# Newbie Timing Belt Tensioner Question



## tuttebenne (Jun 16, 2009)

Hi, first post; hope I don't piss any body off 

My son's (formerly my mom and dad's) '87 Maxima lost the tensioner bearings somewhere on the highway last week and I want to strongly consider fixing the car for sentimental reasons. The belt never broke but there was piston to valve contact because #6 is pretty messed up (no compression). I'm three or four exhaust fasteners away from getting the forward head off (tonight hopefully) and wonder if I will be looking at a hole in the piston. How frequently does a belt failure end in a broken piston or bent rod?


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## tuttebenne (Jun 16, 2009)

FYI, I got the head off (no easy job compared to what I am used to) and the piston is really hammered. The valve head was sitting on the piston and was in two pieces. Now I'm wondering if the rod got bent.


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## Robchaos19 (Sep 6, 2004)

I can say I've never seen a rod bend from piston to valve contact. The valve stems are a very thin diameter and will buckle before that beefy rod even thinks of tweaking. The head of the piston might be scarred from the contact, but I've had more then a few like that where we just do a valve job and leave the bottom end alone. Never had any problems.


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## tuttebenne (Jun 16, 2009)

Robchaos, thanks for the quick reply; I really appreciate it when people share their knowledge. I do this on two other forums but I have no experience with Nissan. I'll remain optimistic base on your experience. However, the piston is more than just scarred (sorry for not being more specific) there are several gouges that are as much as 3 -4 mm deep. I think the inside of the piston might reveal cracks in these areas so if the other bank has no additional problems I will pull the pan and get that one piston out. Would you know of the least expensive way to come up with one standard piston with rings for this motor ('87 Maxima)?


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## Robchaos19 (Sep 6, 2004)

I'd try nissan first


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## tuttebenne (Jun 16, 2009)

Makes sense; yes that probably would be the best way to get the right part(s).


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## tuttebenne (Jun 16, 2009)

Here is an update on my project. 

Nissan was helpless when it came to providing the parts I needed. They wanted almost $600 for a piston, rod, set of rings and exhaust valve and a full gasket set. And there wasn't one rod in the country - they couldn't tell me how long it would take for the backorder to clear but I had to pay for an order the parts before they would do anything (do I look that stupid?) I got SIX pistons, a set of rings, the full gasket set and a recon'd rod from Mizumi auto for under $215!!!! Helen at Mizumi was awesome. They have all sorts of stuff on ebay but I called and she handled everything 1st class.

I had the big end of the rod machined to the exact size of the original and had a fresh piston pressed onto the rod. The pin was shaved 0.020 to get the weight the same as the original piston. The lower end is all buttoned up now and I am waiting for the heads. The chamber that was damaged by the broken valve has been welded up and reground to the original combustion chamber dimensions. New guides are going in this week as well as six new exhaust valves (at $5.00 each). So much for Nissan. Now I know why they are called stealers instead of dealers. 

More to come once the heads are ready. Also, I noticed a crack in the front (left) exhaust manifold. Must have been a stress crack. Anyone have one of these laying around (87 vg30 maxima)?

Andy


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## tuttebenne (Jun 16, 2009)

Okay, everything is back together and she is running quietly if you can overlook an exhaust leak at the engine pipe/cat connection. There are two problems now that everything is back together:
1. On cold start it wants to idle very low and doesn't have much throttle response until running for a minute or so. Once a minute goes by the RPM increases by 150-200 revs and it has the throttle response.
2. On the road it doesn't have the power I think it should have and it surges when cruising. 

I am thinking the mixture is too lean and something(s) are causing this. I checked vacuum connections and all seem fine. I ran propane around the manifold and the vacuum hoses and didn't see the telltale rpm increase that comes with a leak. Any thoughts?


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