Attention Larry, (no response to my PM) As indicated in this post you were so helpful with: http://www.v8buick.com/showthread.ph...roper-oil-type I have followed your advice and installed a mechanical gauge set. At the same time, I had a mechanic I trust remove the engine/trans, do a complete seal and gasket replace, replaced the fuel and water pumps, and re-build the oil pump. It only made since to complete a full trans rebuild at the same time (learned that was much needed after the fact). Prior to this he performed a blow by test that resulted in no blow by. The internals of the engine were in exceptional condition and reflected what I believe to have less than 50K miles on it. Only concern we had was the amount of sludge build up, we think the previous owner may have had some one try a flush, making it actually worse. Following advice from my mechanic I currently have Pen Grade 1 Motor oil 20/50 after 1st using 10w40 first. My concern now is that after warm up, when in gear stopped at a light the pressure goes to 0, even the still connected (new sensor) idiot light starts to lightly flash. My mechanic seems to have no answer and actually tried to locate additional help. As soon as I start to move - increase idle, the pressure quickly rises. I have several questions for you related to my car, for now I think resolving the oil pressure is tops of the list. Let me know what other information I could provide that may help your response. Thanks in advise Mike Jackson
Well, Im not Larry, but it sounds to me like your mechanic didnt set the oil pump clearances right. Does he know they need to be measured? Also what oil filter are you using? Brad Penn oil is a good choice for these older engines, so stick with that.
Not to barge in but to me it sounds like the mechanic failed to rebuild the oil pump correctly. Clearances are crucial to oil pressure in a Buick and especially the oil pump. If you are at 0psi with 20/50, you have clearance issues. Buick's should never need 20/50 for a street engine with proper clearances. Knock, knock, knock....Larry, you around? **added in edit: Brandon, great minds think alike .
Sorry, not Larry either. Based on info provided I'll give your mechanic an "A" for suggesting Penngrade 1 but an "F" for suggesting 20/50 unless we are missing a piece of the puzzle. 20/50 is too heavy and sounds like a cop-out to solving the root cause. While regasketing the engine any sludge could have and should have been cleaned up so that should not be an issue. At that, clogged passages anywhere but the pickup screen would likely result in higher oil pressure not lower Do you have any valve train noise at idle when pressure is zero? If you really had zero pressure the engine should be telling you by sound. What type and brand of gauge did you install? Out of curiosity what is your oil pressure at 2000 RPM hot engine?
The gage is Auto Gage by Auto Meter. My mechanic spent a great deal of time cleaning the engine completely, I dont hear any concerning noise when idle and at zero. The idiot light is also on solid when in gear at idle (completely warm). I dont have a tack, but at cold start up it's about 50, will easily slight rev much higher, at normal running down the road it indicates just below or around 20. I didn't make much note of the high's when at warm, was so concentrated with the low's That help?
Sorry Mike, but a few days ago, my PM mailbox was full, and you might have clicked "send message" but it never went, and I never got it. I'm with the rest of the guys here. I think the pump was not rebuilt correctly. End clearance is very important to hot oil pressure. It must be set as close to .002 as possible. If your timing chain cover is excessively worn, this may not be possible.
The biggest problem with standard Buick oil pump rebuild kits is the one size fits all gasket they supply. Usually way too thick. Get one of these and have your mechanic shoot for around .002". Also one of the oil pump booster plates wouldn't hurt. Run the white 60 psi at the top end oil pressure spring(FYI: It will not make a difference at idle but it will protect the engine at higher rpm.) http://www.taperformance.com/proddetail.asp?prod=TA_1704 http://www.taperformance.com/proddetail.asp?prod=TA_1510 After it is all set up see what you get at a HOT idle. If you are above 20 psi at idle you can try the 10-40. Any factory engine with original parts has wear in them which opens up the bearing clearance which drains off oil pressure so running 20-50 is no big deal. I was told by the dealer in 1974 to run 20-50 in my '67 GS 400 to help out the oil pressure. Of course you could put in new rod and main bearings with a properly recut crank in the hope you can run 10-40. The only thing you have to watch with the 20-50 is not to rev it up when it is especially cold out such as no nailing the throttle when pulling out from the driveway on 40 degree mornings. :3gears: If you need to run 50 get some synthetic stuff and add some ZDDP. A synthetic 50 oil will flow better than any non-synthetic 40. I run 5-50 Syntec with ZDDP.
Great information, thank you to all!!!!! My mechanic is very good and I think if our site was not held up by the recent Google security warning, he may have obtained the same info. I'll find out more about the oil pump rebuild and follow up with results. Thanks Mike
Thanks again Mike, I now have parts in hand you recomended (both) and will be doing the correct re-build on Wednesday. Based on the results I (hopefully good) I'll be able to make a solid decision on what oil is best. My car is a big boat cruser, no hot shots out of the driveway for me. Mike
As a point of reference, here is what my oil pressure runs on the 225. I just hit 160,000 on it last month, engine is pretty much stock/original, never been opened as far as I know (I've owned it since 2000 when it had 80,000). These numbers are coming from a mechanical autometer gauge, 10-30/10-40 mix of oil, and I have a 2.74 rear end. Cold startup: About 60psi At temp, mid to high 70's ambient outside temp Idle in gear: 10-15psi 20mph: At least 20psi 30-45mph: 25-35psi 70mph: 35-40psi Experts, correct me if I'm wrong, but if I'm running those numbers on a high mileage untouched engine, then he should at least be running the same or better on a 50K engine, no?
Zach - typically you want to see the #'s as pressure at an RPM not MPH but you #'s are fine for a cruiser. I LIKE that you've put that kind of mileage on it in the past 14 years :TU: As far as the AutoMeter Auto Gauge - If things are still as they were when Zach started driving his Yacht, then thats about the lowest pressure gauge in their line-up. I had one of them installed back around 1993 or 94 and toasted a motor because it was reading about 10psi too high - I had around 0 when it was reading 10 at idle/hot Since ALL of your agrivation and efforts to releave them moving foward rely on a known VALID reading from the pressure gauge, I would at least verify it by either T'ing in a second better (borrowed?) gauge or replace it with a better unit. I would also suggest you severly limit the amount of time you run this motor
Zach's oil pressures are typical of a stock engine with a stock relief spring. Per the 1970 Buick Chassis manual, normal oil pressure is 40 psi @ 2400 RPM.
You want me to calculate rpms? Do I look like someone who has taken years of Math courses and has a BS from a top engineering school......oh wait :laugh:. Plus I figured I'd let someone else do the calculations, I already have enough work to do replacing all these XP machines. Gauges are Sport-Comps, not the cheaper auto guages.
