Just bought an NB1 for an amazing price. Seemed to run fine, but idle was set high. Didn't think anything about it as it had obviously been completely fettled otherwise with half of the Flyin' Miata catalogue, good paint and reuphostlered interior and new top.
However, once I set the idle down it had a rough idle.
Long story short: valve lash on intake valves was low or negative. Lash on exhaust was generally too tight. Low compression on most cylinders (even though it seems to run well once revved).
My thinking is that it needs the head pulled and checked over. If its been running this way for awhile (obviously, that's why I got it so cheap and the idle was set high to hide it) I'm concerned about the intake valves.
Problem: hard to find anyone willing to pull the head. Most shops I talked to said some version of; we don't do that anymore.
What gives?
Duke
MegaDork
7/30/24 10:31 a.m.
In reply to Brett Tower :
Same reason it's hard to find a decent body shop willing to tackle a restoration project: throughput.
Shops don't want to dick around with something that may tie up a bay for any length of time. It's better return on investment to get cars in and out in a day or two with simple fixes. Going outside the straight and easy path is a great way to risk losing money.
I'm not sure as to why the shops don't seem interested in pulling the head, but several Miata experts pursue the forums–including Keith Tanner from Flyin Miata.
Between all of us here, I'm sure we'll be able to find a solution or at least point you in the right direction.
wae
UltimaDork
7/30/24 10:38 a.m.
My mom & dad have a Subaru Outback with - you guessed it! - a leaking head gasket. The "good" news is that it's an external oil leak. Dad took it down to the shop that they've used for a pretty long time now and they turned him away. It's a pretty big operation with both mechanical and body work going on and a decent number of bays for each. They said it would tie up two bays and a tech for too long so they won't do it. I guess it's nice that they have plenty of other business that they don't need that sort of job....
NOHOME
MegaDork
7/30/24 10:38 a.m.
In reply to Brett Tower :
"Uncertainty". In order to predictably make $$$ a shop needs to know ahead of time what they are getting into and exactly how long it will take so they can meet profits.
Cylinder head issues that can not be measured are an unknown. Does not help that machine shop lead times are long and not predictable either. Nobody wants a partially finished job lingering in the shop with an unknown finished date.
Does not help that an NB is an "Old" car and who knows what parts wont come apart or be out of production and hard to find.
That said, there are shops out there that do this kind of work, it just wont be a dealer or franchise style shop.
Toyman!
MegaDork
7/30/24 10:49 a.m.
My son needed a pinion bearing in the front axle of his XJ. After multiple phone calls, shops said they either wouldn't do it, couldn't do it, or the one shop that actually looked at it said the bearings were fine it just needed $3500 worth of bushings and steering linkages. When I asked them about the 1/8" of slop in the pinion shaft and the glitter-colored gear oil, they said that was normal for a solid axle.
Even the local 4x4 shop said they don't do axle work. WTH. How do you sell ginormous tires and not do gear swaps?
Half a dozen shops later, we rebuilt it ourselves. The pinion-bearing rollers were falling out of the cages they were so worn.
The quality of auto parts is a whole 'nother rant.
It feels like most out shops now a days are charging out the window for jobs most people are able to do themselves but refuse to take more niche/complex jobs that may be out of depth for some people. They are more focused on convenience of time rather than the quality and level of work done.
ShawnG
MegaDork
7/30/24 11:05 a.m.
I'm in my shop, finishing a rebuild on a KX250F engine for a customer.
It's been here 4 months while I tracked down all the parts and sent the head out for rebuilding.
Won't do it again.
Looks like a trend that has been happening and will get worse. I have been through 3 machine shops for head work in the last 20 years. Last one was doing great work on suby heads, the dealer was keeping him busy. He got tired of the work for the money and quit.
Recently getting the baja motor rebuilt was a nightmare. I was delivering the motor out of the car and in no rush. One shop wanted 1500 to take it apart and give me an estimate! Others were estimating 5000 with no guarantee on the number. Ended up driving 6 hours to a shop that gave a price and kept it in spite of needing to replace the crank. So there are still decent shops but they are harder to find.
Brett Tower said:
However, once I set the idle down it had a rough idle.
...
My thinking is that it needs the head pulled and checked over. If its been running this way for awhile (obviously, that's why I got it so cheap and the idle was set high to hide it) I'm concerned about the intake valves.
I would do a leak down test before pulling the head.
ShawnG
MegaDork
7/30/24 11:26 a.m.
In reply to Brett Tower :
Why are you concerned about the valves? The seats have been receding back into the head, causing the clearances to tighten up.
Set the valves properly, do a compression test. If it's good, run it and see what happens. It's probably going to be fine.
rob_mrl
New Reader
7/30/24 11:43 a.m.
In reply to Duke :
We would love to do restorations! The problem is due to all of the challenges you mentioned, they would need to cost more than most people are willing to pay.
Throughput is a real thing. For a "simple" head r&r you are at a week of staring at it everyday. Moreover, the job itself doesn't pay for what it's worth in dollars for the shop or tech and the customer bitching s/p repair about something that wasn't touched but "I last touched it and wasn't broken when they dropped it off.". That's if everything goes right.
Then we can talk about the "technicians"... Most of them couldn't diag if a dog was dead. Anything more than a simple part swap escapes them. Same thing here. The act is simple but the execution/solution is complex. It is why you can't find a decent transmission rebuilder under 50. If I do find one, so many corners are cut to make a finished product, I may as well resort to just fighting trying to get good jasper units.
Mr_Asa
MegaDork
7/30/24 11:45 a.m.
rob_mrl said:
In reply to Duke :
We would love to do restorations! The problem is due to all of the challenges you mentioned, they would need to cost more than most people are willing to pay.
This is pretty much any and all restorations. Doesn't matter if its automotive, antiques, whatever.
People don't want to pay
porschenut said:
Ended up driving 6 hours to a shop that gave a price and kept it in spite of needing to replace the crank. So there are still decent shops but they are harder to find.
Im gonna say it if no one will. Thats berkeleying bullE36 M3. You should have paid for the new crank. It was an estimate to start off with and bad business for not holding you to it. You say good business but I bet much more of that and it will be closed business. And if you didn't quote the estimate to your customer or got a further authorized higher amount, shame on you.
In reply to Ranger50 :
"The act is simple but the execution/solution is complex. It is why you can't find a decent transmission rebuilder under 50"
Mr_Asa said:
rob_mrl said:
In reply to Duke :
We would love to do restorations! The problem is due to all of the challenges you mentioned, they would need to cost more than most people are willing to pay.
This is pretty much any and all restorations. Doesn't matter if its automotive, antiques, whatever.
People don't want to pay
My dad had no problem in paying but when the shop doesn't listen and refuses to budge.... its how I have a resto started and unsellable 66 Ranchero. All for a car that probably would sell for 25k when done after spending 40.
That's the problem I have with my JDM car. It's the uncertainty of the repair and the chance of something going wrong. I talked to multiple shops to get something as easy as an alignment. Even though the car has the same adjustments as the USDM model, no one wants to touch it. So, I learned a new skill.
Let's not even talk about a motor rebuild.
If it makes you all feel any better, our local BMW shop wouldn’t do the rod bearings on my M3.
In reply to David S. Wallens :
"Better" isn't exactly the feels I get from that.
I think between parts issues and most units seemingly being non-rebuildable, this is going to be more and more of a problem.
On most "modern" cars don't they just swap the head for a new one? I remember VW heads complete were pretty cheap.
The other resort is just to DIY.
I agree with the over 50 remark. Those guys learned how to diagnose and actually fix things. It had to work when he was done to so the customer could get to work.
I'm 75 now and I still do all my own repairs - between the poor skills and lack of willingness to actually figure out what's wrong coupled with the incredibly high labor rates - not to mention being on fixed income now - I can't afford to pay a shop to do them.
If you absolutely don't know how to fix things, and don't have tools/shop etc, then you need to have a lot of money or just buy new cars.
It's harder to find shops that do some of everything these days, it's especially common for today's general auto shops to not do major engine work. Look for shops that specialize in engine rebuilds.
I'm not sure which way to go on this. Compression on cylinders 2 and 3 is 85 and 75 psi, respectively. Cylinders 1 and 4 has compression of 140ish (still not great).
However the valve lash doesn't completely align with this. Cylinder 2 has lash of .006 and .005 (front to back), while cylinder 3 has negative lash for both valves, while cylinder 4 has lash of negative and .003. Would think the compression on 4 would be lower than that of two.
Head doesn't seem to be leaking and it generally runs good once the revs get above 2000. Was going to get the valve lash adjusted but no one will do that. I know that the shim in bucket are fiddly especially for the ones that measure negative.
MiniDave said:
On most "modern" cars don't they just swap the head for a new one? I remember VW heads complete were pretty cheap.
not to mention being on fixed income now - I can't afford to pay a shop to do them.
I've always felt if I had a toy I'm the one fixing it. I'm not talking alignments, mounting tires or mufflers. Any work must be mine to keep costs down.
Im looking at some bodywork so that might be interesting......
Wod it be easier to swap a known good head, then take your time finding a good head rebuilder for the original while you drive and enjoy the car?