

1-148
2-140
3-144
4-147
5-140
6-138

What do you think? Would you keep this motor or exchange it? I already spoke to the shop and told them and they said to bring it back.

VID_20130706_174325_zps24b97545.mp4 Video by turb0wned1 | Photobucket (http://s893.photobucket.com/user/turb0wned1/media/VID_20130706_174325_zps24b97545.mp4.html)

fliprayzin240sx
07-07-2013, 03:22 PM
Compression is kinda low but its not complete doo-doo. If the shop would let you bring it back and you're not happy with this one, why the hell not swap it out.

xoxide
07-07-2013, 03:25 PM
Swap it out if the shop is offering. Do a compression test at the shop on the new motor.

Turb0wned
07-07-2013, 03:26 PM
Swap it out if the shop is offering. Do a compression test at the shop on the new motor.

Yeah that is exactly what I told him I was going to do this time. I should have done it the first time around.

xoxide
07-07-2013, 03:28 PM
Wouldve been a good move haha. But atleast now you know.

Kingtal0n
07-09-2013, 02:55 AM
If the engine has been sitting for years and years then suddenly we come along and compression test it will probably be lower than expected. I have seen that before.

In fact, once upon a time, I met an RB25 that had sat on a shelf for maybe 4-8 years. We decide to compression test it and... two or three cylinders came back with around 50-80psi. Of course, everyone says "oh piston rings are gone its been abused"

Well, I took the head off. ok, WE took the head together. And looked inside... and found... that carbon buildup was bad enough that it interfered with the operation of the valves. So, a little time with some high quality toyota brand solvent (forget what the bottle said but my friend brought it from his job at the Toyota dealer) and put it back together for some perfect compression numbers across the board.

Moral is, compression numbers on used shelved engines are not always a full story. From the looks of yours, that is a decent engine and I would have given it a chance, unless you can find something newer with much more steady/higher numbers of course for free. I like to check for signs of non-oemness, if you know what I mean.

I did not listen to the video yet. But if the head has some intermittent noise or a constant obvious problem noise then yes, exchange it quick. Find someone else with the same engine and listen to theirs if you can. I would have at least pulled the valvecover and checked for signs of obvious abuse. You can tell if the oil has been changed frequently or not by the color and ... thickness of whatever is in there.