Five free practice questions on engine block and bottom end: content area C of the ASE A1 Engine Repair test, 4 of its 45 scored questions (8.9%). They are in the ASE format: four options, one best answer. Answer each one before opening the explanation. No account, no email.
01The questions
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During teardown, one cylinder's piston oil cooling jet is found bent so that its oil stream misses the underside of the piston. The jet itself is open and flows normally. Any of these could result EXCEPT:
- scuffing on that piston's skirt.
- carbonized oil under that piston's crown.
- a top ring stuck in its groove.
- a drop in engine oil pressure.
Show the answer
D. Correct. A bent jet still passes the same amount of oil, so the oil pressure is unchanged; it simply sprays in the wrong place. Oil pressure can fall when a jet is broken off, or when a jet with a check valve has it stuck open, because oil then escapes freely; and a misaimed jet is replaced so the piston is cooled again.
Why not the others
A. This could result. Without the jet's oil carrying heat out of the crown, the piston runs hotter and expands, and its skirt can scuff against the cylinder wall.
B. This could result. Oil that splashes onto an overheated crown underside bakes into a hard carbon layer, a common sign that the cooling jet was not doing its job.
C. This could result. A piston running hot cokes the oil in its top ring groove, and the carbon can lock the ring so it no longer seals against the wall.
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New one-piece camshaft bearings are being installed in the block of a pushrod V8. Any of these is part of a correct installation EXCEPT:
- checking oil clearance with plastic gauging strip.
- putting each bearing in the bore position the manufacturer specifies.
- driving each bearing in with a cam bearing installer of its size.
- lining up each bearing's oil hole with its oil passage in the block.
Show the answer
A. Correct. Plastic gauging strip has to be crushed under a removable bearing cap, and a one-piece cam bearing has no cap. Its clearance is found by measuring the installed bearing's inside diameter and subtracting the journal diameter, then the camshaft is checked for free rotation by hand.
Why not the others
B. This is correct practice. Cam bearings in one block can differ in outside diameter or oil hole location from bore to bore, so each goes in the position the manufacturer specifies.
C. This is correct practice. An installer sized to the bearing keeps it square to the bore as it is driven, so the bearing is not cocked, distorted or shaved on the way in.
D. This is correct practice. Each cam bearing is fed through a hole that must line up with the block's oil passage; a misaligned hole starves that cam journal and any passage fed through it.
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Why are the head-bolt and main-cap bolt holes in a cylinder block cleaned with a thread chaser rather than a cutting tap?
- A chaser recuts the threads one size larger for a tighter fit
- A chaser cleans the threads without cutting metal away
- A cutting tap cannot reach the bottom of a blind hole
- A cutting tap leaves the threads too tight for the bolts
Show the answer
B. Correct. A chaser is made to push out rust, old sealer and debris and straighten minor thread damage while leaving the thread form at its original size. A cutting tap can remove metal and loosen the fit, weakening the threads that must hold the bolt's clamp load; holes are then blown clean and dry before assembly.
Why not the others
A. A chaser does not change thread size; it cleans the existing threads. Recutting to a larger size would mean a different bolt or a thread insert, and the point of chasing is to keep the original thread form intact.
C. A bottoming tap reaches the bottom of a blind hole, so reach is not the reason. The concern is that a cutting tap removes metal from good threads, while a chaser only cleans and reforms them.
D. A cutting tap tends to do the opposite: it can cut metal away and leave the threads loose and weaker. A chaser is used because it cleans the threads without removing metal.
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In a high-mileage engine, where in the cylinder bore is wear normally greatest?
- At the bottom of ring travel, where the piston reverses
- Midway down the bore, where piston speed is highest
- Just below the ridge, at the top of ring travel
- Below ring travel, where only the piston skirt rubs
Show the answer
C. Correct. At the top of ring travel the top ring is pushed hardest against the wall by combustion pressure, the wall is hottest and the oil film is thinnest, so wear is greatest there and leaves a ridge above it. Bore diameter is compared there and below ring travel to find taper.
Why not the others
A. Near the bottom of the stroke the combustion pressure behind the rings is low and the wall is cooler and better oiled. The heaviest wear is at the top of ring travel, just below the ridge.
B. Piston speed is highest near mid-stroke, but the rings ride on a good oil film there and the combustion pressure behind them has already fallen. Wear is greatest just below the ridge at the top of ring travel.
D. Below ring travel the rings never touch the wall, so that area wears very little; it is the reference for comparing bore diameter. The greatest wear is at the top of ring travel, just below the ridge.
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On an in-block camshaft with flat-tappet lifters, each lobe is ground with a slight taper across its face and each lifter's face is slightly crowned. What does this do?
- It sets the preload of each hydraulic lifter's plunger
- It keeps each lifter from turning in its bore
- It adds valve lift beyond the height of the lobe itself
- It makes each lifter turn so wear spreads over its face
Show the answer
D. Correct. The tapered lobe touches the crowned lifter face off its center, so each lift event turns the lifter a little and the wear spreads around the face instead of cutting a groove. A lifter that stops turning wears a groove in its face and wipes its lobe in a short time.
Why not the others
A. Hydraulic lifter preload is set by the rocker or pushrod adjustment, not by the lobe and face shape. The taper and crown make the lifter turn in its bore so its face wears evenly.
B. The design does the opposite: the off-center contact between the tapered lobe and crowned face is there to make the lifter turn. A lifter that stops turning wears a groove and fails along with its lobe.
C. The slight taper and crown do not change lift; valve lift is set by the lobe's lift (its height above the base circle) and the rocker ratio. They make the lifter turn so wear spreads over its face.
02Answer key
| Question | Answer |
|---|---|
| Q1 | D |
| Q2 | A |
| Q3 | B |
| Q4 | C |
| Q5 | D |
03What area C covers
This content area covers the short block. Questions deal with removing and tearing down an engine, inspecting the block, cylinder bores and threads, measuring the crankshaft and bearing clearances, reading piston, rod and bearing wear, in-block camshafts and cam bearings, timing drives and balance shafts, dampers and flywheels, the sealants and plugs used on reassembly, and cylinder deactivation parts.
The ASE test specification calls this content area “Engine Block Diagnosis and Repair”. It carries 4 of the 45 scored questions, 8.9% of the test.
- Remove the engine and prime the oil system
- Inspect the block, bores, threads and oil jets
- Measure crankshaft journals and bearing clearance
- Read piston, rod and bearing wear patterns
- Inspect in-block camshafts, cam bearings and timing drives
- Time balance shafts and check dampers and flywheels
- Seal pans, covers and plugs on reassembly
- Check in-block VVT and cylinder deactivation
04What the questions turn on
Out-of-round versus taper
A journal is measured at each end in two positions 90 degrees apart. Out-of-round is the difference between the two positions at one end; taper is the difference between the two ends in one position. Each is compared with its own limit.
Bearing wear points to the cause
A bent connecting rod loads one edge of the upper shell and the opposite edge of the lower shell, a diagonal pattern. Upper main shells worn most at the center journal and less toward the ends point to main bores that are out of line.
Gauging strip needs a removable cap
Plastic gauging strip is crushed under a cap torqued to specification with the crankshaft held still. A one-piece cam bearing has no cap, so its clearance is found by measuring the installed bearing's inside diameter and subtracting the journal diameter.
A damper mark can move
On a rubber-bonded damper the timing mark is on the outer inertia ring, held to the hub only by rubber. Aged or overheated rubber can let the ring turn, so the mark no longer shows true top dead center and the damper is replaced.
05The other content areas
The A1 test has five content areas. Each has its own page of free questions:
The ASE A1 Engine Repair practice test page describes the full question bank. How these questions are written and checked: how our questions are made. Found a mistake? Tell us and we will fix it.
ToolboxPrep is an independent study site. It is not affiliated with or endorsed by ASE (the National Institute for Automotive Service Excellence). Our questions are original practice questions written to the published ASE test specifications; they are not actual test questions.